linux-kernel - Re: [PATCH] gpio: pca953x: do not ignore i2c errors

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Date:   Wed, 29 Sep 2021 20:41:45 +0200
From:   Bartosz Golaszewski <bgolaszewski@...libre.com>
To:     Nikita Yushchenko <nikita.yoush@...entembedded.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        linux-gpio <linux-gpio@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Andrey Gusakov <andrey.gusakov@...entembedded.com>
Subject: Re: [PATCH] gpio: pca953x: do not ignore i2c errors

On Thu, Sep 23, 2021 at 7:22 PM Nikita Yushchenko
<nikita.yoush@...entembedded.com> wrote:
>
> From: Andrey Gusakov <andrey.gusakov@...entembedded.com>
>
> Per gpio_chip interface, error shall be proparated to the caller.
>
> Attempt to silent diagnostics by returning zero (as written in the
> comment) is plain wrong, because the zero return can be interpreted by
> the caller as the gpio value.
>
> Signed-off-by: Andrey Gusakov <andrey.gusakov@...entembedded.com>
> Signed-off-by: Nikita Yushchenko <nikita.yoush@...entembedded.com>
> ---
>  drivers/gpio/gpio-pca953x.c | 11 ++---------
>  1 file changed, 2 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
> index f5cfc0698799..8ebf369b3ba0 100644
> --- a/drivers/gpio/gpio-pca953x.c
> +++ b/drivers/gpio/gpio-pca953x.c
> @@ -468,15 +468,8 @@ static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off)
>         mutex_lock(&chip->i2c_lock);
>         ret = regmap_read(chip->regmap, inreg, &reg_val);
>         mutex_unlock(&chip->i2c_lock);
> -       if (ret < 0) {
> -               /*
> -                * NOTE:
> -                * diagnostic already emitted; that's all we should
> -                * do unless gpio_*_value_cansleep() calls become different
> -                * from their nonsleeping siblings (and report faults).
> -                */
> -               return 0;
> -       }
> +       if (ret < 0)
> +               return ret;
>
>         return !!(reg_val & bit);
>  }
> --
> 2.30.2
>

Applied, thanks!

Bart