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| -rw-r--r-- | Documentation/devicetree/bindings/i3c/i3c.yaml | 180 |
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diff --git a/Documentation/devicetree/bindings/i3c/i3c.yaml b/Documentation/devicetree/bindings/i3c/i3c.yaml new file mode 100644 index 000000000..1f82fc923 --- /dev/null +++ b/Documentation/devicetree/bindings/i3c/i3c.yaml @@ -0,0 +1,180 @@ +# 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 binding + +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>; + }; + }; |