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.

Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Ben Nizette <bn@niasdigital.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 26 insertions, 0 deletions

diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 485eeb6c4ef3..979c6a57f2f1 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -136,6 +136,32 @@ 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                (GPIOF_DIR_IN)
+#define GPIOF_OUT_INIT_LOW      (GPIOF_DIR_OUT | GPIOF_INIT_LOW)
+#define GPIOF_OUT_INIT_HIGH     (GPIOF_DIR_OUT | GPIOF_INIT_HIGH)
+
+/**
+ * struct gpio - a structure describing a GPIO with configuration
+ * @gpio:       the GPIO number
+ * @flags:      GPIO configuration as specified by GPIOF_*
+ * @label:      a literal description string of this GPIO
+ */
+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
 
 /*