usb: typec: Allow power role swapping even without USB PD

Even though originally the USB Type-C Specification did not
describe the steps for power role swapping without USB PD
contract in place, it did not actually mean power role swap
without USB PD was not allowed. The USB Type-C Specification
did not clearly separate the data and power roles until in
the release 1.2 which is why there also were no clear steps
for the scenario where only the power role was swapped
without USB PD contract before that.

Since in the latest version of the specification the power
role swap without USB PD is now clearly mentioned as allowed
operation, removing the check that prevented power role swap
without USB PD support.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20200211112531.86510-4-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/testing/sysfs-class-typec

@@ -20,13 +20,13 @@ Date:		April 2017
 Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
 Description:
 		The supported power roles. This attribute can be used to request
-		power role swap on the port when the port supports USB Power
-		Delivery. Swapping is supported as synchronous operation, so
-		write(2) to the attribute will not return until the operation
-		has finished. The attribute is notified about role changes so
-		that poll(2) on the attribute wakes up. Change on the role will
-		also generate uevent KOBJ_CHANGE. The current role is show in
-		brackets, for example "[source] sink" when in source mode.
+		power role swap on the port. Swapping is supported as
+		synchronous operation, so write(2) to the attribute will not
+		return until the operation has finished. The attribute is
+		notified about role changes so that poll(2) on the attribute
+		wakes up. Change on the role will also generate uevent
+		KOBJ_CHANGE. The current role is show in brackets, for example
+		"[source] sink" when in source mode.
 
 		Valid values: source, sink
 

drivers/usb/typec/class.c

@@ -1112,11 +1112,6 @@ static ssize_t power_role_store(struct device *dev,
 	struct typec_port *port = to_typec_port(dev);
 	int ret;
 
-	if (!port->cap->pd_revision) {
-		dev_dbg(dev, "USB Power Delivery not supported\n");
-		return -EOPNOTSUPP;
-	}
-
 	if (!port->ops || !port->ops->pr_set) {
 		dev_dbg(dev, "power role swapping not supported\n");
 		return -EOPNOTSUPP;
@@ -1338,7 +1333,6 @@ static umode_t typec_attr_is_visible(struct kobject *kobj,
 			return 0444;
 	} else if (attr == &dev_attr_power_role.attr) {
 		if (port->cap->type != TYPEC_PORT_DRP ||
-		    !port->cap->pd_revision ||
 		    !port->ops || !port->ops->pr_set)
 			return 0444;
 	} else if (attr == &dev_attr_vconn_source.attr) {