linux-kernel - Re: [PATCH v2 2/2] extcon: add optional debounce-timeout-ms attribute

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Date:   Thu, 19 Oct 2017 14:22:18 +0900
From:   Chanwoo Choi <cw00.choi@...sung.com>
To:     Raveendra Padasalagi <raveendra.padasalagi@...adcom.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Cc:     bcm-kernel-feedback-list@...adcom.com
Subject: Re: [PATCH v2 2/2] extcon: add optional debounce-timeout-ms
 attribute

On 2017년 10월 19일 13:59, Chanwoo Choi wrote:
> Hi,
> 
> On 2017년 10월 19일 12:26, Raveendra Padasalagi wrote:
>> Add changes to capture optional dt attribute "debounce-timeout-ms"
>> provided in extcon node and used the same value if provided otherwise
>> default value of 20ms is used for id and vbus gpios debounce time.
>>
>> Signed-off-by: Raveendra Padasalagi <raveendra.padasalagi@...adcom.com>
>> Reviewed-by: Ray Jui <ray.jui@...adcom.com>
>> Reviewed-by: Srinath Mannam <srinath.mannam@...adcom.com>
>> ---
>>
>> Changes in v2:
>>  Rename gpio_debounce_timeout_ms to debounce_usecs
>>
>>  drivers/extcon/extcon-usb-gpio.c | 12 +++++++++---
>>  1 file changed, 9 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/extcon/extcon-usb-gpio.c b/drivers/extcon/extcon-usb-gpio.c
>> index 9c925b0..76ef1da 100644
>> --- a/drivers/extcon/extcon-usb-gpio.c
>> +++ b/drivers/extcon/extcon-usb-gpio.c
>> @@ -41,6 +41,7 @@ struct usb_extcon_info {
>>  
>>  	unsigned long debounce_jiffies;
>>  	struct delayed_work wq_detcable;
>> +	unsigned int debounce_usecs;
>>  };
>>  
>>  static const unsigned int usb_extcon_cable[] = {
>> @@ -133,6 +134,11 @@ static int usb_extcon_probe(struct platform_device *pdev)
>>  	if (IS_ERR(info->vbus_gpiod))
>>  		return PTR_ERR(info->vbus_gpiod);
>>  
>> +	ret = of_property_read_u32(np, "input-debounce",
>> +			     &info->debounce_usecs);
>> +	if (ret)
>> +		info->debounce_usecs = USB_GPIO_DEBOUNCE_MS;
> 
> The USB_GPIO_DEBOUNCE_MS indicates 20 millisecond.
> You need to redefine it as following:
> 	-#define USB_GPIO_DEBOUNCE_MS   20      /* ms */
> 	+#define USB_GPIO_DEBOUNCE_USEC 20000
> 
> 	info->debounce_usecs = USB_GPIO_DEBOUNCE_USEC;
> 
> or
> 	info->debounce_usecs = USB_GPIO_DEBOUNCE_MS * 1000;
> 
> 
>> +
>>  	info->edev = devm_extcon_dev_allocate(dev, usb_extcon_cable);
>>  	if (IS_ERR(info->edev)) {
>>  		dev_err(dev, "failed to allocate extcon device\n");
>> @@ -147,13 +153,13 @@ static int usb_extcon_probe(struct platform_device *pdev)
>>  
>>  	if (info->id_gpiod)
>>  		ret = gpiod_set_debounce(info->id_gpiod,
>> -					 USB_GPIO_DEBOUNCE_MS * 1000);
>> +					 info->debounce_usecs * 1000);
> 
> The debounce_usecs is already microsecond, You don't need to mutiply with 1000.
> 
> 
>>  	if (!ret && info->vbus_gpiod)
>>  		ret = gpiod_set_debounce(info->vbus_gpiod,
>> -					 USB_GPIO_DEBOUNCE_MS * 1000);
>> +					 info->debounce_usecs * 1000);

You don't need to mutiply with 1000.

>>  
>>  	if (ret < 0)
>> -		info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEBOUNCE_MS);
>> +		info->debounce_jiffies = msecs_to_jiffies(info->debounce_usecs);

You should you the 'usecs_to_jiffies' because info->debounce_usecs indicates the usec.

-- 
Best Regards,
Chanwoo Choi
Samsung Electronics