[PATCH v3] usb: dwc2: dwc2_vbus_supply_init: fix error check

[Tomeu Vizoso]

devm_regulator_get_optional returns -ENODEV if the regulator isn't
there, so if that's the case we have to make sure not to leave -ENODEV
in the regulator pointer.

Also, make sure we return 0 in that case, but correctly propagate any
other errors. Also propagate the error from _dwc2_hcd_start.

Fixes: 531ef5ebea96 ("usb: dwc2: add support for host mode external vbus supply")
Cc: Amelie Delaunay <amelie.delaunay@xxxxxx>
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>

---

v2: Only overwrite the error in the pointer after checking it (Heiko
    StÃbner <heiko@xxxxxxxxx>)
v3: Remove hunks that shouldn't be in this patch
---
 drivers/usb/dwc2/hcd.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index dcfda5eb4cac..863aed20517f 100644
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -359,8 +359,13 @@ static void dwc2_gusbcfg_init(struct dwc2_hsotg *hsotg)
 static int dwc2_vbus_supply_init(struct dwc2_hsotg *hsotg)
 {
 	hsotg->vbus_supply = devm_regulator_get_optional(hsotg->dev, "vbus");
-	if (IS_ERR(hsotg->vbus_supply))
+	if (PTR_ERR(hsotg->vbus_supply) == -ENODEV) {
+		hsotg->vbus_supply = NULL;
 		return 0;
+	} else if (IS_ERR(hsotg->vbus_supply)) {
+		hsotg->vbus_supply = NULL;
+		return PTR_ERR(hsotg->vbus_supply);
+	}
 
 	return regulator_enable(hsotg->vbus_supply);
 }
@@ -4342,9 +4347,7 @@ static int _dwc2_hcd_start(struct usb_hcd *hcd)
 
 	spin_unlock_irqrestore(&hsotg->lock, flags);
 
-	dwc2_vbus_supply_init(hsotg);
-
-	return 0;
+	return dwc2_vbus_supply_init(hsotg);
 }
 
 /*
-- 
2.14.3