mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-26 05:25:11 +07:00
847989e548
The property "post-power-on-delay-ms" allows a platform to specify the delay needed after power-on, but only via device trees currently. Use device_property_* instead of of_* reads to allow ACPI systems to also provide the same information. This is useful for Wacom hardware on ACPI systems. Signed-off-by: Rajat Jain <rajatja@google.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
45 lines
1.5 KiB
Plaintext
45 lines
1.5 KiB
Plaintext
* HID over I2C Device-Tree bindings
|
|
|
|
HID over I2C provides support for various Human Interface Devices over the
|
|
I2C bus. These devices can be for example touchpads, keyboards, touch screens
|
|
or sensors.
|
|
|
|
The specification has been written by Microsoft and is currently available here:
|
|
http://msdn.microsoft.com/en-us/library/windows/hardware/hh852380.aspx
|
|
|
|
If this binding is used, the kernel module i2c-hid will handle the communication
|
|
with the device and the generic hid core layer will handle the protocol.
|
|
|
|
Required properties:
|
|
- compatible: must be "hid-over-i2c"
|
|
- reg: i2c slave address
|
|
- hid-descr-addr: HID descriptor address
|
|
- interrupt-parent: the phandle for the interrupt controller
|
|
- interrupts: interrupt line
|
|
|
|
Additional optional properties:
|
|
|
|
Some devices may support additional optional properties to help with, e.g.,
|
|
power sequencing. The following properties can be supported by one or more
|
|
device-specific compatible properties, which should be used in addition to the
|
|
"hid-over-i2c" string.
|
|
|
|
- compatible:
|
|
* "wacom,w9013" (Wacom W9013 digitizer). Supports:
|
|
- vdd-supply
|
|
- post-power-on-delay-ms
|
|
|
|
- vdd-supply: phandle of the regulator that provides the supply voltage.
|
|
- post-power-on-delay-ms: time required by the device after enabling its regulators
|
|
or powering it on, before it is ready for communication.
|
|
|
|
Example:
|
|
|
|
i2c-hid-dev@2c {
|
|
compatible = "hid-over-i2c";
|
|
reg = <0x2c>;
|
|
hid-descr-addr = <0x0020>;
|
|
interrupt-parent = <&gpx3>;
|
|
interrupts = <3 2>;
|
|
};
|