[PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

[PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

[Gabriele Mazzotta]

This patch adds the support for the configuration of the keyboard
backlight on supported Dell laptops.

With this patch it is possible to set:
* keyboard backlight level
* timeout after which the backlight will be automatically turned off
* input activity triggers (keyboard, touchpad, mouse) that enable the backlight
* ambient light settings

The settings are exposed via /sys/class/leds/dell::kbd_backlight/

The code is based on the newly released documentation by Dell in the
libsmbios project.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
---
 .../ABI/testing/sysfs-platform-dell-laptop         |   69 ++
 drivers/platform/x86/dell-laptop.c                 | 1089 +++++++++++++++++++-
 2 files changed, 1152 insertions(+), 6 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-platform-dell-laptop

diff --git a/Documentation/ABI/testing/sysfs-platform-dell-laptop b/Documentation/ABI/testing/sysfs-platform-dell-laptop
new file mode 100644
index 0000000..8c6a0b8
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-platform-dell-laptop
@@ -0,0 +1,69 @@
+What:		/sys/class/leds/dell::kbd_backlight/als_enabled
+Date:		December 2014
+KernelVersion:	3.19
+Contact:	Gabriele Mazzotta <gabriele.mzt@gmail.com>,
+		Pali Rohár <pali.rohar@gmail.com>
+Description:
+		This file allows to control the automatic keyboard
+		illumination mode on some systems that have an ambient
+		light sensor. Write 1 to this file to enable the auto
+		mode, 0 to disable it.
+
+What:		/sys/class/leds/dell::kbd_backlight/als_setting
+Date:		December 2014
+KernelVersion:	3.19
+Contact:	Gabriele Mazzotta <gabriele.mzt@gmail.com>,
+		Pali Rohár <pali.rohar@gmail.com>
+Description:
+		This file allows to specifiy the on/off threshold value,
+		as reported by the ambient light sensor.
+
+What:		/sys/class/leds/dell::kbd_backlight/start_triggers
+Date:		December 2014
+KernelVersion:	3.19
+Contact:	Gabriele Mazzotta <gabriele.mzt@gmail.com>,
+		Pali Rohár <pali.rohar@gmail.com>
+Description:
+		This file allows to control the input triggers that
+		turn on the keyboard backlight illumination that is
+		disabled because of inactivity.
+		Read the file to see the triggers available. The ones
+		enabled are preceded by '+', those disabled by '-'.
+
+		To enable a trigger, write its name preceded by '+' to
+		this file. To disable a trigger, write its name preceded
+		by '-' instead.
+
+		For example, to enable the keyboard as trigger run:
+		    echo +keyboard > /sys/class/leds/dell::kbd_backlight/start_triggers
+		To disable it:
+		    echo -keyboard > /sys/class/leds/dell::kbd_backlight/start_triggers
+
+		Note that not all the available triggers can be configured.
+
+What:		/sys/class/leds/dell::kbd_backlight/stop_timeout
+Date:		December 2014
+KernelVersion:	3.19
+Contact:	Gabriele Mazzotta <gabriele.mzt@gmail.com>,
+		Pali Rohár <pali.rohar@gmail.com>
+Description:
+		This file allows to specify the interval after which the
+		keyboard illumination is disabled because of inactivity.
+		The timeouts are expressed in seconds, minutes, hours and
+		days, for which the symbols are 's', 'm', 'h' and 'd'
+		respectively.
+
+		To configure the timeout, write to this file a value along
+		with any the above units. If no unit is specified, the value
+		is assumed to be expressed in seconds.
+
+		For example, to set the timeout to 10 minutes run:
+		    echo 10m > /sys/class/leds/dell::kbd_backlight/stop_timeout
+
+		Note that when this file is read, the returned value might be
+		expressed in a different unit than the one used when the timeout
+		was set.
+
+		Also note that only some timeouts are supported and that
+		some systems might fall back to a specific timeout in case
+		an invalid timeout is written to this file.
diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c
index 3d21efe..d688d80 100644
--- a/drivers/platform/x86/dell-laptop.c
+++ b/drivers/platform/x86/dell-laptop.c
@@ -2,9 +2,11 @@
  *  Driver for Dell laptop extras
  *
  *  Copyright (c) Red Hat <mjg@redhat.com>
+ *  Copyright (c) 2014 Gabriele Mazzotta <gabriele.mzt@gmail.com>
+ *  Copyright (c) 2014 Pali Rohár <pali.rohar@gmail.com>
  *
- *  Based on documentation in the libsmbios package, Copyright (C) 2005 Dell
- *  Inc.
+ *  Based on documentation in the libsmbios package:
+ *  Copyright (C) 2005-2014 Dell Inc.
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License version 2 as
@@ -32,6 +34,13 @@
 #include "../../firmware/dcdbas.h"
 
 #define BRIGHTNESS_TOKEN 0x7d
+#define KBD_LED_OFF_TOKEN 0x01E1
+#define KBD_LED_ON_TOKEN 0x01E2
+#define KBD_LED_AUTO_TOKEN 0x01E3
+#define KBD_LED_AUTO_25_TOKEN 0x02EA
+#define KBD_LED_AUTO_50_TOKEN 0x02EB
+#define KBD_LED_AUTO_75_TOKEN 0x02EC
+#define KBD_LED_AUTO_100_TOKEN 0x02F6
 
 /* This structure will be modified by the firmware when we enter
  * system management mode, hence the volatiles */
@@ -62,6 +71,13 @@ struct calling_interface_structure {
 
 struct quirk_entry {
 	u8 touchpad_led;
+
+	int needs_kbd_timeouts;
+	/*
+	 * Ordered list of timeouts expressed in seconds.
+	 * The list must end with -1
+	 */
+	int kbd_timeouts[];
 };
 
 static struct quirk_entry *quirks;
@@ -76,6 +92,15 @@ static int __init dmi_matched(const struct dmi_system_id *dmi)
 	return 1;
 }
 
+/*
+ * These values come from Windows utility provided by Dell. If any other value
+ * is used then BIOS silently set timeout to 0 without any error message.
+ */
+static struct quirk_entry quirk_dell_xps13_9333 = {
+	.needs_kbd_timeouts = 1,
+	.kbd_timeouts = { 0, 5, 15, 60, 5 * 60, 15 * 60, -1 },
+};
+
 static int da_command_address;
 static int da_command_code;
 static int da_num_tokens;
@@ -267,6 +292,15 @@ static const struct dmi_system_id dell_quirks[] __initconst = {
 		},
 		.driver_data = &quirk_dell_vostro_v130,
 	},
+	{
+		.callback = dmi_matched,
+		.ident = "Dell XPS13 9333",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "XPS13 9333"),
+		},
+		.driver_data = &quirk_dell_xps13_9333,
+	},
 	{ }
 };
 
@@ -331,17 +365,29 @@ static void __init find_tokens(const struct dmi_header *dm, void *dummy)
 	}
 }
 
-static int find_token_location(int tokenid)
+static int find_token_id(int tokenid)
 {
 	int i;
+
 	for (i = 0; i < da_num_tokens; i++) {
 		if (da_tokens[i].tokenID == tokenid)
-			return da_tokens[i].location;
+			return i;
 	}
 
 	return -1;
 }
 
+static int find_token_location(int tokenid)
+{
+	int id;
+
+	id = find_token_id(tokenid);
+	if (id == -1)
+		return -1;
+
+	return da_tokens[id].location;
+}
+
 static struct calling_interface_buffer *
 dell_send_request(struct calling_interface_buffer *buffer, int class,
 		  int select)
@@ -362,6 +408,20 @@ dell_send_request(struct calling_interface_buffer *buffer, int class,
 	return buffer;
 }
 
+static inline int dell_smi_error(int value)
+{
+	switch (value) {
+	case 0: /* Completed successfully */
+		return 0;
+	case -1: /* Completed with error */
+		return -EIO;
+	case -2: /* Function not supported */
+		return -ENXIO;
+	default: /* Unknown error */
+		return -EINVAL;
+	}
+}
+
 /* Derived from information in DellWirelessCtl.cpp:
    Class 17, select 11 is radio control. It returns an array of 32-bit values.
 
@@ -716,7 +776,7 @@ static int dell_send_intensity(struct backlight_device *bd)
 	else
 		dell_send_request(buffer, 1, 1);
 
-out:
+ out:
 	release_buffer();
 	return ret;
 }
@@ -740,7 +800,7 @@ static int dell_get_intensity(struct backlight_device *bd)
 
 	ret = buffer->output[1];
 
-out:
+ out:
 	release_buffer();
 	return ret;
 }
@@ -789,6 +849,1018 @@ static void touchpad_led_exit(void)
 	led_classdev_unregister(&touchpad_led);
 }
 
