target/linux/bcm27xx/patches-5.15/950-0913-overlays-Add-gpio-hog-overlay.patch

   1 From a2948fd59692f1d30ce64035bed33b32997a0ad7 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.com>
   3 Date: Mon, 16 May 2022 12:16:46 +0100
   4 Subject: [PATCH] overlays: Add gpio-hog overlay
   5
   6 Add an overlay to activate a hog on a specified pin. Note that
   7 hogged GPIOs are not available for other uses, i.e. drivers or
   8 gpioset/gpioget.
   9
  10 Inspired by a Forum thread here:
  11
  12     https://forums.raspberrypi.com/viewtopic.php?t=334286
  13
  14 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
  15 ---
  16  arch/arm/boot/dts/overlays/Makefile           |  1 +
  17  arch/arm/boot/dts/overlays/README             | 11 ++++++++
  18  .../boot/dts/overlays/gpio-hog-overlay.dts    | 27 +++++++++++++++++++
  19  3 files changed, 39 insertions(+)
  20  create mode 100644 arch/arm/boot/dts/overlays/gpio-hog-overlay.dts
  21
  22 --- a/arch/arm/boot/dts/overlays/Makefile
  23 +++ b/arch/arm/boot/dts/overlays/Makefile
  24 @@ -59,6 +59,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
  25         goodix.dtbo \
  26         googlevoicehat-soundcard.dtbo \
  27         gpio-fan.dtbo \
  28 +       gpio-hog.dtbo \
  29         gpio-ir.dtbo \
  30         gpio-ir-tx.dtbo \
  31         gpio-key.dtbo \
  32 --- a/arch/arm/boot/dts/overlays/README
  33 +++ b/arch/arm/boot/dts/overlays/README
  34 @@ -1061,6 +1061,17 @@ Params: gpiopin                 GPIO use
  35                                  millicelcius (default 55000)
  36
  37
  38 +Name:   gpio-hog
  39 +Info:   Activate a "hog" for a GPIO - request that the kernel configures it as
  40 +        an output, driven low or high as indicated by the presence or absence
  41 +        of the active_low parameter. Note that a hogged GPIO is not available
  42 +        to other drivers or for gpioset/gpioget.
  43 +Load:   dtoverlay=gpio-hog,<param>=<val>
  44 +Params: gpio                    GPIO pin to hog (default 26)
  45 +        active_low              If set, the hog drives the GPIO low (defaults
  46 +                                to off - the GPIO is driven high)
  47 +
  48 +
  49  Name:   gpio-ir
  50  Info:   Use GPIO pin as rc-core style infrared receiver input. The rc-core-
  51          based gpio_ir_recv driver maps received keys directly to a
  52 --- /dev/null
  53 +++ b/arch/arm/boot/dts/overlays/gpio-hog-overlay.dts
  54 @@ -0,0 +1,27 @@
  55 +// Configure a "hog" on the specified GPIO
  56 +/dts-v1/;
  57 +/plugin/;
  58 +
  59 +#include <dt-bindings/gpio/gpio.h>
  60 +
  61 +/ {
  62 +       compatible = "brcm,bcm2835";
  63 +
  64 +       fragment@0 {
  65 +               target = <&gpio>;
  66 +               __overlay__ {
  67 +                       hog: hog@1a {
  68 +                            gpio-hog;
  69 +                            gpios = <26 GPIO_ACTIVE_HIGH>;
  70 +                            output-high;
  71 +                       };
  72 +               };
  73 +       };
  74 +
  75 +       __overrides__ {
  76 +               gpio =       <&hog>,"reg:0",
  77 +                            <&hog>,"gpios:0";
  78 +               active_low = <&hog>,"output-high!",
  79 +                            <&hog>,"output-low?";
  80 +       };
  81 +};