[PATCH] 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.delau...@st.com>
Signed-off-by: Tomeu Vizoso <tomeu.viz...@collabora.com>
---
 drivers/usb/dwc2/hcd.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index dcfda5eb4cac..4ae211f65e85 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))
-               return 0;
+       if (IS_ERR(hsotg->vbus_supply)) {
+               hsotg->vbus_supply = NULL;
+               if (PTR_ERR(hsotg->vbus_supply) == -ENODEV)
+                       return 0;
+               else
+                       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