backlight: use pr_warn() and pr_debug() instead of printk()

Use pr_warn() and pr_debug() instead of printk to allow dynamic debugging.
The pr_fmt prefix for pr_ macros is used.  Also fix checkpatch warnings
as below:

WARNING: Prefer pr_warn(... to printk(KERN_WARNING, ...

[akpm@linux-foundation.org: use KBUILD_MODNAME, per Joe]
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/backlight/backlight.c

@@ -5,6 +5,8 @@
  *
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/device.h>
@@ -123,7 +125,7 @@ static ssize_t backlight_store_power(struct device *dev,
 	rc = -ENXIO;
 	mutex_lock(&bd->ops_lock);
 	if (bd->ops) {
-		pr_debug("backlight: set power to %lu\n", power);
+		pr_debug("set power to %lu\n", power);
 		if (bd->props.power != power) {
 			bd->props.power = power;
 			backlight_update_status(bd);
@@ -161,8 +163,7 @@ static ssize_t backlight_store_brightness(struct device *dev,
 		if (brightness > bd->props.max_brightness)
 			rc = -EINVAL;
 		else {
-			pr_debug("backlight: set brightness to %lu\n",
-				 brightness);
+			pr_debug("set brightness to %lu\n", brightness);
 			bd->props.brightness = brightness;
 			backlight_update_status(bd);
 			rc = count;
@@ -378,7 +379,7 @@ static int __init backlight_class_init(void)
 {
 	backlight_class = class_create(THIS_MODULE, "backlight");
 	if (IS_ERR(backlight_class)) {
-		printk(KERN_WARNING "Unable to create backlight class; errno = %ld\n",
+		pr_warn("Unable to create backlight class; errno = %ld\n",
 			PTR_ERR(backlight_class));
 		return PTR_ERR(backlight_class);
 	}

drivers/video/backlight/lcd.c

@@ -5,6 +5,8 @@
  *
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/device.h>
@@ -116,7 +118,7 @@ static ssize_t lcd_store_power(struct device *dev,
 
 	mutex_lock(&ld->ops_lock);
 	if (ld->ops && ld->ops->set_power) {
-		pr_debug("lcd: set power to %lu\n", power);
+		pr_debug("set power to %lu\n", power);
 		ld->ops->set_power(ld, power);
 		rc = count;
 	}
@@ -152,7 +154,7 @@ static ssize_t lcd_store_contrast(struct device *dev,
 
 	mutex_lock(&ld->ops_lock);
 	if (ld->ops && ld->ops->set_contrast) {
-		pr_debug("lcd: set contrast to %lu\n", contrast);
+		pr_debug("set contrast to %lu\n", contrast);
 		ld->ops->set_contrast(ld, contrast);
 		rc = count;
 	}
@@ -263,7 +265,7 @@ static int __init lcd_class_init(void)
 {
 	lcd_class = class_create(THIS_MODULE, "lcd");
 	if (IS_ERR(lcd_class)) {
-		printk(KERN_WARNING "Unable to create backlight class; errno = %ld\n",
+		pr_warn("Unable to create backlight class; errno = %ld\n",
 			PTR_ERR(lcd_class));
 		return PTR_ERR(lcd_class);
 	}