Re: [PATCH v5 1/9] dt-bindings: soc: qcom: eud: Add per-path child nodes for UTMI routing

Krzysztof Kozlowski <[email protected]> Fri, 7 Aug 2026 09:20:26 +0200
Newsgroups org.kernel.vger.linux-usb,org.kernel.vger.linux-arm-msm,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-kernel
Message-ID <20260807-shrewd-white-mayfly-a8bfea@quoll>
On Sun, Aug 02, 2026 at 08:15:26PM -0700, Elson Serrao wrote:
> The Qualcomm Embedded USB Debugger (EUD) can intercept one or two
> High-Speed UTMI paths depending on the SoC. For example, SC7280 supports
> EUD on the primary UTMI path only, while SM8350 supports EUD on both
> primary and secondary UTMI paths.
> 
> Each UTMI path connects an independent USB controller/connector pair and
> forms its own role-switch domain. EUD routes traffic based on USB role.
> In device role the debug hub is inserted, while in host role it is
> bypassed.
> 
> The existing binding models EUD using a flattened ports representation.
> While sufficient for fixed device-role configurations, it cannot naturally
> associate a controller, connector, and role switch with a specific
> EUD-routable path. This is problematic for role-switch capable ports and
> becomes more pronounced on SoCs with multiple paths. In such cases, each
> path forms an independent role-switch domain and requires per-path role
> awareness.
> 
> Model each UTMI path as a separate child node with its own OF graph. Add
> an SM8350 compatible for dual-path EUD topologies while retaining the
> legacy ports representation for backward compatibility.
> 
> Signed-off-by: Elson Serrao <[email protected]>
> ---
>  .../bindings/soc/qcom/qcom,eud.yaml           | 128 +++++++++++++++++-
>  1 file changed, 127 insertions(+), 1 deletion(-)

Reviewed-by: Krzysztof Kozlowski <[email protected]>

Best regards,
Krzysztof