usb: typec: fusb302: Check vconn is off when we start toggling

The datasheet says the vconn MUST be off when we start toggling. The
tcpm.c state-machine is responsible to make sure vconn is off, but lets
add a WARN to catch any cases where vconn is not off for some reason.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/tcpm/fusb302.c

@@ -607,6 +607,8 @@ static int fusb302_set_toggling(struct fusb302_chip *chip,
 			return ret;
 		chip->intr_togdone = false;
 	} else {
+		/* Datasheet says vconn MUST be off when toggling */
+		WARN(chip->vconn_on, "Vconn is on during toggle start");
 		/* unmask TOGDONE interrupt */
 		ret = fusb302_i2c_clear_bits(chip, FUSB_REG_MASKA,
 					     FUSB_REG_MASKA_TOGDONE);