[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: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 13 insertions, 7 deletions

diff --git a/arch/arm/mach-pxa/pwm.c b/arch/arm/mach-pxa/pwm.c
index 7c86dd1d108f..ce28cd9fed16 100644
--- a/arch/arm/mach-pxa/pwm.c
+++ b/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);
 
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 8346dfc01cf6..6338d0e2fe07 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/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;
         }