git.openwrt.org Git - openwrt/staging/linusw.git/blob

   1 From 7ec32023e6ad31c242e2acc179fd35084fa9cea5 Mon Sep 17 00:00:00 2001
   2 From: Dave Stevenson <dave.stevenson@raspberrypi.com>
   3 Date: Fri, 21 Jan 2022 14:22:01 +0000
   4 Subject: [PATCH] dtoverlays: Add pwm backlight option to
   5  vc4-kms-dpi-generic
   6
   7 Adds the option of a PWM controlled backlight on a generic
   8 DPI display.
   9
  10 Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
  11 ---
  12  arch/arm/boot/dts/overlays/README             | 17 +++++++
  13  .../overlays/vc4-kms-dpi-generic-overlay.dts  | 51 +++++++++++++++++++
  14  2 files changed, 68 insertions(+)
  15
  16 --- a/arch/arm/boot/dts/overlays/README
  17 +++ b/arch/arm/boot/dts/overlays/README
  18 @@ -3644,6 +3644,23 @@ Params: clock-frequency         Display
  19                                  value. NB also overridden by rgbXXX overrides.
  20          backlight-gpio          Defines a GPIO to be used for backlight control
  21                                  (default of none).
  22 +        backlight-pwm           Defines a PWM channel to be used for backlight
  23 +                                control (default of none). NB Disables audio
  24 +                                headphone output as that also uses PWM.
  25 +        backlight-pwm-chan      Choose channel on &pwm node for backlight
  26 +                                control.
  27 +                                (default 0).
  28 +        backlight-pwm-gpio      GPIO pin to be used for the PWM backlight. See
  29 +                                pwm-2chan for valid options.
  30 +                                (default 18 - note this can only work with
  31 +                                 rgb666-padhi).
  32 +        backlight-pwm-func      Pin function of GPIO used for the PWM
  33 +                                backlight.
  34 +                                See pwm-2chan for valid options.
  35 +                                (default 2).
  36 +        backlight-def-brightness
  37 +                                Set the default brightness. Normal range 1-16.
  38 +                                (default 16).
  39
  40
  41  Name:   vc4-kms-dsi-7inch
  42 --- a/arch/arm/boot/dts/overlays/vc4-kms-dpi-generic-overlay.dts
  43 +++ b/arch/arm/boot/dts/overlays/vc4-kms-dpi-generic-overlay.dts
  44 @@ -80,6 +80,52 @@
  45                 };
  46         };
  47
  48 +       fragment@4 {
  49 +               target = <&panel>;
  50 +               __dormant__  {
  51 +                       backlight = <&backlight_pwm>;
  52 +               };
  53 +       };
  54 +
  55 +       fragment@5 {
  56 +               target-path = "/";
  57 +               __dormant__  {
  58 +                       backlight_pwm: backlight_pwm {
  59 +                               compatible = "pwm-backlight";
  60 +                               brightness-levels = <0 6 8 12 16 24 32 40 48 64 96 128 160 192 224 255>;
  61 +                               default-brightness-level = <16>;
  62 +                               pwms = <&pwm 0 200000>;
  63 +                       };
  64 +               };
  65 +       };
  66 +
  67 +       fragment@6 {
  68 +               target = <&pwm>;
  69 +               __dormant__ {
  70 +                       pinctrl-names = "default";
  71 +                       pinctrl-0 = <&pwm_pins>;
  72 +                       assigned-clock-rates = <1000000>;
  73 +                       status = "okay";
  74 +               };
  75 +       };
  76 +
  77 +       fragment@7 {
  78 +               target = <&gpio>;
  79 +               __dormant__ {
  80 +                       pwm_pins: pwm_pins {
  81 +                               brcm,pins = <18>;
  82 +                               brcm,function = <2>; /* Alt5 */
  83 +                       };
  84 +               };
  85 +       };
  86 +
  87 +       fragment@8 {
  88 +               target = <&audio>;
  89 +               __dormant__  {
  90 +                   brcm,disable-headphones;
  91 +               };
  92 +       };
  93 +
  94         __overrides__ {
  95                 clock-frequency = <&timing>, "clock-frequency:0";
  96                 hactive = <&timing>, "hactive:0";
  97 @@ -107,5 +153,10 @@
  98                 bus-format = <&panel>, "bus-format:0";
  99                 backlight-gpio = <0>, "+2+3",
 100                         <&backlight>, "gpios:4";
 101 +               backlight-pwm = <0>, "+4+5+6+7+8";
 102 +               backlight-pwm-chan = <&backlight_pwm>, "pwms:4";
 103 +               backlight-pwm-gpio = <&pwm_pins>, "brcm,pins:0";
 104 +               backlight-pwm-func = <&pwm_pins>, "brcm,function:0";
 105 +               backlight-def-brightness = <&backlight_pwm>, "default-brightness-level:0";
 106         };
 107  };