xref: /OK3568_Linux_fs/kernel/Documentation/devicetree/bindings/input/hid-over-i2c.txt (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun* HID over I2C Device-Tree bindings
2*4882a593Smuzhiyun
3*4882a593SmuzhiyunHID over I2C provides support for various Human Interface Devices over the
4*4882a593SmuzhiyunI2C bus. These devices can be for example touchpads, keyboards, touch screens
5*4882a593Smuzhiyunor sensors.
6*4882a593Smuzhiyun
7*4882a593SmuzhiyunThe specification has been written by Microsoft and is currently available here:
8*4882a593Smuzhiyunhttp://msdn.microsoft.com/en-us/library/windows/hardware/hh852380.aspx
9*4882a593Smuzhiyun
10*4882a593SmuzhiyunIf this binding is used, the kernel module i2c-hid will handle the communication
11*4882a593Smuzhiyunwith the device and the generic hid core layer will handle the protocol.
12*4882a593Smuzhiyun
13*4882a593SmuzhiyunRequired properties:
14*4882a593Smuzhiyun- compatible: must be "hid-over-i2c"
15*4882a593Smuzhiyun- reg: i2c slave address
16*4882a593Smuzhiyun- hid-descr-addr: HID descriptor address
17*4882a593Smuzhiyun- interrupts: interrupt line
18*4882a593Smuzhiyun
19*4882a593SmuzhiyunAdditional optional properties:
20*4882a593Smuzhiyun
21*4882a593SmuzhiyunSome devices may support additional optional properties to help with, e.g.,
22*4882a593Smuzhiyunpower sequencing. The following properties can be supported by one or more
23*4882a593Smuzhiyundevice-specific compatible properties, which should be used in addition to the
24*4882a593Smuzhiyun"hid-over-i2c" string.
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun- compatible:
27*4882a593Smuzhiyun  * "wacom,w9013" (Wacom W9013 digitizer). Supports:
28*4882a593Smuzhiyun    - vdd-supply (3.3V)
29*4882a593Smuzhiyun    - vddl-supply (1.8V)
30*4882a593Smuzhiyun    - post-power-on-delay-ms
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun- vdd-supply: phandle of the regulator that provides the supply voltage.
33*4882a593Smuzhiyun- post-power-on-delay-ms: time required by the device after enabling its regulators
34*4882a593Smuzhiyun  or powering it on, before it is ready for communication.
35*4882a593Smuzhiyun
36*4882a593SmuzhiyunExample:
37*4882a593Smuzhiyun
38*4882a593Smuzhiyun	i2c-hid-dev@2c {
39*4882a593Smuzhiyun		compatible = "hid-over-i2c";
40*4882a593Smuzhiyun		reg = <0x2c>;
41*4882a593Smuzhiyun		hid-descr-addr = <0x0020>;
42*4882a593Smuzhiyun		interrupt-parent = <&gpx3>;
43*4882a593Smuzhiyun		interrupts = <3 2>;
44*4882a593Smuzhiyun	};
45