platform/chrome: cros_ec_typec: Add Displayport Alternatemode 2.1 Support

Displayport Alternatemode 2.1 requires cable capabilities such as cable
signalling, cable type, DPAM version which then will be used by mux
driver for displayport configuration. These capabilities can be derived
from the Cable VDO.

Acked-by: Prashant Malani <[e-mail]>
Signed-off-by: Utkarsh Patel <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/platform/chrome/cros_ec_typec.c

···
 {
 	struct cros_typec_port *port = typec->ports[port_num];
 	struct typec_displayport_data dp_data;
+	u32 cable_tbt_vdo;
+	u32 cable_dp_vdo;
 	int ret;
 
 	if (typec->pd_ctrl_ver < 2) {
···
 
 	port->state.data = &dp_data;
 	port->state.mode = TYPEC_MODAL_STATE(ffs(pd_ctrl->dp_mode));
+
+	/* Get cable VDO for cables with DPSID to check DPAM2.1 is supported */
+	cable_dp_vdo = cros_typec_get_cable_vdo(port, USB_TYPEC_DP_SID);
+
+	/**
+	 * Get cable VDO for thunderbolt cables and cables with DPSID but does not
+	 * support DPAM2.1.
+	 */
+	cable_tbt_vdo = cros_typec_get_cable_vdo(port, USB_TYPEC_TBT_SID);
+
+	if (cable_dp_vdo & DP_CAP_DPAM_VERSION) {
+		dp_data.conf |= cable_dp_vdo;
+	} else if (cable_tbt_vdo) {
+		dp_data.conf |=  TBT_CABLE_SPEED(cable_tbt_vdo) << DP_CONF_SIGNALLING_SHIFT;
+
+		/* Cable Type */
+		if (cable_tbt_vdo & TBT_CABLE_OPTICAL)
+			dp_data.conf |= DP_CONF_CABLE_TYPE_OPTICAL << DP_CONF_CABLE_TYPE_SHIFT;
+		else if (cable_tbt_vdo & TBT_CABLE_RETIMER)
+			dp_data.conf |= DP_CONF_CABLE_TYPE_RE_TIMER << DP_CONF_CABLE_TYPE_SHIFT;
+		else if (cable_tbt_vdo & TBT_CABLE_ACTIVE_PASSIVE)
+			dp_data.conf |= DP_CONF_CABLE_TYPE_RE_DRIVER << DP_CONF_CABLE_TYPE_SHIFT;
+	} else if (PD_IDH_PTYPE(port->c_identity.id_header) == IDH_PTYPE_PCABLE) {
+		dp_data.conf |= VDO_TYPEC_CABLE_SPEED(port->c_identity.vdo[0]) <<
+				DP_CONF_SIGNALLING_SHIFT;
+	}
 
 	ret = cros_typec_retimer_set(port->retimer, port->state);
 	if (!ret)