ARM64: dts: meson-gxbb-p200: add ADC laddered keys

Add the 5 buttons connected to a resistor laddered matrix and sampled
by the SAR ADC channel 0.

Only the p200 board has these buttons, the P201 doesn't.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

diff --git a/arch/arm64/boot/dts/amlogic/meson-gxbb-p200.dts b/arch/arm64/boot/dts/amlogic/meson-gxbb-p200.dts
index 03e3d76626ddc45c1f35b95725c768e9221c8498..fc0e86cb4cdedc00a8796b2276bc3b53c0df9b03 100644 (file)
--- a/arch/arm64/boot/dts/amlogic/meson-gxbb-p200.dts
+++ b/arch/arm64/boot/dts/amlogic/meson-gxbb-p200.dts
@@ -45,10 +45,55 @@
 /dts-v1/;
 
 #include "meson-gxbb-p20x.dtsi"
+#include <dt-bindings/input/input.h>
 
 / {
        compatible = "amlogic,p200", "amlogic,meson-gxbb";
        model = "Amlogic Meson GXBB P200 Development Board";
+
+       avdd18_usb_adc: regulator-avdd18_usb_adc {
+               compatible = "regulator-fixed";
+               regulator-name = "AVDD18_USB_ADC";
+               regulator-min-microvolt = <1800000>;
+               regulator-max-microvolt = <1800000>;
+       };
+
+       adc_keys {
+               compatible = "adc-keys";
+               io-channels = <&saradc 0>;
+               io-channel-names = "buttons";
+               keyup-threshold-microvolt = <1800000>;
+
+               button-home {
+                       label = "Home";
+                       linux,code = <KEY_HOME>;
+                       press-threshold-microvolt = <900000>; /* 50% */
+               };
+
+               button-esc {
+                       label = "Esc";
+                       linux,code = <KEY_ESC>;
+                       press-threshold-microvolt = <684000>; /* 38% */
+               };
+
+               button-up {
+                       label = "Volume Up";
+                       linux,code = <KEY_VOLUMEUP>;
+                       press-threshold-microvolt = <468000>; /* 26% */
+               };
+
+               button-down {
+                       label = "Volume Down";
+                       linux,code = <KEY_VOLUMEDOWN>;
+                       press-threshold-microvolt = <252000>; /* 14% */
+               };
+
+               button-menu {
+                       label = "Menu";
+                       linux,code = <KEY_MENU>;
+                       press-threshold-microvolt = <0>; /* 0% */
+               };
+       };
 };
 
 &i2c_B {
@@ -56,3 +101,8 @@ &i2c_B {
        pinctrl-0 = <&i2c_b_pins>;
        pinctrl-names = "default";
 };
+
+&saradc {
+       status = "okay";
+       vref-supply = <&avdd18_usb_adc>;
+};