[PATCH 1/2] UPSTREAM: usb: roles: Switch on role-switch uevent reporting

[Bryan O'Donoghue]

Right now we don't report to user-space a role switch when doing a
usb_role_switch_set_role() despite having registered the uevent callbacks.

This patch switches on the notifications allowing user-space to see
role-switch change notifications and subsequently determine the current
controller data-role.

example:
PFX=/devices/platform/soc/78d9000.usb/ci_hdrc.0

root@somebox# udevadm monitor -p

KERNEL[49.894994] change $PFX/usb_role/ci_hdrc.0-role-switch (usb_role)
ACTION=change
DEVPATH=$PFX/usb_role/ci_hdrc.0-role-switch
SUBSYSTEM=usb_role
DEVTYPE=usb_role_switch
USB_ROLE_SWITCH=ci_hdrc.0-role-switch
SEQNUM=2432

Cc: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Cc: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
Cc: Wen Yang <wenyang@xxxxxxxxxxxxxxxxx>
Cc: chenqiwu <chenqiwu@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200508162937.2566818-1-bryan.odonoghue@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
[cherry-pick commit 3e63cff384e625f09758ce8f4d01ae3033402b63 upstream]
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
---
 drivers/usb/roles/class.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
index 1dd492e89719..5e4d5aa929a1 100644
--- a/drivers/usb/roles/class.c
+++ b/drivers/usb/roles/class.c
@@ -48,8 +48,10 @@ int usb_role_switch_set_role(struct usb_role_switch *sw, enum usb_role role)
 	mutex_lock(&sw->lock);
 
 	ret = sw->set(sw->dev.parent, role);
-	if (!ret)
+	if (!ret) {
 		sw->role = role;
+		kobject_uevent(&sw->dev.kobj, KOBJ_CHANGE);
+	}
 
 	mutex_unlock(&sw->lock);
 
-- 
2.25.1