Re: [PATCH v2 4/4] gpio: Hide valid_mask from direct assignments

[Linus Walleij]

On Fri, Feb 28, 2025 at 1:36 PM Matti Vaittinen
<mazziesaccount@xxxxxxxxx> wrote:

> The valid_mask member of the struct gpio_chip is unconditionally written
> by the GPIO core at driver registration. Current documentation does not
> mention this but just says the valid_mask is used if it's not NULL. This
> lured me to try populating it directly in the GPIO driver probe instead
> of using the init_valid_mask() callback. It took some retries with
> different bitmaps and eventually a bit of code-reading to understand why
> the valid_mask was not obeyed. I could've avoided this trial and error if
> the valid_mask was hidden in the struct gpio_device instead of being a
> visible member of the struct gpio_chip.
>
> Help the next developer who decides to directly populate the valid_mask
> in struct gpio_chip by hiding the valid_mask in struct gpio_device and
> keep it internal to the GPIO core.
>
> Suggested-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> Signed-off-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>

Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>

Yours,
Linus Walleij