Am Montag, 26. März 2018, 11:00:01 CEST schrieb 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>
The patch that gets fixed here also breaks display-output on dwc2-based
Rockchip devices (likely even more), probably due to making the regulator
framework hickup.
With this patch applied, apart from not seeing the NULL-ptr, I also get
display output on my rk3288-veycron Chromebook again, so
Tested-by: Heiko Stuebner <heiko@xxxxxxxxx>
> v2: Only overwrite the error in the pointer after checking it (Heiko
> Stübner <heiko@xxxxxxxxx>)
> v3: Remove hunks that shouldn't be in this patch
> v4: Don't overwrite the error code before returning it (kbuild test
> robot <lkp@xxxxxxxxx>)
> ---
> 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 190f95964000..c51b73b3e048 100644
> --- a/drivers/usb/dwc2/hcd.c
> +++ b/drivers/usb/dwc2/hcd.c
> @@ -358,9 +358,14 @@ static void dwc2_gusbcfg_init(struct dwc2_hsotg *hsotg)
>
> static int dwc2_vbus_supply_init(struct dwc2_hsotg *hsotg)
> {
> + int ret;
> +
> hsotg->vbus_supply = devm_regulator_get_optional(hsotg->dev, "vbus");
> - if (IS_ERR(hsotg->vbus_supply))
> - return 0;
> + if (IS_ERR(hsotg->vbus_supply)) {
> + ret = PTR_ERR(hsotg->vbus_supply);
> + hsotg->vbus_supply = NULL;
> + return ret == -ENODEV ? 0 : ret;
> + }
>
> 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);
> }
>
> /*
>
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