Tom Rini | 53633a8 | 2024-02-29 12:33:36 -0500 | [diff] [blame] | 1 | Device-tree bindings for I2C OPAL driver |
| 2 | ---------------------------------------- |
| 3 | |
| 4 | Most of the device node and properties layout is specific to the firmware and |
| 5 | used by the firmware itself for configuring the port. From the linux |
| 6 | perspective, the properties of use are "ibm,port-name" and "ibm,opal-id". |
| 7 | |
| 8 | Required properties: |
| 9 | |
| 10 | - reg: Port-id within a given master |
| 11 | - compatible: must be "ibm,opal-i2c" |
| 12 | - ibm,opal-id: Refers to a specific bus and used to identify it when calling |
| 13 | the relevant OPAL functions. |
| 14 | - bus-frequency: Operating frequency of the i2c bus (in HZ). Informational for |
| 15 | linux, used by the FW though. |
| 16 | |
| 17 | Optional properties: |
| 18 | - ibm,port-name: Firmware provides this name that uniquely identifies the i2c |
| 19 | port. |
| 20 | |
| 21 | The node contains a number of other properties that are used by the FW itself |
| 22 | and depend on the specific hardware implementation. The example below depicts |
| 23 | a P8 on-chip bus. |
| 24 | |
| 25 | Example: |
| 26 | |
| 27 | i2c-bus@0 { |
| 28 | reg = <0x0>; |
| 29 | bus-frequency = <0x61a80>; |
| 30 | compatible = "ibm,power8-i2c-port", "ibm,opal-i2c"; |
| 31 | ibm,opal-id = <0x1>; |
| 32 | ibm,port-name = "p8_00000000_e1p0"; |
| 33 | #address-cells = <0x1>; |
| 34 | phandle = <0x10000006>; |
| 35 | #size-cells = <0x0>; |
| 36 | linux,phandle = <0x10000006>; |
| 37 | }; |