+/*
+ * Derived from information in smbios-keyboard-ctl:
+ *
+ * cbClass 4
+ * cbSelect 11
+ * Keyboard illumination
+ * cbArg1 determines the function to be performed
+ *
+ * cbArg1 0x0 = Get Feature Information
+ *  cbRES1         Standard return codes (0, -1, -2)
+ *  cbRES2, word0  Bitmap of user-selectable modes
+ *     bit 0     Always off (All systems)
+ *     bit 1     Always on (Travis ATG, Siberia)
+ *     bit 2     Auto: ALS-based On; ALS-based Off (Travis ATG)
+ *     bit 3     Auto: ALS- and input-activity-based On; input-activity based Off
+ *     bit 4     Auto: Input-activity-based On; input-activity based Off
+ *     bit 5     Auto: Input-activity-based On (illumination level 25%); input-activity based Off
+ *     bit 6     Auto: Input-activity-based On (illumination level 50%); input-activity based Off
+ *     bit 7     Auto: Input-activity-based On (illumination level 75%); input-activity based Off
+ *     bit 8     Auto: Input-activity-based On (illumination level 100%); input-activity based Off
+ *     bits 9-15 Reserved for future use
+ *  cbRES2, byte2  Reserved for future use
+ *  cbRES2, byte3  Keyboard illumination type
+ *     0         Reserved
+ *     1         Tasklight
+ *     2         Backlight
+ *     3-255     Reserved for future use
+ *  cbRES3, byte0  Supported auto keyboard illumination trigger bitmap.
+ *     bit 0     Any keystroke
+ *     bit 1     Touchpad activity
+ *     bit 2     Pointing stick
+ *     bit 3     Any mouse
+ *     bits 4-7  Reserved for future use
+ *  cbRES3, byte1  Supported timeout unit bitmap
+ *     bit 0     Seconds
+ *     bit 1     Minutes
+ *     bit 2     Hours
+ *     bit 3     Days
+ *     bits 4-7  Reserved for future use
+ *  cbRES3, byte2  Number of keyboard light brightness levels
+ *  cbRES4, byte0  Maximum acceptable seconds value (0 if seconds not supported).
+ *  cbRES4, byte1  Maximum acceptable minutes value (0 if minutes not supported).
+ *  cbRES4, byte2  Maximum acceptable hours value (0 if hours not supported).
+ *  cbRES4, byte3  Maximum acceptable days value (0 if days not supported)
+ *
+ * cbArg1 0x1 = Get Current State
+ *  cbRES1         Standard return codes (0, -1, -2)
+ *  cbRES2, word0  Bitmap of current mode state
+ *     bit 0     Always off (All systems)
+ *     bit 1     Always on (Travis ATG, Siberia)
+ *     bit 2     Auto: ALS-based On; ALS-based Off (Travis ATG)
+ *     bit 3     Auto: ALS- and input-activity-based On; input-activity based Off
+ *     bit 4     Auto: Input-activity-based On; input-activity based Off
+ *     bit 5     Auto: Input-activity-based On (illumination level 25%); input-activity based Off
+ *     bit 6     Auto: Input-activity-based On (illumination level 50%); input-activity based Off
+ *     bit 7     Auto: Input-activity-based On (illumination level 75%); input-activity based Off
+ *     bit 8     Auto: Input-activity-based On (illumination level 100%); input-activity based Off
+ *     bits 9-15 Reserved for future use
+ *     Note: Only One bit can be set
+ *  cbRES2, byte2  Currently active auto keyboard illumination triggers.
+ *     bit 0     Any keystroke
+ *     bit 1     Touchpad activity
+ *     bit 2     Pointing stick
+ *     bit 3     Any mouse
+ *     bits 4-7  Reserved for future use
+ *  cbRES2, byte3  Current Timeout
+ *     bits 7:6  Timeout units indicator:
+ *     00b       Seconds
+ *     01b       Minutes
+ *     10b       Hours
+ *     11b       Days
+ *     bits 5:0  Timeout value (0-63) in sec/min/hr/day
+ *     NOTE: A value of 0 means always on (no timeout) if any bits of RES3 byte
+ *     are set upon return from the [Get feature information] call.
+ *  cbRES3, byte0  Current setting of ALS value that turns the light on or off.
+ *  cbRES3, byte1  Current ALS reading
+ *  cbRES3, byte2  Current keyboard light level.
+ *
+ * cbArg1 0x2 = Set New State
+ *  cbRES1         Standard return codes (0, -1, -2)
+ *  cbArg2, word0  Bitmap of current mode state
+ *     bit 0     Always off (All systems)
+ *     bit 1     Always on (Travis ATG, Siberia)
+ *     bit 2     Auto: ALS-based On; ALS-based Off (Travis ATG)
+ *     bit 3     Auto: ALS- and input-activity-based On; input-activity based Off
+ *     bit 4     Auto: Input-activity-based On; input-activity based Off
+ *     bit 5     Auto: Input-activity-based On (illumination level 25%); input-activity based Off
+ *     bit 6     Auto: Input-activity-based On (illumination level 50%); input-activity based Off
+ *     bit 7     Auto: Input-activity-based On (illumination level 75%); input-activity based Off
+ *     bit 8     Auto: Input-activity-based On (illumination level 100%); input-activity based Off
+ *     bits 9-15 Reserved for future use
+ *     Note: Only One bit can be set
+ *  cbArg2, byte2  Desired auto keyboard illumination triggers. Must remain inactive to allow
+ *                 keyboard to turn off automatically.
+ *     bit 0     Any keystroke
+ *     bit 1     Touchpad activity
+ *     bit 2     Pointing stick
+ *     bit 3     Any mouse
+ *     bits 4-7  Reserved for future use
+ *  cbArg2, byte3  Desired Timeout
+ *     bits 7:6  Timeout units indicator:
+ *     00b       Seconds
+ *     01b       Minutes
+ *     10b       Hours
+ *     11b       Days
+ *     bits 5:0  Timeout value (0-63) in sec/min/hr/day
+ *  cbArg3, byte0  Desired setting of ALS value that turns the light on or off.
+ *  cbArg3, byte2  Desired keyboard light level.
+ */
+
+
+enum kbd_timeout_unit {
+	KBD_TIMEOUT_SECONDS = 0,
+	KBD_TIMEOUT_MINUTES,
+	KBD_TIMEOUT_HOURS,
+	KBD_TIMEOUT_DAYS,
+};
+
+enum kbd_mode_bit {
+	KBD_MODE_BIT_OFF = 0,
+	KBD_MODE_BIT_ON,
+	KBD_MODE_BIT_ALS,
+	KBD_MODE_BIT_TRIGGER_ALS,
+	KBD_MODE_BIT_TRIGGER,
+	KBD_MODE_BIT_TRIGGER_25,
+	KBD_MODE_BIT_TRIGGER_50,
+	KBD_MODE_BIT_TRIGGER_75,
+	KBD_MODE_BIT_TRIGGER_100,
+};
+
+#define kbd_is_als_mode_bit(bit) \
+	((bit) == KBD_MODE_BIT_ALS || (bit) == KBD_MODE_BIT_TRIGGER_ALS)
+#define kbd_is_trigger_mode_bit(bit) \
+	((bit) >= KBD_MODE_BIT_TRIGGER_ALS && (bit) <= KBD_MODE_BIT_TRIGGER_100)
+#define kbd_is_level_mode_bit(bit) \
+	((bit) >= KBD_MODE_BIT_TRIGGER_25 && (bit) <= KBD_MODE_BIT_TRIGGER_100)
+
+struct kbd_info {
+	u16 modes;
+	u8 type;
+	u8 triggers;
+	u8 levels;
+	u8 seconds;
+	u8 minutes;
+	u8 hours;
+	u8 days;
+};
+
+struct kbd_state {
+	u8 mode_bit;
+	u8 triggers;
+	u8 timeout_value;
+	u8 timeout_unit;
+	u8 als_setting;
+	u8 als_value;
+	u8 level;
+};
+
+static const int kbd_tokens[] = {
+	KBD_LED_OFF_TOKEN,
+	KBD_LED_AUTO_25_TOKEN,
+	KBD_LED_AUTO_50_TOKEN,
+	KBD_LED_AUTO_75_TOKEN,
+	KBD_LED_AUTO_100_TOKEN,
+	KBD_LED_ON_TOKEN,
+};
+
+static u16 kbd_token_bits;
+
+static struct kbd_info kbd_info;
+static bool kbd_als_supported;
+static bool kbd_triggers_supported;
+
+static u8 kbd_mode_levels[16];
+static int kbd_mode_levels_count;
+
+static u8 kbd_previous_level;
+static u8 kbd_previous_mode_bit;
+
+static bool kbd_led_present;
+
+/*
+ * NOTE: there are three ways to set the keyboard backlight level.
+ * First, via kbd_state.mode_bit (assigning KBD_MODE_BIT_TRIGGER_* value).
+ * Second, via kbd_state.level (assigning numerical value <= kbd_info.levels).
+ * Third, via SMBIOS tokens (KBD_LED_* in kbd_tokens)
+ *
+ * There are laptops which support only one of these methods. If we want to
+ * support as many machines as possible we need to implement all three methods.
+ * The first two methods use the kbd_state structure. The third uses SMBIOS
+ * tokens. If kbd_info.levels == 0, the machine does not support setting the
+ * keyboard backlight level via kbd_state.level.
+ */
+
+static int kbd_get_info(struct kbd_info *info)
+{
+	u8 units;
+	int ret;
+
+	get_buffer();
+
+	buffer->input[0] = 0x0;
+	dell_send_request(buffer, 4, 11);
+	ret = buffer->output[0];
+
+	if (ret) {
+		ret = dell_smi_error(ret);
+		goto out;
+	}
+
+	info->modes = buffer->output[1] & 0xFFFF;
+	info->type = (buffer->output[1] >> 24) & 0xFF;
+	info->triggers = buffer->output[2] & 0xFF;
+	units = (buffer->output[2] >> 8) & 0xFF;
+	info->levels = (buffer->output[2] >> 16) & 0xFF;
+
+	if (units & BIT(0))
+		info->seconds = (buffer->output[3] >> 0) & 0xFF;
+	if (units & BIT(1))
+		info->minutes = (buffer->output[3] >> 8) & 0xFF;
+	if (units & BIT(2))
+		info->hours = (buffer->output[3] >> 16) & 0xFF;
+	if (units & BIT(3))
+		info->days = (buffer->output[3] >> 24) & 0xFF;
+
+ out:
+	release_buffer();
+	return ret;
+}
+
+static unsigned int kbd_get_max_level(void)
+{
+	if (kbd_info.levels != 0)
+		return kbd_info.levels;
+	if (kbd_mode_levels_count > 0)
+		return kbd_mode_levels_count - 1;
+	return 0;
+}
+
+static int kbd_get_level(struct kbd_state *state)
+{
+	int i;
+
+	if (kbd_info.levels != 0)
+		return state->level;
+
+	if (kbd_mode_levels_count > 0) {
+		for (i = 0; i < kbd_mode_levels_count; ++i)
+			if (kbd_mode_levels[i] == state->mode_bit)
+				return i;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int kbd_set_level(struct kbd_state *state, u8 level)
+{
+	if (kbd_info.levels != 0) {
+		if (level != 0)
+			kbd_previous_level = level;
+		if (state->level == level)
+			return 0;
+		state->level = level;
+		if (level != 0 && state->mode_bit == KBD_MODE_BIT_OFF)
+			state->mode_bit = kbd_previous_mode_bit;
+		else if (level == 0 && state->mode_bit != KBD_MODE_BIT_OFF) {
+			kbd_previous_mode_bit = state->mode_bit;
+			state->mode_bit = KBD_MODE_BIT_OFF;
+		}
+		return 0;
+	}
+
+	if (kbd_mode_levels_count > 0 && level < kbd_mode_levels_count) {
+		if (level != 0)
+			kbd_previous_level = level;
+		state->mode_bit = kbd_mode_levels[level];
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int kbd_get_state(struct kbd_state *state)
+{
+	int ret;
+
+	get_buffer();
+
+	buffer->input[0] = 0x1;
+	dell_send_request(buffer, 4, 11);
+	ret = buffer->output[0];
+
+	if (ret) {
+		ret = dell_smi_error(ret);
+		goto out;
+	}
+
+	state->mode_bit = ffs(buffer->output[1] & 0xFFFF);
+	if (state->mode_bit != 0)
+		state->mode_bit--;
+
+	state->triggers = (buffer->output[1] >> 16) & 0xFF;
+	state->timeout_value = (buffer->output[1] >> 24) & 0x3F;
+	state->timeout_unit = (buffer->output[1] >> 30) & 0x3;
+	state->als_setting = buffer->output[2] & 0xFF;
+	state->als_value = (buffer->output[2] >> 8) & 0xFF;
+	state->level = (buffer->output[2] >> 16) & 0xFF;
+
+ out:
+	release_buffer();
+	return ret;
+}
+
+static int kbd_set_state(struct kbd_state *state)
+{
+	int ret;
+
+	get_buffer();
+	buffer->input[0] = 0x2;
+	buffer->input[1] = BIT(state->mode_bit) & 0xFFFF;
+	buffer->input[1] |= (state->triggers & 0xFF) << 16;
+	buffer->input[1] |= (state->timeout_value & 0x3F) << 24;
+	buffer->input[1] |= (state->timeout_unit & 0x3) << 30;
+	buffer->input[2] = state->als_setting & 0xFF;
+	buffer->input[2] |= (state->level & 0xFF) << 16;
+	dell_send_request(buffer, 4, 11);
+	ret = buffer->output[0];
+	release_buffer();
+
+	return dell_smi_error(ret);
+}
+
+static int kbd_set_state_safe(struct kbd_state *state, struct kbd_state *old)
+{
+	int ret;
+
+	ret = kbd_set_state(state);
+	if (ret == 0)
+		return 0;
+
+	/*
+	 * When setting the new state fails,try to restore the previous one.
+	 * This is needed on some machines where BIOS sets a default state when
+	 * setting a new state fails. This default state could be all off.
+	 */
+
+	if (kbd_set_state(old))
+		pr_err("Setting old previous keyboard state failed\n");
+
+	return ret;
+}
+
+static int kbd_set_token_bit(u8 bit)
+{
+	int id;
+	int ret;
+
+	if (bit >= ARRAY_SIZE(kbd_tokens))
+		return -EINVAL;
+
+	id = find_token_id(kbd_tokens[bit]);
+	if (id == -1)
+		return -EINVAL;
+
+	get_buffer();
+	buffer->input[0] = da_tokens[id].location;
+	buffer->input[1] = da_tokens[id].value;
+	dell_send_request(buffer, 1, 0);
+	ret = buffer->output[0];
+	release_buffer();
+
+	return dell_smi_error(ret);
+}
+
+static int kbd_get_token_bit(u8 bit)
+{
+	int id;
+	int ret;
+	int val;
+
+	if (bit >= ARRAY_SIZE(kbd_tokens))
+		return -EINVAL;
+
+	id = find_token_id(kbd_tokens[bit]);
+	if (id == -1)
+		return -EINVAL;
+
+	get_buffer();
+	buffer->input[0] = da_tokens[id].location;
+	dell_send_request(buffer, 0, 0);
+	ret = buffer->output[0];
+	val = buffer->output[1];
+	release_buffer();
+
+	if (ret)
+		return dell_smi_error(ret);
+
+	return (val == da_tokens[id].value);
+}
+
+static int kbd_get_first_active_token_bit(void)
+{
+	int i;
+	int ret;
+
+	for (i = 0; i < ARRAY_SIZE(kbd_tokens); ++i) {
+		ret = kbd_get_token_bit(i);
+		if (ret == 1)
+			return i;
+	}
+
+	return ret;
+}
+
+static int kbd_get_valid_token_counts(void)
+{
+	return hweight16(kbd_token_bits);
+}
+
+static inline int kbd_init_info(void)
+{
+	struct kbd_state state;
+	int ret;
+	int i;
+
+	ret = kbd_get_info(&kbd_info);
+	if (ret)
+		return ret;
+
+	kbd_get_state(&state);
+
+	/* NOTE: timeout value is stored in 6 bits so max value is 63 */
+	if (kbd_info.seconds > 63)
+		kbd_info.seconds = 63;
+	if (kbd_info.minutes > 63)
+		kbd_info.minutes = 63;
+	if (kbd_info.hours > 63)
+		kbd_info.hours = 63;
+	if (kbd_info.days > 63)
+		kbd_info.days = 63;
+
+	/* NOTE: On tested machines ON mode did not work and caused
+	 *       problems (turned backlight off) so do not use it
+	 */
+	kbd_info.modes &= ~BIT(KBD_MODE_BIT_ON);
+
+	kbd_previous_level = kbd_get_level(&state);
+	kbd_previous_mode_bit = state.mode_bit;
+
+	if (kbd_previous_level == 0 && kbd_get_max_level() != 0)
+		kbd_previous_level = 1;
+
+	if (kbd_previous_mode_bit == KBD_MODE_BIT_OFF) {
+		kbd_previous_mode_bit =
+			ffs(kbd_info.modes & ~BIT(KBD_MODE_BIT_OFF));
+		if (kbd_previous_mode_bit != 0)
+			kbd_previous_mode_bit--;
+	}
+
+	if (kbd_info.modes & (BIT(KBD_MODE_BIT_ALS) |
+			      BIT(KBD_MODE_BIT_TRIGGER_ALS)))
+		kbd_als_supported = true;
+
+	if (kbd_info.modes & (
+	    BIT(KBD_MODE_BIT_TRIGGER_ALS) | BIT(KBD_MODE_BIT_TRIGGER) |
+	    BIT(KBD_MODE_BIT_TRIGGER_25) | BIT(KBD_MODE_BIT_TRIGGER_50) |
+	    BIT(KBD_MODE_BIT_TRIGGER_75) | BIT(KBD_MODE_BIT_TRIGGER_100)
+	   ))
+		kbd_triggers_supported = true;
+
+	/* kbd_mode_levels[0] is reserved, see below */
+	for (i = 0; i < 16; ++i)
+		if (kbd_is_level_mode_bit(i) && (BIT(i) & kbd_info.modes))
+			kbd_mode_levels[1 + kbd_mode_levels_count++] = i;
+
+	/*
+	 * Find the first supported mode and assign to kbd_mode_levels[0].
+	 * This should be 0 (off), but we cannot depend on the BIOS to
+	 * support 0.
+	 */
+	if (kbd_mode_levels_count > 0) {
+		for (i = 0; i < 16; ++i) {
+			if (BIT(i) & kbd_info.modes) {
+				kbd_mode_levels[0] = i;
+				break;
+			}
+		}
+		kbd_mode_levels_count++;
+	}
+
+	return 0;
+
+}
+
+static inline void kbd_init_tokens(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(kbd_tokens); ++i)
+		if (find_token_id(kbd_tokens[i]) != -1)
+			kbd_token_bits |= BIT(i);
+}
+
+static void kbd_init(void)
+{
+	int ret;
+
+	ret = kbd_init_info();
+	kbd_init_tokens();
+
+	if (kbd_token_bits != 0 || ret == 0)
+		kbd_led_present = true;
+}
+
+static ssize_t kbd_led_timeout_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	struct kbd_state new_state;
+	struct kbd_state state;
+	bool convert;
+	int value;
+	int ret;
+	char ch;
+	u8 unit;
+	int i;
+
+	ret = sscanf(buf, "%d %c", &value, &ch);
+	if (ret < 1)
+		return -EINVAL;
+	else if (ret == 1)
+		ch = 's';
+
+	if (value < 0)
+		return -EINVAL;
+
+	convert = false;
+
+	switch (ch) {
+	case 's':
+		if (value > kbd_info.seconds)
+			convert = true;
+		unit = KBD_TIMEOUT_SECONDS;
+		break;
+	case 'm':
+		if (value > kbd_info.minutes)
+			convert = true;
+		unit = KBD_TIMEOUT_MINUTES;
+		break;
+	case 'h':
+		if (value > kbd_info.hours)
+			convert = true;
+		unit = KBD_TIMEOUT_HOURS;
+		break;
+	case 'd':
+		if (value > kbd_info.days)
+			convert = true;
+		unit = KBD_TIMEOUT_DAYS;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (quirks && quirks->needs_kbd_timeouts)
+		convert = true;
+
+	if (convert) {
+		/* Convert value from current units to seconds */
+		switch (unit) {
+		case KBD_TIMEOUT_DAYS:
+			value *= 24;
+		case KBD_TIMEOUT_HOURS:
+			value *= 60;
+		case KBD_TIMEOUT_MINUTES:
+			value *= 60;
+			unit = KBD_TIMEOUT_SECONDS;
+		}
+
+		if (quirks && quirks->needs_kbd_timeouts) {
+			for (i = 0; quirks->kbd_timeouts[i] != -1; i++) {
+				if (value <= quirks->kbd_timeouts[i]) {
+					value = quirks->kbd_timeouts[i];
+					break;
+				}
+			}
+		}
+
+		if (value <= kbd_info.seconds && kbd_info.seconds) {
+			unit = KBD_TIMEOUT_SECONDS;
+		} else if (value / 60 <= kbd_info.minutes && kbd_info.minutes) {
+			value /= 60;
+			unit = KBD_TIMEOUT_MINUTES;
+		} else if (value / (60 * 60) <= kbd_info.hours && kbd_info.hours) {
+			value /= (60 * 60);
+			unit = KBD_TIMEOUT_HOURS;
+		} else if (value / (60 * 60 * 24) <= kbd_info.days && kbd_info.days) {
+			value /= (60 * 60 * 24);
+			unit = KBD_TIMEOUT_DAYS;
+		} else {
+			return -EINVAL;
+		}
+	}
+
+	ret = kbd_get_state(&state);
+	if (ret)
+		return ret;
+
+	new_state = state;
+	new_state.timeout_value = value;
+	new_state.timeout_unit = unit;
+
+	ret = kbd_set_state_safe(&new_state, &state);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static ssize_t kbd_led_timeout_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct kbd_state state;
+	int ret;
+	int len;
+
+	ret = kbd_get_state(&state);
+	if (ret)
+		return ret;
+
+	len = sprintf(buf, "%d", state.timeout_value);
+
+	switch (state.timeout_unit) {
+	case KBD_TIMEOUT_SECONDS:
+		return len + sprintf(buf+len, "s\n");
+	case KBD_TIMEOUT_MINUTES:
+		return len + sprintf(buf+len, "m\n");
+	case KBD_TIMEOUT_HOURS:
+		return len + sprintf(buf+len, "h\n");
+	case KBD_TIMEOUT_DAYS:
+		return len + sprintf(buf+len, "d\n");
+	default:
+		return -EINVAL;
+	}
+
+	return len;
+}
+
+static DEVICE_ATTR(stop_timeout, S_IRUGO | S_IWUSR,
+		   kbd_led_timeout_show, kbd_led_timeout_store);
+
+static const char * const kbd_led_triggers[] = {
+	"keyboard",
+	"touchpad",
+	/*"trackstick"*/ NULL, /* NOTE: trackstick is just alias for touchpad */
+	"mouse",
+};
+
+static ssize_t kbd_led_triggers_store(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t count)
+{
+	struct kbd_state new_state;
+	struct kbd_state state;
+	bool triggers_enabled = false;
+	int trigger_bit = -1;
+	char trigger[21];
+	int i, ret;
+
+	ret = sscanf(buf, "%20s", trigger);
+	if (ret != 1)
+		return -EINVAL;
+
+	if (trigger[0] != '+' && trigger[0] != '-')
+		return -EINVAL;
+
+	ret = kbd_get_state(&state);
+	if (ret)
+		return ret;
+
+	if (kbd_triggers_supported)
+		triggers_enabled = kbd_is_trigger_mode_bit(state.mode_bit);
+
+	if (kbd_triggers_supported) {
+		for (i = 0; i < ARRAY_SIZE(kbd_led_triggers); ++i) {
+			if (!(kbd_info.triggers & BIT(i)))
+				continue;
+			if (!kbd_led_triggers[i])
+				continue;
+			if (strcmp(trigger+1, kbd_led_triggers[i]) != 0)
+				continue;
+			if (trigger[0] == '+' &&
+			    triggers_enabled && (state.triggers & BIT(i)))
+				return count;
+			if (trigger[0] == '-' &&
+			    (!triggers_enabled || !(state.triggers & BIT(i))))
+				return count;
+			trigger_bit = i;
+			break;
+		}
+	}
+
+	if (trigger_bit != -1) {
+		new_state = state;
+		if (trigger[0] == '+')
+			new_state.triggers |= BIT(trigger_bit);
+		else {
+			new_state.triggers &= ~BIT(trigger_bit);
+			/* NOTE: trackstick bit (2) must be disabled when
+			 *       disabling touchpad bit (1), otherwise touchpad
+			 *       bit (1) will not be disabled */
+			if (trigger_bit == 1)
+				new_state.triggers &= ~BIT(2);
+		}
+		if ((kbd_info.triggers & new_state.triggers) !=
+		    new_state.triggers)
+			return -EINVAL;
+		if (new_state.triggers && !triggers_enabled) {
+			new_state.mode_bit = KBD_MODE_BIT_TRIGGER;
+			kbd_set_level(&new_state, kbd_previous_level);
+		} else if (new_state.triggers == 0) {
+			kbd_set_level(&new_state, 0);
+		}
+		if (!(kbd_info.modes & BIT(new_state.mode_bit)))
+			return -EINVAL;
+		ret = kbd_set_state_safe(&new_state, &state);
+		if (ret)
+			return ret;
+		if (new_state.mode_bit != KBD_MODE_BIT_OFF)
+			kbd_previous_mode_bit = new_state.mode_bit;
+		return count;
+	}
+
+	return -EINVAL;
+}
+
+static ssize_t kbd_led_triggers_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct kbd_state state;
+	bool triggers_enabled;
+	int level, i, ret;
+	int len = 0;
+
+	ret = kbd_get_state(&state);
+	if (ret)
+		return ret;
+
+	len = 0;
+
+	if (kbd_triggers_supported) {
+		triggers_enabled = kbd_is_trigger_mode_bit(state.mode_bit);
+		level = kbd_get_level(&state);
+		for (i = 0; i < ARRAY_SIZE(kbd_led_triggers); ++i) {
+			if (!(kbd_info.triggers & BIT(i)))
+				continue;
+			if (!kbd_led_triggers[i])
+				continue;
+			if ((triggers_enabled || level <= 0) &&
+			    (state.triggers & BIT(i)))
+				buf[len++] = '+';
+			else
+				buf[len++] = '-';
+			len += sprintf(buf+len, "%s ", kbd_led_triggers[i]);
+		}
+	}
+
+	if (len)
+		buf[len - 1] = '\n';
+
+	return len;
+}
+
+static DEVICE_ATTR(start_triggers, S_IRUGO | S_IWUSR,
+		   kbd_led_triggers_show, kbd_led_triggers_store);
+
+static ssize_t kbd_led_als_enabled_store(struct device *dev,
+					 struct device_attribute *attr,
+					 const char *buf, size_t count)
+{
+	struct kbd_state new_state;
+	struct kbd_state state;
+	bool triggers_enabled = false;
+	int enable;
+	int ret;
+
+	ret = kstrtoint(buf, 0, &enable);
+	if (ret)
+		return ret;
+
+	ret = kbd_get_state(&state);
+	if (ret)
+		return ret;
+
+	if (enable == kbd_is_als_mode_bit(state.mode_bit))
+		return count;
+
+	new_state = state;
+
+	if (kbd_triggers_supported)
+		triggers_enabled = kbd_is_trigger_mode_bit(state.mode_bit);
+
+	if (enable) {
+		if (triggers_enabled)
+			new_state.mode_bit = KBD_MODE_BIT_TRIGGER_ALS;
+		else
+			new_state.mode_bit = KBD_MODE_BIT_ALS;
+	} else {
+		if (triggers_enabled) {
+			new_state.mode_bit = KBD_MODE_BIT_TRIGGER;
+			kbd_set_level(&new_state, kbd_previous_level);
+		} else {
+			new_state.mode_bit = KBD_MODE_BIT_ON;
+		}
+	}
+	if (!(kbd_info.modes & BIT(new_state.mode_bit)))
+		return -EINVAL;
+
+	ret = kbd_set_state_safe(&new_state, &state);
+	if (ret)
+		return ret;
+	kbd_previous_mode_bit = new_state.mode_bit;
+
+	return count;
+}
+
+static ssize_t kbd_led_als_enabled_show(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct kbd_state state;
+	bool enabled = false;
+	int ret;
+
+	ret = kbd_get_state(&state);
+	if (ret)
+		return ret;
+	enabled = kbd_is_als_mode_bit(state.mode_bit);
+
+	return sprintf(buf, "%d\n", enabled ? 1 : 0);
+}
+
+static DEVICE_ATTR(als_enabled, S_IRUGO | S_IWUSR,
+		   kbd_led_als_enabled_show, kbd_led_als_enabled_store);
+
+static ssize_t kbd_led_als_setting_store(struct device *dev,
+					 struct device_attribute *attr,
+					 const char *buf, size_t count)
+{
+	struct kbd_state state;
+	struct kbd_state new_state;
+	u8 setting;
+	int ret;
+
+	ret = kstrtou8(buf, 10, &setting);
+	if (ret)
+		return ret;
+
+	ret = kbd_get_state(&state);
+	if (ret)
+		return ret;
+
+	new_state = state;
+	new_state.als_setting = setting;
+
+	ret = kbd_set_state_safe(&new_state, &state);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static ssize_t kbd_led_als_setting_show(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct kbd_state state;
+	int ret;
+
+	ret = kbd_get_state(&state);
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%d\n", state.als_setting);
+}
+
+static DEVICE_ATTR(als_setting, S_IRUGO | S_IWUSR,
+		   kbd_led_als_setting_show, kbd_led_als_setting_store);
+
+static struct attribute *kbd_led_attrs[] = {
+	&dev_attr_stop_timeout.attr,
+	&dev_attr_start_triggers.attr,
+	NULL,
+};
+
+static const struct attribute_group kbd_led_group = {
+	.attrs = kbd_led_attrs,
+};
+
+static struct attribute *kbd_led_als_attrs[] = {
+	&dev_attr_als_enabled.attr,
+	&dev_attr_als_setting.attr,
+	NULL,
+};
+
+static const struct attribute_group kbd_led_als_group = {
+	.attrs = kbd_led_als_attrs,
+};
+
+static const struct attribute_group *kbd_led_groups[] = {
+	&kbd_led_group,
+	&kbd_led_als_group,
+	NULL,
+};
+
+static enum led_brightness kbd_led_level_get(struct led_classdev *led_cdev)
+{
+	int ret;
+	u16 num;
+	struct kbd_state state;
+
+	if (kbd_get_max_level()) {
+		ret = kbd_get_state(&state);
+		if (ret)
+			return 0;
+		ret = kbd_get_level(&state);
+		if (ret < 0)
+			return 0;
+		return ret;
+	}
+
+	if (kbd_get_valid_token_counts()) {
+		ret = kbd_get_first_active_token_bit();
+		if (ret < 0)
+			return 0;
+		for (num = kbd_token_bits; num != 0 && ret > 0; --ret)
+			num &= num - 1; /* clear the first bit set */
+		if (num == 0)
+			return 0;
+		return ffs(num) - 1;
+	}
+
+	pr_warn("Keyboard brightness level control not supported\n");
+	return 0;
+}
+
+static void kbd_led_level_set(struct led_classdev *led_cdev,
+			      enum led_brightness value)
+{
+	struct kbd_state state;
+	struct kbd_state new_state;
+	u16 num;
+
+	if (kbd_get_max_level()) {
+		if (kbd_get_state(&state))
+			return;
+		new_state = state;
+		if (kbd_set_level(&new_state, value))
+			return;
+		kbd_set_state_safe(&new_state, &state);
+		return;
+	}
+
+	if (kbd_get_valid_token_counts()) {
+		for (num = kbd_token_bits; num != 0 && value > 0; --value)
+			num &= num - 1; /* clear the first bit set */
+		if (num == 0)
+			return;
+		kbd_set_token_bit(ffs(num) - 1);
+		return;
+	}
+
+	pr_warn("Keyboard brightness level control not supported\n");
+}
+
+static struct led_classdev kbd_led = {
+	.name           = "dell::kbd_backlight",
+	.brightness_set = kbd_led_level_set,
+	.brightness_get = kbd_led_level_get,
+	.groups         = kbd_led_groups,
+};
+
+static int __init kbd_led_init(struct device *dev)
+{
+	kbd_init();
+	if (!kbd_led_present)
+		return -ENODEV;
+	if (!kbd_als_supported)
+		kbd_led_groups[1] = NULL;
+	kbd_led.max_brightness = kbd_get_max_level();
+	if (!kbd_led.max_brightness) {
+		kbd_led.max_brightness = kbd_get_valid_token_counts();
+		if (kbd_led.max_brightness)
+			kbd_led.max_brightness--;
+	}
+	return led_classdev_register(dev, &kbd_led);
+}
+
+static void brightness_set_exit(struct led_classdev *led_cdev,
+				enum led_brightness value)
+{
+	/* Don't change backlight level on exit */
+};
+
+static void kbd_led_exit(void)
+{
+	if (!kbd_led_present)
+		return;
+	kbd_led.brightness_set = brightness_set_exit;
+	led_classdev_unregister(&kbd_led);
+}
+
 static int __init dell_init(void)
 {
 	int max_intensity = 0;
@@ -841,6 +1913,8 @@ static int __init dell_init(void)
 	if (quirks && quirks->touchpad_led)
 		touchpad_led_init(&platform_device->dev);
 
