Re: [PATCH V3 5/7] arm64: dts: qcom: sc7280: Add EUD dt node and dwc3 connector

[Souradeep Chowdhury]

On 1/7/2022 6:23 AM, Bjorn Andersson wrote:
> On Tue 04 Jan 03:58 PST 2022, Souradeep Chowdhury wrote:
>
> > Add the Embedded USB Debugger(EUD) device tree node. The
> > node contains EUD base register region and EUD mode
> > manager register regions along with the interrupt entry.
> > Also add the connector to EUD which is mapped as the child
> > of dwc3. The connector is attached to EUD via port. Also add
> > the role-switch property to dwc3 node.
> >
> > Signed-off-by: Souradeep Chowdhury <quic_schowdhu@xxxxxxxxxxx>
> > ---
> >   arch/arm64/boot/dts/qcom/sc7280.dtsi | 25 +++++++++++++++++++++++++
> >   1 file changed, 25 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/qcom/sc7280.dtsi b/arch/arm64/boot/dts/qcom/sc7280.dtsi
> > index 53a21d0..2d14e5c 100644
> > --- a/arch/arm64/boot/dts/qcom/sc7280.dtsi
> > +++ b/arch/arm64/boot/dts/qcom/sc7280.dtsi
> > @@ -1315,6 +1315,18 @@
> >   				phys = <&usb_2_hsphy>;
> >   				phy-names = "usb2-phy";
> >   				maximum-speed = "high-speed";
> > +				usb-role-switch;
> > +				usb_con: eud_usb_connector {
> I think this is backwards.
>
> Iiuc you have dwc3 <-> EUD <-> connector, where the connector typically
> would be represented in relation to a Type-C controller.
>
> So I think this graph should be looking something like:
>
>
> dwc3 {
>      ports {
>          port {
>              dwc3_eud: endpoint {
>                  remote-endpoint = <&eud_ep>;
>              };
>          };
>      };
> };
>
> eud {
>      ports {
>          port {
>              eud_dwc3: endpoint {
>                  remote-endpoint = <&dwc3_eud>;
>              };
>          };
>
>          port {
>              eud_con: endpoint {
>                  remote-endpoint = <&con_eud>;
>              };
>          };
>      };
> };
>
> connector {
>      compatible = "usb-c-connector";
>
>      ports {
>          port {
>              con_eud: endpoint {
>                  remote-endpoint = <&eud_con>;
>              };
>          };
>      };
> };
>
> With EUD "forwarding" the role switching requests from the connector, or
> overriding them if the EUD is enabled.
>
> Alternatively the dwc3 would be in a graph with both the eud and the
> connector, but I don't know how to ensure that the EUD decision takes
> precedence over the type-c controllers role request...
>
>
> In the case of us having a type-c controller, such as the pmic_glink,
> the connector node would then be a child of the controller.
Ack. Will align the device tree with this structure.
> Regards,
> Bjorn
>
> > +					compatible = "qcom,usb-connector-eud",
> > +						     "usb-c-connector";
> > +					ports {
> > +						port@0 {
> > +							usb2_role_switch: endpoint {
> > +								remote-endpoint = <&eud_ep>;
> > +							};
> > +						};
> > +					};
> > +				};
> >   			};
> >   		};
> >   
> > @@ -1339,6 +1351,19 @@
> >   			interrupts = <GIC_SPI 582 IRQ_TYPE_LEVEL_HIGH>;
> >   		};
> >   
> > +		eud:  eud@88e0000 {
> > +			compatible = "qcom,sc7280-eud","qcom,eud";
> > +			reg = <0 0x88e0000 0 0x2000>,
> > +			      <0 0x88e2000 0 0x1000>;
> > +			interrupt-parent = <&pdc>;
> > +			interrupts = <11 IRQ_TYPE_LEVEL_HIGH>;
> > +			port {
> > +				eud_ep: endpoint {
> > +					remote-endpoint = <&usb2_role_switch>;
> > +				};
> > +			};
> > +		};
> > +
> >   		nsp_noc: interconnect@a0c0000 {
> >   			reg = <0 0x0a0c0000 0 0x10000>;
> >   			compatible = "qcom,sc7280-nsp-noc";
> > --
> > 2.7.4