linux-kernel - Re: [PATCH v4] usb: dwc2: dwc2_vbus_supply

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Message-ID: <4abf7dee-8cb1-6d76-2f75-82db12f096a2@st.com>
Date:   Mon, 26 Mar 2018 10:56:15 +0000
From:   Amelie DELAUNAY <amelie.delaunay@...com>
To:     Tomeu Vizoso <tomeu.vizoso@...labora.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Felipe Balbi <felipe.balbi@...ux.intel.com>,
        Heiko Stuebner <heiko@...ech.de>,
        Minas Harutyunyan <hminas@...opsys.com>,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>
Subject: Re: [PATCH v4] usb: dwc2: dwc2_vbus_supply_init: fix error check

Hi,

On 03/26/2018 11:00 AM, Tomeu Vizoso wrote:
> 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@...com>
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@...labora.com>
> 
> ---
> 
> v2: Only overwrite the error in the pointer after checking it (Heiko
>      Stübner <heiko@...ech.de>)
> v3: Remove hunks that shouldn't be in this patch
> v4: Don't overwrite the error code before returning it (kbuild test
>      robot <lkp@...el.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 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);
>   }
>   
>   /*
> 

Reviewed-by: Amelie Delaunay <amelie.delaunay@...com>

Thanks,
Amelie