Add a binding for the microcontroller (MCU) that fronts the PSE silicon on a range of managed Realtek-based switches. The host talks only to the MCU, over I2C/SMBus or UART, using a fixed message-based protocol; the PSE chips behind it never appear on the bus. The device is the MCU together with its Realtek firmware: the firmware and its host protocol are what the binding describes, not the general-purpose microcontroller they run on. The PSE silicon behind the MCU (Realtek or Broadcom) is reported by the MCU and detected at runtime, so it is not described here - hence the 'realtek' vendor prefix. Two protocol generations exist, both Realtek's, selected by the compatible: gen1 on older boards (fronting Broadcom PSE silicon) and gen2, the altered protocol used with Realtek's own PSE silicon. On an I2C attachment the framing the MCU firmware expects is part of the compatible as well - '-smbus' or raw '-i2c'; a UART attachment carries no framing suffix, as the transport is given by the parent serial node. Each board additionally carries a device-specific compatible that falls back to one of the protocol compatibles above. Drivers bind on the protocol compatible; the device-specific string identifies the board and reserves a place for a future per-board quirk without having to retrofit device trees already in the field. Signed-off-by: Jonas Jelonek Reviewed-by: Conor Dooley Reviewed-by: Oleksij Rempel --- .../net/pse-pd/realtek,pse-mcu-gen1.yaml | 176 ++++++++++++++++++ 1 file changed, 176 insertions(+) create mode 100644 Documentation/devicetree/bindings/net/pse-pd/realtek,pse-mcu-gen1.yaml diff --git a/Documentation/devicetree/bindings/net/pse-pd/realtek,pse-mcu-gen1.yaml b/Documentation/devicetree/bindings/net/pse-pd/realtek,pse-mcu-gen1.yaml new file mode 100644 index 000000000000..2b0661c9e31f --- /dev/null +++ b/Documentation/devicetree/bindings/net/pse-pd/realtek,pse-mcu-gen1.yaml @@ -0,0 +1,176 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/net/pse-pd/realtek,pse-mcu-gen1.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Realtek PSE MCU + +maintainers: + - Jonas Jelonek + +description: | + A microcontroller (MCU) that manages the PSE (Power Sourcing Equipment) + hardware on a range of managed PoE switches. The host CPU talks only to + this MCU - over I2C/SMBus or UART - using a small message-based protocol; + the PSE silicon it drives sits behind the MCU and is never accessed + directly. For example, on the Zyxel GS1900-10HP the SoC reaches the MCU + over UART, and the MCU manages the on-board PSE chip. + + This binding describes the MCU together with its Realtek firmware: the + firmware and its host protocol, which are stable across boards. The + microcontroller silicon is a general-purpose part that varies, and the + PSE silicon behind the MCU (Realtek RTL823x/RTL8239* or Broadcom + BCM59xxx) is reported by the MCU and detected at runtime - neither is + named here. + + Two protocol generations exist, both Realtek's: + gen1 older boards, where the MCU fronts Broadcom PSE silicon + gen2 the altered protocol used with Realtek's own PSE silicon + + On an I2C attachment the framing the MCU firmware expects is part of the + compatible: '-smbus' (reads carry a leading command byte and a repeated + start) or '-i2c' (bare block writes and reads). A UART attachment carries + no framing suffix; the transport is given by the parent 'serial' node. + + Each board additionally carries a device-specific compatible that falls + back to one of the protocol compatibles above. Drivers bind on the + protocol compatible; the device-specific string identifies the board and + reserves a place for a future per-board quirk without having to retrofit + device trees already in the field. + +properties: + compatible: + oneOf: + # UART + - items: + - enum: + - zyxel,gs1900-10hp-a1-pse + - const: realtek,pse-mcu-gen1 + + # I2C, SMBus framing + - items: + - enum: + - zyxel,gs1920-24hp-v2-pse + - const: realtek,pse-mcu-gen1-smbus + + # UART + - items: + - enum: + - zyxel,gs1900-10hp-b1-pse + - zyxel,xmg1915-10ep-pse + - const: realtek,pse-mcu-gen2 + + # I2C, SMBus framing + - items: + - enum: + - zyxel,xs1930-12hp-pse + - const: realtek,pse-mcu-gen2-smbus + + # I2C, raw framing + - items: + - enum: + - linksys,lgs328mpc-v2-pse + - const: realtek,pse-mcu-gen2-i2c + + reg: + maxItems: 1 + + power-supply: + description: Regulator supplying the PoE power rail. + + enable-gpios: + maxItems: 1 + +required: + - compatible + +allOf: + - $ref: pse-controller.yaml# + - $ref: /schemas/serial/serial-peripheral-props.yaml# + # A '-smbus'/'-i2c' compatible is an I2C attachment: it has 'reg' and + # cannot carry serial bus properties. A bare gen compatible is a UART + # attachment: no 'reg', the transport comes from the parent serial node. + - if: + properties: + compatible: + contains: + enum: + - realtek,pse-mcu-gen1-smbus + - realtek,pse-mcu-gen2-smbus + - realtek,pse-mcu-gen2-i2c + then: + required: + - reg + properties: + current-speed: false + max-speed: false + else: + properties: + reg: false + +unevaluatedProperties: false + +examples: + # SMBus-framed I2C attachment + - | + i2c { + #address-cells = <1>; + #size-cells = <0>; + + ethernet-pse@20 { + compatible = "zyxel,xs1930-12hp-pse", "realtek,pse-mcu-gen2-smbus"; + reg = <0x20>; + + pse-pis { + #address-cells = <1>; + #size-cells = <0>; + + pse-pi@0 { + reg = <0>; + #pse-cells = <0>; + }; + }; + }; + }; + + # Raw-I2C-framed attachment + - | + i2c { + #address-cells = <1>; + #size-cells = <0>; + + ethernet-pse@20 { + compatible = "linksys,lgs328mpc-v2-pse", "realtek,pse-mcu-gen2-i2c"; + reg = <0x20>; + + pse-pis { + #address-cells = <1>; + #size-cells = <0>; + + pse-pi@0 { + reg = <0>; + #pse-cells = <0>; + }; + }; + }; + }; + + # UART attachment + - | + serial { + ethernet-pse { + compatible = "zyxel,gs1900-10hp-a1-pse", "realtek,pse-mcu-gen1"; + current-speed = <19200>; + + pse-pis { + #address-cells = <1>; + #size-cells = <0>; + + pse-pi@0 { + reg = <0>; + #pse-cells = <0>; + }; + }; + }; + }; -- 2.53.0