^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) * HID over I2C Device-Tree bindings
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) HID over I2C provides support for various Human Interface Devices over the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) I2C bus. These devices can be for example touchpads, keyboards, touch screens
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) or sensors.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) The specification has been written by Microsoft and is currently available here:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) http://msdn.microsoft.com/en-us/library/windows/hardware/hh852380.aspx
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) If this binding is used, the kernel module i2c-hid will handle the communication
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) with the device and the generic hid core layer will handle the protocol.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) Required properties:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) - compatible: must be "hid-over-i2c"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) - reg: i2c slave address
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) - hid-descr-addr: HID descriptor address
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) - interrupts: interrupt line
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) Additional optional properties:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) Some devices may support additional optional properties to help with, e.g.,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) power sequencing. The following properties can be supported by one or more
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) device-specific compatible properties, which should be used in addition to the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) "hid-over-i2c" string.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) - compatible:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) * "wacom,w9013" (Wacom W9013 digitizer). Supports:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) - vdd-supply (3.3V)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) - vddl-supply (1.8V)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) - post-power-on-delay-ms
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) - vdd-supply: phandle of the regulator that provides the supply voltage.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) - post-power-on-delay-ms: time required by the device after enabling its regulators
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) or powering it on, before it is ready for communication.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) Example:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) i2c-hid-dev@2c {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) compatible = "hid-over-i2c";
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) reg = <0x2c>;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) hid-descr-addr = <0x0020>;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) interrupt-parent = <&gpx3>;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) interrupts = <3 2>;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) };