Merge tag 'backlight-fixes-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git...

Pull backlight fix from Lee Jones:
 "Fix brightness levels when !DT in pwm_bl driver"

* tag 'backlight-fixes-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  backlight: pwm_bl: Fix brightness levels for non-DT case.

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 678b270..f9ef067 100644 (file)
--- 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);