gpio: devm_gpio_* support should not depend on GPIOLIB

Some architectures (e.g. blackfin) provide gpio API without requiring
GPIOLIB support (ARCH_WANT_OPTIONAL_GPIOLIB).  devm_gpio_* functions
should also work for these architectures, since they do not really
depend on GPIOLIB.

Add a new option GPIO_DEVRES (enabled by default) to control the build
of devres.c.  It also removes the empty version of devm_gpio_*
functions for !GENERIC_GPIO build from linux/gpio.h, and moves the
function declarations from asm-generic/gpio.h into linux/gpio.h.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -30,6 +30,9 @@ config ARCH_REQUIRE_GPIOLIB
 	  Selecting this from the architecture code will cause the gpiolib
 	  code to always get built in.
 
+config GPIO_DEVRES
+	def_bool y
+	depends on HAS_IOMEM
 
 
 menuconfig GPIOLIB

drivers/gpio/Makefile

@@ -2,7 +2,8 @@
 
 ccflags-$(CONFIG_DEBUG_GPIO)	+= -DDEBUG
 
-obj-$(CONFIG_GPIOLIB)		+= gpiolib.o devres.o
+obj-$(CONFIG_GPIO_DEVRES)	+= devres.o
+obj-$(CONFIG_GPIOLIB)		+= gpiolib.o
 obj-$(CONFIG_OF_GPIO)		+= gpiolib-of.o
 obj-$(CONFIG_GPIO_ACPI)		+= gpiolib-acpi.o
 

include/asm-generic/gpio.h

@@ -192,12 +192,6 @@ extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *labe
 extern int gpio_request_array(const struct gpio *array, size_t num);
 extern void gpio_free_array(const struct gpio *array, size_t num);
 
-/* bindings for managed devices that want to request gpios */
-int devm_gpio_request(struct device *dev, unsigned gpio, const char *label);
-int devm_gpio_request_one(struct device *dev, unsigned gpio,
-			  unsigned long flags, const char *label);
-void devm_gpio_free(struct device *dev, unsigned int gpio);
-
 #ifdef CONFIG_GPIO_SYSFS
 
 /*

include/linux/gpio.h

@@ -94,24 +94,12 @@ static inline int gpio_request(unsigned gpio, const char *label)
 	return -ENOSYS;
 }
 
-static inline int devm_gpio_request(struct device *dev, unsigned gpio,
-				    const char *label)
-{
-	return -ENOSYS;
-}
-
 static inline int gpio_request_one(unsigned gpio,
 					unsigned long flags, const char *label)
 {
 	return -ENOSYS;
 }
 
-static inline int devm_gpio_request_one(struct device *dev, unsigned gpio,
-					unsigned long flags, const char *label)
-{
-	return -ENOSYS;
-}
-
 static inline int gpio_request_array(const struct gpio *array, size_t num)
 {
 	return -ENOSYS;
@@ -125,14 +113,6 @@ static inline void gpio_free(unsigned gpio)
 	WARN_ON(1);
 }
 
-static inline void devm_gpio_free(struct device *dev, unsigned gpio)
-{
-	might_sleep();
-
-	/* GPIO can never have been requested */
-	WARN_ON(1);
-}
-
 static inline void gpio_free_array(const struct gpio *array, size_t num)
 {
 	might_sleep();
@@ -248,4 +228,12 @@ gpiochip_remove_pin_ranges(struct gpio_chip *chip)
 
 #endif /* ! CONFIG_GENERIC_GPIO */
 
+struct device;
+
+/* bindings for managed devices that want to request gpios */
+int devm_gpio_request(struct device *dev, unsigned gpio, const char *label);
+int devm_gpio_request_one(struct device *dev, unsigned gpio,
+			  unsigned long flags, const char *label);
+void devm_gpio_free(struct device *dev, unsigned int gpio);
+
 #endif /* __LINUX_GPIO_H */