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

Bjorn Andersson
2022-01-07T00:52:32Z

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@quicinc.com>
> ---
> 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.

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
>