UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

backlight: pwm_bl: Fix brightness levels for non-DT case. 

Commit '88ba95bedb79 ("backlight: pwm_bl: Compute brightness of LED
linearly to human eye")' allows the possibility to compute a default
brightness table when there isn't the brightness-levels property in the
DT. Unfortunately the changes made broke the pwm backlight for the
non-DT boards.

Usually, the non-DT boards don't pass the brightness levels via platform
data, instead, it sets the max_brightness in their platform data and the
driver calculates the level without a table. The offending patch assumed
that when there is no brightness levels table we should create one, but this
is clearly wrong for the non-DT case.

After this patch the code handles the DT and the non-DT case taking in
consideration also if max_brightness is set or not.

Fixes: 88ba95bedb ("backlight: pwm_bl: Compute brightness of LED linearly to human eye")
Reported-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Enric Balletbo i Serra 2018-12-10 13:14:37 +01:00 committed by Lee Jones
parent 651022382c
commit d347d0c82a
1 changed files with 35 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
drivers/video/backlight/pwm_bl.c
View File

@ -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) {
@ -570,7 +593,6 @@ 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)
@ -578,6 +600,13 @@ static int pwm_backlight_probe(struct platform_device *pdev)
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);