From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761106AbbA3LKF (ORCPT ); Fri, 30 Jan 2015 06:10:05 -0500 Received: from comal.ext.ti.com ([198.47.26.152]:57317 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754384AbbA3LKB (ORCPT ); Fri, 30 Jan 2015 06:10:01 -0500 Message-ID: <54CB6681.1070008@ti.com> Date: Fri, 30 Jan 2015 13:09:53 +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> <54CA18EF.2060607@ti.com> <54CACAEF.6070208@samsung.com> In-Reply-To: <54CACAEF.6070208@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 30/01/15 02:06, Chanwoo Choi wrote: > Hi Roger, > > On 01/29/2015 08:26 PM, Roger Quadros wrote: >> 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. > > It is not proper solution using id_irqwake. If fail to execute enable_irq_wake(), > usb_extcon_suspend() function have to return error immediately. > Your point is valid. I will now need to investigate why enable_irq_wake() is failing when used for GPIO of PCA857x on DRA7-evm. cheers, -roger