[PATCH v4] usb: common: usb-conn-gpio: Set last role to unknown before initial detection

[Prashanth K]

Currently if we bootup a device without cable connected, then
usb-conn-gpio won't call set_role() since last_role is same as
current role. This happens because during probe last_role gets
initialised to zero.

To avoid this, added a new constant in enum usb_role, last_role
is set to USB_ROLE_UNKNOWN before performing initial detection.

Fixes: 4602f3bff266 ("usb: common: add USB GPIO based connection detection driver")
Signed-off-by: Prashanth K <quic_prashk@xxxxxxxxxxx>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
---
v4: Added Reviewed-by tag.
v3: Added a default case in drivers/usb/cdns3/core.c as pointed out by
    the test robot.
v2: Added USB_ROLE_UNKNWON to enum usb_role.

 drivers/usb/cdns3/core.c           | 2 ++
 drivers/usb/common/usb-conn-gpio.c | 3 +++
 include/linux/usb/role.h           | 1 +
 3 files changed, 6 insertions(+)

diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c
index dbcdf3b..69d2921 100644
--- a/drivers/usb/cdns3/core.c
+++ b/drivers/usb/cdns3/core.c
@@ -252,6 +252,8 @@ static enum usb_role cdns_hw_role_state_machine(struct cdns *cdns)
 		if (!vbus)
 			role = USB_ROLE_NONE;
 		break;
+	default:
+		break;
 	}
 
 	dev_dbg(cdns->dev, "role %d -> %d\n", cdns->role, role);
diff --git a/drivers/usb/common/usb-conn-gpio.c b/drivers/usb/common/usb-conn-gpio.c
index e20874c..30bdb81 100644
--- a/drivers/usb/common/usb-conn-gpio.c
+++ b/drivers/usb/common/usb-conn-gpio.c
@@ -257,6 +257,9 @@ static int usb_conn_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, info);
 	device_set_wakeup_capable(&pdev->dev, true);
 
+	/* Set last role to unknown before performing the initial detection */
+	info->last_role = USB_ROLE_UNKNOWN;
+
 	/* Perform initial detection */
 	usb_conn_queue_dwork(info, 0);
 
diff --git a/include/linux/usb/role.h b/include/linux/usb/role.h
index b5deafd..221d462 100644
--- a/include/linux/usb/role.h
+++ b/include/linux/usb/role.h
@@ -8,6 +8,7 @@
 struct usb_role_switch;
 
 enum usb_role {
+	USB_ROLE_UNKNOWN = -1,
 	USB_ROLE_NONE,
 	USB_ROLE_HOST,
 	USB_ROLE_DEVICE,
-- 
2.7.4