| # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) |
| %YAML 1.2 |
| --- |
| $id: http://devicetree.org/schemas/i3c/i3c.yaml# |
| $schema: http://devicetree.org/meta-schemas/core.yaml# |
| |
| title: I3C bus |
| |
| maintainers: |
| - Alexandre Belloni <alexandre.belloni@bootlin.com> |
| - Miquel Raynal <miquel.raynal@bootlin.com> |
| |
| description: | |
| I3C busses can be described with a node for the primary I3C controller device |
| and a set of child nodes for each I2C or I3C slave on the bus. Each of them |
| may, during the life of the bus, request mastership. |
| |
| properties: |
| $nodename: |
| pattern: "^i3c@[0-9a-f]+$" |
| |
| "#address-cells": |
| const: 3 |
| description: | |
| Each I2C device connected to the bus should be described in a subnode. |
| |
| All I3C devices are supposed to support DAA (Dynamic Address Assignment), |
| and are thus discoverable. So, by default, I3C devices do not have to be |
| described in the device tree. This being said, one might want to attach |
| extra resources to these devices, and those resources may have to be |
| described in the device tree, which in turn means we have to describe |
| I3C devices. |
| |
| Another use case for describing an I3C device in the device tree is when |
| this I3C device has a static I2C address and we want to assign it a |
| specific I3C dynamic address before the DAA takes place (so that other |
| devices on the bus can't take this dynamic address). |
| |
| "#size-cells": |
| const: 0 |
| |
| i3c-scl-hz: |
| description: | |
| Frequency of the SCL signal used for I3C transfers. When undefined, the |
| default value should be 12.5MHz. |
| |
| May not be supported by all controllers. |
| |
| i2c-scl-hz: |
| description: | |
| Frequency of the SCL signal used for I2C transfers. When undefined, the |
| default should be to look at LVR (Legacy Virtual Register) values of |
| I2C devices described in the device tree to determine the maximum I2C |
| frequency. |
| |
| May not be supported by all controllers. |
| |
| mctp-controller: |
| type: boolean |
| description: | |
| Indicates that the system is accessible via this bus as an endpoint for |
| MCTP over I3C transport. |
| |
| required: |
| - "#address-cells" |
| - "#size-cells" |
| |
| patternProperties: |
| "@[0-9a-f]+$": |
| type: object |
| description: | |
| I2C child, should be named: <device-type>@<i2c-address> |
| |
| All properties described in dtschema schemas/i2c/i2c-controller.yaml |
| are valid here, except the reg property whose content is changed. |
| |
| properties: |
| compatible: |
| description: |
| Compatible of the I2C device. |
| |
| reg: |
| items: |
| - items: |
| - description: | |
| I2C address. 10 bit addressing is not supported. Devices with |
| 10-bit address can't be properly passed through DEFSLVS |
| command. |
| minimum: 0 |
| maximum: 0x7f |
| - const: 0 |
| - description: | |
| Shall encode the I3C LVR (Legacy Virtual Register): |
| See include/dt-bindings/i3c/i3c.h |
| bit[31:8]: unused/ignored |
| bit[7:5]: I2C device index. Possible values: |
| * 0: I2C device has a 50 ns spike filter |
| * 1: I2C device does not have a 50 ns spike filter but |
| supports high frequency on SCL |
| * 2: I2C device does not have a 50 ns spike filter and is |
| not tolerant to high frequencies |
| * 3-7: reserved |
| bit[4]: tell whether the device operates in FM (Fast Mode) |
| or FM+ mode: |
| * 0: FM+ mode |
| * 1: FM mode |
| bit[3:0]: device type |
| * 0-15: reserved |
| |
| required: |
| - compatible |
| - reg |
| |
| "@[0-9a-f]+,[0-9a-f]+$": |
| type: object |
| description: | |
| I3C child, should be named: <device-type>@<static-i2c-address>,<i3c-pid> |
| |
| properties: |
| reg: |
| items: |
| - items: |
| - description: | |
| Encodes the static I2C address. Should be 0 if the device does |
| not have one (0 is not a valid I2C address). |
| minimum: 0 |
| maximum: 0x7f |
| - description: | |
| First half of the Provisioned ID (following the PID |
| definition provided by the I3C specification). |
| |
| Contains the manufacturer ID left-shifted by 1. |
| - description: | |
| Second half of the Provisioned ID (following the PID |
| definition provided by the I3C specification). |
| |
| Contains the ORing of the part ID left-shifted by 16, |
| the instance ID left-shifted by 12 and extra information. |
| |
| assigned-address: |
| $ref: /schemas/types.yaml#/definitions/uint32 |
| minimum: 0x1 |
| maximum: 0xff |
| description: | |
| Dynamic address to be assigned to this device. In case static address is |
| present (first cell of the reg property != 0), this address is assigned |
| through SETDASA. If static address is not present, this address is assigned |
| through SETNEWDA after assigning a temporary address via ENTDAA. |
| |
| required: |
| - reg |
| |
| additionalProperties: true |
| |
| examples: |
| - | |
| #include <dt-bindings/i3c/i3c.h> |
| |
| i3c@d040000 { |
| compatible = "cdns,i3c-master"; |
| clocks = <&coreclock>, <&i3csysclock>; |
| clock-names = "pclk", "sysclk"; |
| interrupts = <3 0>; |
| reg = <0x0d040000 0x1000>; |
| #address-cells = <3>; |
| #size-cells = <0>; |
| i2c-scl-hz = <100000>; |
| |
| /* I2C device. */ |
| eeprom@57 { |
| compatible = "atmel,24c01"; |
| reg = <0x57 0x0 (I2C_FM | I2C_FILTER)>; |
| pagesize = <0x8>; |
| }; |
| |
| /* I3C device with a static I2C address and assigned address. */ |
| thermal_sensor: sensor@68,39200144004 { |
| reg = <0x68 0x392 0x144004>; |
| assigned-address = <0xa>; |
| }; |
| |
| /* I3C device with only assigned address. */ |
| pressure_sensor: sensor@0,39200124004 { |
| reg = <0x0 0x392 0x124000>; |
| assigned-address = <0xc>; |
| }; |
| |
| /* |
| * I3C device without a static I2C address but requiring |
| * resources described in the DT. |
| */ |
| sensor@0,39200154004 { |
| reg = <0x0 0x392 0x154004>; |
| clocks = <&clock_provider 0>; |
| }; |
| }; |
