[PATCH 1/2] gpiolib: add gpio_export_with_name

[Jean-Christophe PLAGNIOL-VILLARD <plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org>]

allow to specify a name to an exported gpio

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org>
---
 arch/mips/include/asm/mach-au1x00/gpio-au1000.h |    3 ++-
 arch/mips/include/asm/mach-au1x00/gpio-au1300.h |    3 ++-
 drivers/gpio/gpiolib.c                          |   12 +++++++-----
 include/asm-generic/gpio.h                      |    6 ++++--
 include/linux/gpio.h                            |   23 ++++++++++++++++++++++-
 5 files changed, 37 insertions(+), 10 deletions(-)

diff --git a/arch/mips/include/asm/mach-au1x00/gpio-au1000.h b/arch/mips/include/asm/mach-au1x00/gpio-au1000.h
index 73853b5a..af4accb 100644
--- a/arch/mips/include/asm/mach-au1x00/gpio-au1000.h
+++ b/arch/mips/include/asm/mach-au1x00/gpio-au1000.h
@@ -633,7 +633,8 @@ static inline int gpio_set_debounce(unsigned gpio, unsigned debounce)
 	return -ENOSYS;
 }
 
-static inline int gpio_export(unsigned gpio, bool direction_may_change)
+static inline int gpio_export_with_name(unsigned gpio,
+	bool direction_may_change, const char *name)
 {
 	return -ENOSYS;
 }
diff --git a/arch/mips/include/asm/mach-au1x00/gpio-au1300.h b/arch/mips/include/asm/mach-au1x00/gpio-au1300.h
index fb9975c..fcd152e 100644
--- a/arch/mips/include/asm/mach-au1x00/gpio-au1300.h
+++ b/arch/mips/include/asm/mach-au1x00/gpio-au1300.h
@@ -234,7 +234,8 @@ static inline void gpio_unexport(unsigned gpio)
 {
 }
 
-static inline int gpio_export(unsigned gpio, bool direction_may_change)
+static inline int gpio_export_with_name(unsigned gpio,
+	bool direction_may_change, const char *name)
 {
 	return -ENOSYS;
 }
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index b667f76..2141165 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -714,9 +714,10 @@ static struct class gpio_class = {
 
 
 /**
- * gpio_export - export a GPIO through sysfs
+ * gpio_export_with_name - export a GPIO through sysfs
  * @gpio: gpio to make available, already requested
  * @direction_may_change: true if userspace may change gpio direction
+ * @name: gpio name
  * Context: arch_initcall or later
  *
  * When drivers want to make a GPIO accessible to userspace after they
@@ -728,7 +729,7 @@ static struct class gpio_class = {
  *
  * Returns zero on success, else an error.
  */
-int gpio_export(unsigned gpio, bool direction_may_change)
+int gpio_export_with_name(unsigned gpio, bool direction_may_change, const char *name)
 {
 	unsigned long		flags;
 	struct gpio_desc	*desc;
@@ -766,7 +767,9 @@ int gpio_export(unsigned gpio, bool direction_may_change)
 		direction_may_change = false;
 	spin_unlock_irqrestore(&gpio_lock, flags);
 
-	if (desc->chip->names && desc->chip->names[gpio - desc->chip->base])
+	if (name)
+		ioname = name;
+	else if (desc->chip->names && desc->chip->names[gpio - desc->chip->base])
 		ioname = desc->chip->names[gpio - desc->chip->base];
 
 	dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
@@ -804,7 +807,7 @@ fail_unlock:
 	pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
 	return status;
 }
-EXPORT_SYMBOL_GPL(gpio_export);
+EXPORT_SYMBOL_GPL(gpio_export_with_name);
 
 static int match_export(struct device *dev, void *data)
 {
@@ -856,7 +859,6 @@ done:
 }
 EXPORT_SYMBOL_GPL(gpio_export_link);
 
-
 /**
  * gpio_sysfs_set_active_low - set the polarity of gpio sysfs value
  * @gpio: gpio to change
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index b6516f3..d04fc55 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -204,7 +204,8 @@ void devm_gpio_free(struct device *dev, unsigned int gpio);
  * A sysfs interface can be exported by individual drivers if they want,
  * but more typically is configured entirely from userspace.
  */
-extern int gpio_export(unsigned gpio, bool direction_may_change);
+extern int gpio_export_with_name(unsigned gpio, bool direction_may_change,
+			const char *name);
 extern int gpio_export_link(struct device *dev, const char *name,
 			unsigned gpio);
 extern int gpio_sysfs_set_active_low(unsigned gpio, int value);
@@ -249,7 +250,8 @@ struct device;
 
 /* sysfs support is only available with gpiolib, where it's optional */
 
-static inline int gpio_export(unsigned gpio, bool direction_may_change)
+static inline int gpio_export_with_name(unsigned gpio,
+	bool direction_may_change, const char *name)
 {
 	return -ENOSYS;
 }
diff --git a/include/linux/gpio.h b/include/linux/gpio.h
index 7ba2762..6e01b8c 100644
--- a/include/linux/gpio.h
+++ b/include/linux/gpio.h
@@ -189,7 +189,8 @@ static inline void gpio_set_value_cansleep(unsigned gpio, int value)
 	WARN_ON(1);
 }
 
-static inline int gpio_export(unsigned gpio, bool direction_may_change)
+static inline int gpio_export_with_name(unsigned gpio,
+	bool direction_may_change, const char *name)
 {
 	/* GPIO can never have been requested or set as {in,out}put */
 	WARN_ON(1);
@@ -247,4 +248,24 @@ gpiochip_remove_pin_ranges(struct gpio_chip *chip)
 
 #endif /* ! CONFIG_GENERIC_GPIO */
 
+/**
+ * gpio_export - export a GPIO through sysfs
+ * @gpio: gpio to make available, already requested
+ * @direction_may_change: true if userspace may change gpio direction
+ * Context: arch_initcall or later
+ *
+ * When drivers want to make a GPIO accessible to userspace after they
+ * have requested it -- perhaps while debugging, or as part of their
+ * public interface -- they may use this routine.  If the GPIO can
+ * change direction (some can't) and the caller allows it, userspace
+ * will see "direction" sysfs attribute which may be used to change
+ * the gpio's direction.  A "value" attribute will always be provided.
+ *
+ * Returns zero on success, else an error.
+ */
+static inline int gpio_export(unsigned gpio,bool direction_may_change)
+{
+	return gpio_export_with_name(gpio, direction_may_change, NULL);
+}
+
 #endif /* __LINUX_GPIO_H */
-- 
1.7.10.4