Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt

   1 pwm-backlight bindings
   2
   3 Required properties:
   4   - compatible: "pwm-backlight"
   5   - pwms: OF device-tree PWM specification (see PWM binding[0])
   6   - brightness-levels: Array of distinct brightness levels. Typically these
   7       are in the range from 0 to 255, but any range starting at 0 will do.
   8       The actual brightness level (PWM duty cycle) will be interpolated
   9       from these values. 0 means a 0% duty cycle (darkest/off), while the
  10       last value in the array represents a 100% duty cycle (brightest).
  11   - default-brightness-level: the default brightness level (index into the
  12       array defined by the "brightness-levels" property)
  13   - power-supply: regulator for supply voltage
  14
  15 Optional properties:
  16   - pwm-names: a list of names for the PWM devices specified in the
  17                "pwms" property (see PWM binding[0])
  18   - enable-gpios: contains a single GPIO specifier for the GPIO which enables
  19                   and disables the backlight (see GPIO binding[1])
  20   - post-pwm-on-delay-ms: Delay in ms between setting an initial (non-zero) PWM
  21                           and enabling the backlight using GPIO.
  22   - pwm-off-delay-ms: Delay in ms between disabling the backlight using GPIO
  23                       and setting PWM value to 0.
  24
  25 [0]: Documentation/devicetree/bindings/pwm/pwm.txt
  26 [1]: Documentation/devicetree/bindings/gpio/gpio.txt
  27
  28 Example:
  29
  30         backlight {
  31                 compatible = "pwm-backlight";
  32                 pwms = <&pwm 0 5000000>;
  33
  34                 brightness-levels = <0 4 8 16 32 64 128 255>;
  35                 default-brightness-level = <6>;
  36
  37                 power-supply = <&vdd_bl_reg>;
  38                 enable-gpios = <&gpio 58 0>;
  39                 post-pwm-on-delay-ms = <10>;
  40                 pwm-off-delay-ms = <10>;
  41         };