1 files changed, 35 insertions, 6 deletions

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 678b27063198..f9ef0673a083 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -562,7 +562,30 @@ static int pwm_backlight_probe(struct platform_device *pdev)
                 goto err_alloc;
         }
 
-        if (!data->levels) {
+        if (data->levels) {
+                /*
+                 * For the DT case, only when brightness levels is defined
+                 * data->levels is filled. For the non-DT case, data->levels
+                 * can come from platform data, however is not usual.
+                 */
+                for (i = 0; i <= data->max_brightness; i++) {
+                        if (data->levels[i] > pb->scale)
+                                pb->scale = data->levels[i];
+
+                        pb->levels = data->levels;
+                }
+        } else if (!data->max_brightness) {
+                /*
+                 * If no brightness levels are provided and max_brightness is
+                 * not set, use the default brightness table. For the DT case,
+                 * max_brightness is set to 0 when brightness levels is not
+                 * specified. For the non-DT case, max_brightness is usually
+                 * set to some value.
+                 */
+
+                /* Get the PWM period (in nanoseconds) */
+                pwm_get_state(pb->pwm, &state);
+
                 ret = pwm_backlight_brightness_default(&pdev->dev, data,
                                                        state.period);
                 if (ret < 0) {
@@ -570,13 +593,19 @@ static int pwm_backlight_probe(struct platform_device *pdev)
                                 "failed to setup default brightness table\n");
                         goto err_alloc;
                 }
-        }
 
-        for (i = 0; i <= data->max_brightness; i++) {
-                if (data->levels[i] > pb->scale)
-                        pb->scale = data->levels[i];
+                for (i = 0; i <= data->max_brightness; i++) {
+                        if (data->levels[i] > pb->scale)
+                                pb->scale = data->levels[i];
 
-                pb->levels = data->levels;
+                        pb->levels = data->levels;
+                }
+        } else {
+                /*
+                 * That only happens for the non-DT case, where platform data
+                 * sets the max_brightness value.
+                 */
+                pb->scale = data->max_brightness;
         }
 
         pb->lth_brightness = data->lth_brightness * (state.period / pb->scale);