+	kbd_led_init(&platform_device->dev);
+
 	dell_laptop_dir = debugfs_create_dir("dell_laptop", NULL);
 	if (dell_laptop_dir != NULL)
 		debugfs_create_file("rfkill", 0444, dell_laptop_dir, NULL,
@@ -908,6 +1982,7 @@ static void __exit dell_exit(void)
 	debugfs_remove_recursive(dell_laptop_dir);
 	if (quirks && quirks->touchpad_led)
 		touchpad_led_exit();
+	kbd_led_exit();
 	i8042_remove_filter(dell_laptop_i8042_filter);
 	cancel_delayed_work_sync(&dell_rfkill_work);
 	backlight_device_unregister(dell_backlight_device);
@@ -924,5 +1999,7 @@ module_init(dell_init);
 module_exit(dell_exit);
 
 MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
+MODULE_AUTHOR("Gabriele Mazzotta <gabriele.mzt@gmail.com>");
+MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
 MODULE_DESCRIPTION("Dell laptop driver");
 MODULE_LICENSE("GPL");
-- 
2.1.4

Re: [PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

[Pali Rohár]

[-- Attachment #1: Type: Text/Plain, Size: 1632 bytes --]

On Thursday 19 February 2015 11:58:29 Gabriele Mazzotta wrote:
> This patch adds the support for the configuration of the
> keyboard backlight on supported Dell laptops.
> 
> With this patch it is possible to set:
> * keyboard backlight level
> * timeout after which the backlight will be automatically
> turned off * input activity triggers (keyboard, touchpad,
> mouse) that enable the backlight * ambient light settings
> 
> The settings are exposed via
> /sys/class/leds/dell::kbd_backlight/
> 
> The code is based on the newly released documentation by Dell
> in the libsmbios project.
> 
> Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
> Signed-off-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
> Cc: Dan Carpenter <dan.carpenter@oracle.com>
> ---
>  .../ABI/testing/sysfs-platform-dell-laptop         |   69 ++
>  drivers/platform/x86/dell-laptop.c                 | 1089
> +++++++++++++++++++- 2 files changed, 1152 insertions(+), 6
> deletions(-)
>  create mode 100644
> Documentation/ABI/testing/sysfs-platform-dell-laptop
> 

This patch is same as combination of previous, just contains all 
changes in single patch file. Difference between v3.19-rc5 and 
current version is just als code was moved to separate functions 
and als backlight can be enabled via new sysfs attribute (like in 
second patch which was sent).

I tested this patch on top of linus tree (commit 79513d0) and 
keyboard backlight works fine.

Darren, what do you think, can be this patch which brings 
keyboard backlight support finally moved to mainline kernel?

-- 
Pali Rohár
pali.rohar@gmail.com

[-- Attachment #2: This is a digitally signed message part. --]
[-- Type: application/pgp-signature, Size: 198 bytes --]

Re: [PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

[Darren Hart]

On Sun, Feb 22, 2015 at 12:04:23PM +0100, Pali Rohár wrote:
> On Thursday 19 February 2015 11:58:29 Gabriele Mazzotta wrote:
> > This patch adds the support for the configuration of the
> > keyboard backlight on supported Dell laptops.
> > 
> > With this patch it is possible to set:
> > * keyboard backlight level
> > * timeout after which the backlight will be automatically
> > turned off * input activity triggers (keyboard, touchpad,
> > mouse) that enable the backlight * ambient light settings
> > 
> > The settings are exposed via
> > /sys/class/leds/dell::kbd_backlight/
> > 
> > The code is based on the newly released documentation by Dell
> > in the libsmbios project.
> > 
> > Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
> > Signed-off-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
> > Cc: Dan Carpenter <dan.carpenter@oracle.com>
> > ---
> >  .../ABI/testing/sysfs-platform-dell-laptop         |   69 ++
> >  drivers/platform/x86/dell-laptop.c                 | 1089
> > +++++++++++++++++++- 2 files changed, 1152 insertions(+), 6
> > deletions(-)
> >  create mode 100644
> > Documentation/ABI/testing/sysfs-platform-dell-laptop
> > 
> 
> This patch is same as combination of previous, just contains all 
> changes in single patch file. Difference between v3.19-rc5 and 
> current version is just als code was moved to separate functions 
> and als backlight can be enabled via new sysfs attribute (like in 
> second patch which was sent).
> 
> I tested this patch on top of linus tree (commit 79513d0) and 
> keyboard backlight works fine.
> 
> Darren, what do you think, can be this patch which brings 
> keyboard backlight support finally moved to mainline kernel?

So sorry for the delay folks, bad week :( This landed too late for 3.20... her
durr 4.0, but should make 4.1. Expect to see it in next in the next few days.

-- 
Darren Hart
Intel Open Source Technology Center

Re: [PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

[Darren Hart]

On Thu, Feb 19, 2015 at 11:58:29AM +0100, Gabriele Mazzotta wrote:
> This patch adds the support for the configuration of the keyboard
> backlight on supported Dell laptops.
> 
> With this patch it is possible to set:
> * keyboard backlight level
> * timeout after which the backlight will be automatically turned off
> * input activity triggers (keyboard, touchpad, mouse) that enable the backlight
> * ambient light settings
> 
> The settings are exposed via /sys/class/leds/dell::kbd_backlight/
> 
> The code is based on the newly released documentation by Dell in the
> libsmbios project.
> 
> Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
> Signed-off-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
> Cc: Dan Carpenter <dan.carpenter@oracle.com>

Queued for 4.1, thanks everyone.

-- 
Darren Hart
Intel Open Source Technology Center

Re: [PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

[Pali Rohár]

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On Friday 21 November 2014 23:09:40 Darren Hart wrote:
> On Sat, Nov 22, 2014 at 07:46:25PM +0100, Pali Rohár wrote:
> > > > 0   Completed successfully
> > > > -1  Completed with error
> > > > -2  Function not supported
> > > > 
> > > > So we can return something other too (not always
> > > > -EINVAL). Do you have any idea which errno should we
> > > > return for -1 and -2?
> > > 
> > > For -1, I should think  -EIO (I/O Error)
> > > For -2, I'd expect -ENXIO (No such device or address)
> > 
> > What about -ENOSYS for -2?
> 
> No. This specific topic came up at kernel summit this year.
> ENOSYS is specifically for not implemented system calls.
> 

Ok, I will use -ENXIO.

> > > > > > +	if (convert) {
> > > > > > +		/* NOTE: this switch fall down */
> > > > > 
> > > > > "fall down" ? As in, it intentionally doesn't have
> > > > > breaks?
> > > > 
> > > > This code convert "value" in "units" to new value in
> > > > minutes units. So for unit == days it is: 24*60*60...
> > > > So no breaks.
> > > 
> > > Right, so the language of the comment just wasn't clear,
> > > try:
> > > 
> > > /* Convert value from seconds to minutes */
> > 
> > Err... to seconds :-) But OK, I will change comment.
> 
> Oops, duh.
> 
> /* Convert value from current units to seconds. */
> 
> > > > > > +		switch (unit) {
> > > > > > +		case KBD_TIMEOUT_DAYS:
> > > > > > +			value *= 24;
> > > > > > +		case KBD_TIMEOUT_HOURS:
> > > > > > +			value *= 60;
> > > > > > +		case KBD_TIMEOUT_MINUTES:
> > > > > > +			value *= 60;
> > > > > > +			unit = KBD_TIMEOUT_SECONDS;
> > > > > > +	 	}

-- 
Pali Rohár
pali.rohar@gmail.com

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Re: [PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

[Pali Rohár]

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On Friday 21 November 2014 21:39:30 Darren Hart wrote:
> On Wed, Nov 19, 2014 at 09:41:20PM +0100, Pali Rohár wrote:
> > Hello,
> 
> Hi Pali,
> 
> > I removed other lines so mail is not too long.
> 
> > On Wednesday 19 November 2014 19:34:16 Darren Hart wrote:
> ...
> 
> > > > +}
> > > > +
> > > > +static unsigned int kbd_get_max_level(void)
> > > > +{
> > > > +	if (kbd_info.levels != 0)
> > > > +		return kbd_info.levels;
> > > 
> > > This test.... does nothing? if it is 0, you still return 0
> > > below :-)
> > > 
> > > > +	if (kbd_mode_levels_count > 0)
> > > > +		return kbd_mode_levels_count - 1;
> > > > +	return 0;
> > > 
> > > So the function is:
> > > 
> > > return kbd_mode_levels_count > 0 ? kbd_mode_levels_count -
> > > 1 : kbd_info.levels;
> > > 
> > > The if blocks are more legible, so that's fine, but the
> > > first one doesn't seem to do anything and you can replace
> > > the final return with return kbd_info.levels.
> > 
> > There are two main way for setting keyboard backlight level.
> > One is setting level register and other one is setting
> > special keyboard mode. And some dell laptops support only
> > first and some only second. So this code choose first
> > available/valid method and then return correct data. I'm
> > not sure if those two methods are only one and also do not
> > know if in future there will be something other. Because of
> > this I use code pattern:
> > 
> > if (check_method_1) return value_method_1;
> > if (check_method_2) return value_method_2;
> > ...
> > return unsupported;
> > 
> > Same pattern logic is used in all functions which doing
> > something with keyboard backlight level. (I will not other
> > functions).
> 
> Fair enough. Clear, legible, consistent coding is preferable
> to a few micro optimizations that the compiler is likely to
> catch anyway. I withdraw the comment :-)
> 

Ok.

> > > > +static int kbd_set_state(struct kbd_state *state)
> > > > +{
> > > > +	int ret;
> > > > +
> > > > +	get_buffer();
> > > > +	buffer->input[0] = 0x2;
> > > > +	buffer->input[1] = BIT(state->mode_bit) & 0xFFFF;
> > > > +	buffer->input[1] |= (state->triggers & 0xFF) << 16;
> > > > +	buffer->input[1] |= (state->timeout_value & 0x3F) <<
> > > > 24; +	buffer->input[1] |= (state->timeout_unit & 0x3)
> > > > << 30; +	buffer->input[2] = state->als_setting & 0xFF;
> > > > +	buffer->input[2] |= (state->level & 0xFF) << 16;
> > > > +	dell_send_request(buffer, 4, 11);
> > > > +	ret = buffer->output[0];
> > > > +	release_buffer();
> > > > +
> > > > +	if (ret)
> > > > +		return -EINVAL;
> > > 
> > > Also, is EINVAL right here and elsewhere? Or did something
> > > fail? EXIO?
> > 
> > According to Dell documentation, return value is stored in
> > buffer->output[0] and can be:
> > 
> > 0   Completed successfully
> > -1  Completed with error
> > -2  Function not supported
> > 
> > So we can return something other too (not always -EINVAL).
> > Do you have any idea which errno should we return for -1
> > and -2?
> 
> For -1, I should think  -EIO (I/O Error)
> For -2, I'd expect -ENXIO (No such device or address)
> 

What about -ENOSYS for -2?

> Cc Rafael, Mika, linux-acpi in case they have a better idea.
> 
> > > > +
> > > > +	return 0;
> > > > +}
> > > > +
> > > > +static int kbd_set_state_safe(struct kbd_state *state,
> > > > struct kbd_state *old) +{
> > > > +	int ret;
> > > > +
> > > > +	ret = kbd_set_state(state);
> > > > +	if (ret == 0)
> > > > +		return 0;
> > > > +
> > > > +	if (kbd_set_state(old))
> > > > +		pr_err("Setting old previous keyboard state
> > 
> > failed\n");
> > 
> > > And if we got an error and kbd_set_state(old) doesn't
> > > return !0, what's the state of things? Still a failure a
> > > presume?
> > 
> > In some cases some laptops do not have to support
> > everything. And when I (and Gabriele too) tried to set
> > something unsupported Dell BIOS just resetted all settings
> > to some default values. So this function try to set new
> > state and if it fails then it try to restore previous
> > settings.
> 
> OK, that deserves a comment then as the rationale isn't
> obvious.
> 

Ok, I will add comment.

> > > > +
> > > > +	return ret;
> > > > +}
> > > > 
> > > > +static void kbd_init(void)
> > > > +{
> > > > +	struct kbd_state state;
> > > > +	int ret;
> > > > +	int i;
> > > > +
> > > > +	ret = kbd_get_info(&kbd_info);
> > > > +
> > > > +	if (ret == 0) {
> > > > +
> > > 
> > > Checking for success, let's invert and avoid the
> > > indentation here too.
> > 
> > Again this is hard and not possible. This function first
> > process data from kbd_get_info (if does not fail), then
> > process data for kbd_tokens (via function find_token_id)
> > and then set kbd_led_present to true if at least
> > kbd_get_info or kbd_tokens succed.
> 
> The goal here is to avoid more than 3 levels of indentations
> for improved legibility. Often there are logical inversions
> and such we can make to accomplish this. When that fails, we
> break things up into functions, static inlines, etc.
> 
> For reference:
> https://lkml.org/lkml/2007/6/15/449
> 
> Which elaborates on CodingStyle Chapter 1: Indentation a bit.
> 
> ...
> 

Ok, I will move it into two static inline functions (one for 
kbd_get_info and second for kbd_tokens).

> > > > +static ssize_t kbd_led_timeout_store(struct device
> > > > *dev, +				     struct device_attribute *attr,
> > > > +				     const char *buf, size_t count)
> > > > +{
> > > > +	struct kbd_state state;
> > > > +	struct kbd_state new_state;
> > > > +	int ret;
> > > > +	bool convert;
> > > > +	char ch;
> > > > +	u8 unit;
> > > > +	int value;
> > > > +	int i;
> > > 
> > > Decreasing line lenth please.
> > 
> > What do you mean?
> 
> This is a nit, but one other maintainers have imposed on me,
> as a means to improve legibility. The preference is to
> declare variables in decreasing line length, longest to
> shortest:
> 
> struct kbd_state new_state;
> struct kbd_state state;
> bool convert;
> int value;
> u8 unit;
> char ch;
> int ret;
> int i;
> 
> This is a generalization and sometimes there are good reasons
> for doing something else, such as logical groupings for
> commenting groups, etc. But since this list appeared mostly
> random, defaulting to decreasing line length is preferred.
> 

Ok. I'm not native English speaker and I did not understand what 
"Decreasing line lenth" means...

> > > > +	if (convert) {
> > > > +		/* NOTE: this switch fall down */
> > > 
> > > "fall down" ? As in, it intentionally doesn't have breaks?
> > 
> > This code convert "value" in "units" to new value in minutes
> > units. So for unit == days it is: 24*60*60... So no breaks.
> 
> Right, so the language of the comment just wasn't clear, try:
> 
> /* Convert value from seconds to minutes */
> 

Err... to seconds :-) But OK, I will change comment.

> > > > +		switch (unit) {
> > > > +		case KBD_TIMEOUT_DAYS:
> > > > +			value *= 24;
> > > > +		case KBD_TIMEOUT_HOURS:
> > > > +			value *= 60;
> > > > +		case KBD_TIMEOUT_MINUTES:
> > > > +			value *= 60;
> > > > +			unit = KBD_TIMEOUT_SECONDS;
> > > > +	 	}
> > > > +

-- 
Pali Rohár
pali.rohar@gmail.com

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Re: [PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

[Darren Hart]

On Sat, Nov 22, 2014 at 07:46:25PM +0100, Pali Rohár wrote:

> > > 0   Completed successfully
> > > -1  Completed with error
> > > -2  Function not supported
> > > 
> > > So we can return something other too (not always -EINVAL).
> > > Do you have any idea which errno should we return for -1
> > > and -2?
> > 
> > For -1, I should think  -EIO (I/O Error)
> > For -2, I'd expect -ENXIO (No such device or address)
> > 
> 
> What about -ENOSYS for -2?

No. This specific topic came up at kernel summit this year. ENOSYS is
specifically for not implemented system calls.

> 
> > > > > +	if (convert) {
> > > > > +		/* NOTE: this switch fall down */
> > > > 
> > > > "fall down" ? As in, it intentionally doesn't have breaks?
> > > 
> > > This code convert "value" in "units" to new value in minutes
> > > units. So for unit == days it is: 24*60*60... So no breaks.
> > 
> > Right, so the language of the comment just wasn't clear, try:
> > 
> > /* Convert value from seconds to minutes */
> > 
> 
> Err... to seconds :-) But OK, I will change comment.

Oops, duh.

