From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758385AbbA2L05 (ORCPT ); Thu, 29 Jan 2015 06:26:57 -0500 Received: from arroyo.ext.ti.com ([192.94.94.40]:50260 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753977AbbA2L0s (ORCPT ); Thu, 29 Jan 2015 06:26:48 -0500 Message-ID: <54CA18EF.2060607@ti.com> Date: Thu, 29 Jan 2015 13:26:39 +0200 From: Roger Quadros User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Chanwoo Choi CC: , , , , , , , , Subject: Re: [PATCH v3 1/7] extcon: usb-gpio: Introduce gpio usb extcon driver References: <1422274532-9488-1-git-send-email-rogerq@ti.com> <1422274532-9488-2-git-send-email-rogerq@ti.com> <54C8D2F4.9050404@ti.com> <54C99197.5070605@samsung.com> In-Reply-To: <54C99197.5070605@samsung.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Chanwoo, On 29/01/15 03:49, Chanwoo Choi wrote: > Hi Roger, > > We need to discuss one point about 'id_irqwake'. > I don't recommend to use 'id_irqwake' field. > > And I catch build warning by using "select" keywork in Kconfig. > It is my wrong guide of "select" keyword. So, I'll change it > as 'depends on' keyword. > > Looks good to me except for 'id_irqwake'. > I'll apply this patch on 3.21 queue after completing this discussion. > > On 01/28/2015 09:15 PM, Roger Quadros wrote: >> This driver observes the USB ID pin connected over a GPIO and >> updates the USB cable extcon states accordingly. >> >> The existing GPIO extcon driver is not suitable for this purpose >> as it needs to be taught to understand USB cable states and it >> can't handle more than one cable per instance. >> >> For the USB case we need to handle 2 cable states. >> 1) USB (attach/detach) >> 2) USB-Host (attach/detach) >> >> This driver can be easily updated in the future to handle VBUS >> events in case it happens to be available on GPIO for any platform. >> >> Signed-off-by: Roger Quadros >> --- >> v3: >> - removed IRQF_NO_SUSPEND flag. Added IRQF_TRIGGER_RISING and >> IRQF_TRIGGER_FALLING >> - Added disable_irq() to suspend() and enable_irq() to resume() >> >> .../devicetree/bindings/extcon/extcon-usb-gpio.txt | 18 ++ >> drivers/extcon/Kconfig | 7 + >> drivers/extcon/Makefile | 1 + >> drivers/extcon/extcon-usb-gpio.c | 233 +++++++++++++++++++++ >> 4 files changed, 259 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt >> create mode 100644 drivers/extcon/extcon-usb-gpio.c >> >> diff --git a/Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt b/Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt >> new file mode 100644 >> index 0000000..85fe6b0 >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt >> @@ -0,0 +1,18 @@ >> +USB GPIO Extcon device >> + >> +This is a virtual device used to generate USB cable states from the USB ID pin >> +connected to a GPIO pin. >> + >> +Required properties: >> +- compatible: Should be "linux,extcon-usb-gpio" >> +- id-gpio: gpio for USB ID pin. See gpio binding. >> + >> +Example: >> + extcon_usb1 { >> + compatible = "linux,extcon-usb-gpio"; >> + id-gpio = <&gpio6 1 GPIO_ACTIVE_HIGH>; >> + } >> + >> + &omap_dwc3_1 { >> + extcon = <&extcon_usb1>; >> + }; >> diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig >> index 6a1f7de..fd11536 100644 >> --- a/drivers/extcon/Kconfig >> +++ b/drivers/extcon/Kconfig >> @@ -93,4 +93,11 @@ config EXTCON_SM5502 >> Silicon Mitus SM5502. The SM5502 is a USB port accessory >> detector and switch. >> >> +config EXTCON_USB_GPIO >> + tristate "USB GPIO extcon support" >> + select GPIOLIB > > I catch the build warning if using 'select' instead of 'depends on' as following: > It is my wrong guide to you. So, I'll modify it by using "depends on" as your original patch. OK. Thanks. > > make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- zImage -j 8 > scripts/kconfig/conf --silentoldconfig Kconfig > drivers/gpio/Kconfig:34:error: recursive dependency detected! > drivers/gpio/Kconfig:34: symbol GPIOLIB is selected by EXTCON_USB_GPIO > drivers/extcon/Kconfig:96: symbol EXTCON_USB_GPIO depends on EXTCON > drivers/extcon/Kconfig:1: symbol EXTCON is selected by CHARGER_MANAGER > drivers/power/Kconfig:316: symbol CHARGER_MANAGER depends on POWER_SUPPLY > drivers/power/Kconfig:1: symbol POWER_SUPPLY is selected by HID_SONY > drivers/hid/Kconfig:670: symbol HID_SONY depends on NEW_LEDS > drivers/leds/Kconfig:8: symbol NEW_LEDS is selected by BCMA_DRIVER_GPIO > drivers/bcma/Kconfig:75: