[PATCH 2/3] leds-clevo-mail: hw accelerated LED blink extension

[PATCH 2/3] leds-clevo-mail: hw accelerated LED blink extension

[Németh Márton]

From: Márton Németh <nm127@freemail.hu>

Extends the leds subsystem with a blink_set() callback function which can
be optionally implemented by a LED driver. If implemented, the driver can use
the hardware acceleration for blinking a LED.

Signed-off-by: Márton Németh <nm127@freemail.hu>
---
diff -uprN linux-2.6.23.orig/Documentation/leds-class.txt linux-2.6.23/Documentation/leds-class.txt
--- linux-2.6.23.orig/Documentation/leds-class.txt	2007-10-09 22:31:38.000000000 +0200
+++ linux-2.6.23/Documentation/leds-class.txt	2007-10-18 06:57:37.000000000 +0200
@@ -47,6 +47,18 @@ overhead, I suggest these become part of
 above leaves scope for further attributes should they be needed.


+Hardware accelerated blink of LEDs
+==================================
+
+Some LEDs can be programmed to blink without any CPU interaction. To
+support this feature, a LED driver can optionally implement the
+blink_set() function (see <linux/leds.h>). If implemeted, the
+ledtrig-timer tries to use it. The blink_set() function should return
+0 if the blink setting is supported, or -EINVAL otherwise, which means
+that the LED will be turned on and off from software by the leds
+subsystem.
+
+
 Known Issues
 ============

@@ -55,10 +67,6 @@ would cause nightmare dependency issues.
 compared to the benefits the simple trigger functionality brings. The
 rest of the LED subsystem can be modular.

-Some leds can be programmed to flash in hardware. As this isn't a generic
-LED device property, this should be exported as a device specific sysfs
-attribute rather than part of the class if this functionality is required.
-

 Future Development
 ==================
diff -uprN linux-2.6.23.orig/drivers/leds/ledtrig-timer.c linux-2.6.23/drivers/leds/ledtrig-timer.c
--- linux-2.6.23.orig/drivers/leds/ledtrig-timer.c	2007-10-09 22:31:38.000000000 +0200
+++ linux-2.6.23/drivers/leds/ledtrig-timer.c	2007-10-18 07:15:14.000000000 +0200
@@ -77,8 +77,21 @@ static ssize_t led_delay_on_store(struct
 		count++;

 	if (count == size) {
-		timer_data->delay_on = state;
-		mod_timer(&timer_data->timer, jiffies + 1);
+		if (timer_data->delay_on != state) {
+			/* the new value differs from the previous */
+			timer_data->delay_on = state;
+
+			/* deactivate previous settings */
+			del_timer_sync(&timer_data->timer);
+
+			/* try to activate hardware acceleration, if any */
+			if (!led_cdev->blink_set ||
+			    led_cdev->blink_set(led_cdev,
+				timer_data->delay_on, timer_data->delay_off)) {
+				/* no hardware acceleration, blink via timer */
+				mod_timer(&timer_data->timer, jiffies + 1);
+			}
+		}
 		ret = count;
 	}

@@ -110,8 +123,21 @@ static ssize_t led_delay_off_store(struc
 		count++;

 	if (count == size) {
-		timer_data->delay_off = state;
-		mod_timer(&timer_data->timer, jiffies + 1);
+		if (timer_data->delay_off != state) {
+			/* the new value differs from the previous */
+			timer_data->delay_off = state;
+
+			/* deactivate previous settings */
+			del_timer_sync(&timer_data->timer);
+
+			/* try to activate hardware acceleration, if any */
+			if (!led_cdev->blink_set ||
+			    led_cdev->blink_set(led_cdev,
+				timer_data->delay_on, timer_data->delay_off)) {
+				/* no hardware acceleration, blink via timer */
+				mod_timer(&timer_data->timer, jiffies + 1);
+			}
+		}
 		ret = count;
 	}

diff -uprN linux-2.6.23.orig/include/linux/leds.h linux-2.6.23/include/linux/leds.h
--- linux-2.6.23.orig/include/linux/leds.h	2007-10-09 22:31:38.000000000 +0200
+++ linux-2.6.23/include/linux/leds.h	2007-10-18 07:17:30.000000000 +0200
@@ -37,6 +37,10 @@ struct led_classdev {
 	void		(*brightness_set)(struct led_classdev *led_cdev,
 					  enum led_brightness brightness);

+	/* Activate hardware accelerated blink */
+	int		(*blink_set)(struct led_classdev *led_cdev,
+				     int delay_on, int delay_off);
+
 	struct device		*dev;
 	struct list_head	 node;			/* LED Device list */
 	char			*default_trigger;	/* Trigger to use */

Re: [PATCH 2/3] leds-clevo-mail: hw accelerated LED blink extension

[Németh Márton]

From: Márton Németh <nm127@freemail.hu>

Extends the leds subsystem with a blink_set() callback function which can
be optionally implemented by a LED driver. If implemented, the driver can use
the hardware acceleration for blinking a LED.

