linux-kernel - [PATCH] gpio: introduce gpio_request

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Date:	Fri, 8 Jan 2010 13:14:57 +0800
From:	Eric Miao <eric.y.miao@...il.com>
To:	David Brownell <david-b@...bell.net>
Cc:	linux-kernel <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...l.org>
Subject: [PATCH] gpio: introduce gpio_request_one() and friends

commit 29cd35f57699fd93a12132186d52109a55ed57e7
Author: Eric Miao <eric.y.miao@...il.com>
Date:   Fri Jan 8 12:16:28 2010 +0800

    gpio: introduce gpio_request_one() and friends

    gpio_request() without initial configuration of the GPIO is normally
    useless, introduce gpio_request_one() together with GPIOF_ flags for
    input/output direction and initial output level.

    gpio_{request,free}_array() for multiple GPIOs.

    Cc: David Brownell <dbrownell@...rs.sourceforge.net>
    Signed-off-by: Eric Miao <eric.y.miao@...il.com>

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index a25ad28..e80a1f8 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1239,6 +1239,48 @@ void gpio_free(unsigned gpio)
 }
 EXPORT_SYMBOL_GPL(gpio_free);

+int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
+{
+	int err;
+
+	err = gpio_request(gpio, label);
+	if (err)
+		return err;
+
+	if (flags & GPIOF_DIR_IN)
+		err = gpio_direction_input(gpio);
+	else
+		err = gpio_direction_output(gpio,
+				(flags & GPIOF_INIT_HIGH) ? 1 : 0);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(gpio_request_one);
+
+int gpio_request_array(struct gpio *array, size_t num)
+{
+	int i, err;
+
+	for (i = 0; i < num; i++, array++) {
+		err = gpio_request_one(array->gpio, array->flags, array->label);
+		if (err)
+			goto err_free;
+	}
+	return 0;
+
+err_free:
+	while (i--)
+		gpio_free((--array)->gpio);
+	return err;
+}
+EXPORT_SYMBOL_GPL(gpio_request_array);
+
+void gpio_free_array(struct gpio *array, size_t num)
+{
+	while (num--)
+		gpio_free((array++)->gpio);
+}
+EXPORT_SYMBOL_GPL(gpio_free_array);

 /**
  * gpiochip_is_requested - return string iff signal was requested
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 485eeb6..a9e0b94 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -136,6 +136,26 @@ extern int __gpio_cansleep(unsigned gpio);

 extern int __gpio_to_irq(unsigned gpio);

+#define GPIOF_DIR_OUT	(0 << 0)
+#define GPIOF_DIR_IN	(1 << 0)
+
+#define GPIOF_INIT_LOW	(0 << 1)
+#define GPIOF_INIT_HIGH	(1 << 1)
+
+#define GPIOF_IN		(GPIO_DIR_IN)
+#define GPIOF_OUT_INIT_LOW	(GPIO_DIR_OUT | GPIO_INIT_LOW)
+#define GPIOF_OUT_INIT_HIGH	(GPIO_DIR_OUT | GPIO_INIT_HIGH)
+
+struct gpio {
+	unsigned	gpio;
+	unsigned long	flags;
+	const char	*label;
+};
+
+extern int gpio_request_one(unsigned gpio, unsigned long flags, const
char *label);
+extern int gpio_request_array(struct gpio *array, size_t num);
+extern void gpio_free_array(struct gpio *array, size_t num);
+
 #ifdef CONFIG_GPIO_SYSFS

 /*
--
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