Re: [PATCH v6 3/9] usb: misc: qcom_eud: add per-path High-Speed PHY control
From: Konrad Dybcio
Date: Mon Aug 24 2026 - 05:20:17 EST
On 8/11/26 11:36 PM, Elson Serrao wrote:
> EUD hardware can support multiple High-Speed USB paths, each routed
> through its own PHY. The active path is selected in hardware via the
> EUD_PORT_SEL register. As a High-Speed hub, EUD requires access to
> the High-Speed PHY associated with the active path. To support this
> multi-path capability, the driver must manage PHY resources on a
> per-path basis, ensuring that the PHY for the currently selected
> path is properly initialized and powered.
>
> This patch restructures the driver to implement per-path PHY management.
> The driver now powers the appropriate PHY based on the selected and
> enabled UTMI path, ensuring correct operation when EUD is enabled.
>
> Historically, EUD appeared to work on single-path systems because the
> USB controller kept the PHY initialized. However, EUD is designed to
> operate independently of the USB controller and therefore requires
> explicit PHY control for proper operation.
>
> Reviewed-by: Peter Chen <peter.chen@xxxxxxxxxx>
> Signed-off-by: Elson Serrao <elson.serrao@xxxxxxxxxxxxxxxx>
> ---
Reviewed-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx>
Konrad