Re: [PATCH] extcon-usb-gpio: add enable pin support

Sergei Shtylyov
2015-12-11T18:33:32Z

Hello.

On 12/11/2015 06:53 AM, Rob Herring wrote:

>> Sometimes there's a real OTG chip behind the USB ID signal mapped to a GPIO
>> pin: in my case it's Maxim Integrated MAX3355E which integrates Vbus charge
>> pump and comparators and passes thru the ID signal from an OTG connector.
>> This chip also has the SHDN# pin which should be driven high for the normal
>> operation and low to save power; it is connected to a GPIO pin as well on,
>> hence we'll have to teach the driver to parse the new optional device tree
>> property, "enable-gpio"...
>
> Some wierd spacing going on here.

I like my text properly filling up the given columns. What's the problem? :-)

>> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
>>
>> ---
>> The patch is against the 'extcon-next' branch of the 'extcon.git' repo.
>>
>> Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt | 3 +++
>> drivers/extcon/extcon-usb-gpio.c | 5 +++++
>> 2 files changed, 8 insertions(+)
>>
>> Index: extcon/Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt
>> ===================================================================
>> --- extcon.orig/Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt
>> +++ extcon/Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt
>> @@ -7,6 +7,9 @@ Required properties:
>> - compatible: Should be "linux,extcon-usb-gpio"
>> - id-gpio: gpio for USB ID pin. See gpio binding.
>>
>> +Optional properties:
>> +- enable-gpio: gpio for the enable pin. See gpio binding.
>
> Use -gpios as -gpio is deprecated.

Didn't know, thanks.

[...]
>> Index: extcon/drivers/extcon/extcon-usb-gpio.c
>> ===================================================================
>> --- extcon.orig/drivers/extcon/extcon-usb-gpio.c
>> +++ extcon/drivers/extcon/extcon-usb-gpio.c
[...]
>> @@ -99,6 +100,8 @@ static int usb_extcon_probe(struct platf
>> return -ENOMEM;
>>
>> info->dev = dev;
>> + info->enable_gpiod = devm_gpiod_get_optional(&pdev->dev, "enable",
>> + GPIOD_OUT_HIGH);
>> info->id_gpiod = devm_gpiod_get(&pdev->dev, "id", GPIOD_IN);
>> if (IS_ERR(info->id_gpiod)) {
>> dev_err(dev, "failed to get ID GPIO\n");
>> @@ -155,6 +158,8 @@ static int usb_extcon_remove(struct plat
>>
>> cancel_delayed_work_sync(&info->wq_detcable);
>>
>> + gpiod_set_value_cansleep(info->enable_gpiod, 0);

> Shouldn't you support either polarity?

The gpiolib does that for me -- devm_gpiod_get_optional() should read the
polarity from DT.

> Rob

MBR, Sergei