[PATCH v7] 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.

While at it, also handle default case for the usb_role switch
in cdns3, intel-xhci-usb-role-switch & musb/jz4740 to avoid
build warnings.

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>
---
v7: Added default case in musb/jz4740.c & intel-xhci-usb-role-switch.c to
    avoid build warnings.
v6: Moved USB_ROLE_UNKNOWN towards the end of enum usb_role.
v5: Update commit text to mention the changes made in cdns3 driver.
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 +++
 drivers/usb/musb/jz4740.c                      | 2 ++
 drivers/usb/roles/intel-xhci-usb-role-switch.c | 2 ++
 include/linux/usb/role.h                       | 1 +
 5 files changed, 10 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/drivers/usb/musb/jz4740.c b/drivers/usb/musb/jz4740.c
index 5aabdd7..6d880c4 100644
--- a/drivers/usb/musb/jz4740.c
+++ b/drivers/usb/musb/jz4740.c
@@ -95,6 +95,8 @@ static int jz4740_musb_role_switch_set(struct usb_role_switch *sw,
 	case USB_ROLE_HOST:
 		atomic_notifier_call_chain(&phy->notifier, USB_EVENT_ID, phy);
 		break;
+	default:
+		break;
 	}
 
 	return 0;
diff --git a/drivers/usb/roles/intel-xhci-usb-role-switch.c b/drivers/usb/roles/intel-xhci-usb-role-switch.c
index 5c96e92..4d6a3dd 100644
--- a/drivers/usb/roles/intel-xhci-usb-role-switch.c
+++ b/drivers/usb/roles/intel-xhci-usb-role-switch.c
@@ -97,6 +97,8 @@ static int intel_xhci_usb_set_role(struct usb_role_switch *sw,
 		val |= SW_VBUS_VALID;
 		drd_config = DRD_CONFIG_STATIC_DEVICE;
 		break;
+	default:
+		break;
 	}
 	val |= SW_IDPIN_EN;
 	if (data->enable_sw_switch) {
diff --git a/include/linux/usb/role.h b/include/linux/usb/role.h
index b5deafd..65e790a 100644
--- a/include/linux/usb/role.h
+++ b/include/linux/usb/role.h
@@ -11,6 +11,7 @@ enum usb_role {
 	USB_ROLE_NONE,
 	USB_ROLE_HOST,
 	USB_ROLE_DEVICE,
+	USB_ROLE_UNKNOWN,
 };
 
 typedef int (*usb_role_switch_set_t)(struct usb_role_switch *sw,
-- 
2.7.4