On Wed, Jun 29, 2022 at 9:01 AM Pin-yen Lin <treapking@xxxxxxxxxxxx> wrote: > > On Wed, Jun 29, 2022 at 10:33 PM Pin-yen Lin <treapking@xxxxxxxxxxxx> wrote: > > > > On Wed, Jun 29, 2022 at 2:23 AM Rob Herring <robh@xxxxxxxxxx> wrote: > > > > > > On Mon, Jun 27, 2022 at 02:43:39PM -0700, Prashant Malani wrote: > > > > Hello Rob, > > > > > > > > On Mon, Jun 27, 2022 at 2:04 PM Rob Herring <robh@xxxxxxxxxx> wrote: > > > > > > > > > > On Wed, Jun 22, 2022 at 05:34:30PM +0000, Prashant Malani wrote: > > > > > > Introduce a binding which represents a component that can control the > > > > > > routing of USB Type-C data lines as well as address data line > > > > > > orientation (based on CC lines' orientation). > > > > > > > > > > > > Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> > > > > > > Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx> > > > > > > Reviewed-by: Nícolas F. R. A. Prado <nfraprado@xxxxxxxxxxxxx> > > > > > > Tested-by: Nícolas F. R. A. Prado <nfraprado@xxxxxxxxxxxxx> > > > > > > Signed-off-by: Prashant Malani <pmalani@xxxxxxxxxxxx> > > > > > > --- > > > > > > > > > > > > Changes since v4: > > > > > > - Added Reviewed-by tags. > > > > > > - Patch moved to 1/9 position (since Patch v4 1/7 and 2/7 were > > > > > > applied to usb-next) > > > > > > > > > > > > Changes since v3: > > > > > > - No changes. > > > > > > > > > > > > Changes since v2: > > > > > > - Added Reviewed-by and Tested-by tags. > > > > > > > > > > > > Changes since v1: > > > > > > - Removed "items" from compatible. > > > > > > - Fixed indentation in example. > > > > > > > > > > > > .../devicetree/bindings/usb/typec-switch.yaml | 74 +++++++++++++++++++ > > > > > > 1 file changed, 74 insertions(+) > > > > > > create mode 100644 Documentation/devicetree/bindings/usb/typec-switch.yaml > > > > > > > > > > > > diff --git a/Documentation/devicetree/bindings/usb/typec-switch.yaml b/Documentation/devicetree/bindings/usb/typec-switch.yaml > > > > > > new file mode 100644 > > > > > > index 000000000000..78b0190c8543 > > > > > > --- /dev/null > > > > > > +++ b/Documentation/devicetree/bindings/usb/typec-switch.yaml > > > > > > @@ -0,0 +1,74 @@ > > > > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > > > > > > +%YAML 1.2 > > > > > > +--- > > > > > > +$id: http://devicetree.org/schemas/usb/typec-switch.yaml# > > > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > > > > > + > > > > > > +title: USB Type-C Switch > > > > > > + > > > > > > +maintainers: > > > > > > + - Prashant Malani <pmalani@xxxxxxxxxxxx> > > > > > > + > > > > > > +description: > > > > > > + A USB Type-C switch represents a component which routes USB Type-C data > > > > > > + lines to various protocol host controllers (e.g USB, VESA DisplayPort, > > > > > > + Thunderbolt etc.) depending on which mode the Type-C port, port partner > > > > > > + and cable are operating in. It can also modify lane routing based on > > > > > > + the orientation of a connected Type-C peripheral. > > > > > > + > > > > > > +properties: > > > > > > + compatible: > > > > > > + const: typec-switch > > > > > > + > > > > > > + mode-switch: > > > > > > + type: boolean > > > > > > + description: Specify that this switch can handle alternate mode switching. > > > > > > + > > > > > > + orientation-switch: > > > > > > + type: boolean > > > > > > + description: Specify that this switch can handle orientation switching. > > > > > > + > > > > > > + ports: > > > > > > + $ref: /schemas/graph.yaml#/properties/ports > > > > > > + description: OF graph binding modelling data lines to the Type-C switch. > > > > > > + > > > > > > + properties: > > > > > > + port@0: > > > > > > + $ref: /schemas/graph.yaml#/properties/port > > > > > > + description: Link between the switch and a Type-C connector. > > > > > > + > > > > > > + required: > > > > > > + - port@0 > > > > > > + > > > > > > +required: > > > > > > + - compatible > > > > > > + - ports > > > > > > + > > > > > > +anyOf: > > > > > > + - required: > > > > > > + - mode-switch > > > > > > + - required: > > > > > > + - orientation-switch > > > > > > + > > > > > > +additionalProperties: true > > > > > > + > > > > > > +examples: > > > > > > + - | > > > > > > + drm-bridge { > > > > > > + usb-switch { > > > > > > + compatible = "typec-switch"; > > > > > > > > > > Unless this child is supposed to represent what the parent output is > > > > > connected to, this is just wrong as, at least for the it6505 chip, it > > > > > doesn't know anything about Type-C functionality. The bridge is > > > > > just a protocol converter AFAICT. > > > > > > > > I'll let Pin-Yen comment on the specifics of the it6505 chip. > > > > > > We're all waiting... > > > > Yes it6505 is just a protocol converter. But in our use case, the output DP > > lines are connected to the Type-C ports and the chip has to know which > > port has DP Alt mode enabled. Does this justify a child node here? > > > > Does it make more sense if we we eliminate the usb-switch node here > > and list the ports in the top level? In the it6505 node? No, the it6505 h/w knows nothing about Type-C switching so neither should its binding. What device controls the switching in this case? Again, block diagrams please if you want advice on what the binding should look like. > > > > > If the child node represents what the output is connected to (like a > > > > > bus), then yes that is a pattern we have used. > > > > > > > > For the anx7625 case, the child node does represent what the output is connected > > > > to (the usb-c-connector via the switch). Does that not qualify? Or do you mean > > > > the child node should be a usb-c-connector itself? > > > > > > > > > For example, a panel > > > > > represented as child node of a display controller. However, that only > > > > > works for simple cases, and is a pattern we have gotten away from in > > > > > favor of using the graph binding. > > > > > > > > The child node will still use a OF graph binding to connect to the > > > > usb-c-connector. > > > > Is that insufficient to consider a child node usage here? > > > > By "using the graph binding", do you mean "only use the top-level ports" ? > > > > I'm trying to clarify this, so that it will inform future versions and patches. > > > > > > What I want to see is block diagrams of possible h/w with different > > > scenarios and then what the binding looks like in those cases. The > > > switching/muxing could be in the SoC, a bridge chip, a Type C > > > controller, a standalone mux chip, or ????. If you want a somewhat > > > genericish binding, then you need to consider all of these. > > Then, is it suitable to put the switch binding into the drivers own bindings > (i.e., the bindings for it6505 and anx7625), and introduce some helper > functions to eliminate the duplication in the code? Only for h/w devices that have switch h/w. > Though we will have two similar bindings in two drivers with this approach. While the anx7625 driver having Type-C awareness makes sense given it has a switch and a type-C controller, that doesn't make sense for it6505 (and every other bridge driver that's just providing DP output). Rob
