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linux-next/Documentation/devicetree/bindings/input/sun4i-lradc-keys.txt
Hans de Goede af6a5af8e8 Input: add new sun4i-lradc-keys driver
Allwinnner sunxi SoCs have a low resolution adc (called lradc) which is
specifically designed to have various (tablet) keys (ie home, back, search,
etc). attached to it using a resistor network. This adds a driver for this.

There are 2 channels, currently this driver only supports chan0 since there
are no boards known to use chan1.

This has been tested on an olimex a10s-olinuxino-micro, a13-olinuxino, and
a20-olinuxino-micro.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2014-12-21 18:59:21 -08:00

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Allwinner sun4i low res adc attached tablet keys
------------------------------------------------
Required properties:
- compatible: "allwinner,sun4i-a10-lradc-keys"
- reg: mmio address range of the chip
- interrupts: interrupt to which the chip is connected
- vref-supply: powersupply for the lradc reference voltage
Each key is represented as a sub-node of "allwinner,sun4i-a10-lradc-keys":
Required subnode-properties:
- label: Descriptive name of the key.
- linux,code: Keycode to emit.
- channel: Channel this key is attached to, mut be 0 or 1.
- voltage: Voltage in µV at lradc input when this key is pressed.
Example:
#include <dt-bindings/input/input.h>
lradc: lradc@01c22800 {
compatible = "allwinner,sun4i-a10-lradc-keys";
reg = <0x01c22800 0x100>;
interrupts = <31>;
vref-supply = <&reg_vcc3v0>;
button@191 {
label = "Volume Up";
linux,code = <KEY_VOLUMEUP>;
channel = <0>;
voltage = <191274>;
};
button@392 {
label = "Volume Down";
linux,code = <KEY_VOLUMEDOWN>;
channel = <0>;
voltage = <392644>;
};
button@601 {
label = "Menu";
linux,code = <KEY_MENU>;
channel = <0>;
voltage = <601151>;
};
button@795 {
label = "Enter";
linux,code = <KEY_ENTER>;
channel = <0>;
voltage = <795090>;
};
button@987 {
label = "Home";
linux,code = <KEY_HOMEPAGE>;
channel = <0>;
voltage = <987387>;
};
};