usb: typec: tcpci: add cable_comm_capable attribute

Add cable_comm_capable to tcpci_data for tcpci drivers to indicate that
the port tcpc is capable of communicating to cables over SOP. A
corresponding tcpci callback tcpci_cable_comm_capable returns this value.
The tcpm will primarily use this in later patches to determine if the port
can transmit and receive SOP' messages.

Maxim based tcpci drivers are capable of SOP' communication, so the
cable_comm_capable flag is set to true.
Signed-off-by: RD Babiera <rdbabiera@google.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20240108191620.987785-17-rdbabiera@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/tcpm/tcpci.c

@@ -584,6 +584,13 @@ static int tcpci_pd_transmit(struct tcpc_dev *tcpc, enum tcpm_transmit_type type
 	return 0;
 }
 
+static bool tcpci_cable_comm_capable(struct tcpc_dev *tcpc)
+{
+	struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
+
+	return tcpci->data->cable_comm_capable;
+}
+
 static int tcpci_init(struct tcpc_dev *tcpc)
 {
 	struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
@@ -793,6 +800,7 @@ struct tcpci *tcpci_register_port(struct device *dev, struct tcpci_data *data)
 	tcpci->tcpc.enable_frs = tcpci_enable_frs;
 	tcpci->tcpc.frs_sourcing_vbus = tcpci_frs_sourcing_vbus;
 	tcpci->tcpc.set_partner_usb_comm_capable = tcpci_set_partner_usb_comm_capable;
+	tcpci->tcpc.cable_comm_capable = tcpci_cable_comm_capable;
 
 	if (tcpci->data->check_contaminant)
 		tcpci->tcpc.check_contaminant = tcpci_check_contaminant;

drivers/usb/typec/tcpm/tcpci_maxim_core.c

@@ -478,6 +478,7 @@ static int max_tcpci_probe(struct i2c_client *client)
 	chip->data.vbus_vsafe0v = true;
 	chip->data.set_partner_usb_comm_capable = max_tcpci_set_partner_usb_comm_capable;
 	chip->data.check_contaminant = max_tcpci_check_contaminant;
+	chip->data.cable_comm_capable = true;
 
 	max_tcpci_init_regs(chip);
 	chip->tcpci = tcpci_register_port(chip->dev, &chip->data);

include/linux/usb/tcpci.h

@@ -198,12 +198,15 @@ struct tcpci;
  *		Chip level drivers are expected to check for contaminant and call
  *		tcpm_clean_port when the port is clean to put the port back into
  *		toggling state.
+ * @cable_comm_capable
+ *		optional; Set when TCPC can communicate with cable plugs over SOP'
  */
 struct tcpci_data {
 	struct regmap *regmap;
 	unsigned char TX_BUF_BYTE_x_hidden:1;
 	unsigned char auto_discharge_disconnect:1;
 	unsigned char vbus_vsafe0v:1;
+	unsigned char cable_comm_capable:1;
 
 	int (*init)(struct tcpci *tcpci, struct tcpci_data *data);
 	int (*set_vconn)(struct tcpci *tcpci, struct tcpci_data *data,

include/linux/usb/tcpm.h

@@ -119,6 +119,9 @@ enum tcpm_transmit_type {
  *		at the end of the deboumce period or when the port is still
  *		toggling. Chip level drivers are expected to check for contaminant
  *		and call tcpm_clean_port when the port is clean.
+ * @cable_comm_capable
+ *		Optional; Returns whether cable communication over SOP' is supported
+ *		by the tcpc
  */
 struct tcpc_dev {
 	struct fwnode_handle *fwnode;
@@ -154,6 +157,7 @@ struct tcpc_dev {
 	bool (*is_vbus_vsafe0v)(struct tcpc_dev *dev);
 	void (*set_partner_usb_comm_capable)(struct tcpc_dev *dev, bool enable);
 	void (*check_contaminant)(struct tcpc_dev *dev);
+	bool (*cable_comm_capable)(struct tcpc_dev *dev);
 };
 
 struct tcpm_port;