drivers/video/backlight: use devm_ functions

The various devm_ functions allocate memory that is released when a driver
detaches.  This patch uses these functions for data that is allocated in
the probe function of a platform device and is only freed in the remove
function.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 7496d04..342b7d7 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -102,7 +102,7 @@
 			return ret;
 	}
 
-	pb = kzalloc(sizeof(*pb), GFP_KERNEL);
+	pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL);
 	if (!pb) {
 		dev_err(&pdev->dev, "no memory for state\n");
 		ret = -ENOMEM;
@@ -121,7 +121,7 @@
 	if (IS_ERR(pb->pwm)) {
 		dev_err(&pdev->dev, "unable to request PWM for backlight\n");
 		ret = PTR_ERR(pb->pwm);
-		goto err_pwm;
+		goto err_alloc;
 	} else
 		dev_dbg(&pdev->dev, "got pwm for backlight\n");
 
@@ -144,8 +144,6 @@
 
 err_bl:
 	pwm_free(pb->pwm);
-err_pwm:
-	kfree(pb);
 err_alloc:
 	if (data->exit)
 		data->exit(&pdev->dev);
@@ -162,7 +160,6 @@
 	pwm_config(pb->pwm, 0, pb->period);
 	pwm_disable(pb->pwm);
 	pwm_free(pb->pwm);
-	kfree(pb);
 	if (data->exit)
 		data->exit(&pdev->dev);
 	return 0;