On Wed, May 7, 2025 at 4:54 PM Thomas Richard <[email protected]> wrote: > On 5/7/25 15:24, Andy Shevchenko wrote: > > On Wed, May 7, 2025 at 1:10 PM Thomas Richard > > <[email protected]> wrote: > >> On 5/7/25 08:34, Andy Shevchenko wrote: > >>> On Tue, May 6, 2025 at 6:21 PM Thomas Richard > >>> <[email protected]> wrote:
... > >>>> + /* > >>>> + * get_direction() is called during gpiochip registration, > >>>> return input > >>>> + * direction if there is no descriptor for the line. > >>>> + */ > >>>> + if (!test_bit(offset, fwd->valid_mask)) > >>>> + return GPIO_LINE_DIRECTION_IN; > >>> > >>> Can you remind me why we choose a valid return for invalid line? From > >>> a pure code perspective this should return an error. > >> > >> I reproduced gpiolib behavior. During gpiochip registration, we get the > >> direction of all lines. In the case the line is not valid, it is marked > >> as input if direction_input operation exists, otherwise it is marked as > >> output. [1] > >> > >> But in fact we could return an error and the core will mark the line as > >> input. Maybe ENODEV ? > > > > I am fine with this error code, but do we have similar cases already > > in the kernel? Do they use the same or different error code(s)? > > I dumped all get_direction() operations in drivers/gpio and > drivers/pinctrl and returned values are: > - GPIO_LINE_DIRECTION_OUT and GPIO_LINE_DIRECTION_IN (make sense). > - -EINVAL (for example [1]). > - -EBADE in gpiochip_get_direction() [2]. > - regmap_read() return code. > > But from my point of view -EINVAL and -EBADE do not match our case. Hmm... I believe we need a GPIO maintainer to have a look at this. -- With Best Regards, Andy Shevchenko
