Re: [PATCH 3/5] usb: typec: mux: ps883x: refactor DP altmode handling and support TYPEC_DP_STATE_F

[Heikki Krogerus]

On Sat, Jul 18, 2026 at 07:06:31PM +0200, Jens Glathe via B4 Relay wrote:
> From: Jens Glathe <jens.glathe@xxxxxxxxxxxxxxxxxxxxxx>
> 
> Several docks, including the Lenovo 40B0 and SSK SC220, still send the
> legacy TYPEC_DP_STATE_F mode request (deprecated since DisplayPort Alt
> Mode spec version 1.0b). Treat it as USB3 + DP altmode (same as
> TYPEC_DP_STATE_D) so that DP altmode works correctly, especially on
> the 40B0 in Type-C fallback mode.
> 
> Extract the state handling into ps883x_apply_dp_altmode() (modelled
> after qmp-combo-phy) for consistency.
> 
> Assisted-by: Grok(xAI):4.3
> Signed-off-by: Jens Glathe <jens.glathe@xxxxxxxxxxxxxxxxxxxxxx>

Acked-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>

> ---
>  drivers/usb/typec/mux/ps883x.c | 35 ++++++++++++++++++++---------------
>  1 file changed, 20 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/usb/typec/mux/ps883x.c b/drivers/usb/typec/mux/ps883x.c
> index 3fa26ce01a9c9..3533d4f363286 100644
> --- a/drivers/usb/typec/mux/ps883x.c
> +++ b/drivers/usb/typec/mux/ps883x.c
> @@ -188,6 +188,25 @@ static int ps883x_configure(struct ps883x_retimer *retimer, int cfg0,
>  	return 0;
>  }
>  
> +static void ps883x_apply_dp_altmode(int *cfg0, int *cfg1, int dp_state)
> +{
> +	*cfg1 |= CONN_STATUS_1_DP_CONNECTED | CONN_STATUS_1_DP_HPD_LEVEL;
> +
> +	switch (dp_state) {
> +	case TYPEC_DP_STATE_D:
> +	case TYPEC_DP_STATE_F:
> +		*cfg0 |= CONN_STATUS_0_USB_3_1_CONNECTED;
> +		fallthrough;
> +	case TYPEC_DP_STATE_C:
> +	case TYPEC_DP_STATE_E:
> +		*cfg1 |= CONN_STATUS_1_DP_SINK_REQUESTED |
> +			 CONN_STATUS_1_DP_PIN_ASSIGNMENT_C_D;
> +		break;
> +	default:
> +		break;
> +	}
> +}
> +
>  static int ps883x_set(struct ps883x_retimer *retimer, struct typec_retimer_state *state)
>  {
>  	struct typec_thunderbolt_data *tb_data;
> @@ -203,24 +222,10 @@ static int ps883x_set(struct ps883x_retimer *retimer, struct typec_retimer_state
>  	if (state->alt) {
>  		switch (state->alt->svid) {
>  		case USB_TYPEC_DP_SID:
> -			cfg1 |= CONN_STATUS_1_DP_CONNECTED |
> -				CONN_STATUS_1_DP_HPD_LEVEL;
> -
> -			switch (state->mode)  {
> -			case TYPEC_DP_STATE_D:
> -				cfg0 |= CONN_STATUS_0_USB_3_1_CONNECTED;
> -				fallthrough;
> -			case TYPEC_DP_STATE_C:
> -				cfg1 |= CONN_STATUS_1_DP_SINK_REQUESTED |
> -					CONN_STATUS_1_DP_PIN_ASSIGNMENT_C_D;
> -				break;
> -			default: /* MODE_E */
> -				break;
> -			}
> +			ps883x_apply_dp_altmode(&cfg0, &cfg1, state->mode);
>  			break;
>  		case USB_TYPEC_TBT_SID:
>  			tb_data = state->data;
> -
>  			/* Unconditional */
>  			cfg2 |= CONN_STATUS_2_TBT_CONNECTED;
>  
> 
> -- 
> 2.53.0
> 

-- 
heikki