45 lines
1.5 KiB
Plaintext
45 lines
1.5 KiB
Plaintext
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* HID over I2C Device-Tree bindings
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HID over I2C provides support for various Human Interface Devices over the
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I2C bus. These devices can be for example touchpads, keyboards, touch screens
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or sensors.
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The specification has been written by Microsoft and is currently available here:
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http://msdn.microsoft.com/en-us/library/windows/hardware/hh852380.aspx
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If this binding is used, the kernel module i2c-hid will handle the communication
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with the device and the generic hid core layer will handle the protocol.
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Required properties:
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- compatible: must be "hid-over-i2c"
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- reg: i2c slave address
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- hid-descr-addr: HID descriptor address
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- interrupt-parent: the phandle for the interrupt controller
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- interrupts: interrupt line
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Additional optional properties:
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Some devices may support additional optional properties to help with, e.g.,
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power sequencing. The following properties can be supported by one or more
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device-specific compatible properties, which should be used in addition to the
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"hid-over-i2c" string.
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- compatible:
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* "wacom,w9013" (Wacom W9013 digitizer). Supports:
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- vdd-supply
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- post-power-on-delay-ms
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- vdd-supply: phandle of the regulator that provides the supply voltage.
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- post-power-on-delay-ms: time required by the device after enabling its regulators
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before it is ready for communication. Must be used with 'vdd-supply'.
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Example:
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i2c-hid-dev@2c {
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compatible = "hid-over-i2c";
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reg = <0x2c>;
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hid-descr-addr = <0x0020>;
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interrupt-parent = <&gpx3>;
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interrupts = <3 2>;
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};
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