linux-kernel - Re: [PATCH v2] gpio: pca953x: Add optional reset gpio control

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Date:   Tue, 10 Jan 2017 22:01:18 +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 v2] gpio: pca953x: Add optional reset gpio control

On Tue, Jan 10, 2017 at 9:29 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.
>
> Signed-off-by: Steve Longerbeam <steve_longerbeam@...tor.com>
> Cc: Linus Walleij <linus.walleij@...aro.org>
> Cc: Alexandre Courbot <gnurou@...il.com>
> Cc: linux-gpio@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org


> --
>
> v2:
> - Specify that reset signal to PCA953x chip is active low, in
>   binding doc.
> - reorder includes in gpio-pca953x.c.
> - remove dev_err() on devm_gpiod_get_optional() error return.

This should go after delimiter.

FWIW:
Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>

> ---
>  Documentation/devicetree/bindings/gpio/gpio-pca953x.txt | 4 ++++
>  drivers/gpio/gpio-pca953x.c                             | 9 +++++++++
>  2 files changed, 13 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
> index 08dd15f..e639357 100644
> --- a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
> +++ b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
> @@ -29,6 +29,10 @@ Required properties:
>         onsemi,pca9654
>         exar,xra1202
>
> +Optional properties:
> + - reset-gpios: GPIO specification for the RESET input. This is an
> +               active low signal to the PCA953x.
> +
>  Example:
>
>
> diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
> index d5d72d8..d44232a 100644
> --- a/drivers/gpio/gpio-pca953x.c
> +++ b/drivers/gpio/gpio-pca953x.c
> @@ -14,6 +14,7 @@
>  #include <linux/module.h>
>  #include <linux/init.h>
>  #include <linux/gpio.h>
> +#include <linux/gpio/consumer.h>
>  #include <linux/interrupt.h>
>  #include <linux/i2c.h>
>  #include <linux/platform_data/pca953x.h>
> @@ -754,8 +755,16 @@ 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 */
> +               reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
> +                                                    GPIOD_OUT_LOW);
> +               if (IS_ERR(reset_gpio))
> +                       return PTR_ERR(reset_gpio);
>         }
>
>         chip->client = client;
> --
> 2.7.4
>



-- 
With Best Regards,
Andy Shevchenko