[PATCH 2/2] rockchip: rk3568: Disable USB3OTG U3 ports early

[Quentin Schulz]

Hi Jonas,

On 10/19/25 5:09 PM, Jonas Karlman wrote:
> The RK3568 SoC comes with USB OTG support using a DWC3 controller with
> a USB2 PHY and a USB3 PHY (COMBPHY).
> 
> Some board designs may not use the COMBPHY for USB3 purpose. For these
> board to use USB OTG the input clock source must change to use UTMI clk
> instead of PIPE clk.
> 
> Change to always disable the USB3OTG U3 ports early and leave it to the
> COMBPHY driver to re-enable the U3 port when a usb3-phy is described in
> the board device tree.
> 
> Please note that this may break use of USB 3.0 on RK3568 on Linux kernel
> prior to version 6.6.112, 6.12.53, 6.17.3 and 6.18-rc1.
> 
> Signed-off-by: Jonas Karlman <jonas at kwiboo.se>
> ---
> It may be too soon to apply this patch, we should possible give more
> time for OS to adopt to these changes.
> 
> The first patch in this series should however be safe to apply.

What's the cost of *NOT* applying this? I imagine if the PHY isn't used 
in the kernel it can be turned off by runtime PM? So would that be only 
about reducing power consumption while in U-Boot?

It may not be worth it to possibly break devices if we're simply talking 
about power efficiency for a boot stage that shouldn't last long anyway.

We cannot know what the user will be booting as kernel so there 
technically is not a safe date when this could be merged.

Cheers,
Quentin