Signed-off-by: Márton Németh <nm127@freemail.hu>
---
diff -uprN linux-2.6.23.orig/Documentation/leds-class.txt linux-2.6.23/Documentation/leds-class.txt
--- linux-2.6.23.orig/Documentation/leds-class.txt	2007-10-09 22:31:38.000000000 +0200
+++ linux-2.6.23/Documentation/leds-class.txt	2007-10-21 10:45:35.000000000 +0200
@@ -47,6 +49,19 @@ overhead, I suggest these become part of
 above leaves scope for further attributes should they be needed.


+
+Hardware accelerated blink of LEDs
+==================================
+
+Some LEDs can be programmed to blink without any CPU interaction. To
+support this feature, a LED driver can optionally implement the
+blink_set() function (see <linux/leds.h>). If implemeted, the
+ledtrig-timer tries to use it. The blink_set() function should return
+0 if the blink setting is supported, or -EINVAL otherwise, which means
+that the LED will be turned on and off from software by the leds
+subsystem.
+
+
 Known Issues
 ============

@@ -55,10 +70,6 @@ would cause nightmare dependency issues.
 compared to the benefits the simple trigger functionality brings. The
 rest of the LED subsystem can be modular.

-Some leds can be programmed to flash in hardware. As this isn't a generic
-LED device property, this should be exported as a device specific sysfs
-attribute rather than part of the class if this functionality is required.
-

 Future Development
 ==================
diff -uprN linux-2.6.23.orig/drivers/leds/Kconfig linux-2.6.23/drivers/leds/Kconfig
--- linux-2.6.23.orig/drivers/leds/Kconfig	2007-10-09 22:31:38.000000000 +0200
+++ linux-2.6.23/drivers/leds/Kconfig	2007-10-21 12:04:50.000000000 +0200
@@ -115,7 +148,11 @@ config LEDS_TRIGGER_TIMER
 	depends on LEDS_TRIGGERS
 	help
 	  This allows LEDs to be controlled by a programmable timer
-	  via sysfs. If unsure, say Y.
+	  via sysfs. Some LED hardware can be programmed to start
+	  blinking the LED without any further software interaction.
+	  For more details read Documentation/leds-class.txt.
+
+	  If unsure, say Y.

 config LEDS_TRIGGER_IDE_DISK
 	bool "LED IDE Disk Trigger"
diff -uprN linux-2.6.23.orig/drivers/leds/ledtrig-timer.c linux-2.6.23/drivers/leds/ledtrig-timer.c
--- linux-2.6.23.orig/drivers/leds/ledtrig-timer.c	2007-10-09 22:31:38.000000000 +0200
+++ linux-2.6.23/drivers/leds/ledtrig-timer.c	2007-10-18 18:21:34.000000000 +0200
@@ -77,8 +77,21 @@ static ssize_t led_delay_on_store(struct
 		count++;

 	if (count == size) {
-		timer_data->delay_on = state;
-		mod_timer(&timer_data->timer, jiffies + 1);
+		if (timer_data->delay_on != state) {
+			/* the new value differs from the previous */
+			timer_data->delay_on = state;
+
+			/* deactivate previous settings */
+			del_timer_sync(&timer_data->timer);
+
+			/* try to activate hardware acceleration, if any */
+			if (!led_cdev->blink_set ||
+			    led_cdev->blink_set(led_cdev,
+				timer_data->delay_on, timer_data->delay_off)) {
+				/* no hardware acceleration, blink via timer */
+				mod_timer(&timer_data->timer, jiffies + 1);
+			}
+		}
 		ret = count;
 	}

