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. [1] https://elixir.bootlin.com/linux/v6.15-rc5/source/drivers/gpio/gpio-cros-ec.c#L70 [2] https://elixir.bootlin.com/linux/v6.15-rc5/source/drivers/gpio/gpiolib.c#L359 Regards, Thomas