/* Convert value from current units to seconds. */

> 
> > > > > +		switch (unit) {
> > > > > +		case KBD_TIMEOUT_DAYS:
> > > > > +			value *= 24;
> > > > > +		case KBD_TIMEOUT_HOURS:
> > > > > +			value *= 60;
> > > > > +		case KBD_TIMEOUT_MINUTES:
> > > > > +			value *= 60;
> > > > > +			unit = KBD_TIMEOUT_SECONDS;
> > > > > +	 	}

-- 
Darren Hart
Intel Open Source Technology Center

Re: [PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

[Darren Hart]

On Wed, Nov 19, 2014 at 09:41:20PM +0100, Pali Rohár wrote:
> Hello,

Hi Pali,

> 
> I removed other lines so mail is not too long.
> 
> On Wednesday 19 November 2014 19:34:16 Darren Hart wrote:
...
> > > +}
> > > +
> > > +static unsigned int kbd_get_max_level(void)
> > > +{
> > > +	if (kbd_info.levels != 0)
> > > +		return kbd_info.levels;
> > 
> > This test.... does nothing? if it is 0, you still return 0
> > below :-)
> > 
> > > +	if (kbd_mode_levels_count > 0)
> > > +		return kbd_mode_levels_count - 1;
> > > +	return 0;
> > 
> > So the function is:
> > 
> > return kbd_mode_levels_count > 0 ? kbd_mode_levels_count - 1 :
> > kbd_info.levels;
> > 
> > The if blocks are more legible, so that's fine, but the first
> > one doesn't seem to do anything and you can replace the final
> > return with return kbd_info.levels.
> > 
> 
> There are two main way for setting keyboard backlight level. One 
> is setting level register and other one is setting special 
> keyboard mode. And some dell laptops support only first and some 
> only second. So this code choose first available/valid method and 
> then return correct data. I'm not sure if those two methods are 
> only one and also do not know if in future there will be 
> something other. Because of this I use code pattern:
> 
> if (check_method_1) return value_method_1;
> if (check_method_2) return value_method_2;
> ...
> return unsupported;
> 
> Same pattern logic is used in all functions which doing something 
> with keyboard backlight level. (I will not other functions).

Fair enough. Clear, legible, consistent coding is preferable to a few micro
optimizations that the compiler is likely to catch anyway. I withdraw the
comment :-)

> 
> > > +static int kbd_set_state(struct kbd_state *state)
> > > +{
> > > +	int ret;
> > > +
> > > +	get_buffer();
> > > +	buffer->input[0] = 0x2;
> > > +	buffer->input[1] = BIT(state->mode_bit) & 0xFFFF;
> > > +	buffer->input[1] |= (state->triggers & 0xFF) << 16;
> > > +	buffer->input[1] |= (state->timeout_value & 0x3F) << 24;
> > > +	buffer->input[1] |= (state->timeout_unit & 0x3) << 30;
> > > +	buffer->input[2] = state->als_setting & 0xFF;
> > > +	buffer->input[2] |= (state->level & 0xFF) << 16;
> > > +	dell_send_request(buffer, 4, 11);
> > > +	ret = buffer->output[0];
> > > +	release_buffer();
> > > +
> > > +	if (ret)
> > > +		return -EINVAL;
> > 
> > Also, is EINVAL right here and elsewhere? Or did something
> > fail? EXIO?
> > 
> 
> According to Dell documentation, return value is stored in 
> buffer->output[0] and can be:
> 
> 0   Completed successfully
> -1  Completed with error
> -2  Function not supported
> 
> So we can return something other too (not always -EINVAL). Do you 
> have any idea which errno should we return for -1 and -2?

For -1, I should think  -EIO (I/O Error)
For -2, I'd expect -ENXIO (No such device or address)

Cc Rafael, Mika, linux-acpi in case they have a better idea.

> 
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int kbd_set_state_safe(struct kbd_state *state,
> > > struct kbd_state *old) +{
> > > +	int ret;
> > > +
> > > +	ret = kbd_set_state(state);
> > > +	if (ret == 0)
> > > +		return 0;
> > > +
> > > +	if (kbd_set_state(old))
> > > +		pr_err("Setting old previous keyboard state 
> failed\n");
> > 
> > And if we got an error and kbd_set_state(old) doesn't return
> > !0, what's the state of things? Still a failure a presume?
> > 
> 
> In some cases some laptops do not have to support everything. And 
> when I (and Gabriele too) tried to set something unsupported Dell 
> BIOS just resetted all settings to some default values. So this 
> function try to set new state and if it fails then it try to 
> restore previous settings.

OK, that deserves a comment then as the rationale isn't obvious.

> 
> > > +
> > > +	return ret;
> > > +}
> 
> > > +static void kbd_init(void)
> > > +{
> > > +	struct kbd_state state;
> > > +	int ret;
> > > +	int i;
> > > +
> > > +	ret = kbd_get_info(&kbd_info);
> > > +
> > > +	if (ret == 0) {
> > > +
> > 
> > Checking for success, let's invert and avoid the indentation
> > here too.
> > 
> 
> Again this is hard and not possible. This function first process 
> data from kbd_get_info (if does not fail), then process data for 
> kbd_tokens (via function find_token_id) and then set 
> kbd_led_present to true if at least kbd_get_info or kbd_tokens 
> succed.

The goal here is to avoid more than 3 levels of indentations for improved
legibility. Often there are logical inversions and such we can make to
accomplish this. When that fails, we break things up into functions, static
inlines, etc.

For reference:
https://lkml.org/lkml/2007/6/15/449

Which elaborates on CodingStyle Chapter 1: Indentation a bit.

...
> > > +static ssize_t kbd_led_timeout_store(struct device *dev,
> > > +				     struct device_attribute *attr,
> > > +				     const char *buf, size_t count)
> > > +{
> > > +	struct kbd_state state;
> > > +	struct kbd_state new_state;
> > > +	int ret;
> > > +	bool convert;
> > > +	char ch;
> > > +	u8 unit;
> > > +	int value;
> > > +	int i;
> > 
> > Decreasing line lenth please.
> > 
> 
> What do you mean?

This is a nit, but one other maintainers have imposed on me, as a means to
improve legibility. The preference is to declare variables in decreasing line
length, longest to shortest:

struct kbd_state new_state;
struct kbd_state state;
bool convert;
int value;
u8 unit;
char ch;
int ret;
int i;

This is a generalization and sometimes there are good reasons for doing
something else, such as logical groupings for commenting groups, etc. But since
this list appeared mostly random, defaulting to decreasing line length is
preferred.

> 
> > > +	if (convert) {
> > > +		/* NOTE: this switch fall down */
> > 
> > "fall down" ? As in, it intentionally doesn't have breaks?
> > 
> 
> This code convert "value" in "units" to new value in minutes 
> units. So for unit == days it is: 24*60*60... So no breaks.
> 

Right, so the language of the comment just wasn't clear, try:

/* Convert value from seconds to minutes */

> > > +		switch (unit) {
> > > +		case KBD_TIMEOUT_DAYS:
> > > +			value *= 24;
> > > +		case KBD_TIMEOUT_HOURS:
> > > +			value *= 60;
> > > +		case KBD_TIMEOUT_MINUTES:
> > > +			value *= 60;
> > > +			unit = KBD_TIMEOUT_SECONDS;
> > > +	 	}
> > > +

-- 
Darren Hart
Intel Open Source Technology Center

Re: [PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

[Pali Rohár]

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Hello,

I removed other lines so mail is not too long.

On Wednesday 19 November 2014 19:34:16 Darren Hart wrote:
> > +static int kbd_get_info(struct kbd_info *info)
> > +{
> > +	u8 units;
> > +	int ret;
> > +
> > +	get_buffer();
> > +
> > +	buffer->input[0] = 0x0;
> > +	dell_send_request(buffer, 4, 11);
> > +	ret = buffer->output[0];
> > +
> > +	if (ret == 0) {
> 
> Generally speaking, check for error to keep the main logic
> from getting indented.
> 
> 	if (buffer->output[0]) {
> 		ret = -EINVAL;
> 		goto out;
> 	}
> 
> > +		info->modes = buffer->output[1] & 0xFFFF;
> > +		info->type = (buffer->output[1] >> 24) & 0xFF;
> > +		info->triggers = buffer->output[2] & 0xFF;
> > +		units = (buffer->output[2] >> 8) & 0xFF;
> > +		info->levels = (buffer->output[2] >> 16) & 0xFF;
> > +		if (units & BIT(0))
> > +			info->seconds = (buffer->output[3] >> 0) & 0xFF;
> > +		if (units & BIT(1))
> > +			info->minutes = (buffer->output[3] >> 8) & 0xFF;
> > +		if (units & BIT(2))
> > +			info->hours = (buffer->output[3] >> 16) & 0xFF;
> > +		if (units & BIT(3))
> > +			info->days = (buffer->output[3] >> 24) & 0xFF;
> > +	}
> > +
> 
>  out:
> > +	release_buffer();
> > +
> > +	if (ret)
> > +		return -EINVAL;
> 
> Drop this.
> 
> > +	return 0;
> 
> return ret;
> 
> In this particular case, it might be shorter by a line or two
> to drop the ret variable and simply release_buffer() and
> return -EINVAL in the error check above and just return 0
> here.
> 

Ok. But somewhere it is not possible.

> > +}
> > +
> > +static unsigned int kbd_get_max_level(void)
> > +{
> > +	if (kbd_info.levels != 0)
> > +		return kbd_info.levels;
> 
> This test.... does nothing? if it is 0, you still return 0
> below :-)
> 
> > +	if (kbd_mode_levels_count > 0)
> > +		return kbd_mode_levels_count - 1;
> > +	return 0;
> 
> So the function is:
> 
> return kbd_mode_levels_count > 0 ? kbd_mode_levels_count - 1 :
> kbd_info.levels;
> 
> The if blocks are more legible, so that's fine, but the first
> one doesn't seem to do anything and you can replace the final
> return with return kbd_info.levels.
> 

There are two main way for setting keyboard backlight level. One 
is setting level register and other one is setting special 
keyboard mode. And some dell laptops support only first and some 
only second. So this code choose first available/valid method and 
then return correct data. I'm not sure if those two methods are 
only one and also do not know if in future there will be 
something other. Because of this I use code pattern:

if (check_method_1) return value_method_1;
if (check_method_2) return value_method_2;
...
return unsupported;

Same pattern logic is used in all functions which doing something 
with keyboard backlight level. (I will not other functions).

> > +static int kbd_set_state(struct kbd_state *state)
> > +{
> > +	int ret;
> > +
> > +	get_buffer();
> > +	buffer->input[0] = 0x2;
> > +	buffer->input[1] = BIT(state->mode_bit) & 0xFFFF;
> > +	buffer->input[1] |= (state->triggers & 0xFF) << 16;
> > +	buffer->input[1] |= (state->timeout_value & 0x3F) << 24;
> > +	buffer->input[1] |= (state->timeout_unit & 0x3) << 30;
> > +	buffer->input[2] = state->als_setting & 0xFF;
> > +	buffer->input[2] |= (state->level & 0xFF) << 16;
> > +	dell_send_request(buffer, 4, 11);
> > +	ret = buffer->output[0];
> > +	release_buffer();
> > +
> > +	if (ret)
> > +		return -EINVAL;
> 
> Also, is EINVAL right here and elsewhere? Or did something
> fail? EXIO?
> 

According to Dell documentation, return value is stored in 
buffer->output[0] and can be:

0   Completed successfully
-1  Completed with error
-2  Function not supported

So we can return something other too (not always -EINVAL). Do you 
have any idea which errno should we return for -1 and -2?

> > +
> > +	return 0;
> > +}
> > +
> > +static int kbd_set_state_safe(struct kbd_state *state,
> > struct kbd_state *old) +{
> > +	int ret;
> > +
> > +	ret = kbd_set_state(state);
> > +	if (ret == 0)
> > +		return 0;
> > +
> > +	if (kbd_set_state(old))
> > +		pr_err("Setting old previous keyboard state 
failed\n");
> 
> And if we got an error and kbd_set_state(old) doesn't return
> !0, what's the state of things? Still a failure a presume?
> 

In some cases some laptops do not have to support everything. And 
when I (and Gabriele too) tried to set something unsupported Dell 
BIOS just resetted all settings to some default values. So this 
function try to set new state and if it fails then it try to 
restore previous settings.

> > +
> > +	return ret;
> > +}

> > +static void kbd_init(void)
> > +{
> > +	struct kbd_state state;
> > +	int ret;
> > +	int i;
> > +
> > +	ret = kbd_get_info(&kbd_info);
> > +
> > +	if (ret == 0) {
> > +
> 
> Checking for success, let's invert and avoid the indentation
> here too.
> 

Again this is hard and not possible. This function first process 
data from kbd_get_info (if does not fail), then process data for 
kbd_tokens (via function find_token_id) and then set 
kbd_led_present to true if at least kbd_get_info or kbd_tokens 
succed.

> > +		....
> > +
> > +	}
> > +
> > +	for (i = 0; i < ARRAY_SIZE(kbd_tokens); ++i)
> > +		if (find_token_id(kbd_tokens[i]) != -1)
> > +			kbd_token_bits |= BIT(i);
> > +
> > +	if (kbd_token_bits != 0 || ret == 0)
> > +		kbd_led_present = true;
> > +}
> > +
> > +static ssize_t kbd_led_timeout_store(struct device *dev,
> > +				     struct device_attribute *attr,
> > +				     const char *buf, size_t count)
> > +{
> > +	struct kbd_state state;
> > +	struct kbd_state new_state;
> > +	int ret;
> > +	bool convert;
> > +	char ch;
> > +	u8 unit;
> > +	int value;
> > +	int i;
> 
> Decreasing line lenth please.
> 

What do you mean?

> > +	if (convert) {
> > +		/* NOTE: this switch fall down */
> 
> "fall down" ? As in, it intentionally doesn't have breaks?
> 

This code convert "value" in "units" to new value in minutes 
units. So for unit == days it is: 24*60*60... So no breaks.

> > +		switch (unit) {
> > +		case KBD_TIMEOUT_DAYS:
> > +			value *= 24;
> > +		case KBD_TIMEOUT_HOURS:
> > +			value *= 60;
> > +		case KBD_TIMEOUT_MINUTES:
> > +			value *= 60;
> > +			unit = KBD_TIMEOUT_SECONDS;
> > +	 	}
> > +
> > +		if (value <= kbd_info.seconds && kbd_info.seconds) {
> > +			unit = KBD_TIMEOUT_SECONDS;
> > +		} else if (value/60 <= kbd_info.minutes &&
> > kbd_info.minutes) {
> 
> One space around operators like / and * please, applies
> throughout.
> 

Ok.

> > +	if (kbd_als_supported)
> > +		als_enabled = kbd_is_als_mode_bit(state.mode_bit);
> > +	else
> > +		als_enabled = false;
> > +
> > +	if (kbd_triggers_supported)
> > +		triggers_enabled =
> > kbd_is_trigger_mode_bit(state.mode_bit); +	else
> > +		triggers_enabled = false;
> 
> Could skip the else blocks with initial assignments.
> 

Ok.

> > +
> > +	enable_als = false;
> > +	disable_als = false;
> 
> Can skip these too.
> 

Ok.

> > +			if (triggers_enabled) {
> > +				new_state.mode_bit = KBD_MODE_BIT_TRIGGER;
> > +				kbd_set_level(&new_state, kbd_previous_level);
> > +			} else
> > +				new_state.mode_bit = KBD_MODE_BIT_ON;
> 
> if one block needs braces, use them throughout.
> Apply throughout.
> 

Ok.

> > +static enum led_brightness kbd_led_level_get(struct
> > led_classdev *led_cdev) +{
> > +	int ret;
> > +	u16 num;
> > +	struct kbd_state state;
> > +
> > +	if (kbd_get_max_level()) {
> > +		ret = kbd_get_state(&state);
> > +		if (ret)
> > +			return 0;
> > +		ret = kbd_get_level(&state);
> > +		if (ret < 0)
> > +			return 0;
> > +		return ret;
> > +	} else if (kbd_get_valid_token_counts()) {
> > +		ret = kbd_get_first_active_token_bit();
> > +		if (ret < 0)
> > +			return 0;
> > +		for (num = kbd_token_bits; num != 0 && ret > 0; --ret)
> > +			num &= num - 1; /* clear the first bit set */
> > +		if (num == 0)
> > +			return 0;
> > +		return ffs(num) - 1;
> > +	} else {
> > +		pr_warn("Keyboard brightness level control not
> > supported\n"); +		return 0;
> > +	}
> 
> You can drop the else blocks from the above as every case
> returns explicitly.
> 
> if (condA)
> 	return retA;
> if (condB)
> 	return retB
> return ret
> 
> (checkpatch.pl catches this)
> 

Ok, this is possible. I will change it.

-- 
Pali Rohár
pali.rohar@gmail.com

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Re: [PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

[Pali Rohár]

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On Wednesday 19 November 2014 20:23:36 Matthew Garrett wrote:
> On Wed, Nov 19, 2014 at 10:34:16AM -0800, Darren Hart wrote:
> > I'm somewhat concerned that this patch doubles the size of
> > this driver. When we're adding this much code, I have to
> > ask - does it make sense to grow this driver rather than
> > create a new one?
> 
> There'd be a fair amount of code duplication in splitting it.
> 

Yes. dell-laptop.ko implements functions for doing Dell SMBIOS 
calls which are needed for keyboard backlight.

> > There is no ACPI backlight driver on these systems? We need
> > a platform driver?
> 
> ACPI doesn't specify keyboard backlight control, so this ends
> up being very vendor specific.

dell-laptop.ko is not ACPI driver. It is using Dell SMBIOS calls. 
And I do not know about Dell specific ACPI interface for keyboard 
backlight. So Darren, ask this question someone from Dell.

-- 
Pali Rohár
pali.rohar@gmail.com

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Re: [PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

[Matthew Garrett]

On Wed, Nov 19, 2014 at 10:34:16AM -0800, Darren Hart wrote:

> I'm somewhat concerned that this patch doubles the size of this driver. When
> we're adding this much code, I have to ask - does it make sense to grow this
> driver rather than create a new one?

There'd be a fair amount of code duplication in splitting it. 

> There is no ACPI backlight driver on these systems? We need a platform driver?

ACPI doesn't specify keyboard backlight control, so this ends up being 
very vendor specific.
 
-- 
Matthew Garrett | mjg59@srcf.ucam.org

Re: [PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

[Darren Hart]

On Wed, Nov 19, 2014 at 08:51:28PM +0100, Pali Rohár wrote:
> On Wednesday 19 November 2014 20:23:36 Matthew Garrett wrote:
> > On Wed, Nov 19, 2014 at 10:34:16AM -0800, Darren Hart wrote:
> > > I'm somewhat concerned that this patch doubles the size of
> > > this driver. When we're adding this much code, I have to
> > > ask - does it make sense to grow this driver rather than
> > > create a new one?
> > 
> > There'd be a fair amount of code duplication in splitting it.
> > 
> 
> Yes. dell-laptop.ko implements functions for doing Dell SMBIOS 
> calls which are needed for keyboard backlight.
> 
> > > There is no ACPI backlight driver on these systems? We need
> > > a platform driver?
> > 
> > ACPI doesn't specify keyboard backlight control, so this ends
> > up being very vendor specific.
> 
> dell-laptop.ko is not ACPI driver. It is using Dell SMBIOS calls. 
> And I do not know about Dell specific ACPI interface for keyboard 
> backlight. So Darren, ask this question someone from Dell.

Right, I asked because there is a block in the original driver to defer
to an ACPI backlight driver if it exists. I understand this is a
keyboard backlight driver and is different, but I wanted to check.

So let's go ahead and move forward with dell-laptop.c being the right
place for this addition.