@@ -110,8 +123,21 @@ static ssize_t led_delay_off_store(struc
 		count++;

 	if (count == size) {
-		timer_data->delay_off = state;
-		mod_timer(&timer_data->timer, jiffies + 1);
+		if (timer_data->delay_off != state) {
+			/* the new value differs from the previous */
+			timer_data->delay_off = state;
+
+			/* deactivate previous settings */
+			del_timer_sync(&timer_data->timer);
+
+			/* try to activate hardware acceleration, if any */
+			if (!led_cdev->blink_set ||
+			    led_cdev->blink_set(led_cdev,
+				timer_data->delay_on, timer_data->delay_off)) {
+				/* no hardware acceleration, blink via timer */
+				mod_timer(&timer_data->timer, jiffies + 1);
+			}
+		}
 		ret = count;
 	}

diff -uprN linux-2.6.23.orig/include/linux/leds.h linux-2.6.23/include/linux/leds.h
--- linux-2.6.23.orig/include/linux/leds.h	2007-10-09 22:31:38.000000000 +0200
+++ linux-2.6.23/include/linux/leds.h	2007-10-18 18:21:34.000000000 +0200
@@ -37,6 +37,10 @@ struct led_classdev {
 	void		(*brightness_set)(struct led_classdev *led_cdev,
 					  enum led_brightness brightness);

+	/* Activate hardware accelerated blink */
+	int		(*blink_set)(struct led_classdev *led_cdev,
+				     int delay_on, int delay_off);
+
 	struct device		*dev;
 	struct list_head	 node;			/* LED Device list */
 	char			*default_trigger;	/* Trigger to use */

Re: [PATCH 2/3] leds-clevo-mail: hw accelerated LED blink extension

[Richard Purdie]

On Sun, 2007-10-21 at 14:54 +0200, Németh Márton wrote:
> From: Márton Németh <nm127@freemail.hu>
> 
> Extends the leds subsystem with a blink_set() callback function which can
> be optionally implemented by a LED driver. If implemented, the driver can use
> the hardware acceleration for blinking a LED.
> 
> Signed-off-by: Márton Németh <nm127@freemail.hu>
> ---
> diff -uprN linux-2.6.23.orig/Documentation/leds-class.txt linux-2.6.23/Documentation/leds-class.txt
> --- linux-2.6.23.orig/Documentation/leds-class.txt	2007-10-09 22:31:38.000000000 +0200
> +++ linux-2.6.23/Documentation/leds-class.txt	2007-10-21 10:45:35.000000000 +0200
> @@ -47,6 +49,19 @@ overhead, I suggest these become part of
>  above leaves scope for further attributes should they be needed.
> 
> 
> +
> +Hardware accelerated blink of LEDs
> +==================================
> +
> +Some LEDs can be programmed to blink without any CPU interaction. To
> +support this feature, a LED driver can optionally implement the
> +blink_set() function (see <linux/leds.h>). If implemeted, the
> +ledtrig-timer tries to use it. The blink_set() function should return
> +0 if the blink setting is supported, or -EINVAL otherwise, which means
> +that the LED will be turned on and off from software by the leds
> +subsystem.

Hardware acceleration of the timer triggers is great to see and worst
case I'll happily apply this patch to the LED tree, thanks.

Before I do, I did wonder if we should enhance the meaning of the
set_blink function a bit. If set_blink is called with delay_on = 0,
delay_off = 0 it could mean "blink with some user friendly value,
hardware assisted". The use for this would be a more generic blink
trigger where you wouldn't need to know about magically hardware
assisted values for blinking, it would simply make an LED blink in a
hardware assisted way.

We also need to document that the brightness_set overrides any blinking
which may or may not be active (which is implied in your driver).

Cheers,

Richard

Re: [PATCH 2/3] leds-clevo-mail: hw accelerated LED blink extension

[Németh Márton]

From: Márton Németh <nm127@freemail.hu>

Extends the leds subsystem with a blink_set() callback function which can
optionally implemented by a LED driver. If implemented, the driver can use the
hardware acceleration for blinking a LED.

Signed-off-by: Márton Németh <nm127@freemail.hu>
---
diff -uprN linux-2.6.22.orig/Documentation/leds-class.txt linux-2.6.22/Documentation/leds-class.txt
--- linux-2.6.22.orig/Documentation/leds-class.txt	2007-07-09 01:32:17.000000000 +0200
+++ linux-2.6.22/Documentation/leds-class.txt	2007-07-17 17:07:44.000000000 +0200
@@ -47,6 +47,17 @@ overhead, I suggest these become part of
  above leaves scope for further attributes should they be needed.


