linux-kernel - Re: [PATCH 6/8] extcon: gpio: Get debounce setting from device property

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Date:   Tue, 26 Sep 2017 11:23:25 +0900
From:   Chanwoo Choi <cw00.choi@...sung.com>
To:     Linus Walleij <linus.walleij@...aro.org>,
        MyungJoo Ham <myungjoo.ham@...sung.com>
Cc:     linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org,
        John Stultz <john.stultz@...aro.org>,
        Guenter Roeck <linux@...ck-us.net>
Subject: Re: [PATCH 6/8] extcon: gpio: Get debounce setting from device
 property

Hi Linus,

On 2017년 09월 24일 23:56, Linus Walleij wrote:
> Look up the debouncing value using the device property that will
> pick it from device tree or ACPI DSDT or whatever is available.
> 
> Reintroduce the debounce handling previously deleted in the
> series, setting the delayed worker to delay 0 ms if the GPIO
> driver supports debouncing for us, else just delay the reading
> of the value delayed by jiffies.
> 
> Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
> ---
>  drivers/extcon/extcon-gpio.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)

I checked the pinctrl-bindings.txt[1] in order to check
the property name of 'input-debounce'. It looks good to me.
[1] Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt

Acked-by: Chanwoo Choi <cw00.choi@...sung.com>

> 
> diff --git a/drivers/extcon/extcon-gpio.c b/drivers/extcon/extcon-gpio.c
> index 6d9cb4ed11c2..8fc52631c8a2 100644
> --- a/drivers/extcon/extcon-gpio.c
> +++ b/drivers/extcon/extcon-gpio.c
> @@ -24,6 +24,7 @@
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/platform_device.h>
> +#include <linux/property.h>
>  #include <linux/slab.h>
>  #include <linux/workqueue.h>
>  
> @@ -35,7 +36,6 @@
>   *			value.
>   * @gpiod:		GPIO descriptor for this external connector.
>   * @extcon_id:		The unique id of specific external connector.
> - * @debounce:		Debounce time for GPIO IRQ in ms.
>   * @check_on_resume:	Boolean describing whether to check the state of gpio
>   *			while resuming from sleep.
>   */
> @@ -45,7 +45,6 @@ struct gpio_extcon_data {
>  	unsigned long debounce_jiffies;
>  	struct gpio_desc *gpiod;
>  	unsigned int extcon_id;
> -	unsigned long debounce;
>  	bool check_on_resume;
>  };
>  
> @@ -74,6 +73,7 @@ static int gpio_extcon_probe(struct platform_device *pdev)
>  	struct gpio_extcon_data *data;
>  	struct device *dev = &pdev->dev;
>  	unsigned long irq_flags;
> +	u32 debounce_usecs;
>  	int irq;
>  	int ret;
>  
> @@ -109,6 +109,15 @@ static int gpio_extcon_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  	}
>  
> +	ret = device_property_read_u32(dev, "input-debounce", &debounce_usecs);
> +	if (ret || !debounce_usecs) {
> +		dev_err(dev, "illegal debounce value, set to 20 ms\n");
> +		debounce_usecs = 20000;
> +	}
> +	ret = gpiod_set_debounce(data->gpiod, debounce_usecs);
> +	if (ret)
> +		data->debounce_jiffies = msecs_to_jiffies(debounce_usecs * 1000);
> +
>  	ret = devm_extcon_dev_register(dev, data->edev);
>  	if (ret < 0)
>  		return ret;
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics