For backlight curves calculated with the CIE 1931 algorithm set
the brightness scale type to non-linear. This makes the scale type
available to userspace via the 'scale' sysfs attribute.

Signed-off-by: Matthias Kaehlcke <m...@chromium.org>
Tested-by: Enric Balletbo i Serra <enric.balle...@collabora.com>
Acked-by: Daniel Thompson <daniel.thomp...@linaro.org>
---
Changes in v3:
- mark scale as non-linear instead of using the CIE1931 type which
  has been removed
- updated commit message

Changes in v2:
- added Enric's 'Tested-by' tag
- added Daniel's 'Acked-by' tag
---
 drivers/video/backlight/pwm_bl.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index fb45f866b923..7c6dfc4a601d 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -553,6 +553,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
                goto err_alloc;
        }
 
+       memset(&props, 0, sizeof(struct backlight_properties));
+
        if (data->levels) {
                /*
                 * For the DT case, only when brightness levels is defined
@@ -591,6 +593,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 
                        pb->levels = data->levels;
                }
+
+               props.scale = BACKLIGHT_SCALE_NON_LINEAR;
        } else {
                /*
                 * That only happens for the non-DT case, where platform data
@@ -601,7 +605,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 
        pb->lth_brightness = data->lth_brightness * (state.period / pb->scale);
 
-       memset(&props, 0, sizeof(struct backlight_properties));
        props.type = BACKLIGHT_RAW;
        props.max_brightness = data->max_brightness;
        bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb,
-- 
2.22.0.410.gd8fdbe21b5-goog

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