[ARM] 5141/1: PWM: pwm_request() should return an PTR_ERR() instead of NULL.

Make the return of pwm_request() be more informative than just
being NULL on error by using PTR_ERR() to respond with an
approriate error.
Signed-off-by: NBen Dooks <ben-linux@fluff.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-pxa/pwm.c

@@ -119,17 +119,23 @@ struct pwm_device *pwm_request(int pwm_id, const char *label)
 	mutex_lock(&pwm_lock);
 
 	list_for_each_entry(pwm, &pwm_list, node) {
-		if (pwm->pwm_id == pwm_id && pwm->use_count == 0) {
-			pwm->use_count++;
-			pwm->label = label;
+		if (pwm->pwm_id == pwm_id) {
 			found = 1;
 			break;
 		}
 	}
 
-	mutex_unlock(&pwm_lock);
+	if (found) {
+		if (pwm->use_count == 0) {
+			pwm->use_count++;
+			pwm->label = label;
+		} else
+			pwm = ERR_PTR(-EBUSY);
+	} else
+		pwm = ERR_PTR(-ENOENT);
 
-	return (found) ? pwm : NULL;
+	mutex_unlock(&pwm_lock);
+	return pwm;
 }
 EXPORT_SYMBOL(pwm_request);
 

drivers/video/backlight/pwm_bl.c

@@ -87,9 +87,9 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 	pb->notify = data->notify;
 
 	pb->pwm = pwm_request(data->pwm_id, "backlight");
-	if (pb->pwm == NULL) {
+	if (IS_ERR(pb->pwm)) {
 		dev_err(&pdev->dev, "unable to request PWM for backlight\n");
-		ret = -EBUSY;
+		ret = PTR_ERR(pb->pwm);
 		goto err_pwm;
 	}