backlight: as3711_bl: Fix Device Tree node lookup

Fix child-node lookup during probe, which ended up searching the whole
device tree depth-first starting at the parent rather than just matching
on its children.

To make things worse, the parent mfd node was also prematurely freed.

Cc: stable <stable@vger.kernel.org>     # 3.10
Fixes: 59eb2b5e57ea ("drivers/video/backlight/as3711_bl.c: add OF support")
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

1 files changed, 23 insertions, 10 deletions

diff --git a/drivers/video/backlight/as3711_bl.c b/drivers/video/backlight/as3711_bl.c
index 734a9158946b..e55304d5cf07 100644
--- a/drivers/video/backlight/as3711_bl.c
+++ b/drivers/video/backlight/as3711_bl.c
@@ -262,10 +262,10 @@ static int as3711_bl_register(struct platform_device *pdev,
 static int as3711_backlight_parse_dt(struct device *dev)
 {
         struct as3711_bl_pdata *pdata = dev_get_platdata(dev);
-        struct device_node *bl =
-                of_find_node_by_name(dev->parent->of_node, "backlight"), *fb;
+        struct device_node *bl, *fb;
         int ret;
 
+        bl = of_get_child_by_name(dev->parent->of_node, "backlight");
         if (!bl) {
                 dev_dbg(dev, "backlight node not found\n");
                 return -ENODEV;
@@ -279,7 +279,7 @@ static int as3711_backlight_parse_dt(struct device *dev)
                 if (pdata->su1_max_uA <= 0)
                         ret = -EINVAL;
                 if (ret < 0)
-                        return ret;
+                        goto err_put_bl;
         }
 
         fb = of_parse_phandle(bl, "su2-dev", 0);
@@ -292,7 +292,7 @@ static int as3711_backlight_parse_dt(struct device *dev)
                 if (pdata->su2_max_uA <= 0)
                         ret = -EINVAL;
                 if (ret < 0)
-                        return ret;
+                        goto err_put_bl;
 
                 if (of_find_property(bl, "su2-feedback-voltage", NULL)) {
                         pdata->su2_feedback = AS3711_SU2_VOLTAGE;
@@ -314,8 +314,10 @@ static int as3711_backlight_parse_dt(struct device *dev)
                         pdata->su2_feedback = AS3711_SU2_CURR_AUTO;
                         count++;
                 }
-                if (count != 1)
-                        return -EINVAL;
+                if (count != 1) {
+                        ret = -EINVAL;
+                        goto err_put_bl;
+                }
 
                 count = 0;
                 if (of_find_property(bl, "su2-fbprot-lx-sd4", NULL)) {
@@ -334,8 +336,10 @@ static int as3711_backlight_parse_dt(struct device *dev)
                         pdata->su2_fbprot = AS3711_SU2_GPIO4;
                         count++;
                 }
-                if (count != 1)
-                        return -EINVAL;
+                if (count != 1) {
+                        ret = -EINVAL;
+                        goto err_put_bl;
+                }
 
                 count = 0;
                 if (of_find_property(bl, "su2-auto-curr1", NULL)) {
@@ -355,11 +359,20 @@ static int as3711_backlight_parse_dt(struct device *dev)
                  * At least one su2-auto-curr* must be specified iff
                  * AS3711_SU2_CURR_AUTO is used
                  */
-                if (!count ^ (pdata->su2_feedback != AS3711_SU2_CURR_AUTO))
-                        return -EINVAL;
+                if (!count ^ (pdata->su2_feedback != AS3711_SU2_CURR_AUTO)) {
+                        ret = -EINVAL;
+                        goto err_put_bl;
+                }
         }
 
+        of_node_put(bl);
+
         return 0;
+
+err_put_bl:
+        of_node_put(bl);
+
+        return ret;
 }
 
 static int as3711_backlight_probe(struct platform_device *pdev)