linux-kernel - Re: [PATCH] gpiolib: Fix gpio_direction

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Date:   Tue, 25 Sep 2018 09:36:14 +0200
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>,
        Bartosz Golaszewski <brgl@...ev.pl>
Cc:     Timur Tabi <timur@...eaurora.org>,
        Stephen Boyd <swboyd@...omium.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] gpiolib: Fix gpio_direction_* for single direction GPIOs

Hi Ricardo,

thanks for the patch and sorry for taking time before responding.

On Fri, Sep 21, 2018 at 12:36 PM Ricardo Ribalda Delgado
<ricardo.ribalda@...il.com> wrote:
> GPIOs with no programmable direction are not required to implement
> direction_output nor direction_input.
>
> If we try to set an output direction on an output-only GPIO or input
> direction on an input-only GPIO simply return 0.
>
> This allows this single direction GPIO to be used by libgpiod.
>
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>

It makes perfect sense, patch applied.

I'll go in and add some comments to the code so I understand it
right as well in the future.

Yours,
Linus Walleij