On Thu, Feb 10, 2022 at 12:37 AM Matt Johnston <matt@xxxxxxxxxxxxxxxxxxxx> wrote: > No need to resend, but the DT list should be CCed so that checks run. They do fail sometimes after I've reviewed patches. > Used to define a local endpoint to communicate with MCTP peripherals > attached to an I2C bus. This I2C endpoint can communicate with remote > MCTP devices on the I2C bus. > > In the example I2C topology below (matching the second yaml example) we > have MCTP devices on busses i2c1 and i2c6. MCTP-supporting busses are > indicated by the 'mctp-controller' DT property on an I2C bus node. > > A mctp-i2c-controller I2C client DT node is placed at the top of the > mux topology, since only the root I2C adapter will support I2C slave > functionality. > .-------. > |eeprom | > .------------. .------. /'-------' > | adapter | | mux --@0,i2c5------' > | i2c1 ----.*| --@1,i2c6--.--. > |............| \'------' \ \ ......... > | mctp-i2c- | \ \ \ .mctpB . > | controller | \ \ '.0x30 . > | | \ ......... \ '.......' > | 0x50 | \ .mctpA . \ ......... > '------------' '.0x1d . '.mctpC . > '.......' '.0x31 . > '.......' > (mctpX boxes above are remote MCTP devices not included in the DT at > present, they can be hotplugged/probed at runtime. A DT binding for > specific fixed MCTP devices could be added later if required) > > Signed-off-by: Matt Johnston <matt@xxxxxxxxxxxxxxxxxxxx> > Reviewed-by: Rob Herring <robh@xxxxxxxxxx> > --- > Documentation/devicetree/bindings/i2c/i2c.txt | 4 + > .../bindings/net/mctp-i2c-controller.yaml | 92 +++++++++++++++++++ > 2 files changed, 96 insertions(+) > create mode 100644 Documentation/devicetree/bindings/net/mctp-i2c-controller.yaml > > diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt > index b864916e087f..fc3dd7ec0445 100644 > --- a/Documentation/devicetree/bindings/i2c/i2c.txt > +++ b/Documentation/devicetree/bindings/i2c/i2c.txt > @@ -95,6 +95,10 @@ wants to support one of the below features, it should adapt these bindings. > - smbus-alert > states that the optional SMBus-Alert feature apply to this bus. > > +- mctp-controller > + indicates that the system is accessible via this bus as an endpoint for > + MCTP over I2C transport. > + > Required properties (per child device) > -------------------------------------- > > diff --git a/Documentation/devicetree/bindings/net/mctp-i2c-controller.yaml b/Documentation/devicetree/bindings/net/mctp-i2c-controller.yaml > new file mode 100644 > index 000000000000..afd11c9422fa > --- /dev/null > +++ b/Documentation/devicetree/bindings/net/mctp-i2c-controller.yaml > @@ -0,0 +1,92 @@ > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/net/mctp-i2c-controller.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: MCTP I2C transport binding > + > +maintainers: > + - Matt Johnston <matt@xxxxxxxxxxxxxxxxxxxx> > + > +description: | > + An mctp-i2c-controller defines a local MCTP endpoint on an I2C controller. > + MCTP I2C is specified by DMTF DSP0237. > + > + An mctp-i2c-controller must be attached to an I2C adapter which supports > + slave functionality. I2C busses (either directly or as subordinate mux > + busses) are attached to the mctp-i2c-controller with a 'mctp-controller' > + property on each used bus. Each mctp-controller I2C bus will be presented > + to the host system as a separate MCTP I2C instance. > + > +properties: > + compatible: > + const: mctp-i2c-controller > + > + reg: > + minimum: 0x40000000 > + maximum: 0x4000007f > + description: | > + 7 bit I2C address of the local endpoint. > + I2C_OWN_SLAVE_ADDRESS (1<<30) flag must be set. > + > +additionalProperties: false > + > +required: > + - compatible > + - reg > + > +examples: > + - | > + // Basic case of a single I2C bus > + #include <dt-bindings/i2c/i2c.h> > + > + i2c { > + #address-cells = <1>; > + #size-cells = <0>; > + mctp-controller; > + > + mctp@30 { > + compatible = "mctp-i2c-controller"; > + reg = <(0x30 | I2C_OWN_SLAVE_ADDRESS)>; > + }; > + }; > + > + - | > + // Mux topology with multiple MCTP-handling busses under > + // a single mctp-i2c-controller. > + // i2c1 and i2c6 can have MCTP devices, i2c5 does not. > + #include <dt-bindings/i2c/i2c.h> > + > + i2c1: i2c { > + #address-cells = <1>; > + #size-cells = <0>; > + mctp-controller; > + > + mctp@50 { > + compatible = "mctp-i2c-controller"; > + reg = <(0x50 | I2C_OWN_SLAVE_ADDRESS)>; > + }; > + }; > + > + i2c-mux { > + #address-cells = <1>; > + #size-cells = <0>; > + i2c-parent = <&i2c1>; > + > + i2c5: i2c@0 { > + #address-cells = <1>; > + #size-cells = <0>; > + reg = <0>; > + eeprom@33 { > + reg = <0x33>; > + }; > + }; > + > + i2c6: i2c@1 { > + #address-cells = <1>; > + #size-cells = <0>; > + reg = <1>; > + mctp-controller; > + }; > + }; > -- > 2.32.0 >
