Re: [PATCH v12 06/36] phy: rockchip: usbdp: Drop seamless DP takeover

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Missing hardware reset at probe leads to system lockups if bootloader leaves PHY active
--

--- Patch [6]: [PATCH v12 06/36] phy: rockchip: usbdp: Drop seamless DP takeover ---
commit 871e6d2aea7ac2c888b4917f93fff1eda368209d
Author: Sebastian Reichel <sebastian.reichel@collabora.com>

phy: rockchip: usbdp: Drop seamless DP takeover

This patch removes support for seamless DP takeover from the bootloader,
noting that the current DRM drivers do not support it and the code is
untested. It removes the initial status check and corresponding reset logic.

Closes: https://lore.kernel.org/linux-phy/20260612164107.C7DB21F000E9@smtp.kernel.org/

> diff --git a/drivers/phy/rockchip/phy-rockchip-usbdp.c b/drivers/phy/rockchip/phy-rockchip-usbdp.c
> index 3fc8222fcaec2..6cb9f6b4dbf6d 100644
> --- a/drivers/phy/rockchip/phy-rockchip-usbdp.c
> +++ b/drivers/phy/rockchip/phy-rockchip-usbdp.c

[ ... ]

> @@ -1495,10 +1468,6 @@ static int rk_udphy_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> -	ret = rk_udphy_get_initial_status(udphy);
> -	if (ret)
> -		return ret;
> -

[Severity: High]
Does removing this initial status check leave the PHY hardware in an unmanaged
state if the bootloader enabled it?

Without this initialization step, the driver no longer explicitly manages the
PHY resets or increments the clock enable count during probe. If a bootloader
leaves the PHY active (such as for a display splash screen or USB fastboot),
and the consumer driver is not loaded or defers probing, the clock framework's
clk_disable_unused will execute at late_initcall and cut the unclaimed PHY
clocks.

On Rockchip SoCs, cutting clocks to an un-reset, active peripheral frequently
causes an AXI bus hang or prevents the power domain from safely shutting down.
Is an explicit reset still needed in rk_udphy_probe() to ensure the hardware
is put into a quiescent state during boot?

>  	mutex_init(&udphy->mutex);
>  	platform_set_drvdata(pdev, udphy);
>

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260710-rockchip-usbdp-cleanup-v12-0-8b41a9a9bef0@collabora.com?part=6