lcd: add devm_lcd_device_{register,unregister}()

These functions allow the driver core to automatically clean up any
allocation made by lcd drivers.  Thus it simplifies the error paths.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/video/backlight/lcd.c b/drivers/video/backlight/lcd.c
index 3649fd9ddb3a951b6e6ff669ef36dbcee8f3ebed..41964a71a036c676c7ff256f190cb7186c245b6c 100644 (file)
--- a/drivers/video/backlight/lcd.c
+++ b/drivers/video/backlight/lcd.c
@@ -260,6 +260,76 @@ void lcd_device_unregister(struct lcd_device *ld)
 }
 EXPORT_SYMBOL(lcd_device_unregister);
 
+static void devm_lcd_device_release(struct device *dev, void *res)
+{
+       struct lcd_device *lcd = *(struct lcd_device **)res;
+
+       lcd_device_unregister(lcd);
+}
+
+static int devm_lcd_device_match(struct device *dev, void *res, void *data)
+{
+       struct lcd_device **r = res;
+
+       return *r == data;
+}
+
+/**
+ * devm_lcd_device_register - resource managed lcd_device_register()
+ * @dev: the device to register
+ * @name: the name of the device
+ * @parent: a pointer to the parent device
+ * @devdata: an optional pointer to be stored for private driver use
+ * @ops: the lcd operations structure
+ *
+ * @return a struct lcd on success, or an ERR_PTR on error
+ *
+ * Managed lcd_device_register(). The lcd_device returned from this function
+ * are automatically freed on driver detach. See lcd_device_register()
+ * for more information.
+ */
+struct lcd_device *devm_lcd_device_register(struct device *dev,
+               const char *name, struct device *parent,
+               void *devdata, struct lcd_ops *ops)
+{
+       struct lcd_device **ptr, *lcd;
+
+       ptr = devres_alloc(devm_lcd_device_release, sizeof(*ptr), GFP_KERNEL);
+       if (!ptr)
+               return ERR_PTR(-ENOMEM);
+
+       lcd = lcd_device_register(name, parent, devdata, ops);
+       if (!IS_ERR(lcd)) {
+               *ptr = lcd;
+               devres_add(dev, ptr);
+       } else {
+               devres_free(ptr);
+       }
+
+       return lcd;
+}
+EXPORT_SYMBOL(devm_lcd_device_register);
+
+/**
+ * devm_lcd_device_unregister - resource managed lcd_device_unregister()
+ * @dev: the device to unregister
+ * @ld: the lcd device to unregister
+ *
+ * Deallocated a lcd allocated with devm_lcd_device_register(). Normally
+ * this function will not need to be called and the resource management
+ * code will ensure that the resource is freed.
+ */
+void devm_lcd_device_unregister(struct device *dev, struct lcd_device *ld)
+{
+       int rc;
+
+       rc = devres_release(dev, devm_lcd_device_release,
+                               devm_lcd_device_match, ld);
+       WARN_ON(rc);
+}
+EXPORT_SYMBOL(devm_lcd_device_unregister);
+
+
 static void __exit lcd_class_exit(void)
 {
        class_destroy(lcd_class);

diff --git a/include/linux/lcd.h b/include/linux/lcd.h
index e00c3b0ebc6bd7303afdb0ffa448a31c0d000911..504f6246f38f38feb59d3eb0faee7a4e663379b7 100644 (file)
--- a/include/linux/lcd.h
+++ b/include/linux/lcd.h
@@ -112,7 +112,12 @@ static inline void lcd_set_power(struct lcd_device *ld, int power)
 
 extern struct lcd_device *lcd_device_register(const char *name,
        struct device *parent, void *devdata, struct lcd_ops *ops);
+extern struct lcd_device *devm_lcd_device_register(struct device *dev,
+       const char *name, struct device *parent,
+       void *devdata, struct lcd_ops *ops);
 extern void lcd_device_unregister(struct lcd_device *ld);
+extern void devm_lcd_device_unregister(struct device *dev,
+       struct lcd_device *ld);
 
 #define to_lcd_device(obj) container_of(obj, struct lcd_device, dev)