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|
# 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:
$nodename:
pattern: "^i3c-master@[0-9a-f]+$"
"#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.
required:
- "#address-cells"
- "#size-cells"
patternProperties:
"@[0-9a-f]+$":
type: object
description: |
I2C child, should be named: <device-type>@<i2c-address>
All properties described in Documentation/devicetree/bindings/i2c/i2c.txt
are valid here, except the reg property whose content is changed.
properties:
compatible:
description:
Compatible of the I2C device.
reg:
items:
- items:
- description: |
I2C address. 10 bit addressing is not supported. Devices with
10-bit address can't be properly passed through DEFSLVS
command.
minimum: 0
maximum: 0x7f
- const: 0
- description: |
Shall encode the I3C LVR (Legacy Virtual Register):
bit[31:8]: unused/ignored
bit[7:5]: I2C device index. Possible values:
* 0: I2C device has a 50 ns spike filter
* 1: I2C device does not have a 50 ns spike filter but
supports high frequency on SCL
* 2: I2C device does not have a 50 ns spike filter and is
not tolerant to high frequencies
* 3-7: reserved
bit[4]: tell whether the device operates in FM (Fast Mode)
or FM+ mode:
* 0: FM+ mode
* 1: FM mode
bit[3:0]: device type
* 0-15: reserved
required:
- compatible
- reg
"@[0-9a-f]+,[0-9a-f]+$":
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 Provisional ID (following the PID
definition provided by the I3C specification).
Contains the manufacturer ID left-shifted by 1.
- description: |
Second half of the Provisional 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. This property is only
valid if the I3C device has a static address (first cell of the reg
property != 0).
required:
- reg
additionalProperties: true
examples:
- |
i3c-master@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 0x10>;
pagesize = <0x8>;
};
/* I3C device with a static I2C address. */
thermal_sensor: sensor@68,39200144004 {
reg = <0x68 0x392 0x144004>;
assigned-address = <0xa>;
};
/*
* 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>;
};
};
|
