181 lines
5.8 KiB
YAML
181 lines
5.8 KiB
YAML
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# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/i3c/i3c.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: I3C bus
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maintainers:
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- Alexandre Belloni <alexandre.belloni@bootlin.com>
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- Miquel Raynal <miquel.raynal@bootlin.com>
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description: |
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I3C busses can be described with a node for the primary I3C controller device
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and a set of child nodes for each I2C or I3C slave on the bus. Each of them
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may, during the life of the bus, request mastership.
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properties:
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$nodename:
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pattern: "^i3c-master@[0-9a-f]+$"
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"#address-cells":
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const: 3
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description: |
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Each I2C device connected to the bus should be described in a subnode.
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All I3C devices are supposed to support DAA (Dynamic Address Assignment),
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and are thus discoverable. So, by default, I3C devices do not have to be
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described in the device tree. This being said, one might want to attach
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extra resources to these devices, and those resources may have to be
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described in the device tree, which in turn means we have to describe
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I3C devices.
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Another use case for describing an I3C device in the device tree is when
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this I3C device has a static I2C address and we want to assign it a
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specific I3C dynamic address before the DAA takes place (so that other
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devices on the bus can't take this dynamic address).
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"#size-cells":
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const: 0
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i3c-scl-hz:
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description: |
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Frequency of the SCL signal used for I3C transfers. When undefined, the
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default value should be 12.5MHz.
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May not be supported by all controllers.
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i2c-scl-hz:
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description: |
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Frequency of the SCL signal used for I2C transfers. When undefined, the
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default should be to look at LVR (Legacy Virtual Register) values of
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I2C devices described in the device tree to determine the maximum I2C
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frequency.
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May not be supported by all controllers.
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required:
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- "#address-cells"
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- "#size-cells"
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patternProperties:
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"@[0-9a-f]+$":
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type: object
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description: |
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I2C child, should be named: <device-type>@<i2c-address>
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All properties described in Documentation/devicetree/bindings/i2c/i2c.txt
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are valid here, except the reg property whose content is changed.
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properties:
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compatible:
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description:
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Compatible of the I2C device.
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reg:
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items:
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- items:
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- description: |
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I2C address. 10 bit addressing is not supported. Devices with
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10-bit address can't be properly passed through DEFSLVS
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command.
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minimum: 0
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maximum: 0x7f
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- const: 0
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- description: |
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Shall encode the I3C LVR (Legacy Virtual Register):
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bit[31:8]: unused/ignored
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bit[7:5]: I2C device index. Possible values:
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* 0: I2C device has a 50 ns spike filter
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* 1: I2C device does not have a 50 ns spike filter but
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supports high frequency on SCL
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* 2: I2C device does not have a 50 ns spike filter and is
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not tolerant to high frequencies
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* 3-7: reserved
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bit[4]: tell whether the device operates in FM (Fast Mode)
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or FM+ mode:
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* 0: FM+ mode
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* 1: FM mode
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bit[3:0]: device type
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* 0-15: reserved
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required:
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- compatible
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- reg
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"@[0-9a-f]+,[0-9a-f]+$":
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type: object
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description: |
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I3C child, should be named: <device-type>@<static-i2c-address>,<i3c-pid>
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properties:
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reg:
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items:
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- items:
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- description: |
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Encodes the static I2C address. Should be 0 if the device does
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not have one (0 is not a valid I2C address).
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minimum: 0
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maximum: 0x7f
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- description: |
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First half of the Provisional ID (following the PID
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definition provided by the I3C specification).
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Contains the manufacturer ID left-shifted by 1.
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- description: |
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Second half of the Provisional ID (following the PID
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definition provided by the I3C specification).
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Contains the ORing of the part ID left-shifted by 16,
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the instance ID left-shifted by 12 and extra information.
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assigned-address:
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$ref: /schemas/types.yaml#/definitions/uint32
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minimum: 0x1
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maximum: 0xff
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description: |
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Dynamic address to be assigned to this device. This property is only
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valid if the I3C device has a static address (first cell of the reg
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property != 0).
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required:
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- reg
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additionalProperties: true
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examples:
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- |
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i3c-master@d040000 {
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compatible = "cdns,i3c-master";
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clocks = <&coreclock>, <&i3csysclock>;
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clock-names = "pclk", "sysclk";
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interrupts = <3 0>;
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reg = <0x0d040000 0x1000>;
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#address-cells = <3>;
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#size-cells = <0>;
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i2c-scl-hz = <100000>;
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/* I2C device. */
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eeprom@57 {
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compatible = "atmel,24c01";
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reg = <0x57 0x0 0x10>;
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pagesize = <0x8>;
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};
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/* I3C device with a static I2C address. */
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thermal_sensor: sensor@68,39200144004 {
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reg = <0x68 0x392 0x144004>;
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assigned-address = <0xa>;
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};
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/*
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* I3C device without a static I2C address but requiring
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* resources described in the DT.
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*/
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sensor@0,39200154004 {
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reg = <0x0 0x392 0x154004>;
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clocks = <&clock_provider 0>;
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};
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};
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