Thanks,

-- 
Darren Hart
Intel Open Source Technology Center

Re: [PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

[Darren Hart]

On Fri, Nov 14, 2014 at 01:23:33PM +0100, Pali Rohár wrote:
> This patch adds support for configuring keyboard backlight settings on supported
> Dell laptops. It exports kernel leds interface and uses Dell SMBIOS tokens or
> keyboard class interface.
> 
> With this patch it is possible to set:
> * keyboard backlight level
> * timeout after which will be backlight automatically turned off
> * input activity triggers (keyboard, touchpad, mouse) which enable backlight
> * ambient light settings
> 
> Settings are exported via sysfs:
> /sys/class/leds/dell::kbd_backlight/
> 
> Code is based on newly released documentation by Dell in libsmbios project.
> 
> Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
> Signed-off-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>

Hi Pali,

Apologies for the delay.

I'm somewhat concerned that this patch doubles the size of this driver. When
we're adding this much code, I have to ask - does it make sense to grow this
driver rather than create a new one?

There is no ACPI backlight driver on these systems? We need a platform driver?

Matthew, I'd appreciate your thoughts as you're listed as the module author.

My main commentary throughout is surrounding large indented logic blocks which
could be less nested by checking for errors and returning/jumping rather than
using an if (success) block for the main logic. There are various places where
some logic reduction would result in some significantly tighter code.

Specific comments below.

> ---
>  drivers/platform/x86/dell-laptop.c | 1001 +++++++++++++++++++++++++++++++++++-
>  1 file changed, 997 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c
> index 233d2ee..bf5b1cc 100644
> --- a/drivers/platform/x86/dell-laptop.c
> +++ b/drivers/platform/x86/dell-laptop.c
> @@ -2,9 +2,11 @@
>   *  Driver for Dell laptop extras
>   *
>   *  Copyright (c) Red Hat <mjg@redhat.com>
> + *  Copyright (c) 2014 Gabriele Mazzotta <gabriele.mzt@gmail.com>
> + *  Copyright (c) 2014 Pali Rohár <pali.rohar@gmail.com>
>   *
> - *  Based on documentation in the libsmbios package, Copyright (C) 2005 Dell
> - *  Inc.
> + *  Based on documentation in the libsmbios package:
> + *  Copyright (C) 2005-2014 Dell Inc.
>   *
>   *  This program is free software; you can redistribute it and/or modify
>   *  it under the terms of the GNU General Public License version 2 as
> @@ -32,6 +34,13 @@
>  #include "../../firmware/dcdbas.h"
>  
>  #define BRIGHTNESS_TOKEN 0x7d
> +#define KBD_LED_OFF_TOKEN 0x01E1
> +#define KBD_LED_ON_TOKEN 0x01E2
> +#define KBD_LED_AUTO_TOKEN 0x01E3
> +#define KBD_LED_AUTO_25_TOKEN 0x02EA
> +#define KBD_LED_AUTO_50_TOKEN 0x02EB
> +#define KBD_LED_AUTO_75_TOKEN 0x02EC
> +#define KBD_LED_AUTO_100_TOKEN 0x02F6
>  
>  /* This structure will be modified by the firmware when we enter
>   * system management mode, hence the volatiles */
> @@ -62,6 +71,10 @@ struct calling_interface_structure {
>  
>  struct quirk_entry {
>  	u8 touchpad_led;
> +
> +	/* Ordered list of timeouts expressed in seconds.
> +	 * The list must end with -1 */
> +	int kbd_timeouts[];
>  };
>  
>  static struct quirk_entry *quirks;
> @@ -76,6 +89,10 @@ static int __init dmi_matched(const struct dmi_system_id *dmi)
>  	return 1;
>  }
>  
> +static struct quirk_entry quirk_dell_xps13_9333 = {
> +	.kbd_timeouts = { 0, 5, 15, 60, 5*60, 15*60, -1 },
> +};
> +
>  static int da_command_address;
>  static int da_command_code;
>  static int da_num_tokens;
> @@ -268,6 +285,15 @@ static const struct dmi_system_id dell_quirks[] __initconst = {
>  		},
>  		.driver_data = &quirk_dell_vostro_v130,
>  	},
> +	{
> +		.callback = dmi_matched,
> +		.ident = "Dell XPS13 9333",
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "XPS13 9333"),
> +		},
> +		.driver_data = &quirk_dell_xps13_9333,
> +	},
>  	{ }
>  };
>  
> @@ -332,17 +358,29 @@ static void __init find_tokens(const struct dmi_header *dm, void *dummy)
>  	}
>  }
>  
> -static int find_token_location(int tokenid)
> +static int find_token_id(int tokenid)
>  {
>  	int i;
> +
>  	for (i = 0; i < da_num_tokens; i++) {
>  		if (da_tokens[i].tokenID == tokenid)
> -			return da_tokens[i].location;
> +			return i;
>  	}
>  
>  	return -1;
>  }
>  
> +static int find_token_location(int tokenid)
> +{
> +	int id;
> +
> +	id = find_token_id(tokenid);
> +	if (id == -1)
> +		return -1;
> +
> +	return da_tokens[id].location;
> +}
> +
>  static struct calling_interface_buffer *
>  dell_send_request(struct calling_interface_buffer *buffer, int class,
>  		  int select)
> @@ -790,6 +828,956 @@ static void touchpad_led_exit(void)
>  	led_classdev_unregister(&touchpad_led);
>  }
>  
> +/* Derived from information in smbios-keyboard-ctl:
> +
> + cbClass 4
> + cbSelect 11
> + Keyboar illumination
> + cbArg1 determines the function to be performed
> +
> + cbArg1 0x0 = Get Feature Information
> +  cbRES1         Standard return codes (0, -1, -2)
> +  cbRES2, word0  Bitmap of user-selectable modes
> +     bit 0     Always off (All systems)
> +     bit 1     Always on (Travis ATG, Siberia)
> +     bit 2     Auto: ALS-based On; ALS-based Off (Travis ATG)
> +     bit 3     Auto: ALS- and input-activity-based On; input-activity based Off
> +     bit 4     Auto: Input-activity-based On; input-activity based Off
> +     bit 5     Auto: Input-activity-based On (illumination level 25%); input-activity based Off
> +     bit 6     Auto: Input-activity-based On (illumination level 50%); input-activity based Off
> +     bit 7     Auto: Input-activity-based On (illumination level 75%); input-activity based Off
> +     bit 8     Auto: Input-activity-based On (illumination level 100%); input-activity based Off
> +     bits 9-15 Reserved for future use
> +  cbRES2, byte2  Reserved for future use
> +  cbRES2, byte3  Keyboard illumination type
> +     0         Reserved
> +     1         Tasklight
> +     2         Backlight
> +     3-255     Reserved for future use
> +  cbRES3, byte0  Supported auto keyboard illumination trigger bitmap.
> +     bit 0     Any keystroke
> +     bit 1     Touchpad activity
> +     bit 2     Pointing stick
> +     bit 3     Any mouse
> +     bits 4-7  Reserved for future use
> +  cbRES3, byte1  Supported timeout unit bitmap
> +     bit 0     Seconds
> +     bit 1     Minutes
> +     bit 2     Hours
> +     bit 3     Days
> +     bits 4-7  Reserved for future use
> +  cbRES3, byte2  Number of keyboard light brightness levels
> +  cbRES4, byte0  Maximum acceptable seconds value (0 if seconds not supported).
> +  cbRES4, byte1  Maximum acceptable minutes value (0 if minutes not supported).
> +  cbRES4, byte2  Maximum acceptable hours value (0 if hours not supported).
> +  cbRES4, byte3  Maximum acceptable days value (0 if days not supported)
> +
> + cbArg1 0x1 = Get Current State
> +  cbRES1         Standard return codes (0, -1, -2)
> +  cbRES2, word0  Bitmap of current mode state
> +     bit 0     Always off (All systems)
> +     bit 1     Always on (Travis ATG, Siberia)
> +     bit 2     Auto: ALS-based On; ALS-based Off (Travis ATG)
> +     bit 3     Auto: ALS- and input-activity-based On; input-activity based Off
> +     bit 4     Auto: Input-activity-based On; input-activity based Off
> +     bit 5     Auto: Input-activity-based On (illumination level 25%); input-activity based Off
> +     bit 6     Auto: Input-activity-based On (illumination level 50%); input-activity based Off
> +     bit 7     Auto: Input-activity-based On (illumination level 75%); input-activity based Off
> +     bit 8     Auto: Input-activity-based On (illumination level 100%); input-activity based Off
> +     bits 9-15 Reserved for future use
> +     Note: Only One bit can be set
> +  cbRES2, byte2  Currently active auto keyboard illumination triggers.
> +     bit 0     Any keystroke
> +     bit 1     Touchpad activity
> +     bit 2     Pointing stick
> +     bit 3     Any mouse
> +     bits 4-7  Reserved for future use
> +  cbRES2, byte3  Current Timeout
> +     bits 7:6  Timeout units indicator:
> +     00b       Seconds
> +     01b       Minutes
> +     10b       Hours
> +     11b       Days
> +     bits 5:0  Timeout value (0-63) in sec/min/hr/day
> +     NOTE: A value of 0 means always on (no timeout) if any bits of RES3 byte
> +     are set upon return from the [Get feature information] call.
> +  cbRES3, byte0  Current setting of ALS value that turns the light on or off.
> +  cbRES3, byte1  Current ALS reading
> +  cbRES3, byte2  Current keyboard light level.
> +
> + cbArg1 0x2 = Set New State
> +  cbRES1         Standard return codes (0, -1, -2)
> +  cbArg2, word0  Bitmap of current mode state
> +     bit 0     Always off (All systems)
> +     bit 1     Always on (Travis ATG, Siberia)
> +     bit 2     Auto: ALS-based On; ALS-based Off (Travis ATG)
> +     bit 3     Auto: ALS- and input-activity-based On; input-activity based Off
> +     bit 4     Auto: Input-activity-based On; input-activity based Off
> +     bit 5     Auto: Input-activity-based On (illumination level 25%); input-activity based Off
> +     bit 6     Auto: Input-activity-based On (illumination level 50%); input-activity based Off
> +     bit 7     Auto: Input-activity-based On (illumination level 75%); input-activity based Off
> +     bit 8     Auto: Input-activity-based On (illumination level 100%); input-activity based Off
> +     bits 9-15 Reserved for future use
> +     Note: Only One bit can be set
> +  cbArg2, byte2  Desired auto keyboard illumination triggers. Must remain inactive to allow
> +                 keyboard to turn off automatically.
> +     bit 0     Any keystroke
> +     bit 1     Touchpad activity
> +     bit 2     Pointing stick
> +     bit 3     Any mouse
> +     bits 4-7  Reserved for future use
> +  cbArg2, byte3  Desired Timeout
> +     bits 7:6  Timeout units indicator:
> +     00b       Seconds
> +     01b       Minutes
> +     10b       Hours
> +     11b       Days
> +     bits 5:0  Timeout value (0-63) in sec/min/hr/day
> +  cbArg3, byte0  Desired setting of ALS value that turns the light on or off.
> +  cbArg3, byte2  Desired keyboard light level.
> +*/
> +
> +
> +enum kbd_timeout_unit {
> +	KBD_TIMEOUT_SECONDS = 0,
> +	KBD_TIMEOUT_MINUTES,
> +	KBD_TIMEOUT_HOURS,
> +	KBD_TIMEOUT_DAYS,
> +};
> +
> +enum kbd_mode_bit {
> +	KBD_MODE_BIT_OFF = 0,
> +	KBD_MODE_BIT_ON,
> +	KBD_MODE_BIT_ALS,
> +	KBD_MODE_BIT_TRIGGER_ALS,
> +	KBD_MODE_BIT_TRIGGER,
> +	KBD_MODE_BIT_TRIGGER_25,
> +	KBD_MODE_BIT_TRIGGER_50,
> +	KBD_MODE_BIT_TRIGGER_75,
> +	KBD_MODE_BIT_TRIGGER_100,
> +};
> +
> +#define kbd_is_als_mode_bit(bit) \
> +	((bit) == KBD_MODE_BIT_ALS || (bit) == KBD_MODE_BIT_TRIGGER_ALS)
> +#define kbd_is_trigger_mode_bit(bit) \
> +	((bit) >= KBD_MODE_BIT_TRIGGER_ALS && (bit) <= KBD_MODE_BIT_TRIGGER_100)
> +#define kbd_is_level_mode_bit(bit) \
> +	((bit) >= KBD_MODE_BIT_TRIGGER_25 && (bit) <= KBD_MODE_BIT_TRIGGER_100)
> +
> +struct kbd_info {
> +	u16 modes;
> +	u8 type;
> +	u8 triggers;
> +	u8 levels;
> +	u8 seconds;
> +	u8 minutes;
> +	u8 hours;
> +	u8 days;
> +};
> +
> +struct kbd_state {
> +	u8 mode_bit;
> +	u8 triggers;
> +	u8 timeout_value;
> +	u8 timeout_unit;
> +	u8 als_setting;
> +	u8 als_value;
> +	u8 level;
> +};
> +
> +static const int kbd_tokens[] = {
> +	KBD_LED_OFF_TOKEN,
> +	KBD_LED_AUTO_25_TOKEN,
> +	KBD_LED_AUTO_50_TOKEN,
> +	KBD_LED_AUTO_75_TOKEN,
> +	KBD_LED_AUTO_100_TOKEN,
> +	KBD_LED_ON_TOKEN,
> +};
> +
> +static u16 kbd_token_bits;
> +
> +static struct kbd_info kbd_info;
> +static bool kbd_als_supported;
> +static bool kbd_triggers_supported;
> +
> +static u8 kbd_mode_levels[16];
> +static int kbd_mode_levels_count;
> +
> +static u8 kbd_previous_level;
> +static u8 kbd_previous_mode_bit;
> +
> +static bool kbd_led_present;
> +
> +static int kbd_get_info(struct kbd_info *info)
> +{
> +	u8 units;
> +	int ret;
> +
> +	get_buffer();
> +
> +	buffer->input[0] = 0x0;
> +	dell_send_request(buffer, 4, 11);
> +	ret = buffer->output[0];
> +
> +	if (ret == 0) {

Generally speaking, check for error to keep the main logic from getting
indented.

	if (buffer->output[0]) {
		ret = -EINVAL;
		goto out;
	}

> +		info->modes = buffer->output[1] & 0xFFFF;
> +		info->type = (buffer->output[1] >> 24) & 0xFF;
> +		info->triggers = buffer->output[2] & 0xFF;
> +		units = (buffer->output[2] >> 8) & 0xFF;
> +		info->levels = (buffer->output[2] >> 16) & 0xFF;
> +		if (units & BIT(0))
> +			info->seconds = (buffer->output[3] >> 0) & 0xFF;
> +		if (units & BIT(1))
> +			info->minutes = (buffer->output[3] >> 8) & 0xFF;
> +		if (units & BIT(2))
> +			info->hours = (buffer->output[3] >> 16) & 0xFF;
> +		if (units & BIT(3))
> +			info->days = (buffer->output[3] >> 24) & 0xFF;
> +	}
> +

 out:

> +	release_buffer();
> +
> +	if (ret)
> +		return -EINVAL;

Drop this.

> +	return 0;

return ret;

In this particular case, it might be shorter by a line or two to drop the ret
variable and simply release_buffer() and return -EINVAL in the error check above
and just return 0 here.

> +}
> +
> +static unsigned int kbd_get_max_level(void)
> +{
> +	if (kbd_info.levels != 0)
> +		return kbd_info.levels;

This test.... does nothing? if it is 0, you still return 0 below :-)

> +	if (kbd_mode_levels_count > 0)
> +		return kbd_mode_levels_count - 1;
> +	return 0;

So the function is:

return kbd_mode_levels_count > 0 ? kbd_mode_levels_count - 1 : kbd_info.levels;

The if blocks are more legible, so that's fine, but the first one doesn't seem
to do anything and you can replace the final return with return kbd_info.levels.

> +}
> +
> +static int kbd_get_level(struct kbd_state *state)
> +{
> +	int i;
> +
> +	if (kbd_info.levels != 0)
> +		return state->level;
> +
> +	if (kbd_mode_levels_count > 0) {

The if test is redundant, the for loop will simply run 0 iterations in this
case.

> +		for (i = 0; i < kbd_mode_levels_count; ++i)
> +			if (kbd_mode_levels[i] == state->mode_bit)
> +				return i;
> +		return 0;
> +	}
> +
> +	return -EINVAL;

Ah, so you're testing for an invalid kbd_mode_levels_count? Is that possible?
Should that perhaps be an unsigned integer, then we only have to worry about 0.
Can we test for that at driver init? How do we get to here with a bad
kbd_mode_levels_count?

> +}
> +
> +static int kbd_set_level(struct kbd_state *state, u8 level)
> +{
> +	if (kbd_info.levels != 0) {

Again, generally speaking, test for errors and indent those, rather than the
core logic.

> +		if (level != 0)
> +			kbd_previous_level = level;
> +		if (state->level == level)
> +			return 0;
> +		state->level = level;
> +		if (level != 0 && state->mode_bit == KBD_MODE_BIT_OFF)
> +			state->mode_bit = kbd_previous_mode_bit;
> +		else if (level == 0 && state->mode_bit != KBD_MODE_BIT_OFF) {
> +			kbd_previous_mode_bit = state->mode_bit;
> +			state->mode_bit = KBD_MODE_BIT_OFF;
> +		}
> +		return 0;
> +	}
> +
> +	if (kbd_mode_levels_count > 0 && level < kbd_mode_levels_count) {
> +		if (level != 0)
> +			kbd_previous_level = level;
> +		state->mode_bit = kbd_mode_levels[level];
> +		return 0;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int kbd_get_state(struct kbd_state *state)
> +{
> +	int ret;
> +
> +	get_buffer();
> +
> +	buffer->input[0] = 0x1;
> +	dell_send_request(buffer, 4, 11);
> +	ret = buffer->output[0];
> +
> +	if (ret == 0) {
> +		state->mode_bit = ffs(buffer->output[1] & 0xFFFF);
> +		if (state->mode_bit != 0)
> +			state->mode_bit--;
> +		state->triggers = (buffer->output[1] >> 16) & 0xFF;
> +		state->timeout_value = (buffer->output[1] >> 24) & 0x3F;
> +		state->timeout_unit = (buffer->output[1] >> 30) & 0x3;
> +		state->als_setting = buffer->output[2] & 0xFF;
> +		state->als_value = (buffer->output[2] >> 8) & 0xFF;
> +		state->level = (buffer->output[2] >> 16) & 0xFF;
> +	}
> +
> +	release_buffer();
> +
> +	if (ret)
> +		return -EINVAL;
> +
> +	return 0;

Same comment about error checking approach and indentation.

> +}
> +
> +static int kbd_set_state(struct kbd_state *state)
> +{
> +	int ret;
> +
> +	get_buffer();
> +	buffer->input[0] = 0x2;
> +	buffer->input[1] = BIT(state->mode_bit) & 0xFFFF;
> +	buffer->input[1] |= (state->triggers & 0xFF) << 16;
> +	buffer->input[1] |= (state->timeout_value & 0x3F) << 24;
> +	buffer->input[1] |= (state->timeout_unit & 0x3) << 30;
> +	buffer->input[2] = state->als_setting & 0xFF;
> +	buffer->input[2] |= (state->level & 0xFF) << 16;
> +	dell_send_request(buffer, 4, 11);
> +	ret = buffer->output[0];
> +	release_buffer();
> +
> +	if (ret)
> +		return -EINVAL;

Also, is EINVAL right here and elsewhere? Or did something fail? EXIO?

