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From: Vincent Whitchurch <vincent.whitchurch@axis.com>
To: Mike Looijmans <mike.looijmans@topic.nl>
Cc: <linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<balbi@kernel.org>, <gregkh@linuxfoundation.org>,
	<lgirdwood@gmail.com>, <broonie@kernel.org>
Subject: Re: [PATCH v3] usb: dwc3: Add support for VBUS power control
Date: Thu, 23 Jul 2020 09:56:14 +0200	[thread overview]
Message-ID: <20200723075612.tn5dbkhes2chohwh@axis.com> (raw)
In-Reply-To: <20200619142512.19824-1-mike.looijmans@topic.nl>

On Fri, Jun 19, 2020 at 04:25:12PM +0200, Mike Looijmans wrote:
> +void dwc3_set_vbus(struct dwc3 *dwc, bool enable)
> +{
> +	int ret;
> +
> +	if (enable != dwc->vbus_reg_enabled) {
> +		if (enable)
> +			ret = regulator_enable(dwc->vbus_reg);
> +		else
> +			ret = regulator_disable(dwc->vbus_reg);

dwc->vbus_reg is set to NULL when the regulator is not present.  These
regulator_* functions expect a non-NULL pointer so a NULL check is
required before calling them.

> +		if (!ret)
> +			dwc->vbus_reg_enabled = enable;
> +	}
> +
> +	if (dwc->usb2_phy)
> +		otg_set_vbus(dwc->usb2_phy->otg, enable);
> +}
> +
>  static void __dwc3_set_mode(struct work_struct *work)
>  {
>  	struct dwc3 *dwc = work_to_dwc(work);
> @@ -164,8 +182,7 @@ static void __dwc3_set_mode(struct work_struct *work)
>  		if (ret) {
>  			dev_err(dwc->dev, "failed to initialize host\n");
>  		} else {
> -			if (dwc->usb2_phy)
> -				otg_set_vbus(dwc->usb2_phy->otg, true);
> +			dwc3_set_vbus(dwc, true);
>  			phy_set_mode(dwc->usb2_generic_phy, PHY_MODE_USB_HOST);
>  			phy_set_mode(dwc->usb3_generic_phy, PHY_MODE_USB_HOST);
>  		}
> @@ -173,8 +190,7 @@ static void __dwc3_set_mode(struct work_struct *work)
>  	case DWC3_GCTL_PRTCAP_DEVICE:
>  		dwc3_event_buffers_setup(dwc);
>  
> -		if (dwc->usb2_phy)
> -			otg_set_vbus(dwc->usb2_phy->otg, false);
> +		dwc3_set_vbus(dwc, false);
>  		phy_set_mode(dwc->usb2_generic_phy, PHY_MODE_USB_DEVICE);
>  		phy_set_mode(dwc->usb3_generic_phy, PHY_MODE_USB_DEVICE);
>  
> @@ -1183,8 +1199,7 @@ static int dwc3_core_init_mode(struct dwc3 *dwc)
>  	case USB_DR_MODE_PERIPHERAL:
>  		dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_DEVICE);
>  
> -		if (dwc->usb2_phy)
> -			otg_set_vbus(dwc->usb2_phy->otg, false);
> +		dwc3_set_vbus(dwc, false);
>  		phy_set_mode(dwc->usb2_generic_phy, PHY_MODE_USB_DEVICE);
>  		phy_set_mode(dwc->usb3_generic_phy, PHY_MODE_USB_DEVICE);
>  
> @@ -1198,8 +1213,7 @@ static int dwc3_core_init_mode(struct dwc3 *dwc)
>  	case USB_DR_MODE_HOST:
>  		dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_HOST);
>  
> -		if (dwc->usb2_phy)
> -			otg_set_vbus(dwc->usb2_phy->otg, true);
> +		dwc3_set_vbus(dwc, true);
>  		phy_set_mode(dwc->usb2_generic_phy, PHY_MODE_USB_HOST);
>  		phy_set_mode(dwc->usb3_generic_phy, PHY_MODE_USB_HOST);
>  
> @@ -1470,6 +1484,14 @@ static int dwc3_probe(struct platform_device *pdev)
>  
>  	dwc3_get_properties(dwc);
>  
> +	dwc->vbus_reg = devm_regulator_get_optional(dev, "vbus");
> +	if (IS_ERR(dwc->vbus_reg)) {
> +		if (PTR_ERR(dwc->vbus_reg) == -EPROBE_DEFER)
> +			return -EPROBE_DEFER;

Some drivers seem to do it this way, but I think it would be more
correct to return all errors that aren't ENODEV, like
drivers/gpu/drm/exynos/exynos_hdmi.c does.  That way you would allow the
regulator to not be present, but you also wouldn't silently ignore other
errors such as ENOMEM.

> +
> +		dwc->vbus_reg = NULL;
> +	}
> +

  reply	other threads:[~2020-07-23  7:56 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-19 14:25 [PATCH v3] usb: dwc3: Add support for VBUS power control Mike Looijmans
2020-07-23  7:56 ` Vincent Whitchurch [this message]
     [not found]   ` <1b153bce-a66a-45ee-a5c6-963ea6fb1c82.949ef384-8293-46b8-903f-40a477c056ae.2698920d-90ba-4c46-abda-83e18e2093c8@emailsignatures365.codetwo.com>
2020-07-23 11:05   ` Mark Brown
2020-07-26  7:10     ` Mike Looijmans
2020-07-27 10:23       ` Mark Brown
2020-07-27 11:50         ` Mike Looijmans
2020-07-27 11:53           ` Mark Brown
2020-07-28  7:29             ` Mike Looijmans
2020-09-07  7:44           ` Felipe Balbi
2020-09-07  7:50             ` Mike Looijmans

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