gpiolib: make cdev a build option

Make the gpiolib-cdev module a build option.  This allows the CDEV
interface to be removed from the kernel to reduce kernel size in
applications where is it not required, and provides the parent for
other CDEV interface specific build options to follow.

Suggested-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index c7292a5..cbf8a60 100644 (file)
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -66,8 +66,21 @@ config GPIO_SYSFS
 
          This ABI is deprecated. If you want to use GPIO from userspace,
          use the character device /dev/gpiochipN with the appropriate
-         ioctl() operations instead. The character device is always
-         available.
+         ioctl() operations instead.
+
+config GPIO_CDEV
+       bool
+       prompt "Character device (/dev/gpiochipN) support" if EXPERT
+       default y
+       help
+         Say Y here to add the character device /dev/gpiochipN interface
+         for GPIOs. The character device allows userspace to control GPIOs
+         using ioctl() operations.
+
+         Only say N if you are sure that the GPIO character device is not
+         required.
+
+         If unsure, say Y.
 
 config GPIO_GENERIC
        depends on HAS_IOMEM # Only for IOMEM drivers

diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 639275e..6c3791a 100644 (file)
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -6,8 +6,8 @@ ccflags-$(CONFIG_DEBUG_GPIO)    += -DDEBUG
 obj-$(CONFIG_GPIOLIB)          += gpiolib.o
 obj-$(CONFIG_GPIOLIB)          += gpiolib-devres.o
 obj-$(CONFIG_GPIOLIB)          += gpiolib-legacy.o
-obj-$(CONFIG_GPIOLIB)          += gpiolib-cdev.o
 obj-$(CONFIG_OF_GPIO)          += gpiolib-of.o
+obj-$(CONFIG_GPIO_CDEV)                += gpiolib-cdev.o
 obj-$(CONFIG_GPIO_SYSFS)       += gpiolib-sysfs.o
 obj-$(CONFIG_GPIO_ACPI)                += gpiolib-acpi.o
 

diff --git a/drivers/gpio/gpiolib-cdev.h b/drivers/gpio/gpiolib-cdev.h
index 973578e..19a4e3d 100644 (file)
--- a/drivers/gpio/gpiolib-cdev.h
+++ b/drivers/gpio/gpiolib-cdev.h
@@ -5,7 +5,22 @@
 
 #include <linux/device.h>
 
+#ifdef CONFIG_GPIO_CDEV
+
 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt);
 void gpiolib_cdev_unregister(struct gpio_device *gdev);
 
+#else
+
+static inline int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
+{
+       return 0;
+}
+
+static inline void gpiolib_cdev_unregister(struct gpio_device *gdev)
+{
+}
+
+#endif /* CONFIG_GPIO_CDEV */
+
 #endif /* GPIOLIB_CDEV_H */