Re: [PATCH v4 2/4] dt-bindings: phy: Add documentation for Airoha AN7581 USB PHY
From: Conor Dooley
Date: Fri Nov 07 2025 - 13:13:23 EST
On Fri, Nov 07, 2025 at 05:02:44PM +0100, Christian Marangi wrote:
> Add documentation for Airoha AN7581 USB PHY that describe the USB PHY
> for the USB controller.
>
> Airoha AN7581 SoC support a maximum of 2 USB port. The USB 2.0 mode is
> always supported. The USB 3.0 mode is optional and depends on the Serdes
> mode currently configured on the system for the relevant USB port.
>
> To correctly calibrate, the USB 2.0 port require correct value in
> "airoha,usb2-monitor-clk-sel" property. Both the 2 USB 2.0 port permit
> selecting one of the 4 monitor clock for calibration (internal clock not
> exposed to the system) but each port have only one of the 4 actually
> connected in HW hence the correct value needs to be specified in DT
> based on board and the physical port. Normally it's monitor clock 1 for
> USB1 and monitor clock 2 for USB2.
>
> To correctly setup the Serdes mode attached to the USB 3.0 mode, the
> "airoha,usb3-serdes" property is required. This can be either
> AIROHA_SCU_SERDES_USB1 or AIROHA_SCU_SERDES_USB2 and is used to identify
> what modes support the PHY and what register to use to setup the
> requested mode.
>
> The first USB port on the SoC can be both used for USB 3.0 operation or
> Ethernet (HSGMII).
> The second USB port on the SoC can be both used for USB 3.0 operation or
> for an additional PCIe line.
>
> Signed-off-by: Christian Marangi <ansuelsmth@xxxxxxxxx>
Reviewed-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
Thanks for the updates.
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