usb: typec: tcpci: Support BIST test data mode for compliance.

Quoting from TCPCI spec:
"Setting this bit to 1 is intended to be used only when a USB compliance
tester is using USB BIST Test Data to test the PHY layer of the TCPC. The
TCPM should clear this bit when a disconnect is detected.
0: Normal Operation. Incoming messages enabled by RECEIVE_DETECT
passed to TCPM via Alert.
1: BIST Test Mode. Incoming messages enabled by RECEIVE_DETECT
result in GoodCRC response but may not be passed to the TCPM via
Alert."

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200716034128.1251728-2-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/tcpm/tcpci.c

@@ -227,6 +227,14 @@ static int tcpci_set_vconn(struct tcpc_dev *tcpc, bool enable)
 				enable ? TCPC_POWER_CTRL_VCONN_ENABLE : 0);
 }
 
+static int tcpci_set_bist_data(struct tcpc_dev *tcpc, bool enable)
+{
+	struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
+
+	return regmap_update_bits(tcpci->regmap, TCPC_TCPC_CTRL, TCPC_TCPC_CTRL_BIST_TM,
+				 enable ? TCPC_TCPC_CTRL_BIST_TM : 0);
+}
+
 static int tcpci_set_roles(struct tcpc_dev *tcpc, bool attached,
 			   enum typec_role role, enum typec_data_role data)
 {
@@ -530,6 +538,7 @@ struct tcpci *tcpci_register_port(struct device *dev, struct tcpci_data *data)
 	tcpci->tcpc.set_pd_rx = tcpci_set_pd_rx;
 	tcpci->tcpc.set_roles = tcpci_set_roles;
 	tcpci->tcpc.pd_transmit = tcpci_pd_transmit;
+	tcpci->tcpc.set_bist_data = tcpci_set_bist_data;
 
 	err = tcpci_parse_config(tcpci);
 	if (err < 0)

drivers/usb/typec/tcpm/tcpci.h

@@ -36,6 +36,7 @@
 
 #define TCPC_TCPC_CTRL			0x19
 #define TCPC_TCPC_CTRL_ORIENTATION	BIT(0)
+#define TCPC_TCPC_CTRL_BIST_TM		BIT(1)
 
 #define TCPC_ROLE_CTRL			0x1a
 #define TCPC_ROLE_CTRL_DRP		BIT(6)