linux-kernel - [PATCH 2/2] gpiolib: Implement devm_gpio_request

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Message-Id: <1335959206-8138-2-git-send-email-broonie@opensource.wolfsonmicro.com>
Date:	Wed,  2 May 2012 12:46:46 +0100
From:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
To:	Grant Likely <grant.likely@...retlab.ca>,
	Linus Walleij <linus.walleij@...ricsson.com>
Cc:	linux-kernel@...r.kernel.org,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Subject: [PATCH 2/2] gpiolib: Implement devm_gpio_request_one()

Allow drivers to use the modern request and configure idiom together
with devres.

As with plain gpio_request() and gpio_request_one() we can't implement
the old school version in terms of _one() as this would force the
explicit selection of a direction in gpio_request() which could break
systems if we pick the wrong one.  Implementing devm_gpio_request_one()
in terms of devm_gpio_request() would needlessly complicate things or
lead to duplication from the unmanaged version depending on how it's
done.

Signed-off-by: Mark Brown <broonie@...nsource.wolfsonmicro.com>
---
 drivers/gpio/devres.c      |   29 +++++++++++++++++++++++++++++
 include/asm-generic/gpio.h |    2 ++
 include/linux/gpio.h       |    6 ++++++
 3 files changed, 37 insertions(+)

diff --git a/drivers/gpio/devres.c b/drivers/gpio/devres.c
index 3dd2939..d21a9ff 100644
--- a/drivers/gpio/devres.c
+++ b/drivers/gpio/devres.c
@@ -71,6 +71,35 @@ int devm_gpio_request(struct device *dev, unsigned gpio, const char *label)
 EXPORT_SYMBOL(devm_gpio_request);
 
 /**
+ *	devm_gpio_request_one - request a single GPIO with initial setup
+ *	@dev:   device to request for
+ *	@gpio:	the GPIO number
+ *	@flags:	GPIO configuration as specified by GPIOF_*
+ *	@label:	a literal description string of this GPIO
+ */
+int devm_gpio_request_one(struct device *dev, unsigned gpio,
+			  unsigned long flags, const char *label)
+{
+	unsigned *dr;
+	int rc;
+
+	dr = devres_alloc(devm_gpio_release, sizeof(unsigned), GFP_KERNEL);
+	if (!dr)
+		return -ENOMEM;
+
+	rc = gpio_request_one(gpio, flags, label);
+	if (rc) {
+		devres_free(dr);
+		return rc;
+	}
+
+	*dr = gpio;
+	devres_add(dev, dr);
+
+	return 0;
+}
+
+/**
  *      devm_gpio_free - free an interrupt
  *      @dev: device to free gpio for
  *      @gpio: gpio to free
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 5f52690..4ead123 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -179,6 +179,8 @@ extern void gpio_free_array(const struct gpio *array, size_t num);
 
 /* bindings for managed devices that want to request gpios */
 int devm_gpio_request(struct device *dev, unsigned gpio, const char *label);
+int devm_gpio_request_one(struct device *dev, unsigned gpio,
+			  unsigned long flags, const char *label);
 void devm_gpio_free(struct device *dev, unsigned int gpio);
 
 #ifdef CONFIG_GPIO_SYSFS
diff --git a/include/linux/gpio.h b/include/linux/gpio.h
index 8e0fe1b..a68024e 100644
--- a/include/linux/gpio.h
+++ b/include/linux/gpio.h
@@ -78,6 +78,12 @@ static inline int gpio_request_one(unsigned gpio,
 	return -ENOSYS;
 }
 
+static inline int devm_gpio_request_one(struct device *dev, unsigned gpio,
+					unsigned long flags, const char *label)
+{
+	return -ENOSYS;
+}
+
 static inline int gpio_request_array(const struct gpio *array, size_t num)
 {
 	return -ENOSYS;
-- 
1.7.10

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