UPSTREAM: backlight: pwm_bl: Fix broken PWM backlight for non-dt platforms

Commit ee65ad0e2a9e ("backlight: pwm_bl: Avoid backlight flicker when
probed from DT") tries to dereference the device of_node pointer
unconditionally, causing a NULL pointer dereference on non-dt platforms.
Fix it by replacing the phandle variable with a node variable and
by checking that for NULL before dereferencing it.

Reported-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
(cherry picked from commit 8777078015bb77f0561303b6dea23d40bd9f3053)

Change-Id: If98d57968b7ae64164ae4d5995c8bf3007a35c0c
Signed-off-by: David Wu <david.wu@rock-chips.com>

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 3daf9cc9bc3127cd2f0da4a63f5ce91ecb487448..a22c1ec29de754c0de475b38a9785f47c0454c1c 100644 (file)
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -198,8 +198,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
        struct platform_pwm_backlight_data defdata;
        struct backlight_properties props;
        struct backlight_device *bl;
+       struct device_node *node = pdev->dev.of_node;
        struct pwm_bl_data *pb;
-       phandle phandle = pdev->dev.of_node->phandle;
        int initial_blank = FB_BLANK_UNBLANK;
        int ret;
 
@@ -273,7 +273,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
                 * assume that another driver will enable the backlight at the
                 * appropriate time. Therefore, if it is disabled, keep it so.
                 */
-               if (phandle &&
+               if (node && node->phandle &&
                    gpiod_get_direction(pb->enable_gpio) == GPIOF_DIR_OUT &&
                    gpiod_get_value(pb->enable_gpio) == 0)
                        initial_blank = FB_BLANK_POWERDOWN;
@@ -287,12 +287,11 @@ static int pwm_backlight_probe(struct platform_device *pdev)
                goto err_alloc;
        }
 
-       if (phandle && !regulator_is_enabled(pb->power_supply))
+       if (node && node->phandle && !regulator_is_enabled(pb->power_supply))
                initial_blank = FB_BLANK_POWERDOWN;
 
        pb->pwm = devm_pwm_get(&pdev->dev, NULL);
-       if (IS_ERR(pb->pwm) && PTR_ERR(pb->pwm) != -EPROBE_DEFER
-           && !pdev->dev.of_node) {
+       if (IS_ERR(pb->pwm) && PTR_ERR(pb->pwm) != -EPROBE_DEFER && !node) {
                dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
                pb->legacy = true;
                pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");