From mboxrd@z Thu Jan 1 00:00:00 1970 From: slongerbeam@gmail.com (Steve Longerbeam) Date: Thu, 29 Dec 2016 14:27:25 -0800 Subject: [PATCH 10/20] gpio: pca953x: Add optional reset gpio control In-Reply-To: <1483050455-10683-1-git-send-email-steve_longerbeam@mentor.com> References: <1483050455-10683-1-git-send-email-steve_longerbeam@mentor.com> Message-ID: <1483050455-10683-11-git-send-email-steve_longerbeam@mentor.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 Cc: Linus Walleij Cc: Alexandre Courbot Cc: linux-gpio at vger.kernel.org Cc: linux-kernel at vger.kernel.org --- v2: - documented optional reset-gpios property in Documentation/devicetree/bindings/gpio/gpio-pca953x.txt. --- Documentation/devicetree/bindings/gpio/gpio-pca953x.txt | 4 ++++ drivers/gpio/gpio-pca953x.c | 17 +++++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt index 08dd15f..da54f4c 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 + + Example: diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c index d5d72d8..d1c0bd5 100644 --- a/drivers/gpio/gpio-pca953x.c +++ b/drivers/gpio/gpio-pca953x.c @@ -22,6 +22,7 @@ #include #include #include +#include #define PCA953X_INPUT 0 #define PCA953X_OUTPUT 1 @@ -133,6 +134,7 @@ struct pca953x_chip { const char *const *names; unsigned long driver_data; struct regulator *regulator; + struct gpio_desc *reset_gpio; const struct pca953x_reg_config *regs; @@ -756,6 +758,21 @@ static int pca953x_probe(struct i2c_client *client, } else { chip->gpio_start = -1; irq_base = 0; + + /* see if we need to de-assert a reset pin */ + chip->reset_gpio = devm_gpiod_get_optional(&client->dev, + "reset", + GPIOD_OUT_LOW); + if (IS_ERR(chip->reset_gpio)) { + dev_err(&client->dev, "request for reset pin failed\n"); + return PTR_ERR(chip->reset_gpio); + } + + if (chip->reset_gpio) { + /* bring chip out of reset */ + dev_info(&client->dev, "releasing reset\n"); + gpiod_set_value(chip->reset_gpio, 0); + } } chip->client = client; -- 2.7.4