Re: [PATCH v11 10/36] phy: rockchip: usbdp: Add missing mode_change update

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The newly introduced rk_udphy_mode_set() helper incorrectly returns early if the logical mode matches, failing to trigger PHY hardware reinitialization on Type-C cable orientation flips.
--

--- Patch [10]: [PATCH v11 10/36] phy: rockchip: usbdp: Add missing mode_change update ---
commit 3a5a910ac8d7d8bee622a7fda0b441c254a882fe
Author: Sebastian Reichel <sebastian.reichel@collabora.com>

phy: rockchip: usbdp: Add missing mode_change update

This commit introduces a new helper rk_udphy_mode_set() to update available
modes and set the mode_change flag. It aims to fix an issue where missing
re-initialization caused DisplayPort to stop working.

> diff --git a/drivers/phy/rockchip/phy-rockchip-usbdp.c b/drivers/phy/rockchip/phy-rockchip-usbdp.c
> index 982315535caf7..7540c897dde13 100644
> --- a/drivers/phy/rockchip/phy-rockchip-usbdp.c
> +++ b/drivers/phy/rockchip/phy-rockchip-usbdp.c

[ ... ]

> @@ -617,6 +617,15 @@ static void rk_udphy_dp_hpd_event_trigger(struct rk_udphy *udphy, bool hpd)
>  	rk_udphy_grfreg_write(udphy->vogrf, &cfg->vogrfcfg[udphy->id].hpd_trigger, hpd);
>  }
>  
> +static void rk_udphy_mode_set(struct rk_udphy *udphy, u8 mode)
> +{
> +	if (udphy->mode == mode)
> +		return;
> +
> +	udphy->mode_change = true;
> +	udphy->mode = mode;
> +}
> +
>  static void rk_udphy_set_typec_default_mapping(struct rk_udphy *udphy)
>  {
>  	if (udphy->flip) {
> @@ -647,7 +656,7 @@ static void rk_udphy_set_typec_default_mapping(struct rk_udphy *udphy)
>  		gpiod_set_value_cansleep(udphy->sbu2_dc_gpio, 1);
>  	}
>  
> -	udphy->mode = UDPHY_MODE_DP_USB;
> +	rk_udphy_mode_set(udphy, UDPHY_MODE_DP_USB);

[Severity: High]
Will this early return in rk_udphy_mode_set() prevent PHY re-initialization
during a Type-C cable orientation flip?

When the cable is rapidly flipped and replugged, the USB driver might keep the
PHY powered on temporarily due to runtime PM autosuspend, meaning udphy->status
can remain UDPHY_MODE_USB. 

In this scenario, rk_udphy_set_typec_default_mapping() recalculates the new
reversed physical lane mappings and calls the new helper:

rk_udphy_orien_sw_set() ->
   rk_udphy_set_typec_default_mapping() ->
      // physical lane mappings are updated here
      rk_udphy_mode_set(udphy, UDPHY_MODE_DP_USB);

Since udphy->mode is already UDPHY_MODE_DP_USB, the helper returns early
without setting mode_change to true. 

Consequently, when DP power-on occurs in rk_udphy_power_on(), the hardware
initialization step is skipped because mode_change is false. The hardware's
lane mux registers are never updated with the new reversed mappings, which
causes DisplayPort to fail.

Does the mode_change flag need to be set during an orientation change even if
the logical mode remains the same?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260709-rockchip-usbdp-cleanup-v11-0-a149ac60f76c@collabora.com?part=10