usb: typec: tcpm: Refactor logic to enable/disable auto vbus dicharge

The logic to enable vbus auto discharge on disconnect is used in
more than one place. Since this is repetitive code, moving this into
its own method.

Fixes: f321a02c ("usb: typec: tcpm: Implement enabling Auto Discharge disconnect support")
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Link: https://lore.kernel.org/r/20210517192112.40934-2-badhri@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/tcpm/tcpm.c

@@ -774,6 +774,21 @@ static void tcpm_set_cc(struct tcpm_port *port, enum typec_cc_status cc)
 	port->tcpc->set_cc(port->tcpc, cc);
 }
 
+static int tcpm_enable_auto_vbus_discharge(struct tcpm_port *port, bool enable)
+{
+	int ret = 0;
+
+	if (port->tcpc->enable_auto_vbus_discharge) {
+		ret = port->tcpc->enable_auto_vbus_discharge(port->tcpc, enable);
+		tcpm_log_force(port, "%s vbus discharge ret:%d", enable ? "enable" : "disable",
+			       ret);
+		if (!ret)
+			port->auto_vbus_discharge_enabled = enable;
+	}
+
+	return ret;
+}
+
 /*
  * Determine RP value to set based on maximum current supported
  * by a port if configured as source.
@@ -3472,12 +3487,7 @@ static int tcpm_src_attach(struct tcpm_port *port)
 	if (ret < 0)
 		return ret;
 
-	if (port->tcpc->enable_auto_vbus_discharge) {
-		ret = port->tcpc->enable_auto_vbus_discharge(port->tcpc, true);
-		tcpm_log_force(port, "enable vbus discharge ret:%d", ret);
-		if (!ret)
-			port->auto_vbus_discharge_enabled = true;
-	}
+	tcpm_enable_auto_vbus_discharge(port, true);
 
 	ret = tcpm_set_roles(port, true, TYPEC_SOURCE, tcpm_data_role_for_source(port));
 	if (ret < 0)
@@ -3554,14 +3564,7 @@ static void tcpm_set_partner_usb_comm_capable(struct tcpm_port *port, bool capab
 
 static void tcpm_reset_port(struct tcpm_port *port)
 {
-	int ret;
-
-	if (port->tcpc->enable_auto_vbus_discharge) {
-		ret = port->tcpc->enable_auto_vbus_discharge(port->tcpc, false);
-		tcpm_log_force(port, "Disable vbus discharge ret:%d", ret);
-		if (!ret)
-			port->auto_vbus_discharge_enabled = false;
-	}
+	tcpm_enable_auto_vbus_discharge(port, false);
 	port->in_ams = false;
 	port->ams = NONE_AMS;
 	port->vdm_sm_running = false;
@@ -3629,13 +3632,7 @@ static int tcpm_snk_attach(struct tcpm_port *port)
 	if (ret < 0)
 		return ret;
 
-	if (port->tcpc->enable_auto_vbus_discharge) {
-		tcpm_set_auto_vbus_discharge_threshold(port, TYPEC_PWR_MODE_USB, false, VSAFE5V);
-		ret = port->tcpc->enable_auto_vbus_discharge(port->tcpc, true);
-		tcpm_log_force(port, "enable vbus discharge ret:%d", ret);
-		if (!ret)
-			port->auto_vbus_discharge_enabled = true;
-	}
+	tcpm_enable_auto_vbus_discharge(port, true);
 
 	ret = tcpm_set_roles(port, true, TYPEC_SINK, tcpm_data_role_for_sink(port));
 	if (ret < 0)