From 47c9db1acefcc6c0b34fb01fde87a300617f5565 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Fri, 28 Sep 2012 10:20:20 +1000 Subject: [PATCH] pwm_backlight-add-device-tree-support-for-low-threshold-brightness-fix Cc: "Philip, Avinash" Cc: Florian Tobias Schandinat Cc: Grant Likely Cc: Philip, Avinash Cc: Richard Purdie Cc: Thierry Reding Signed-off-by: Andrew Morton --- .../bindings/video/backlight/pwm-backlight.txt | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt index 4e2991214e54..c02d5ccd6e62 100644 --- a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt +++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt @@ -14,15 +14,15 @@ Required properties: Optional properties: - pwm-names: a list of names for the PWM devices specified in the "pwms" property (see PWM binding[0]) - - low-threshold-brightness: brightness threshold low level. Low threshold - brightness set to value so that backlight present on low end of - brightness. - Some panels, backlight would absent if duty percentage of PWM wave is less - than certain level (say 20%). By setting low-threshold-brightness to a - value above (percentage of brightness-levels max) 50 (20% of 255, if 255 - is max). On setting low-threshold-brightness, range of brightness-levels - is calculated in a region of low-threshold-brightness to brightness-levels - max. + - low-threshold-brightness: brightness threshold low level. Sets the lowest + brightness value. + On some panels the backlight misbehaves if the duty cycle percentage of the + PWM wave is less than a certain level (say 20%). In this example the user + can set low-threshold-brightness to a value above 50 (ie, 20% of 255), thus + preventing the PWM duty cycle from going too low. + On setting low-threshold-brightness the range of brightness levels is + calculated in the range low-threshold-brightness to the maximum value in + brightness-levels, described above. [0]: Documentation/devicetree/bindings/pwm/pwm.txt -- 2.39.5