> +
> +	return 0;
> +}
> +
> +static int kbd_set_state_safe(struct kbd_state *state, struct kbd_state *old)
> +{
> +	int ret;
> +
> +	ret = kbd_set_state(state);
> +	if (ret == 0)
> +		return 0;
> +
> +	if (kbd_set_state(old))
> +		pr_err("Setting old previous keyboard state failed\n");

And if we got an error and kbd_set_state(old) doesn't return !0, what's the
state of things? Still a failure a presume?

> +
> +	return ret;
> +}
> +
> +static int kbd_set_token_bit(u8 bit)
> +{
> +	int id;
> +	int ret;
> +
> +	if (bit >= ARRAY_SIZE(kbd_tokens))
> +		return -EINVAL;
> +
> +	id = find_token_id(kbd_tokens[bit]);
> +	if (id == -1)
> +		return -EINVAL;
> +
> +	get_buffer();
> +	buffer->input[0] = da_tokens[id].location;
> +	buffer->input[1] = da_tokens[id].value;
> +	dell_send_request(buffer, 1, 0);
> +	ret = buffer->output[0];
> +	release_buffer();
> +
> +	if (ret)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int kbd_get_token_bit(u8 bit)
> +{
> +	int id;
> +	int ret;
> +	int val;
> +
> +	if (bit >= ARRAY_SIZE(kbd_tokens))
> +		return -EINVAL;
> +
> +	id = find_token_id(kbd_tokens[bit]);
> +	if (id == -1)
> +		return -EINVAL;
> +
> +	get_buffer();
> +	buffer->input[0] = da_tokens[id].location;
> +	dell_send_request(buffer, 0, 0);
> +	ret = buffer->output[0];
> +	val = buffer->output[1];
> +	release_buffer();
> +
> +	if (ret)
> +		return -EINVAL;
> +
> +	return (val == da_tokens[id].value);
> +}
> +
> +static int kbd_get_first_active_token_bit(void)
> +{
> +	int i;
> +	int ret;
> +
> +	for (i = 0; i < ARRAY_SIZE(kbd_tokens); ++i) {
> +		ret = kbd_get_token_bit(i);
> +		if (ret == 1)
> +			return i;
> +	}
> +
> +	return ret;
> +}
> +
> +static int kbd_get_valid_token_counts(void)
> +{
> +	return hweight16(kbd_token_bits);
> +}
> +
> +static void kbd_init(void)
> +{
> +	struct kbd_state state;
> +	int ret;
> +	int i;
> +
> +	ret = kbd_get_info(&kbd_info);
> +
> +	if (ret == 0) {
> +

Checking for success, let's invert and avoid the indentation here too.

> +		kbd_get_state(&state);
> +
> +		/* NOTE: timeout value is stored in 6 bits so max value is 63 */
> +		if (kbd_info.seconds > 63)
> +			kbd_info.seconds = 63;
> +		if (kbd_info.minutes > 63)
> +			kbd_info.minutes = 63;
> +		if (kbd_info.hours > 63)
> +			kbd_info.hours = 63;
> +		if (kbd_info.days > 63)
> +			kbd_info.days = 63;
> +
> +		/* NOTE: On tested machines ON mode did not work and caused
> +		 *       problems (turned backlight off) so do not use it
> +		 */
> +		kbd_info.modes &= ~BIT(KBD_MODE_BIT_ON);
> +
> +		kbd_previous_level = kbd_get_level(&state);
> +		kbd_previous_mode_bit = state.mode_bit;
> +
> +		if (kbd_previous_level == 0) {
> +			if (kbd_get_max_level() != 0)
> +				kbd_previous_level = 1;
> +		}
> +
> +		if (kbd_previous_mode_bit == KBD_MODE_BIT_OFF) {
> +			kbd_previous_mode_bit =
> +				ffs(kbd_info.modes & ~BIT(KBD_MODE_BIT_OFF));
> +			if (kbd_previous_mode_bit != 0)
> +				kbd_previous_mode_bit--;
> +		}
> +
> +		if (kbd_info.modes & (BIT(KBD_MODE_BIT_ALS) |
> +				      BIT(KBD_MODE_BIT_TRIGGER_ALS)))
> +			kbd_als_supported = true;
> +
> +		if (kbd_info.modes & (
> +		    BIT(KBD_MODE_BIT_TRIGGER_ALS) | BIT(KBD_MODE_BIT_TRIGGER) |
> +		    BIT(KBD_MODE_BIT_TRIGGER_25) | BIT(KBD_MODE_BIT_TRIGGER_50) |
> +		    BIT(KBD_MODE_BIT_TRIGGER_75) | BIT(KBD_MODE_BIT_TRIGGER_100)
> +		   ))
> +			kbd_triggers_supported = true;
> +
> +		for (i = 0; i < 16; ++i)
> +			if (kbd_is_level_mode_bit(i) &&
> +			    (BIT(i) & kbd_info.modes))
> +				kbd_mode_levels[1+kbd_mode_levels_count++] = i;
> +
> +		if (kbd_mode_levels_count > 0) {
> +			for (i = 0; i < 16; ++i) {
> +				if (BIT(i) & kbd_info.modes) {
> +					kbd_mode_levels[0] = i;
> +					break;
> +				}
> +			}
> +			kbd_mode_levels_count++;
> +		}
> +
> +	}
> +
> +	for (i = 0; i < ARRAY_SIZE(kbd_tokens); ++i)
> +		if (find_token_id(kbd_tokens[i]) != -1)
> +			kbd_token_bits |= BIT(i);
> +
> +	if (kbd_token_bits != 0 || ret == 0)
> +		kbd_led_present = true;
> +}
> +
> +static ssize_t kbd_led_timeout_store(struct device *dev,
> +				     struct device_attribute *attr,
> +				     const char *buf, size_t count)
> +{
> +	struct kbd_state state;
> +	struct kbd_state new_state;
> +	int ret;
> +	bool convert;
> +	char ch;
> +	u8 unit;
> +	int value;
> +	int i;

Decreasing line lenth please.

> +
> +	ret = sscanf(buf, "%d %c", &value, &ch);
> +	if (ret < 1)
> +		return -EINVAL;
> +	else if (ret == 1)
> +		ch = 's';
> +
> +	if (value < 0)
> +		return -EINVAL;
> +
> +	convert = false;
> +
> +	switch (ch) {
> +	case 's':
> +		if (value > kbd_info.seconds)
> +			convert = true;
> +		unit = KBD_TIMEOUT_SECONDS;
> +		break;
> +	case 'm':
> +		if (value > kbd_info.minutes)
> +			convert = true;
> +		unit = KBD_TIMEOUT_MINUTES;
> +		break;
> +	case 'h':
> +		if (value > kbd_info.hours)
> +			convert = true;
> +		unit = KBD_TIMEOUT_HOURS;
> +		break;
> +	case 'd':
> +		if (value > kbd_info.days)
> +			convert = true;
> +		unit = KBD_TIMEOUT_DAYS;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	if (quirks && quirks->kbd_timeouts)
> +		convert = true;
> +
> +	if (convert) {
> +		/* NOTE: this switch fall down */

"fall down" ? As in, it intentionally doesn't have breaks?

> +		switch (unit) {
> +		case KBD_TIMEOUT_DAYS:
> +			value *= 24;
> +		case KBD_TIMEOUT_HOURS:
> +			value *= 60;
> +		case KBD_TIMEOUT_MINUTES:
> +			value *= 60;
> +			unit = KBD_TIMEOUT_SECONDS;
> +	 	}
> +
> +		if (quirks && quirks->kbd_timeouts) {
> +			for (i = 0; quirks->kbd_timeouts[i] != -1; i++) {
> +				if (value <= quirks->kbd_timeouts[i]) {
> +					value = quirks->kbd_timeouts[i];
> +					break;
> +				}
> +			}
> +		}
> +
> +		if (value <= kbd_info.seconds && kbd_info.seconds) {
> +			unit = KBD_TIMEOUT_SECONDS;
> +		} else if (value/60 <= kbd_info.minutes && kbd_info.minutes) {

One space around operators like / and * please, applies throughout.

> +			value /= 60;
> +			unit = KBD_TIMEOUT_MINUTES;
> +		} else if (value/(60*60) <= kbd_info.hours && kbd_info.hours) {
> +			value /= (60*60);
> +			unit = KBD_TIMEOUT_HOURS;
> +		} else if (value/(60*60*24) <= kbd_info.days && kbd_info.days) {
> +			value /= (60*60*24);
> +			unit = KBD_TIMEOUT_DAYS;
> +		} else {
> +			return -EINVAL;
> +		}
> +	}
> +
> +	ret = kbd_get_state(&state);
> +	if (ret)
> +		return ret;
> +
> +	new_state = state;
> +	new_state.timeout_value = value;
> +	new_state.timeout_unit = unit;
> +
> +	ret = kbd_set_state_safe(&new_state, &state);
> +	if (ret)
> +		return ret;
> +
> +	return count;
> +}
> +
> +static ssize_t kbd_led_timeout_show(struct device *dev,
> +				    struct device_attribute *attr, char *buf)
> +{
> +	struct kbd_state state;
> +	int ret;
> +	int len;
> +
> +	ret = kbd_get_state(&state);
> +	if (ret)
> +		return ret;
> +
> +	len = sprintf(buf, "%d", state.timeout_value);
> +
> +	switch (state.timeout_unit) {
> +	case KBD_TIMEOUT_SECONDS:
> +		return len + sprintf(buf+len, "s\n");
> +	case KBD_TIMEOUT_MINUTES:
> +		return len + sprintf(buf+len, "m\n");
> +	case KBD_TIMEOUT_HOURS:
> +		return len + sprintf(buf+len, "h\n");
> +	case KBD_TIMEOUT_DAYS:
> +		return len + sprintf(buf+len, "d\n");
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return len;
> +}
> +
> +static DEVICE_ATTR(stop_timeout, S_IRUGO | S_IWUSR,
> +		   kbd_led_timeout_show, kbd_led_timeout_store);
> +
> +static const char * const kbd_led_triggers[] = {
> +	"keyboard",
> +	"touchpad",
> +	/*"trackstick"*/ NULL, /* NOTE: trackstick is just alias for touchpad */
> +	"mouse",
> +};
> +
> +static ssize_t kbd_led_triggers_store(struct device *dev,
> +				      struct device_attribute *attr,
> +				      const char *buf, size_t count)
> +{
> +	struct kbd_state state;
> +	struct kbd_state new_state;
> +	char trigger[21];
> +	bool als_enabled;
> +	bool triggers_enabled;
> +	bool enable_als;
> +	bool disable_als;
> +	int trigger_bit;
> +	int i;
> +	int ret;
> +
> +	ret = sscanf(buf, "%20s", trigger);
> +	if (ret != 1)
> +		return -EINVAL;
> +
> +	if (trigger[0] != '+' && trigger[0] != '-')
> +		return -EINVAL;
> +
> +	ret = kbd_get_state(&state);
> +	if (ret)
> +		return ret;
> +
> +	if (kbd_als_supported)
> +		als_enabled = kbd_is_als_mode_bit(state.mode_bit);
> +	else
> +		als_enabled = false;
> +
> +	if (kbd_triggers_supported)
> +		triggers_enabled = kbd_is_trigger_mode_bit(state.mode_bit);
> +	else
> +		triggers_enabled = false;

Could skip the else blocks with initial assignments.

> +
> +	enable_als = false;
> +	disable_als = false;

Can skip these too.

> +
> +	if (kbd_als_supported) {
> +		if (strcmp(trigger, "+als") == 0) {
> +			if (als_enabled)
> +				return count;
> +			enable_als = true;
> +		} else if (strcmp(trigger, "-als") == 0) {
> +			if (!als_enabled)
> +				return count;
> +			disable_als = true;
> +		}
> +	}
> +
> +	if (enable_als || disable_als) {
> +		new_state = state;
> +		if (enable_als) {
> +			if (triggers_enabled)
> +				new_state.mode_bit = KBD_MODE_BIT_TRIGGER_ALS;
> +			else
> +				new_state.mode_bit = KBD_MODE_BIT_ALS;
> +		} else {
> +			if (triggers_enabled) {
> +				new_state.mode_bit = KBD_MODE_BIT_TRIGGER;
> +				kbd_set_level(&new_state, kbd_previous_level);
> +			} else
> +				new_state.mode_bit = KBD_MODE_BIT_ON;

if one block needs braces, use them throughout.
Apply throughout.

> +		}
> +		if (!(kbd_info.modes & BIT(new_state.mode_bit)))
> +			return -EINVAL;
> +		ret = kbd_set_state_safe(&new_state, &state);
> +		if (ret)
> +			return ret;
> +		kbd_previous_mode_bit = new_state.mode_bit;
> +		return count;
> +	}
> +
> +	trigger_bit = -1;
> +
> +	if (kbd_triggers_supported) {
> +		for (i = 0; i < ARRAY_SIZE(kbd_led_triggers); ++i) {
> +			if (!(kbd_info.triggers & BIT(i)))
> +				continue;
> +			if (!kbd_led_triggers[i])
> +				continue;
> +			if (strcmp(trigger+1, kbd_led_triggers[i]) != 0)
> +				continue;
> +			if (trigger[0] == '+' &&
> +			    triggers_enabled && (state.triggers & BIT(i)))
> +				return count;
> +			if (trigger[0] == '-' &&
> +			    (!triggers_enabled || !(state.triggers & BIT(i))))
> +				return count;
> +			trigger_bit = i;
> +			break;
> +		}
> +	}
> +
> +	if (trigger_bit != -1) {
> +		new_state = state;
> +		if (trigger[0] == '+')
> +			new_state.triggers |= BIT(trigger_bit);
> +		else {
> +			new_state.triggers &= ~BIT(trigger_bit);
> +			/* NOTE: trackstick bit (2) must be disabled when
> +			 *       disabling touchpad bit (1), otherwise touchpad
> +			 *       bit (1) will not be disabled */
> +			if (trigger_bit == 1)
> +				new_state.triggers &= ~BIT(2);
> +		}
> +		if ((kbd_info.triggers & new_state.triggers) !=
> +		    new_state.triggers)
> +			return -EINVAL;
> +		if (new_state.triggers && !triggers_enabled) {
> +			if (als_enabled)
> +				new_state.mode_bit = KBD_MODE_BIT_TRIGGER_ALS;
> +			else {
> +				new_state.mode_bit = KBD_MODE_BIT_TRIGGER;
> +				kbd_set_level(&new_state, kbd_previous_level);
> +			}
> +		} else if (new_state.triggers == 0) {
> +			if (als_enabled)
> +				new_state.mode_bit = KBD_MODE_BIT_ALS;
> +			else
> +				kbd_set_level(&new_state, 0);
> +		}
> +		if (!(kbd_info.modes & BIT(new_state.mode_bit)))
> +			return -EINVAL;
> +		ret = kbd_set_state_safe(&new_state, &state);
> +		if (ret)
> +			return ret;
> +		if (new_state.mode_bit != KBD_MODE_BIT_OFF)
> +			kbd_previous_mode_bit = new_state.mode_bit;
> +		return count;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static ssize_t kbd_led_triggers_show(struct device *dev,
> +				     struct device_attribute *attr, char *buf)
> +{
> +	struct kbd_state state;
> +	bool triggers_enabled;
> +	int level;
> +	int i;
> +	int ret;
> +	int len;
> +
> +	ret = kbd_get_state(&state);
> +	if (ret)
> +		return ret;
> +
> +	len = 0;
> +
> +	if (kbd_triggers_supported) {
> +		triggers_enabled = kbd_is_trigger_mode_bit(state.mode_bit);
> +		level = kbd_get_level(&state);
> +		for (i = 0; i < ARRAY_SIZE(kbd_led_triggers); ++i) {
> +			if (!(kbd_info.triggers & BIT(i)))
> +				continue;
> +			if (!kbd_led_triggers[i])
> +				continue;
> +			if ((triggers_enabled || level <= 0) &&
> +			    (state.triggers & BIT(i)))
> +				buf[len++] = '+';
> +			else
> +				buf[len++] = '-';
> +			len += sprintf(buf+len, "%s ", kbd_led_triggers[i]);
> +		}
> +	}
> +
> +	if (kbd_als_supported) {
> +		if (kbd_is_als_mode_bit(state.mode_bit))
> +			len += sprintf(buf+len, "+als ");
> +		else
> +			len += sprintf(buf+len, "-als ");
> +	}
> +
> +	if (len)
> +		buf[len - 1] = '\n';
> +
> +	return len;
> +}
> +
> +static DEVICE_ATTR(start_triggers, S_IRUGO | S_IWUSR,
> +		   kbd_led_triggers_show, kbd_led_triggers_store);
> +
> +static ssize_t kbd_led_als_store(struct device *dev,
> +				 struct device_attribute *attr,
> +				 const char *buf, size_t count)
> +{
> +	struct kbd_state state;
> +	struct kbd_state new_state;
> +	u8 setting;
> +	int ret;
> +
> +	ret = kstrtou8(buf, 10, &setting);
> +	if (ret)
> +		return ret;
> +
> +	ret = kbd_get_state(&state);
> +	if (ret)
> +		return ret;
> +
> +	new_state = state;
> +	new_state.als_setting = setting;
> +
> +	ret = kbd_set_state_safe(&new_state, &state);
> +	if (ret)
> +		return ret;
> +
> +	return count;
> +}
> +
> +static ssize_t kbd_led_als_show(struct device *dev,
> +				struct device_attribute *attr, char *buf)
> +{
> +	struct kbd_state state;
> +	int ret;
> +
> +	ret = kbd_get_state(&state);
> +	if (ret)
> +		return ret;
> +
> +	return sprintf(buf, "%d\n", state.als_setting);
> +}
> +
> +static DEVICE_ATTR(als_setting, S_IRUGO | S_IWUSR,
> +		   kbd_led_als_show, kbd_led_als_store);
> +
> +static struct attribute *kbd_led_attrs[] = {
> +	&dev_attr_stop_timeout.attr,
> +	&dev_attr_start_triggers.attr,
> +	&dev_attr_als_setting.attr,
> +	NULL,
> +};
> +ATTRIBUTE_GROUPS(kbd_led);
> +
> +static enum led_brightness kbd_led_level_get(struct led_classdev *led_cdev)
> +{
> +	int ret;
> +	u16 num;
> +	struct kbd_state state;
> +
> +	if (kbd_get_max_level()) {
> +		ret = kbd_get_state(&state);
> +		if (ret)
> +			return 0;
> +		ret = kbd_get_level(&state);
> +		if (ret < 0)
> +			return 0;
> +		return ret;
> +	} else if (kbd_get_valid_token_counts()) {
> +		ret = kbd_get_first_active_token_bit();
> +		if (ret < 0)
> +			return 0;
> +		for (num = kbd_token_bits; num != 0 && ret > 0; --ret)
> +			num &= num - 1; /* clear the first bit set */
> +		if (num == 0)
> +			return 0;
> +		return ffs(num) - 1;
> +	} else {
> +		pr_warn("Keyboard brightness level control not supported\n");
> +		return 0;
> +	}

You can drop the else blocks from the above as every case returns explicitly.

if (condA)
	return retA;
if (condB)
	return retB
return ret

(checkpatch.pl catches this)

