linux/3.3: backport an upstream GPIO patch

The backported patch introduces new flags to
automatically export GPIOs when using the
convenience unctions gpio_request_one() or
gpio_request_array().

This will be used by ar71xx/ramips platforms.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@34081 3c298f89-4303-0410-b956-a3cf2f4a3e73

target/linux/generic/patches-3.3/070-gpio-add-flags-to-export-GPIOs-when-requesting.patch

@@ -0,0 +1,68 @@
+From fc3a1f04f5040255cbc086c419e4237f29f89f88 Mon Sep 17 00:00:00 2001
+From: Wolfram Sang <w.sang@pengutronix.de>
+Date: Tue, 13 Dec 2011 18:34:01 +0100
+Subject: [PATCH] gpio: add flags to export GPIOs when requesting
+
+commit fc3a1f04f5040255cbc086c419e4237f29f89f88 upstream.
+
+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>
+---
+ Documentation/gpio.txt |    3 +++
+ drivers/gpio/gpiolib.c |   12 +++++++++++-
+ include/linux/gpio.h   |    5 +++++
+ 3 files changed, 19 insertions(+), 1 deletion(-)
+
+--- a/Documentation/gpio.txt
++++ b/Documentation/gpio.txt
+@@ -303,6 +303,9 @@ where 'flags' is currently defined to sp
+ 	* GPIOF_INIT_LOW	- as output, set initial level to LOW
+ 	* GPIOF_INIT_HIGH	- as output, set initial level to HIGH
+ 
++	* 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:
+ 
+--- a/drivers/gpio/gpiolib.c
++++ b/drivers/gpio/gpiolib.c
+@@ -1289,8 +1289,18 @@ int gpio_request_one(unsigned gpio, unsi
+ 				(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);
+--- a/include/linux/gpio.h
++++ b/include/linux/gpio.h
+@@ -14,6 +14,11 @@
+ #define GPIOF_OUT_INIT_LOW	(GPIOF_DIR_OUT | GPIOF_INIT_LOW)
+ #define GPIOF_OUT_INIT_HIGH	(GPIOF_DIR_OUT | GPIOF_INIT_HIGH)
+ 
++#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