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| author | Enric Balletbo i Serra <enric.balletbo@collabora.com> | 2018-04-09 10:33:31 +0200 |
|---|---|---|
| committer | Lee Jones <lee.jones@linaro.org> | 2018-07-04 11:31:18 +0200 |
| commit | 1e5e7cc794b5a332c23216dade0a2e937d694b7f (patch) | |
| tree | cc70709be606271643554a68d33af26324b22433 /Documentation | |
| parent | backlight: pwm_bl: Linear interpolation between brightness-levels (diff) | |
| download | linux-1e5e7cc794b5a332c23216dade0a2e937d694b7f.tar.xz linux-1e5e7cc794b5a332c23216dade0a2e937d694b7f.zip | |
dt-bindings: pwm-backlight: Add a num-interpolation-steps property
The num-interpolated-steps property specifies the number of
interpolated steps between each value of brightness-level table. This is
useful for high resolution PWMs to not have to list out every possible
value in the brightness-level array.
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt index 310810906613..ce9b5746b774 100644 --- a/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt +++ b/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt @@ -21,6 +21,11 @@ Optional properties: and enabling the backlight using GPIO. - pwm-off-delay-ms: Delay in ms between disabling the backlight using GPIO and setting PWM value to 0. + - num-interpolated-steps: Number of interpolated steps between each value + of brightness-levels table. This way a high + resolution pwm duty cycle can be used without + having to list out every possible value in the + brightness-level array. [0]: Documentation/devicetree/bindings/pwm/pwm.txt [1]: Documentation/devicetree/bindings/gpio/gpio.txt @@ -39,3 +44,17 @@ Example: post-pwm-on-delay-ms = <10>; pwm-off-delay-ms = <10>; }; + +Example using num-interpolation-steps: + + backlight { + compatible = "pwm-backlight"; + pwms = <&pwm 0 5000000>; + + brightness-levels = <0 2048 4096 8192 16384 65535>; + num-interpolated-steps = <2048>; + default-brightness-level = <4096>; + + power-supply = <&vdd_bl_reg>; + enable-gpios = <&gpio 58 0>; + }; |