Re: [PATCH v4 07/16] phy: rockchip: usbdp: Support single-lane DP

[Neil Armstrong <neil.armstrong@linaro.org>]

On 4/28/26 18:13, Sebastian Reichel wrote:
> From: Zhang Yubing <yubing.zhang@rock-chips.com>
> 
> Implement support for using just a single DisplayPort line.
> 
> Signed-off-by: Zhang Yubing <yubing.zhang@rock-chips.com>
> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> ---
>   drivers/phy/rockchip/phy-rockchip-usbdp.c | 61 +++++++++++++------------------
>   1 file changed, 25 insertions(+), 36 deletions(-)
> 
> diff --git a/drivers/phy/rockchip/phy-rockchip-usbdp.c b/drivers/phy/rockchip/phy-rockchip-usbdp.c
> index febc148a754e..bf8394174294 100644
> --- a/drivers/phy/rockchip/phy-rockchip-usbdp.c
> +++ b/drivers/phy/rockchip/phy-rockchip-usbdp.c
> @@ -193,6 +193,7 @@ struct rk_udphy {
>   	int id;
>   
>   	bool dp_in_use;
> +	int dp_lanes;
>   
>   	/* PHY const config */
>   	const struct rk_udphy_cfg *cfgs;
> @@ -537,6 +538,13 @@ static void rk_udphy_usb_bvalid_enable(struct rk_udphy *udphy, u8 enable)
>    * <0 1>                  dpln0         dpln1       usbrx         usbtx
>    * <2 3>                  usbrx         usbtx       dpln0         dpln1
>    * ---------------------------------------------------------------------------
> + * if 1 lane for dp function, 2 lane for usb function, define rockchip,dp-lane-mux = <x>;
> + * sample as follow:
> + * ---------------------------------------------------------------------------
> + *                        B11-B10       A2-A3       A11-A10       B2-B3
> + * rockchip,dp-lane-mux   ln0(tx/rx)    ln1(tx)     ln2(tx/rx)    ln3(tx)
> + * <0>                    dpln0         \           usbrx         usbtx
> + * ---------------------------------------------------------------------------
>    */
>   
>   static void rk_udphy_dplane_select(struct rk_udphy *udphy)
> @@ -544,18 +552,18 @@ static void rk_udphy_dplane_select(struct rk_udphy *udphy)
>   	const struct rk_udphy_cfg *cfg = udphy->cfgs;
>   	u32 value = 0;
>   
> -	switch (udphy->mode) {
> -	case UDPHY_MODE_DP:
> -		value |= 2 << udphy->dp_lane_sel[2] * 2;
> +	switch (udphy->dp_lanes) {
> +	case 4:
>   		value |= 3 << udphy->dp_lane_sel[3] * 2;
> +		value |= 2 << udphy->dp_lane_sel[2] * 2;
>   		fallthrough;
>   
> -	case UDPHY_MODE_DP_USB:
> -		value |= 0 << udphy->dp_lane_sel[0] * 2;
> +	case 2:
>   		value |= 1 << udphy->dp_lane_sel[1] * 2;
> -		break;
> +		fallthrough;
>   
> -	case UDPHY_MODE_USB:
> +	case 1:
> +		value |= 0 << udphy->dp_lane_sel[0] * 2;

What's the point of keeping this no-op calculation ?