> +}
> +
> +static void kbd_led_level_set(struct led_classdev *led_cdev,
> +			      enum led_brightness value)
> +{
> +	struct kbd_state state;
> +	struct kbd_state new_state;
> +	u16 num;
> +
> +	if (kbd_get_max_level()) {
> +		if (kbd_get_state(&state))
> +			return;
> +		new_state = state;
> +		if (kbd_set_level(&new_state, value))
> +			return;
> +		kbd_set_state_safe(&new_state, &state);
> +	} else if (kbd_get_valid_token_counts()) {
> +		for (num = kbd_token_bits; num != 0 && value > 0; --value)
> +			num &= num - 1; /* clear the first bit set */
> +		if (num == 0)
> +			return;
> +		kbd_set_token_bit(ffs(num) - 1);
> +	} else {
> +		pr_warn("Keyboard brightness level control not supported\n");
> +	}
> +}
> +
> +static struct led_classdev kbd_led = {
> +	.name           = "dell::kbd_backlight",
> +	.brightness_set = kbd_led_level_set,
> +	.brightness_get = kbd_led_level_get,
> +	.groups         = kbd_led_groups,
> +};
> +
> +static int __init kbd_led_init(struct device *dev)
> +{
> +	kbd_init();
> +	if (!kbd_led_present)
> +		return -ENODEV;
> +	kbd_led.max_brightness = kbd_get_max_level();
> +	if (!kbd_led.max_brightness) {
> +		kbd_led.max_brightness = kbd_get_valid_token_counts();
> +		if (kbd_led.max_brightness)
> +			kbd_led.max_brightness--;
> +	}
> +	return led_classdev_register(dev, &kbd_led);
> +}
> +
> +static void brightness_set_exit(struct led_classdev *led_cdev,
> +				enum led_brightness value)
> +{
> +	/* Don't change backlight level on exit */
> +};
> +
> +static void kbd_led_exit(void)
> +{
> +	if (!kbd_led_present)
> +		return;
> +	kbd_led.brightness_set = brightness_set_exit;
> +	led_classdev_unregister(&kbd_led);
> +}
> +
>  static int __init dell_init(void)
>  {
>  	int max_intensity = 0;
> @@ -842,6 +1830,8 @@ static int __init dell_init(void)
>  	if (quirks && quirks->touchpad_led)
>  		touchpad_led_init(&platform_device->dev);
>  
> +	kbd_led_init(&platform_device->dev);
> +
>  	dell_laptop_dir = debugfs_create_dir("dell_laptop", NULL);
>  	if (dell_laptop_dir != NULL)
>  		debugfs_create_file("rfkill", 0444, dell_laptop_dir, NULL,
> @@ -909,6 +1899,7 @@ static void __exit dell_exit(void)
>  	debugfs_remove_recursive(dell_laptop_dir);
>  	if (quirks && quirks->touchpad_led)
>  		touchpad_led_exit();
> +	kbd_led_exit();
>  	i8042_remove_filter(dell_laptop_i8042_filter);
>  	cancel_delayed_work_sync(&dell_rfkill_work);
>  	backlight_device_unregister(dell_backlight_device);
> @@ -925,5 +1916,7 @@ module_init(dell_init);
>  module_exit(dell_exit);
>  
>  MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
> +MODULE_AUTHOR("Gabriele Mazzotta <gabriele.mzt@gmail.com>");
> +MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
>  MODULE_DESCRIPTION("Dell laptop driver");
>  MODULE_LICENSE("GPL");
> -- 
> 1.7.9.5
> 
> 

-- 
Darren Hart
Intel Open Source Technology Center

[PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

[Pali Rohár]

This patch adds support for configuring keyboard backlight settings on supported
Dell laptops. It exports kernel leds interface and uses Dell SMBIOS tokens or
keyboard class interface.

With this patch it is possible to set:
* keyboard backlight level
* timeout after which will be backlight automatically turned off
* input activity triggers (keyboard, touchpad, mouse) which enable backlight
* ambient light settings

Settings are exported via sysfs:
/sys/class/leds/dell::kbd_backlight/

Code is based on newly released documentation by Dell in libsmbios project.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
---
 drivers/platform/x86/dell-laptop.c | 1001 +++++++++++++++++++++++++++++++++++-
 1 file changed, 997 insertions(+), 4 deletions(-)

diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c
index 233d2ee..bf5b1cc 100644
--- a/drivers/platform/x86/dell-laptop.c
+++ b/drivers/platform/x86/dell-laptop.c
@@ -2,9 +2,11 @@
  *  Driver for Dell laptop extras
  *
  *  Copyright (c) Red Hat <mjg@redhat.com>
+ *  Copyright (c) 2014 Gabriele Mazzotta <gabriele.mzt@gmail.com>
+ *  Copyright (c) 2014 Pali Rohár <pali.rohar@gmail.com>
  *
- *  Based on documentation in the libsmbios package, Copyright (C) 2005 Dell
- *  Inc.
+ *  Based on documentation in the libsmbios package:
+ *  Copyright (C) 2005-2014 Dell Inc.
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License version 2 as
@@ -32,6 +34,13 @@
 #include "../../firmware/dcdbas.h"
 
 #define BRIGHTNESS_TOKEN 0x7d
+#define KBD_LED_OFF_TOKEN 0x01E1
+#define KBD_LED_ON_TOKEN 0x01E2
+#define KBD_LED_AUTO_TOKEN 0x01E3
+#define KBD_LED_AUTO_25_TOKEN 0x02EA
+#define KBD_LED_AUTO_50_TOKEN 0x02EB
+#define KBD_LED_AUTO_75_TOKEN 0x02EC
+#define KBD_LED_AUTO_100_TOKEN 0x02F6
 
 /* This structure will be modified by the firmware when we enter
  * system management mode, hence the volatiles */
@@ -62,6 +71,10 @@ struct calling_interface_structure {
 
 struct quirk_entry {
 	u8 touchpad_led;
+
+	/* Ordered list of timeouts expressed in seconds.
+	 * The list must end with -1 */
+	int kbd_timeouts[];
 };
 
 static struct quirk_entry *quirks;
@@ -76,6 +89,10 @@ static int __init dmi_matched(const struct dmi_system_id *dmi)
 	return 1;
 }
 
+static struct quirk_entry quirk_dell_xps13_9333 = {
+	.kbd_timeouts = { 0, 5, 15, 60, 5*60, 15*60, -1 },
+};
+
 static int da_command_address;
 static int da_command_code;
 static int da_num_tokens;
@@ -268,6 +285,15 @@ static const struct dmi_system_id dell_quirks[] __initconst = {
 		},
 		.driver_data = &quirk_dell_vostro_v130,
 	},
+	{
+		.callback = dmi_matched,
+		.ident = "Dell XPS13 9333",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "XPS13 9333"),
+		},
+		.driver_data = &quirk_dell_xps13_9333,
+	},
 	{ }
 };
 
@@ -332,17 +358,29 @@ static void __init find_tokens(const struct dmi_header *dm, void *dummy)
 	}
 }
 
-static int find_token_location(int tokenid)
+static int find_token_id(int tokenid)
 {
 	int i;
+
 	for (i = 0; i < da_num_tokens; i++) {
 		if (da_tokens[i].tokenID == tokenid)
-			return da_tokens[i].location;
+			return i;
 	}
 
 	return -1;
 }
 
+static int find_token_location(int tokenid)
+{
+	int id;
+
+	id = find_token_id(tokenid);
+	if (id == -1)
+		return -1;
+
+	return da_tokens[id].location;
+}
+
 static struct calling_interface_buffer *
 dell_send_request(struct calling_interface_buffer *buffer, int class,
 		  int select)
@@ -790,6 +828,956 @@ static void touchpad_led_exit(void)
 	led_classdev_unregister(&touchpad_led);
 }
 
