usb: typec: ucsi: Add support for USB role switch

UCSI already conveys the information about a port's connection
status, whether it is operating in UFP or DFP mode, and whether the
partner supports USB data or not. This information can be used to
notify a dual-role controller to start up its host or peripheral
mode accordingly. Add optional support for this by querying each
port's fwnode to look for an associated USB role switch device.
If present, call usb_role_switch_set() with the determined data
role upon Connect Change or Connector Partner Change updates.
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Mayank Rana <mrana@codeaurora.org>
Signed-off-by: Jack Pham <jackp@codeaurora.org>
Link: https://lore.kernel.org/r/20210111215520.18476-1-jackp@codeaurora.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/ucsi/ucsi.c

@@ -588,6 +588,7 @@ static void ucsi_unregister_partner(struct ucsi_connector *con)
 
 static void ucsi_partner_change(struct ucsi_connector *con)
 {
+	enum usb_role u_role = USB_ROLE_NONE;
 	int ret;
 
 	if (!con->partner)
@@ -595,11 +596,14 @@ static void ucsi_partner_change(struct ucsi_connector *con)
 
 	switch (UCSI_CONSTAT_PARTNER_TYPE(con->status.flags)) {
 	case UCSI_CONSTAT_PARTNER_TYPE_UFP:
-	case UCSI_CONSTAT_PARTNER_TYPE_CABLE:
 	case UCSI_CONSTAT_PARTNER_TYPE_CABLE_AND_UFP:
+		u_role = USB_ROLE_HOST;
+		fallthrough;
+	case UCSI_CONSTAT_PARTNER_TYPE_CABLE:
 		typec_set_data_role(con->port, TYPEC_HOST);
 		break;
 	case UCSI_CONSTAT_PARTNER_TYPE_DFP:
+		u_role = USB_ROLE_DEVICE;
 		typec_set_data_role(con->port, TYPEC_DEVICE);
 		break;
 	default:
@@ -610,6 +614,15 @@ static void ucsi_partner_change(struct ucsi_connector *con)
 	if (!completion_done(&con->complete))
 		complete(&con->complete);
 
+	/* Only notify USB controller if partner supports USB data */
+	if (!(UCSI_CONSTAT_PARTNER_FLAGS(con->status.flags) & UCSI_CONSTAT_PARTNER_FLAG_USB))
+		u_role = USB_ROLE_NONE;
+
+	ret = usb_role_switch_set_role(con->usb_role_sw, u_role);
+	if (ret)
+		dev_err(con->ucsi->dev, "con:%d: failed to set usb role:%d\n",
+			con->num, u_role);
+
 	/* Can't rely on Partner Flags field. Always checking the alt modes. */
 	ret = ucsi_register_altmodes(con, UCSI_RECIPIENT_SOP);
 	if (ret)
@@ -628,6 +641,7 @@ static void ucsi_handle_connector_change(struct work_struct *work)
 	struct ucsi_connector_status pre_ack_status;
 	struct ucsi_connector_status post_ack_status;
 	enum typec_role role;
+	enum usb_role u_role = USB_ROLE_NONE;
 	u16 inferred_changes;
 	u16 changed_flags;
 	u64 command;
@@ -753,11 +767,14 @@ static void ucsi_handle_connector_change(struct work_struct *work)
 
 		switch (UCSI_CONSTAT_PARTNER_TYPE(con->status.flags)) {
 		case UCSI_CONSTAT_PARTNER_TYPE_UFP:
-		case UCSI_CONSTAT_PARTNER_TYPE_CABLE:
 		case UCSI_CONSTAT_PARTNER_TYPE_CABLE_AND_UFP:
+			u_role = USB_ROLE_HOST;
+			fallthrough;
+		case UCSI_CONSTAT_PARTNER_TYPE_CABLE:
 			typec_set_data_role(con->port, TYPEC_HOST);
 			break;
 		case UCSI_CONSTAT_PARTNER_TYPE_DFP:
+			u_role = USB_ROLE_DEVICE;
 			typec_set_data_role(con->port, TYPEC_DEVICE);
 			break;
 		default:
@@ -770,6 +787,16 @@ static void ucsi_handle_connector_change(struct work_struct *work)
 			ucsi_unregister_partner(con);
 
