Re: [PATCH] pinctrl: bcm2835: Make pin freeing behavior configurable

Stefan Wahren
2024-05-02T12:21:25Z

Am 02.05.24 um 13:15 schrieb Kent Gibson:
> On Thu, May 02, 2024 at 01:11:06PM +0200, Stefan Wahren wrote:
>> Hi Kent,
>>
>> Am 02.05.24 um 13:04 schrieb Kent Gibson:
>>> On Thu, May 02, 2024 at 12:22:07PM +0200, Stefan Wahren wrote:
>>>> Am 19.04.24 um 22:40 schrieb Stefan Wahren:
>>>>> Until now after a bcm2835 pin was freed its pinmux was set to GPIO_IN.
>>>>> So in case it was configured as GPIO_OUT before the configured output
>>>>> level also get lost. As long as GPIO sysfs was used this wasn't
>>>>> actually a problem because the pins and their possible output level
>>>>> were kept by sysfs.
>>>>>
>>>>> Since more and more Raspberry Pi users start using libgpiod they are
>>>>> confused about this behavior. So make the pin freeing behavior of
>>>>> GPIO_OUT configurable via module parameter. In case
>>>>> pinctrl-bcm2835.strict_gpiod is set to 0, the output level is kept.
>>>>>
>>>>> This patch based on the downstream work of Phil Elwell.
>>>>>
>>>>> Link: https://github.com/raspberrypi/linux/pull/6117
>>>>> Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
>>>>> ---
>>>>> drivers/pinctrl/bcm/pinctrl-bcm2835.c | 20 ++++++++++++++++----
>>>>> 1 file changed, 16 insertions(+), 4 deletions(-)
>>>> Gentle ping ...
>>> I can't comment on the substance of the change as pinctrl is outside my
>>> wheelhouse, but the "strict_gpiod" name could be better.
>>> The point is to make GPIO outputs persist, right?
>> Yes, correct.
>>> The name should better reflect that.
>> Finding good and short names is hard, do you have a suggestion?
>>
> How about "persist_gpio_outputs"?
I'm fine with that. I'll wait until tomorrow before sending a new version.
>
> Cheers,
> Kent.