+/* Derived from information in smbios-keyboard-ctl:
+
+ cbClass 4
+ cbSelect 11
+ Keyboar illumination
+ cbArg1 determines the function to be performed
+
+ cbArg1 0x0 = Get Feature Information
+  cbRES1         Standard return codes (0, -1, -2)
+  cbRES2, word0  Bitmap of user-selectable modes
+     bit 0     Always off (All systems)
+     bit 1     Always on (Travis ATG, Siberia)
+     bit 2     Auto: ALS-based On; ALS-based Off (Travis ATG)
+     bit 3     Auto: ALS- and input-activity-based On; input-activity based Off
+     bit 4     Auto: Input-activity-based On; input-activity based Off
+     bit 5     Auto: Input-activity-based On (illumination level 25%); input-activity based Off
+     bit 6     Auto: Input-activity-based On (illumination level 50%); input-activity based Off
+     bit 7     Auto: Input-activity-based On (illumination level 75%); input-activity based Off
+     bit 8     Auto: Input-activity-based On (illumination level 100%); input-activity based Off
+     bits 9-15 Reserved for future use
+  cbRES2, byte2  Reserved for future use
+  cbRES2, byte3  Keyboard illumination type
+     0         Reserved
+     1         Tasklight
+     2         Backlight
+     3-255     Reserved for future use
+  cbRES3, byte0  Supported auto keyboard illumination trigger bitmap.
+     bit 0     Any keystroke
+     bit 1     Touchpad activity
+     bit 2     Pointing stick
+     bit 3     Any mouse
+     bits 4-7  Reserved for future use
+  cbRES3, byte1  Supported timeout unit bitmap
+     bit 0     Seconds
+     bit 1     Minutes
+     bit 2     Hours
+     bit 3     Days
+     bits 4-7  Reserved for future use
+  cbRES3, byte2  Number of keyboard light brightness levels
+  cbRES4, byte0  Maximum acceptable seconds value (0 if seconds not supported).
+  cbRES4, byte1  Maximum acceptable minutes value (0 if minutes not supported).
+  cbRES4, byte2  Maximum acceptable hours value (0 if hours not supported).
+  cbRES4, byte3  Maximum acceptable days value (0 if days not supported)
+
+ cbArg1 0x1 = Get Current State
+  cbRES1         Standard return codes (0, -1, -2)
+  cbRES2, word0  Bitmap of current mode state
+     bit 0     Always off (All systems)
+     bit 1     Always on (Travis ATG, Siberia)
+     bit 2     Auto: ALS-based On; ALS-based Off (Travis ATG)
+     bit 3     Auto: ALS- and input-activity-based On; input-activity based Off
+     bit 4     Auto: Input-activity-based On; input-activity based Off
+     bit 5     Auto: Input-activity-based On (illumination level 25%); input-activity based Off
+     bit 6     Auto: Input-activity-based On (illumination level 50%); input-activity based Off
+     bit 7     Auto: Input-activity-based On (illumination level 75%); input-activity based Off
+     bit 8     Auto: Input-activity-based On (illumination level 100%); input-activity based Off
+     bits 9-15 Reserved for future use
+     Note: Only One bit can be set
+  cbRES2, byte2  Currently active auto keyboard illumination triggers.
+     bit 0     Any keystroke
+     bit 1     Touchpad activity
+     bit 2     Pointing stick
+     bit 3     Any mouse
+     bits 4-7  Reserved for future use
+  cbRES2, byte3  Current Timeout
+     bits 7:6  Timeout units indicator:
+     00b       Seconds
+     01b       Minutes
+     10b       Hours
+     11b       Days
+     bits 5:0  Timeout value (0-63) in sec/min/hr/day
+     NOTE: A value of 0 means always on (no timeout) if any bits of RES3 byte
+     are set upon return from the [Get feature information] call.
+  cbRES3, byte0  Current setting of ALS value that turns the light on or off.
+  cbRES3, byte1  Current ALS reading
+  cbRES3, byte2  Current keyboard light level.
+
+ cbArg1 0x2 = Set New State
+  cbRES1         Standard return codes (0, -1, -2)
+  cbArg2, word0  Bitmap of current mode state
+     bit 0     Always off (All systems)
+     bit 1     Always on (Travis ATG, Siberia)
+     bit 2     Auto: ALS-based On; ALS-based Off (Travis ATG)
+     bit 3     Auto: ALS- and input-activity-based On; input-activity based Off
+     bit 4     Auto: Input-activity-based On; input-activity based Off
+     bit 5     Auto: Input-activity-based On (illumination level 25%); input-activity based Off
+     bit 6     Auto: Input-activity-based On (illumination level 50%); input-activity based Off
+     bit 7     Auto: Input-activity-based On (illumination level 75%); input-activity based Off
+     bit 8     Auto: Input-activity-based On (illumination level 100%); input-activity based Off
+     bits 9-15 Reserved for future use
+     Note: Only One bit can be set
+  cbArg2, byte2  Desired auto keyboard illumination triggers. Must remain inactive to allow
+                 keyboard to turn off automatically.
+     bit 0     Any keystroke
+     bit 1     Touchpad activity
+     bit 2     Pointing stick
+     bit 3     Any mouse
+     bits 4-7  Reserved for future use
+  cbArg2, byte3  Desired Timeout
+     bits 7:6  Timeout units indicator:
+     00b       Seconds
+     01b       Minutes
+     10b       Hours
+     11b       Days
+     bits 5:0  Timeout value (0-63) in sec/min/hr/day
+  cbArg3, byte0  Desired setting of ALS value that turns the light on or off.
+  cbArg3, byte2  Desired keyboard light level.
+*/
+
+
+enum kbd_timeout_unit {
+	KBD_TIMEOUT_SECONDS = 0,
+	KBD_TIMEOUT_MINUTES,
+	KBD_TIMEOUT_HOURS,
+	KBD_TIMEOUT_DAYS,
+};
+
+enum kbd_mode_bit {
+	KBD_MODE_BIT_OFF = 0,
+	KBD_MODE_BIT_ON,
+	KBD_MODE_BIT_ALS,
+	KBD_MODE_BIT_TRIGGER_ALS,
+	KBD_MODE_BIT_TRIGGER,
+	KBD_MODE_BIT_TRIGGER_25,
+	KBD_MODE_BIT_TRIGGER_50,
+	KBD_MODE_BIT_TRIGGER_75,
+	KBD_MODE_BIT_TRIGGER_100,
+};
+
+#define kbd_is_als_mode_bit(bit) \
+	((bit) == KBD_MODE_BIT_ALS || (bit) == KBD_MODE_BIT_TRIGGER_ALS)
+#define kbd_is_trigger_mode_bit(bit) \
+	((bit) >= KBD_MODE_BIT_TRIGGER_ALS && (bit) <= KBD_MODE_BIT_TRIGGER_100)
+#define kbd_is_level_mode_bit(bit) \
+	((bit) >= KBD_MODE_BIT_TRIGGER_25 && (bit) <= KBD_MODE_BIT_TRIGGER_100)
+
+struct kbd_info {
+	u16 modes;
+	u8 type;
+	u8 triggers;
+	u8 levels;
+	u8 seconds;
+	u8 minutes;
+	u8 hours;
+	u8 days;
+};
+
+struct kbd_state {
+	u8 mode_bit;
+	u8 triggers;
+	u8 timeout_value;
+	u8 timeout_unit;
+	u8 als_setting;
+	u8 als_value;
+	u8 level;
+};
+
+static const int kbd_tokens[] = {
+	KBD_LED_OFF_TOKEN,
+	KBD_LED_AUTO_25_TOKEN,
+	KBD_LED_AUTO_50_TOKEN,
+	KBD_LED_AUTO_75_TOKEN,
+	KBD_LED_AUTO_100_TOKEN,
+	KBD_LED_ON_TOKEN,
+};
+
+static u16 kbd_token_bits;
+
+static struct kbd_info kbd_info;
+static bool kbd_als_supported;
+static bool kbd_triggers_supported;
+
+static u8 kbd_mode_levels[16];
+static int kbd_mode_levels_count;
+
+static u8 kbd_previous_level;
+static u8 kbd_previous_mode_bit;
+
+static bool kbd_led_present;
+
+static int kbd_get_info(struct kbd_info *info)
+{
+	u8 units;
+	int ret;
+
+	get_buffer();
+
+	buffer->input[0] = 0x0;
+	dell_send_request(buffer, 4, 11);
+	ret = buffer->output[0];
+
+	if (ret == 0) {
+		info->modes = buffer->output[1] & 0xFFFF;
+		info->type = (buffer->output[1] >> 24) & 0xFF;
+		info->triggers = buffer->output[2] & 0xFF;
+		units = (buffer->output[2] >> 8) & 0xFF;
+		info->levels = (buffer->output[2] >> 16) & 0xFF;
+		if (units & BIT(0))
+			info->seconds = (buffer->output[3] >> 0) & 0xFF;
+		if (units & BIT(1))
+			info->minutes = (buffer->output[3] >> 8) & 0xFF;
+		if (units & BIT(2))
+			info->hours = (buffer->output[3] >> 16) & 0xFF;
+		if (units & BIT(3))
+			info->days = (buffer->output[3] >> 24) & 0xFF;
+	}
+
+	release_buffer();
+
+	if (ret)
+		return -EINVAL;
+
+	return 0;
+}
+
+static unsigned int kbd_get_max_level(void)
+{
+	if (kbd_info.levels != 0)
+		return kbd_info.levels;
+	if (kbd_mode_levels_count > 0)
+		return kbd_mode_levels_count - 1;
+	return 0;
+}
+
+static int kbd_get_level(struct kbd_state *state)
+{
+	int i;
+
+	if (kbd_info.levels != 0)
+		return state->level;
+
+	if (kbd_mode_levels_count > 0) {
+		for (i = 0; i < kbd_mode_levels_count; ++i)
+			if (kbd_mode_levels[i] == state->mode_bit)
+				return i;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int kbd_set_level(struct kbd_state *state, u8 level)
+{
+	if (kbd_info.levels != 0) {
+		if (level != 0)
+			kbd_previous_level = level;
+		if (state->level == level)
+			return 0;
+		state->level = level;
+		if (level != 0 && state->mode_bit == KBD_MODE_BIT_OFF)
+			state->mode_bit = kbd_previous_mode_bit;
+		else if (level == 0 && state->mode_bit != KBD_MODE_BIT_OFF) {
+			kbd_previous_mode_bit = state->mode_bit;
+			state->mode_bit = KBD_MODE_BIT_OFF;
+		}
+		return 0;
+	}
+
+	if (kbd_mode_levels_count > 0 && level < kbd_mode_levels_count) {
+		if (level != 0)
+			kbd_previous_level = level;
+		state->mode_bit = kbd_mode_levels[level];
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int kbd_get_state(struct kbd_state *state)
+{
+	int ret;
+
+	get_buffer();
+
+	buffer->input[0] = 0x1;
+	dell_send_request(buffer, 4, 11);
+	ret = buffer->output[0];
+
+	if (ret == 0) {
+		state->mode_bit = ffs(buffer->output[1] & 0xFFFF);
+		if (state->mode_bit != 0)
+			state->mode_bit--;
+		state->triggers = (buffer->output[1] >> 16) & 0xFF;
+		state->timeout_value = (buffer->output[1] >> 24) & 0x3F;
+		state->timeout_unit = (buffer->output[1] >> 30) & 0x3;
+		state->als_setting = buffer->output[2] & 0xFF;
+		state->als_value = (buffer->output[2] >> 8) & 0xFF;
+		state->level = (buffer->output[2] >> 16) & 0xFF;
+	}
+
+	release_buffer();
+
+	if (ret)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int kbd_set_state(struct kbd_state *state)
+{
+	int ret;
+
+	get_buffer();
+	buffer->input[0] = 0x2;
+	buffer->input[1] = BIT(state->mode_bit) & 0xFFFF;
+	buffer->input[1] |= (state->triggers & 0xFF) << 16;
+	buffer->input[1] |= (state->timeout_value & 0x3F) << 24;
+	buffer->input[1] |= (state->timeout_unit & 0x3) << 30;
+	buffer->input[2] = state->als_setting & 0xFF;
+	buffer->input[2] |= (state->level & 0xFF) << 16;
+	dell_send_request(buffer, 4, 11);
+	ret = buffer->output[0];
+	release_buffer();
+
+	if (ret)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int kbd_set_state_safe(struct kbd_state *state, struct kbd_state *old)
+{
+	int ret;
+
+	ret = kbd_set_state(state);
+	if (ret == 0)
+		return 0;
+
+	if (kbd_set_state(old))
+		pr_err("Setting old previous keyboard state failed\n");
+
+	return ret;
+}
+
+static int kbd_set_token_bit(u8 bit)
+{
+	int id;
+	int ret;
+
+	if (bit >= ARRAY_SIZE(kbd_tokens))
+		return -EINVAL;
+
+	id = find_token_id(kbd_tokens[bit]);
+	if (id == -1)
+		return -EINVAL;
+
+	get_buffer();
+	buffer->input[0] = da_tokens[id].location;
+	buffer->input[1] = da_tokens[id].value;
+	dell_send_request(buffer, 1, 0);
+	ret = buffer->output[0];
+	release_buffer();
+
+	if (ret)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int kbd_get_token_bit(u8 bit)
+{
+	int id;
+	int ret;
+	int val;
+
+	if (bit >= ARRAY_SIZE(kbd_tokens))
+		return -EINVAL;
+
+	id = find_token_id(kbd_tokens[bit]);
+	if (id == -1)
+		return -EINVAL;
+
+	get_buffer();
+	buffer->input[0] = da_tokens[id].location;
+	dell_send_request(buffer, 0, 0);
+	ret = buffer->output[0];
+	val = buffer->output[1];
+	release_buffer();
+
+	if (ret)
+		return -EINVAL;
+
+	return (val == da_tokens[id].value);
+}
+
+static int kbd_get_first_active_token_bit(void)
+{
+	int i;
+	int ret;
+
+	for (i = 0; i < ARRAY_SIZE(kbd_tokens); ++i) {
+		ret = kbd_get_token_bit(i);
+		if (ret == 1)
+			return i;
+	}
+
+	return ret;
+}
+
+static int kbd_get_valid_token_counts(void)
+{
+	return hweight16(kbd_token_bits);
+}
+
+static void kbd_init(void)
+{
+	struct kbd_state state;
+	int ret;
+	int i;
+
+	ret = kbd_get_info(&kbd_info);
+
+	if (ret == 0) {
+
+		kbd_get_state(&state);
+
+		/* NOTE: timeout value is stored in 6 bits so max value is 63 */
+		if (kbd_info.seconds > 63)
+			kbd_info.seconds = 63;
+		if (kbd_info.minutes > 63)
+			kbd_info.minutes = 63;
+		if (kbd_info.hours > 63)
+			kbd_info.hours = 63;
+		if (kbd_info.days > 63)
+			kbd_info.days = 63;
+
+		/* NOTE: On tested machines ON mode did not work and caused
+		 *       problems (turned backlight off) so do not use it
+		 */
+		kbd_info.modes &= ~BIT(KBD_MODE_BIT_ON);
+
+		kbd_previous_level = kbd_get_level(&state);
+		kbd_previous_mode_bit = state.mode_bit;
+
+		if (kbd_previous_level == 0) {
+			if (kbd_get_max_level() != 0)
+				kbd_previous_level = 1;
+		}
+
+		if (kbd_previous_mode_bit == KBD_MODE_BIT_OFF) {
+			kbd_previous_mode_bit =
+				ffs(kbd_info.modes & ~BIT(KBD_MODE_BIT_OFF));
+			if (kbd_previous_mode_bit != 0)
+				kbd_previous_mode_bit--;
+		}
+
+		if (kbd_info.modes & (BIT(KBD_MODE_BIT_ALS) |
+				      BIT(KBD_MODE_BIT_TRIGGER_ALS)))
+			kbd_als_supported = true;
+
+		if (kbd_info.modes & (
+		    BIT(KBD_MODE_BIT_TRIGGER_ALS) | BIT(KBD_MODE_BIT_TRIGGER) |
+		    BIT(KBD_MODE_BIT_TRIGGER_25) | BIT(KBD_MODE_BIT_TRIGGER_50) |
+		    BIT(KBD_MODE_BIT_TRIGGER_75) | BIT(KBD_MODE_BIT_TRIGGER_100)
+		   ))
+			kbd_triggers_supported = true;
+
+		for (i = 0; i < 16; ++i)
+			if (kbd_is_level_mode_bit(i) &&
+			    (BIT(i) & kbd_info.modes))
+				kbd_mode_levels[1+kbd_mode_levels_count++] = i;
+
+		if (kbd_mode_levels_count > 0) {
+			for (i = 0; i < 16; ++i) {
+				if (BIT(i) & kbd_info.modes) {
+					kbd_mode_levels[0] = i;
+					break;
+				}
+			}
+			kbd_mode_levels_count++;
+		}
+
+	}
+
+	for (i = 0; i < ARRAY_SIZE(kbd_tokens); ++i)
+		if (find_token_id(kbd_tokens[i]) != -1)
+			kbd_token_bits |= BIT(i);
+
+	if (kbd_token_bits != 0 || ret == 0)
+		kbd_led_present = true;
+}
+
+static ssize_t kbd_led_timeout_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	struct kbd_state state;
+	struct kbd_state new_state;
+	int ret;
+	bool convert;
+	char ch;
+	u8 unit;
+	int value;
+	int i;
+
+	ret = sscanf(buf, "%d %c", &value, &ch);
+	if (ret < 1)
+		return -EINVAL;
+	else if (ret == 1)
+		ch = 's';
+
+	if (value < 0)
+		return -EINVAL;
+
+	convert = false;
+
+	switch (ch) {
+	case 's':
+		if (value > kbd_info.seconds)
+			convert = true;
+		unit = KBD_TIMEOUT_SECONDS;
+		break;
+	case 'm':
+		if (value > kbd_info.minutes)
+			convert = true;
+		unit = KBD_TIMEOUT_MINUTES;
+		break;
+	case 'h':
+		if (value > kbd_info.hours)
+			convert = true;
+		unit = KBD_TIMEOUT_HOURS;
+		break;
+	case 'd':
+		if (value > kbd_info.days)
+			convert = true;
+		unit = KBD_TIMEOUT_DAYS;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (quirks && quirks->kbd_timeouts)
+		convert = true;
+
+	if (convert) {
+		/* NOTE: this switch fall down */
+		switch (unit) {
+		case KBD_TIMEOUT_DAYS:
+			value *= 24;
+		case KBD_TIMEOUT_HOURS:
+			value *= 60;
+		case KBD_TIMEOUT_MINUTES:
+			value *= 60;
+			unit = KBD_TIMEOUT_SECONDS;
+		}
+
+		if (quirks && quirks->kbd_timeouts) {
+			for (i = 0; quirks->kbd_timeouts[i] != -1; i++) {
+				if (value <= quirks->kbd_timeouts[i]) {
+					value = quirks->kbd_timeouts[i];
+					break;
+				}
+			}
+		}
+
+		if (value <= kbd_info.seconds && kbd_info.seconds) {
+			unit = KBD_TIMEOUT_SECONDS;
+		} else if (value/60 <= kbd_info.minutes && kbd_info.minutes) {
+			value /= 60;
+			unit = KBD_TIMEOUT_MINUTES;
+		} else if (value/(60*60) <= kbd_info.hours && kbd_info.hours) {
+			value /= (60*60);
+			unit = KBD_TIMEOUT_HOURS;
+		} else if (value/(60*60*24) <= kbd_info.days && kbd_info.days) {
+			value /= (60*60*24);
+			unit = KBD_TIMEOUT_DAYS;
+		} else {
+			return -EINVAL;
+		}
+	}
+
+	ret = kbd_get_state(&state);
+	if (ret)
+		return ret;
+
+	new_state = state;
+	new_state.timeout_value = value;
+	new_state.timeout_unit = unit;
+
+	ret = kbd_set_state_safe(&new_state, &state);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static ssize_t kbd_led_timeout_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct kbd_state state;
+	int ret;
+	int len;
+
+	ret = kbd_get_state(&state);
+	if (ret)
+		return ret;
+
+	len = sprintf(buf, "%d", state.timeout_value);
+
+	switch (state.timeout_unit) {
+	case KBD_TIMEOUT_SECONDS:
+		return len + sprintf(buf+len, "s\n");
+	case KBD_TIMEOUT_MINUTES:
+		return len + sprintf(buf+len, "m\n");
+	case KBD_TIMEOUT_HOURS:
+		return len + sprintf(buf+len, "h\n");
+	case KBD_TIMEOUT_DAYS:
+		return len + sprintf(buf+len, "d\n");
+	default:
+		return -EINVAL;
+	}
+
+	return len;
+}
+
+static DEVICE_ATTR(stop_timeout, S_IRUGO | S_IWUSR,
+		   kbd_led_timeout_show, kbd_led_timeout_store);
+
+static const char * const kbd_led_triggers[] = {
+	"keyboard",
+	"touchpad",
+	/*"trackstick"*/ NULL, /* NOTE: trackstick is just alias for touchpad */
+	"mouse",
+};
+
+static ssize_t kbd_led_triggers_store(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t count)
+{
+	struct kbd_state state;
+	struct kbd_state new_state;
+	char trigger[21];
+	bool als_enabled;
+	bool triggers_enabled;
+	bool enable_als;
+	bool disable_als;
+	int trigger_bit;
+	int i;
+	int ret;
+
+	ret = sscanf(buf, "%20s", trigger);
+	if (ret != 1)
+		return -EINVAL;
+
+	if (trigger[0] != '+' && trigger[0] != '-')
+		return -EINVAL;
+
+	ret = kbd_get_state(&state);
+	if (ret)
+		return ret;
+
+	if (kbd_als_supported)
+		als_enabled = kbd_is_als_mode_bit(state.mode_bit);
+	else
+		als_enabled = false;
+
+	if (kbd_triggers_supported)
+		triggers_enabled = kbd_is_trigger_mode_bit(state.mode_bit);
+	else
+		triggers_enabled = false;
+
+	enable_als = false;
+	disable_als = false;
+
+	if (kbd_als_supported) {
+		if (strcmp(trigger, "+als") == 0) {
+			if (als_enabled)
+				return count;
+			enable_als = true;
+		} else if (strcmp(trigger, "-als") == 0) {
+			if (!als_enabled)
+				return count;
+			disable_als = true;
+		}
+	}
+
+	if (enable_als || disable_als) {
+		new_state = state;
+		if (enable_als) {
+			if (triggers_enabled)
+				new_state.mode_bit = KBD_MODE_BIT_TRIGGER_ALS;
+			else
+				new_state.mode_bit = KBD_MODE_BIT_ALS;
+		} else {
+			if (triggers_enabled) {
+				new_state.mode_bit = KBD_MODE_BIT_TRIGGER;
+				kbd_set_level(&new_state, kbd_previous_level);
+			} else
+				new_state.mode_bit = KBD_MODE_BIT_ON;
+		}
+		if (!(kbd_info.modes & BIT(new_state.mode_bit)))
+			return -EINVAL;
+		ret = kbd_set_state_safe(&new_state, &state);
+		if (ret)
+			return ret;
+		kbd_previous_mode_bit = new_state.mode_bit;
+		return count;
+	}
+
+	trigger_bit = -1;
+
+	if (kbd_triggers_supported) {
+		for (i = 0; i < ARRAY_SIZE(kbd_led_triggers); ++i) {
+			if (!(kbd_info.triggers & BIT(i)))
+				continue;
+			if (!kbd_led_triggers[i])
+				continue;
+			if (strcmp(trigger+1, kbd_led_triggers[i]) != 0)
+				continue;
+			if (trigger[0] == '+' &&
+			    triggers_enabled && (state.triggers & BIT(i)))
+				return count;
+			if (trigger[0] == '-' &&
+			    (!triggers_enabled || !(state.triggers & BIT(i))))
+				return count;
+			trigger_bit = i;
+			break;
+		}
+	}
+
+	if (trigger_bit != -1) {
+		new_state = state;
+		if (trigger[0] == '+')
+			new_state.triggers |= BIT(trigger_bit);
+		else {
+			new_state.triggers &= ~BIT(trigger_bit);
+			/* NOTE: trackstick bit (2) must be disabled when
+			 *       disabling touchpad bit (1), otherwise touchpad
+			 *       bit (1) will not be disabled */
+			if (trigger_bit == 1)
+				new_state.triggers &= ~BIT(2);
+		}
+		if ((kbd_info.triggers & new_state.triggers) !=
+		    new_state.triggers)
+			return -EINVAL;
+		if (new_state.triggers && !triggers_enabled) {
+			if (als_enabled)
+				new_state.mode_bit = KBD_MODE_BIT_TRIGGER_ALS;
+			else {
+				new_state.mode_bit = KBD_MODE_BIT_TRIGGER;
+				kbd_set_level(&new_state, kbd_previous_level);
+			}
+		} else if (new_state.triggers == 0) {
+			if (als_enabled)
+				new_state.mode_bit = KBD_MODE_BIT_ALS;
+			else
+				kbd_set_level(&new_state, 0);
+		}
+		if (!(kbd_info.modes & BIT(new_state.mode_bit)))
+			return -EINVAL;
+		ret = kbd_set_state_safe(&new_state, &state);
+		if (ret)
+			return ret;
+		if (new_state.mode_bit != KBD_MODE_BIT_OFF)
+			kbd_previous_mode_bit = new_state.mode_bit;
+		return count;
+	}
+
+	return -EINVAL;
+}
+
+static ssize_t kbd_led_triggers_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct kbd_state state;
+	bool triggers_enabled;
+	int level;
+	int i;
+	int ret;
+	int len;
+
+	ret = kbd_get_state(&state);
+	if (ret)
+		return ret;
+
+	len = 0;
+
+	if (kbd_triggers_supported) {
+		triggers_enabled = kbd_is_trigger_mode_bit(state.mode_bit);
+		level = kbd_get_level(&state);
+		for (i = 0; i < ARRAY_SIZE(kbd_led_triggers); ++i) {
+			if (!(kbd_info.triggers & BIT(i)))
+				continue;
+			if (!kbd_led_triggers[i])
+				continue;
+			if ((triggers_enabled || level <= 0) &&
+			    (state.triggers & BIT(i)))
+				buf[len++] = '+';
+			else
+				buf[len++] = '-';
+			len += sprintf(buf+len, "%s ", kbd_led_triggers[i]);
+		}
+	}
+
+	if (kbd_als_supported) {
+		if (kbd_is_als_mode_bit(state.mode_bit))
+			len += sprintf(buf+len, "+als ");
+		else
+			len += sprintf(buf+len, "-als ");
+	}
+
+	if (len)
+		buf[len - 1] = '\n';
+
+	return len;
+}
+
+static DEVICE_ATTR(start_triggers, S_IRUGO | S_IWUSR,
+		   kbd_led_triggers_show, kbd_led_triggers_store);
+
+static ssize_t kbd_led_als_store(struct device *dev,
+				 struct device_attribute *attr,
+				 const char *buf, size_t count)
+{
+	struct kbd_state state;
+	struct kbd_state new_state;
+	u8 setting;
+	int ret;
+
+	ret = kstrtou8(buf, 10, &setting);
+	if (ret)
+		return ret;
+
+	ret = kbd_get_state(&state);
+	if (ret)
+		return ret;
+
+	new_state = state;
+	new_state.als_setting = setting;
+
+	ret = kbd_set_state_safe(&new_state, &state);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static ssize_t kbd_led_als_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct kbd_state state;
+	int ret;
+
+	ret = kbd_get_state(&state);
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%d\n", state.als_setting);
+}
+
+static DEVICE_ATTR(als_setting, S_IRUGO | S_IWUSR,
+		   kbd_led_als_show, kbd_led_als_store);
+
+static struct attribute *kbd_led_attrs[] = {
+	&dev_attr_stop_timeout.attr,
+	&dev_attr_start_triggers.attr,
+	&dev_attr_als_setting.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(kbd_led);
+
+static enum led_brightness kbd_led_level_get(struct led_classdev *led_cdev)
+{
+	int ret;
+	u16 num;
+	struct kbd_state state;
+
+	if (kbd_get_max_level()) {
+		ret = kbd_get_state(&state);
+		if (ret)
+			return 0;
+		ret = kbd_get_level(&state);
+		if (ret < 0)
+			return 0;
+		return ret;
+	} else if (kbd_get_valid_token_counts()) {
+		ret = kbd_get_first_active_token_bit();
+		if (ret < 0)
+			return 0;
+		for (num = kbd_token_bits; num != 0 && ret > 0; --ret)
+			num &= num - 1; /* clear the first bit set */
+		if (num == 0)
+			return 0;
+		return ffs(num) - 1;
+	} else {
+		pr_warn("Keyboard brightness level control not supported\n");
+		return 0;
+	}
+}
+
+static void kbd_led_level_set(struct led_classdev *led_cdev,
+			      enum led_brightness value)
+{
+	struct kbd_state state;
+	struct kbd_state new_state;
+	u16 num;
+
+	if (kbd_get_max_level()) {
+		if (kbd_get_state(&state))
+			return;
+		new_state = state;
+		if (kbd_set_level(&new_state, value))
+			return;
+		kbd_set_state_safe(&new_state, &state);
+	} else if (kbd_get_valid_token_counts()) {
+		for (num = kbd_token_bits; num != 0 && value > 0; --value)
+			num &= num - 1; /* clear the first bit set */
+		if (num == 0)
+			return;
+		kbd_set_token_bit(ffs(num) - 1);
+	} else {
+		pr_warn("Keyboard brightness level control not supported\n");
+	}
+}
+
+static struct led_classdev kbd_led = {
+	.name           = "dell::kbd_backlight",
+	.brightness_set = kbd_led_level_set,
+	.brightness_get = kbd_led_level_get,
+	.groups         = kbd_led_groups,
+};
+
+static int __init kbd_led_init(struct device *dev)
+{
+	kbd_init();
+	if (!kbd_led_present)
+		return -ENODEV;
+	kbd_led.max_brightness = kbd_get_max_level();
+	if (!kbd_led.max_brightness) {
+		kbd_led.max_brightness = kbd_get_valid_token_counts();
+		if (kbd_led.max_brightness)
+			kbd_led.max_brightness--;
+	}
+	return led_classdev_register(dev, &kbd_led);
+}
+
+static void brightness_set_exit(struct led_classdev *led_cdev,
+				enum led_brightness value)
+{
+	/* Don't change backlight level on exit */
+};
+
+static void kbd_led_exit(void)
+{
+	if (!kbd_led_present)
+		return;
+	kbd_led.brightness_set = brightness_set_exit;
+	led_classdev_unregister(&kbd_led);
+}
+
 static int __init dell_init(void)
 {
 	int max_intensity = 0;
@@ -842,6 +1830,8 @@ static int __init dell_init(void)
 	if (quirks && quirks->touchpad_led)
 		touchpad_led_init(&platform_device->dev);
 
+	kbd_led_init(&platform_device->dev);
+
 	dell_laptop_dir = debugfs_create_dir("dell_laptop", NULL);
 	if (dell_laptop_dir != NULL)
 		debugfs_create_file("rfkill", 0444, dell_laptop_dir, NULL,
@@ -909,6 +1899,7 @@ static void __exit dell_exit(void)
 	debugfs_remove_recursive(dell_laptop_dir);
 	if (quirks && quirks->touchpad_led)
 		touchpad_led_exit();
+	kbd_led_exit();
 	i8042_remove_filter(dell_laptop_i8042_filter);
 	cancel_delayed_work_sync(&dell_rfkill_work);
 	backlight_device_unregister(dell_backlight_device);
@@ -925,5 +1916,7 @@ module_init(dell_init);
 module_exit(dell_exit);
 
 MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
+MODULE_AUTHOR("Gabriele Mazzotta <gabriele.mzt@gmail.com>");
+MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
 MODULE_DESCRIPTION("Dell laptop driver");
 MODULE_LICENSE("GPL");
-- 
1.7.9.5