0001 * HID over I2C Device-Tree bindings
0002
0003 HID over I2C provides support for various Human Interface Devices over the
0004 I2C bus. These devices can be for example touchpads, keyboards, touch screens
0005 or sensors.
0006
0007 The specification has been written by Microsoft and is currently available here:
0008 http://msdn.microsoft.com/en-us/library/windows/hardware/hh852380.aspx
0009
0010 If this binding is used, the kernel module i2c-hid will handle the communication
0011 with the device and the generic hid core layer will handle the protocol.
0012
0013 Required properties:
0014 - compatible: must be "hid-over-i2c"
0015 - reg: i2c slave address
0016 - hid-descr-addr: HID descriptor address
0017 - interrupts: interrupt line
0018
0019 Additional optional properties:
0020
0021 Some devices may support additional optional properties to help with, e.g.,
0022 power sequencing. The following properties can be supported by one or more
0023 device-specific compatible properties, which should be used in addition to the
0024 "hid-over-i2c" string.
0025
0026 - compatible:
0027 * "wacom,w9013" (Wacom W9013 digitizer). Supports:
0028 - vdd-supply (3.3V)
0029 - vddl-supply (1.8V)
0030 - post-power-on-delay-ms
0031
0032 - vdd-supply: phandle of the regulator that provides the supply voltage.
0033 - post-power-on-delay-ms: time required by the device after enabling its regulators
0034 or powering it on, before it is ready for communication.
0035 - touchscreen-inverted-x: See touchscreen.txt
0036 - touchscreen-inverted-y: See touchscreen.txt
0037
0038 Example:
0039
0040 i2c-hid-dev@2c {
0041 compatible = "hid-over-i2c";
0042 reg = <0x2c>;
0043 hid-descr-addr = <0x0020>;
0044 interrupt-parent = <&gpx3>;
0045 interrupts = <3 2>;
0046 };
