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From:   Grigor Tovmasyan <Grigor.Tovmasyan@synopsys.com>
To:     Tomeu Vizoso <tomeu.vizoso@collabora.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     Felipe Balbi <felipe.balbi@linux.intel.com>,
        Heiko Stuebner <heiko@sntech.de>,
        Amelie Delaunay <amelie.delaunay@st.com>,
        "Minas Harutyunyan" <Minas.Harutyunyan@synopsys.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>
Subject: Re: [PATCH v4] usb: dwc2: dwc2_vbus_supply_init: fix error check
Thread-Topic: [PATCH v4] usb: dwc2: dwc2_vbus_supply_init: fix error check
Thread-Index: AQHTxOD/EnRsRkoOHE2ZtYRlyd+fGg==
Date:   Thu, 5 Apr 2018 08:58:54 +0000
Message-ID: <32EB88BF8EC1614E9FB18BD3718BE1A116412614@am04wembxb.internal.synopsys.com>
References: <20180322093943.49717-1-tomeu.vizoso@collabora.com>
 <20180326090001.57627-1-tomeu.vizoso@collabora.com>
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On 3/26/2018 1:01 PM, 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@st.com>
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
> 
> ---
> 
> v2: Only overwrite the error in the pointer after checking it (Heiko
>      St?bner <heiko@sntech.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@intel.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: Grigor Tovmasyan <tovmasya@synopsys.com>