diff options
| author | Marek Szyprowski <m.szyprowski@samsung.com> | 2021-02-18 11:33:14 +0100 |
|---|---|---|
| committer | Neil Armstrong <narmstrong@baylibre.com> | 2021-02-18 11:37:26 +0100 |
| commit | e1b03d6b0bb96157ac9abb8ff4c959da4daa3941 (patch) | |
| tree | d8de65de68cd3bd2153f2dab9e1eaea9c9d03345 /doc/device-tree-bindings | |
| parent | 496f49464d90b564da5f1a2f4eecb5553e01edf9 (diff) | |
dt-bindings: input: adc-keys bindings documentation
Dump adc-keys bindings documentation from Linux kernel source tree from
commit 698dc0cf9447 ("dt-bindings: input: adc-keys: clarify
description").
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Diffstat (limited to 'doc/device-tree-bindings')
| -rw-r--r-- | doc/device-tree-bindings/input/adc-keys.txt | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/doc/device-tree-bindings/input/adc-keys.txt b/doc/device-tree-bindings/input/adc-keys.txt new file mode 100644 index 0000000000..6c8be6a9ac --- /dev/null +++ b/doc/device-tree-bindings/input/adc-keys.txt @@ -0,0 +1,67 @@ +ADC attached resistor ladder buttons +------------------------------------ + +Required properties: + - compatible: "adc-keys" + - io-channels: Phandle to an ADC channel + - io-channel-names = "buttons"; + - keyup-threshold-microvolt: Voltage above or equal to which all the keys are + considered up. + +Optional properties: + - poll-interval: Poll interval time in milliseconds + - autorepeat: Boolean, Enable auto repeat feature of Linux input + subsystem. + +Each button (key) is represented as a sub-node of "adc-keys": + +Required subnode-properties: + - label: Descriptive name of the key. + - linux,code: Keycode to emit. + - press-threshold-microvolt: voltage above or equal to which this key is + considered pressed. + +No two values of press-threshold-microvolt may be the same. +All values of press-threshold-microvolt must be less than +keyup-threshold-microvolt. + +Example: + +#include <dt-bindings/input/input.h> + + adc-keys { + compatible = "adc-keys"; + io-channels = <&lradc 0>; + io-channel-names = "buttons"; + keyup-threshold-microvolt = <2000000>; + + button-up { + label = "Volume Up"; + linux,code = <KEY_VOLUMEUP>; + press-threshold-microvolt = <1500000>; + }; + + button-down { + label = "Volume Down"; + linux,code = <KEY_VOLUMEDOWN>; + press-threshold-microvolt = <1000000>; + }; + + button-enter { + label = "Enter"; + linux,code = <KEY_ENTER>; + press-threshold-microvolt = <500000>; + }; + }; + ++--------------------------------+------------------------+ +| 2.000.000 <= value | no key pressed | ++--------------------------------+------------------------+ +| 1.500.000 <= value < 2.000.000 | KEY_VOLUMEUP pressed | ++--------------------------------+------------------------+ +| 1.000.000 <= value < 1.500.000 | KEY_VOLUMEDOWN pressed | ++--------------------------------+------------------------+ +| 500.000 <= value < 1.000.000 | KEY_ENTER pressed | ++--------------------------------+------------------------+ +| value < 500.000 | no key pressed | ++--------------------------------+------------------------+ |