+Hardware accelerated blink of LEDs
+==================================
+
+Some LEDs can be programmed to blink without any CPU interaction. To
+support this feature, a LED driver can optionally implement the
+blink_set() function (see <linux/leds.h>). If implemeted, the
+ledtrig-timer tries to use it. The blink_set() function should return
+0 if the blink setting is supported, or -EINVAL otherwise, which means
+that the LED will be turned on and off from software.
+
+
  Known Issues
  ============

@@ -55,10 +66,6 @@ would cause nightmare dependency issues.
  compared to the benefits the simple trigger functionality brings. The
  rest of the LED subsystem can be modular.

-Some leds can be programmed to flash in hardware. As this isn't a generic
-LED device property, this should be exported as a device specific sysfs
-attribute rather than part of the class if this functionality is required.
-

  Future Development
  ==================
diff -uprN linux-2.6.22.orig/drivers/leds/ledtrig-timer.c linux-2.6.22/drivers/leds/ledtrig-timer.c
--- linux-2.6.22.orig/drivers/leds/ledtrig-timer.c	2007-07-09 01:32:17.000000000 +0200
+++ linux-2.6.22/drivers/leds/ledtrig-timer.c	2007-07-17 17:45:56.000000000 +0200
@@ -76,8 +76,21 @@ static ssize_t led_delay_on_store(struct
  		count++;

  	if (count == size) {
-		timer_data->delay_on = state;
-		mod_timer(&timer_data->timer, jiffies + 1);
+		if (timer_data->delay_on != state) {
+			/* the new value differs from the previous */
+			timer_data->delay_on = state;
+
+			/* deactivate previous settings */
+			del_timer_sync(&timer_data->timer);
+
+			/* try to activate hardware acceleration, if any */
+			if (!led_cdev->blink_set ||
+			    led_cdev->blink_set(led_cdev,
+				timer_data->delay_on, timer_data->delay_off)) {
+				/* no hardware acceleration, blink via timer */
+				mod_timer(&timer_data->timer, jiffies + 1);
+			}
+		}
  		ret = count;
  	}

@@ -108,8 +121,21 @@ static ssize_t led_delay_off_store(struc
  		count++;

  	if (count == size) {
-		timer_data->delay_off = state;
-		mod_timer(&timer_data->timer, jiffies + 1);
+		if (timer_data->delay_off != state) {
+			/* the new value differs from the previous */
+			timer_data->delay_off = state;
+
+			/* deactivate previous settings */
+			del_timer_sync(&timer_data->timer);
+
+			/* try to activate hardware acceleration, if any */
+			if (!led_cdev->blink_set ||
+			    led_cdev->blink_set(led_cdev,
+				timer_data->delay_on, timer_data->delay_off)) {
+				/* no hardware acceleration, blink via timer */
+				mod_timer(&timer_data->timer, jiffies + 1);
+			}
+		}
  		ret = count;
  	}

diff -uprN linux-2.6.22.orig/include/linux/leds.h linux-2.6.22/include/linux/leds.h
--- linux-2.6.22.orig/include/linux/leds.h	2007-07-09 01:32:17.000000000 +0200
+++ linux-2.6.22/include/linux/leds.h	2007-07-17 10:52:18.000000000 +0200
@@ -38,6 +38,11 @@ struct led_classdev {
  	void		(*brightness_set)(struct led_classdev *led_cdev,
  					  enum led_brightness brightness);

+	/* Activate hardware accelerated blink */
+	int		(*blink_set)(struct led_classdev *led_cdev,
+				     int delay_on, int delay_off);
+
+
  	struct class_device	*class_dev;
  	struct list_head	 node;			/* LED Device list */
  	char			*default_trigger;	/* Trigger to use */

Re: [PATCH 2/3] leds-clevo-mail: hw accelerated LED blink extension

[Dmitry Torokhov]

On 7/17/07, Németh Márton <nm127@freemail.hu> wrote:
>
> +Hardware accelerated blink of LEDs
> +==================================
> +
> +Some LEDs can be programmed to blink without any CPU interaction. To
> +support this feature, a LED driver can optionally implement the
> +blink_set() function (see <linux/leds.h>). If implemeted, the
> +ledtrig-timer tries to use it. The blink_set() function should return
> +1 if the blink setting is supported, or 0 otherwise, which means that
> +the LED will be turned on and off from software.

Normally object methods in kernel return 0 on success and error code
(such as -EINVAL for unsupported parameters) on error.

