Re: [PATCH 3/5] mmc: slot-gpio: use gpiod_set_active_[low|high]()

Linus Walleij
2023-09-13T12:24:43Z

On Wed, Sep 13, 2023 at 1:50 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> We have new, less cumbersome and clearer interfaces for controlling GPIO
> polarity. Use them in the MMC code.
>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

I like the looks of the code better, obviously but this looks like this for
a reason unfortunately.

See the following from
Documentation/devicetree/bindings/mmc/mmc-controller.yaml:

# CD and WP lines can be implemented on the hardware in one of two
# ways: as GPIOs, specified in cd-gpios and wp-gpios properties, or
# as dedicated pins. Polarity of dedicated pins can be specified,
# using *-inverted properties. GPIO polarity can also be specified
# using the GPIO_ACTIVE_LOW flag. This creates an ambiguity in the
# latter case. We choose to use the XOR logic for GPIO CD and WP
# lines. This means, the two properties are "superimposed," for
# example leaving the GPIO_ACTIVE_LOW flag clear and specifying the
# respective *-inverted property property results in a
# double-inversion and actually means the "normal" line polarity is
# in effect.

Will you still provide the desired "double inversion" after this patch?

Yours,
Linus Walleij