 		ucsi_port_psy_changed(con);
+
+		/* Only notify USB controller if partner supports USB data */
+		if (!(UCSI_CONSTAT_PARTNER_FLAGS(con->status.flags) &
+				UCSI_CONSTAT_PARTNER_FLAG_USB))
+			u_role = USB_ROLE_NONE;
+
+		ret = usb_role_switch_set_role(con->usb_role_sw, u_role);
+		if (ret)
+			dev_err(ucsi->dev, "con:%d: failed to set usb role:%d\n",
+				con->num, u_role);
 	}
 
 	if (con->status.change & UCSI_CONSTAT_PARTNER_CHANGE)
@@ -988,6 +1015,7 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
 	struct ucsi_connector *con = &ucsi->connector[index];
 	struct typec_capability *cap = &con->typec_cap;
 	enum typec_accessory *accessory = cap->accessory;
+	enum usb_role u_role = USB_ROLE_NONE;
 	u64 command;
 	int ret;
 
@@ -1066,11 +1094,14 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
 
 	switch (UCSI_CONSTAT_PARTNER_TYPE(con->status.flags)) {
 	case UCSI_CONSTAT_PARTNER_TYPE_UFP:
-	case UCSI_CONSTAT_PARTNER_TYPE_CABLE:
 	case UCSI_CONSTAT_PARTNER_TYPE_CABLE_AND_UFP:
+		u_role = USB_ROLE_HOST;
+		fallthrough;
+	case UCSI_CONSTAT_PARTNER_TYPE_CABLE:
 		typec_set_data_role(con->port, TYPEC_HOST);
 		break;
 	case UCSI_CONSTAT_PARTNER_TYPE_DFP:
+		u_role = USB_ROLE_DEVICE;
 		typec_set_data_role(con->port, TYPEC_DEVICE);
 		break;
 	default:
@@ -1086,6 +1117,24 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
 		ucsi_port_psy_changed(con);
 	}
 
+	con->usb_role_sw = fwnode_usb_role_switch_get(cap->fwnode);
+	if (IS_ERR(con->usb_role_sw)) {
+		dev_err(ucsi->dev, "con%d: failed to get usb role switch\n",
+			con->num);
+		con->usb_role_sw = NULL;
+	}
+
+	/* Only notify USB controller if partner supports USB data */
+	if (!(UCSI_CONSTAT_PARTNER_FLAGS(con->status.flags) & UCSI_CONSTAT_PARTNER_FLAG_USB))
+		u_role = USB_ROLE_NONE;
+
+	ret = usb_role_switch_set_role(con->usb_role_sw, u_role);
+	if (ret) {
+		dev_err(ucsi->dev, "con:%d: failed to set usb role:%d\n",
+			con->num, u_role);
+		ret = 0;
+	}
+
 	if (con->partner) {
 		ret = ucsi_register_altmodes(con, UCSI_RECIPIENT_SOP);
 		if (ret) {

drivers/usb/typec/ucsi/ucsi.h

@@ -8,6 +8,7 @@
 #include <linux/power_supply.h>
 #include <linux/types.h>
 #include <linux/usb/typec.h>
+#include <linux/usb/role.h>
 
 /* -------------------------------------------------------------------------- */
 
@@ -331,6 +332,8 @@ struct ucsi_connector {
 	u32 rdo;
 	u32 src_pdos[UCSI_MAX_PDOS];
 	int num_pdos;
+
+	struct usb_role_switch *usb_role_sw;
 };
 
 int ucsi_send_command(struct ucsi *ucsi, u64 command,