linux-kernel - Re: [PATCH 3/5] mmc: slot-gpio: use gpiod_set_active

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Date:   Wed, 13 Sep 2023 14:24:27 +0200
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Bartosz Golaszewski <brgl@...ev.pl>
Cc:     Andy Shevchenko <andy@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Paul Cercueil <paul@...pouillou.net>,
        Harvey Hunt <harveyhuntnexus@...il.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        Daniel Scally <djrscally@...il.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Mark Gross <markgross@...nel.org>,
        Heiner Kallweit <hkallweit1@...il.com>,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mmc@...r.kernel.org, linux-mips@...r.kernel.org,
        linux-mtd@...ts.infradead.org, platform-driver-x86@...r.kernel.org,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH 3/5] mmc: slot-gpio: use gpiod_set_active_[low|high]()

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

> From: Bartosz Golaszewski <bartosz.golaszewski@...aro.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@...aro.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