Staging
v0.8.1
https://github.com/torvalds/linux
Raw File
Tip revision: 1c23f9e627a7b412978b4e852793c5e3c3efc555 authored by Linus Torvalds on 22 August 2022, 00:32:54 UTC
Linux 6.0-rc2
Tip revision: 1c23f9e
i2c-opal.txt
Device-tree bindings for I2C OPAL driver
----------------------------------------

Most of the device node and properties layout is specific to the firmware and
used by the firmware itself for configuring the port. From the linux
perspective, the properties of use are "ibm,port-name" and "ibm,opal-id".

Required properties:

- reg: Port-id within a given master
- compatible: must be "ibm,opal-i2c"
- ibm,opal-id: Refers to a specific bus and used to identify it when calling
	       the relevant OPAL functions.
- bus-frequency: Operating frequency of the i2c bus (in HZ). Informational for
		 linux, used by the FW though.

Optional properties:
- ibm,port-name: Firmware provides this name that uniquely identifies the i2c
		 port.

The node contains a number of other properties that are used by the FW itself
and depend on the specific hardware implementation. The example below depicts
a P8 on-chip bus.

Example:

i2c-bus@0 {
	reg = <0x0>;
	bus-frequency = <0x61a80>;
	compatible = "ibm,power8-i2c-port", "ibm,opal-i2c";
	ibm,opal-id = <0x1>;
	ibm,port-name = "p8_00000000_e1p0";
	#address-cells = <0x1>;
	phandle = <0x10000006>;
	#size-cells = <0x0>;
	linux,phandle = <0x10000006>;
};
back to top