symbol BCMA_DRIVER_GPIO depends on GPIOLIB > >> + help >> + Say Y here to enable GPIO based USB cable detection extcon support. >> + Used typically if GPIO is used for USB ID pin detection. >> + >> endif # MULTISTATE_SWITCH >> diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile >> index 0370b42..6a08a98 100644 >> --- a/drivers/extcon/Makefile >> +++ b/drivers/extcon/Makefile >> @@ -12,3 +12,4 @@ obj-$(CONFIG_EXTCON_MAX8997) += extcon-max8997.o >> obj-$(CONFIG_EXTCON_PALMAS) += extcon-palmas.o >> obj-$(CONFIG_EXTCON_RT8973A) += extcon-rt8973a.o >> obj-$(CONFIG_EXTCON_SM5502) += extcon-sm5502.o >> +obj-$(CONFIG_EXTCON_USB_GPIO) += extcon-usb-gpio.o >> diff --git a/drivers/extcon/extcon-usb-gpio.c b/drivers/extcon/extcon-usb-gpio.c >> new file mode 100644 >> index 0000000..99a58b2 >> --- /dev/null >> +++ b/drivers/extcon/extcon-usb-gpio.c >> @@ -0,0 +1,233 @@ >> +/** >> + * drivers/extcon/extcon-usb-gpio.c - USB GPIO extcon driver >> + * >> + * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com >> + * Author: Roger Quadros >> + * >> + * 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 >> + * published by the Free Software Foundation. >> + * >> + * This program is distributed in the hope that it will be useful, >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the >> + * GNU General Public License for more details. >> + */ >> + >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> + >> +#define USB_GPIO_DEBOUNCE_MS 20 /* ms */ >> + >> +struct usb_extcon_info { >> + struct device *dev; >> + struct extcon_dev *edev; >> + >> + struct gpio_desc *id_gpiod; >> + int id_irq; >> + bool id_irqwake; /* ID wakeup enabled flag */ > > Do you really think id_irqwake is necessary? > I think it is not necessary. I will explain below why it is necessary. > >> + >> + unsigned long debounce_jiffies; >> + struct delayed_work wq_detcable; >> +}; >> + >> +/* List of detectable cables */ >> +enum { >> + EXTCON_CABLE_USB = 0, >> + EXTCON_CABLE_USB_HOST, >> + >> + EXTCON_CABLE_END, >> +}; >> + >> +static const char *usb_extcon_cable[] = { >> + [EXTCON_CABLE_USB] = "USB", >> + [EXTCON_CABLE_USB_HOST] = "USB-Host", >> + NULL, >> +}; >> + > > [snip] > >> + >> +static int usb_extcon_remove(struct platform_device *pdev) >> +{ >> + struct usb_extcon_info *info = platform_get_drvdata(pdev); >> + >> + cancel_delayed_work_sync(&info->wq_detcable); >> + >> + return 0; >> +} >> + >> +#ifdef CONFIG_PM_SLEEP >> +static int usb_extcon_suspend(struct device *dev) >> +{ >> + struct usb_extcon_info *info = dev_get_drvdata(dev); >> + >> + if (device_may_wakeup(dev)) >> + if (!enable_irq_wake(info->id_irq)) >> + info->id_irqwake = true; >> + > > You can simplify this code as following without 'id_irqwake': > > if (device_may_wakeup(dev)) > enable_irq_wake(info->id_irq); enable_irq_wake() can fail. And if it does we need to keep track of it to prevent unbalanced disable_irq_wake() call in resume(). That's the reason I've added the id_irqwake flag in struct usb_extcon_info. > >> + /* >> + * We don't want to process any IRQs after this point >> + * as GPIOs used behind I2C subsystem might not be >> + * accessible until resume completes. So disable IRQ. >> + */ >> + disable_irq(info->id_irq); >> + >> + return 0; >> +} >> + >> +static int usb_extcon_resume(struct device *dev) >> +{ >> + struct usb_extcon_info *info = dev_get_drvdata(dev); >> + >> + if (info->id_irqwake) { >> + disable_irq_wake(info->id_irq); >> + info->id_irqwake = false; >> + } > > ditto. > > if (device_may_wakeup(dev)) > disable_irq_wake(info->id_irq); > >> + >> + enable_irq(info->id_irq); >> + >> + return 0; >> +} >> +#endif >> + >> +static SIMPLE_DEV_PM_OPS(usb_extcon_pm_ops, >> + usb_extcon_suspend, usb_extcon_resume); >> + >> +static struct of_device_id usb_extcon_dt_match[] = { >> + { .compatible = "linux,extcon-usb-gpio", }, >> + { /* sentinel */ } >> +}; >> +MODULE_DEVICE_TABLE(of, usb_extcon_dt_match); >> + >> +static struct platform_driver usb_extcon_driver = { >> + .probe = usb_extcon_probe, >> + .remove = usb_extcon_remove, >> + .driver = { >> + .name = "extcon-usb-gpio", >> + .pm = &usb_extcon_pm_ops, >> + .of_match_table = usb_extcon_dt_match, >> + }, >> +}; >> + >> +module_platform_driver(usb_extcon_driver); >> + >> +MODULE_AUTHOR("Roger Quadros "); >> +MODULE_DESCRIPTION("USB GPIO extcon driver"); >> +MODULE_LICENSE("GPL v2"); >> > cheers, -roger