linux-kernel - Re: [PATCH] gpio: pca953x: Add optional reset gpio control

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Date:   Wed, 4 Jan 2017 01:37:23 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Steve Longerbeam <slongerbeam@...il.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Alexandre Courbot <gnurou@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Steve Longerbeam <steve_longerbeam@...tor.com>
Subject: Re: [PATCH] gpio: pca953x: Add optional reset gpio control

On Mon, Jan 2, 2017 at 11:07 PM, Steve Longerbeam <slongerbeam@...il.com> wrote:
> Add optional reset-gpios pin control. If present, de-assert the
> specified reset gpio pin to bring the chip out of reset.

> --- a/drivers/gpio/gpio-pca953x.c
> +++ b/drivers/gpio/gpio-pca953x.c
> @@ -22,6 +22,7 @@
>  #include <linux/of_platform.h>
>  #include <linux/acpi.h>
>  #include <linux/regulator/consumer.h>

> +#include <linux/gpio/consumer.h>

Please, try to put it somehow alphabetically ordered (yes, I see it's
not in general, but try to squeeze it into longest part which is
ordered).

>
>  #define PCA953X_INPUT          0
>  #define PCA953X_OUTPUT         1
> @@ -754,8 +755,18 @@ static int pca953x_probe(struct i2c_client *client,
>                 invert = pdata->invert;
>                 chip->names = pdata->names;
>         } else {
> +               struct gpio_desc *reset_gpio;
> +
>                 chip->gpio_start = -1;
>                 irq_base = 0;
> +
> +               /* see if we need to de-assert a reset pin */

see -> See

> +               reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
> +                                                    GPIOD_OUT_LOW);

Shouldn't be _optional_exclusive?
See this recent discussion https://patchwork.ozlabs.org/patch/706002/

> +               if (IS_ERR(reset_gpio)) {
> +                       dev_err(&client->dev, "request for reset pin failed\n");
> +                       return PTR_ERR(reset_gpio);
> +               }
>         }

-- 
With Best Regards,
Andy Shevchenko