gpio: add flags to export GPIOs when requesting

Introduce new flags to automatically export GPIOs when using the convenience
functions gpio_request_one() or gpio_request_array(). This eases support for
custom boards where lots of GPIOs need to be exported for customer
applications.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt
index 620a078..e08a883 100644 (file)
--- a/Documentation/gpio.txt
+++ b/Documentation/gpio.txt
@@ -322,6 +322,9 @@ where 'flags' is currently defined to specify the following properties:
        * GPIOF_OPEN_DRAIN      - gpio pin is open drain type.
        * GPIOF_OPEN_SOURCE     - gpio pin is open source type.
 
+       * GPIOF_EXPORT_DIR_FIXED        - export gpio to sysfs, keep direction
+       * GPIOF_EXPORT_DIR_CHANGEABLE   - also export, allow changing direction
+
 since GPIOF_INIT_* are only valid when configured as output, so group valid
 combinations as:
 

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 5a75510..566d012 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1302,8 +1302,18 @@ int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
                                (flags & GPIOF_INIT_HIGH) ? 1 : 0);
 
        if (err)
-               gpio_free(gpio);
+               goto free_gpio;
+
+       if (flags & GPIOF_EXPORT) {
+               err = gpio_export(gpio, flags & GPIOF_EXPORT_CHANGEABLE);
+               if (err)
+                       goto free_gpio;
+       }
+
+       return 0;
 
+ free_gpio:
+       gpio_free(gpio);
        return err;
 }
 EXPORT_SYMBOL_GPL(gpio_request_one);

diff --git a/include/linux/gpio.h b/include/linux/gpio.h
index 6155ecf..af511a6 100644 (file)
--- a/include/linux/gpio.h
+++ b/include/linux/gpio.h
@@ -20,6 +20,11 @@
 /* Gpio pin is open source */
 #define GPIOF_OPEN_SOURCE      (1 << 3)
 
+#define GPIOF_EXPORT           (1 << 2)
+#define GPIOF_EXPORT_CHANGEABLE        (1 << 3)
+#define GPIOF_EXPORT_DIR_FIXED (GPIOF_EXPORT)
+#define GPIOF_EXPORT_DIR_CHANGEABLE (GPIOF_EXPORT | GPIOF_EXPORT_CHANGEABLE)
+
 /**
  * struct gpio - a structure describing a GPIO with configuration
  * @gpio:      the GPIO number