-- 
Dmitry

[PATCH 2/3] leds-clevo-mail: hw accelerated LED blink extension

[Németh Márton]

From: Márton Németh <nm127@freemail.hu>

Extends the leds subsystem with a blink_set() callback function which can
optionally implemented by a LED driver. If implemented, the driver can use the
hardware acceleration for blinking a LED.

Signed-off-by: Márton Németh <nm127@freemail.hu>
---
diff -uprN linux-2.6.22.orig/Documentation/leds-class.txt linux-2.6.22/Documentation/leds-class.txt
--- linux-2.6.22.orig/Documentation/leds-class.txt	2007-07-09 01:32:17.000000000 +0200
+++ linux-2.6.22/Documentation/leds-class.txt	2007-07-16 20:53:38.000000000 +0200
@@ -47,6 +47,17 @@ overhead, I suggest these become part of
  above leaves scope for further attributes should they be needed.


+Hardware accelerated blink of LEDs
+==================================
+
+Some LEDs can be programmed to blink without any CPU interaction. To
+support this feature, a LED driver can optionally implement the
+blink_set() function (see <linux/leds.h>). If implemeted, the
+ledtrig-timer tries to use it. The blink_set() function should return
+1 if the blink setting is supported, or 0 otherwise, which means that
+the LED will be turned on and off from software.
+
+
  Known Issues
  ============

@@ -55,10 +66,6 @@ would cause nightmare dependency issues.
  compared to the benefits the simple trigger functionality brings. The
  rest of the LED subsystem can be modular.

-Some leds can be programmed to flash in hardware. As this isn't a generic
-LED device property, this should be exported as a device specific sysfs
-attribute rather than part of the class if this functionality is required.
-

  Future Development
  ==================
diff -uprN linux-2.6.22.orig/drivers/leds/ledtrig-timer.c linux-2.6.22/drivers/leds/ledtrig-timer.c
--- linux-2.6.22.orig/drivers/leds/ledtrig-timer.c	2007-07-09 01:32:17.000000000 +0200
+++ linux-2.6.22/drivers/leds/ledtrig-timer.c	2007-07-17 09:43:20.000000000 +0200
@@ -76,8 +76,21 @@ static ssize_t led_delay_on_store(struct
  		count++;

  	if (count == size) {
-		timer_data->delay_on = state;
-		mod_timer(&timer_data->timer, jiffies + 1);
+		if (timer_data->delay_on != state) {
+			/* the new value differs from the previous */
+			timer_data->delay_on = state;
+
+			/* deactivate previous settings */
+			del_timer_sync(&timer_data->timer);
+
+			/* try to activate hardware acceleration, if any */
+			if (!led_cdev->blink_set ||
+			    !led_cdev->blink_set(led_cdev,
+				timer_data->delay_on, timer_data->delay_off)) {
+				/* no hardware acceleration, blink via timer */
+				mod_timer(&timer_data->timer, jiffies + 1);
+			}
+		}
  		ret = count;
  	}

@@ -108,8 +121,21 @@ static ssize_t led_delay_off_store(struc
  		count++;

  	if (count == size) {
-		timer_data->delay_off = state;
-		mod_timer(&timer_data->timer, jiffies + 1);
+		if (timer_data->delay_off != state) {
+			/* the new value differs from the previous */
+			timer_data->delay_off = state;
+
+			/* deactivate previous settings */
+			del_timer_sync(&timer_data->timer);
+
+			/* try to activate hardware acceleration, if any */
+			if (!led_cdev->blink_set ||
+			    !led_cdev->blink_set(led_cdev,
+				timer_data->delay_on, timer_data->delay_off)) {
+				/* no hardware acceleration, blink via timer */
+				mod_timer(&timer_data->timer, jiffies + 1);
+			}
+		}
  		ret = count;
  	}

diff -uprN linux-2.6.22.orig/include/linux/leds.h linux-2.6.22/include/linux/leds.h
--- linux-2.6.22.orig/include/linux/leds.h	2007-07-09 01:32:17.000000000 +0200
+++ linux-2.6.22/include/linux/leds.h	2007-07-16 20:53:38.000000000 +0200
@@ -38,6 +38,11 @@ struct led_classdev {
  	void		(*brightness_set)(struct led_classdev *led_cdev,
  					  enum led_brightness brightness);

+	/* Activate hardware accelerated blink */
+	int		(*blink_set)(struct led_classdev *led_cdev,
+				     int delay_on, int delay_off);
+
+
  	struct class_device	*class_dev;
  	struct list_head	 node;			/* LED Device list */
  	char			*default_trigger;	/* Trigger to use */