>   		break;
>   
>   	default:
> @@ -568,28 +576,6 @@ static void rk_udphy_dplane_select(struct rk_udphy *udphy)
>   		     FIELD_PREP(DP_AUX_DOUT_SEL, udphy->dp_aux_dout_sel) | value);
>   }
>   
> -static int rk_udphy_dplane_get(struct rk_udphy *udphy)
> -{
> -	int dp_lanes;
> -
> -	switch (udphy->mode) {
> -	case UDPHY_MODE_DP:
> -		dp_lanes = 4;
> -		break;
> -
> -	case UDPHY_MODE_DP_USB:
> -		dp_lanes = 2;
> -		break;
> -
> -	case UDPHY_MODE_USB:
> -	default:
> -		dp_lanes = 0;
> -		break;
> -	}
> -
> -	return dp_lanes;
> -}
> -
>   static void rk_udphy_dplane_enable(struct rk_udphy *udphy, int dp_lanes)
>   {
>   	u32 val = 0;
> @@ -659,6 +645,7 @@ static void rk_udphy_set_typec_default_mapping(struct rk_udphy *udphy)
>   	}
>   
>   	rk_udphy_mode_set(udphy, UDPHY_MODE_DP_USB);
> +	udphy->dp_lanes = 2;
>   }
>   
>   static int rk_udphy_orien_sw_set(struct typec_switch_dev *sw,
> @@ -897,7 +884,7 @@ static int rk_udphy_parse_lane_mux_data(struct rk_udphy *udphy)
>   		return 0;
>   	}
>   
> -	if (num_lanes != 2 && num_lanes != 4)
> +	if (num_lanes != 1 && num_lanes != 2 && num_lanes != 4)
>   		return dev_err_probe(udphy->dev, -EINVAL,
>   				     "invalid number of lane mux\n");
>   
> @@ -923,7 +910,8 @@ static int rk_udphy_parse_lane_mux_data(struct rk_udphy *udphy)
>   	}
>   
>   	udphy->mode = UDPHY_MODE_DP;
> -	if (num_lanes == 2) {
> +	udphy->dp_lanes = num_lanes;
> +	if (num_lanes == 1 || num_lanes == 2) {
>   		udphy->mode |= UDPHY_MODE_USB;
>   		udphy->flip = (udphy->lane_mux_sel[0] == PHY_LANE_MUX_DP);
>   	}
> @@ -1074,18 +1062,17 @@ static int rk_udphy_dp_phy_exit(struct phy *phy)
>   static int rk_udphy_dp_phy_power_on(struct phy *phy)
>   {
>   	struct rk_udphy *udphy = phy_get_drvdata(phy);
> -	int ret, dp_lanes;
> +	int ret;
>   
>   	mutex_lock(&udphy->mutex);
>   
> -	dp_lanes = rk_udphy_dplane_get(udphy);
> -	phy_set_bus_width(phy, dp_lanes);
> +	phy_set_bus_width(phy, udphy->dp_lanes);
>   
>   	ret = rk_udphy_power_on(udphy, UDPHY_MODE_DP);
>   	if (ret)
>   		goto unlock;
>   
> -	rk_udphy_dplane_enable(udphy, dp_lanes);
> +	rk_udphy_dplane_enable(udphy, udphy->dp_lanes);
>   
>   	rk_udphy_dplane_select(udphy);
>   
> @@ -1365,6 +1352,7 @@ static int rk_udphy_typec_mux_set(struct typec_mux_dev *mux,
>   		udphy->lane_mux_sel[2] = PHY_LANE_MUX_DP;
>   		udphy->lane_mux_sel[3] = PHY_LANE_MUX_DP;
>   		mode = UDPHY_MODE_DP;
> +		udphy->dp_lanes = 4;
>   		break;
>   
>   	case TYPEC_DP_STATE_D:
> @@ -1381,6 +1369,7 @@ static int rk_udphy_typec_mux_set(struct typec_mux_dev *mux,
>   			udphy->lane_mux_sel[3] = PHY_LANE_MUX_DP;
>   		}
>   		mode = UDPHY_MODE_DP_USB;
> +		udphy->dp_lanes = 2;
>   		break;
>   	}
>   
> @@ -1529,7 +1518,7 @@ static int rk_udphy_probe(struct platform_device *pdev)
>   		ret = PTR_ERR(udphy->phy_dp);
>   		return dev_err_probe(dev, ret, "failed to create DP phy\n");
>   	}
> -	phy_set_bus_width(udphy->phy_dp, rk_udphy_dplane_get(udphy));
> +	phy_set_bus_width(udphy->phy_dp, udphy->dp_lanes);
>   	udphy->phy_dp->attrs.max_link_rate = 8100;
>   	phy_set_drvdata(udphy->phy_dp, udphy);
>   
>