linux-kernel - Re: [PATCH v2 1/7] usb: dwc3: get "usb_phy" only if the platform indicates the presence of PHY's

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Message-ID: <5265168A.3060309@ti.com>
Date:	Mon, 21 Oct 2013 17:26:58 +0530
From:	Kishon Vijay Abraham I <kishon@...com>
To:	<balbi@...com>
CC:	<gregkh@...uxfoundation.org>, <rob.herring@...xeda.com>,
	<pawel.moll@....com>, <mark.rutland@....com>,
	<swarren@...dotorg.org>, <ijc+devicetree@...lion.org.uk>,
	<rob@...dley.net>, <bcousson@...libre.com>, <tony@...mide.com>,
	<linux@....linux.org.uk>, <grant.likely@...aro.org>,
	<s.nawrocki@...sung.com>, <galak@...eaurora.org>,
	<devicetree@...r.kernel.org>, <linux-doc@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <linux-omap@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-usb@...r.kernel.org>
Subject: Re: [PATCH v2 1/7] usb: dwc3: get "usb_phy" only if the platform
 indicates the presence of PHY's

Hi,

On Thursday 17 October 2013 10:08 PM, Felipe Balbi wrote:
> Hi,
> 
> On Wed, Oct 16, 2013 at 01:24:11AM +0530, Kishon Vijay Abraham I wrote:
>> There can be systems which does not have a external usb_phy, so get
>> usb_phy only if dt data indicates the presence of PHY in the case of dt boot or
>> if platform_data indicates the presence of PHY. Also remove checking if
>> return value is -ENXIO since it's now changed to always enable usb_phy layer.
>>
>> Signed-off-by: Kishon Vijay Abraham I <kishon@...com>
> 
> I'm fine with this patch, but one comment below:
> 
>> @@ -387,16 +388,49 @@ static int dwc3_probe(struct platform_device *pdev)
>>  	if (node) {
>>  		dwc->maximum_speed = of_usb_get_maximum_speed(node);
>>  
>> -		dwc->usb2_phy = devm_usb_get_phy_by_phandle(dev, "usb-phy", 0);
>> -		dwc->usb3_phy = devm_usb_get_phy_by_phandle(dev, "usb-phy", 1);
>> +		count = of_count_phandle_with_args(node, "usb-phy", NULL);
>> +		switch (count) {
>> +		case 2:
>> +			dwc->usb3_phy = devm_usb_get_phy_by_phandle(dev,
>> +				"usb-phy", 1);
>> +			if (IS_ERR(dwc->usb3_phy)) {
>> +				dev_err(dev, "usb3 phy not found\n");
>> +				return PTR_ERR(dwc->usb3_phy);
>> +			}
>> +		case 1:
>> +			dwc->usb2_phy = devm_usb_get_phy_by_phandle(dev,
>> +				"usb-phy", 0);
>> +			if (IS_ERR(dwc->usb2_phy)) {
>> +				dev_err(dev, "usb2 phy not found\n");
>> +				return PTR_ERR(dwc->usb2_phy);
>> +			}
>> +			break;
>> +		default:
>> +			dev_err(dev, "usb phy nodes not configured\n");
>> +		}
>>  
>>  		dwc->needs_fifo_resize = of_property_read_bool(node, "tx-fifo-resize");
>>  		dwc->dr_mode = of_usb_get_dr_mode(node);
>>  	} else if (pdata) {
>>  		dwc->maximum_speed = pdata->maximum_speed;
>>  
>> -		dwc->usb2_phy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB2);
>> -		dwc->usb3_phy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB3);
>> +		if (pdata->usb2_phy) {
>> +			dwc->usb2_phy = devm_usb_get_phy(dev,
>> +				USB_PHY_TYPE_USB2);
>> +			if (IS_ERR(dwc->usb2_phy)) {
>> +				dev_err(dev, "usb2 phy not found\n");
>> +				return PTR_ERR(dwc->usb2_phy);
>> +			}
>> +		}
>> +
>> +		if (pdata->usb3_phy) {
>> +			dwc->usb3_phy = devm_usb_get_phy(dev,
>> +				USB_PHY_TYPE_USB3);
>> +			if (IS_ERR(dwc->usb3_phy)) {
>> +				dev_err(dev, "usb3 phy not found\n");
>> +				return PTR_ERR(dwc->usb3_phy);
>> +			}
>> +		}
>>  
>>  		dwc->needs_fifo_resize = pdata->tx_fifo_resize;
>>  		dwc->dr_mode = pdata->dr_mode;
>> @@ -409,36 +443,6 @@ static int dwc3_probe(struct platform_device *pdev)
>>  	if (dwc->maximum_speed == USB_SPEED_UNKNOWN)
>>  		dwc->maximum_speed = USB_SPEED_SUPER;
>>  
>> -	if (IS_ERR(dwc->usb2_phy)) {
>> -		ret = PTR_ERR(dwc->usb2_phy);
>> -
>> -		/*
>> -		 * if -ENXIO is returned, it means PHY layer wasn't
>> -		 * enabled, so it makes no sense to return -EPROBE_DEFER
>> -		 * in that case, since no PHY driver will ever probe.
>> -		 */
>> -		if (ret == -ENXIO)
>> -			return ret;
>> -
>> -		dev_err(dev, "no usb2 phy configured\n");
>> -		return -EPROBE_DEFER;
>> -	}
>> -
>> -	if (IS_ERR(dwc->usb3_phy)) {
>> -		ret = PTR_ERR(dwc->usb3_phy);
>> -
>> -		/*
>> -		 * if -ENXIO is returned, it means PHY layer wasn't
>> -		 * enabled, so it makes no sense to return -EPROBE_DEFER
>> -		 * in that case, since no PHY driver will ever probe.
>> -		 */
>> -		if (ret == -ENXIO)
>> -			return ret;
>> -
>> -		dev_err(dev, "no usb3 phy configured\n");
>> -		return -EPROBE_DEFER;
>> -	}
> 
> the idea for doing the error checking here was actually to avoid
> duplicating it in all previous cases, as you did. Please keep the error
> checking here and you're good to go.

Ok.
> 
>> -
>>  	dwc->xhci_resources[0].start = res->start;
>>  	dwc->xhci_resources[0].end = dwc->xhci_resources[0].start +
>>  					DWC3_XHCI_REGS_END;
>> diff --git a/drivers/usb/dwc3/platform_data.h b/drivers/usb/dwc3/platform_data.h
>> index 7db34f0..49ffa6d 100644
>> --- a/drivers/usb/dwc3/platform_data.h
>> +++ b/drivers/usb/dwc3/platform_data.h
>> @@ -24,4 +24,6 @@ struct dwc3_platform_data {
>>  	enum usb_device_speed maximum_speed;
>>  	enum usb_dr_mode dr_mode;
>>  	bool tx_fifo_resize;
>> +	bool usb2_phy;
>> +	bool usb3_phy;
> 
> This would look better as a quirks flag, then we could:
> 
> unsigned long quirks;
> #define DWC3_QUIRK_NO_USB3_PHY	BIT(0)
> #define DWC3_QUIRK_NO_USB2_PHY	BIT(1)
> 
> ...
> 
> if (!test_bit(DWC3_QUIRK_NO_USB3_PHY), &dwc->quirks &&
> 	dwc->has_usb3_phy) {
> 	grab_usb3_phy();
> }

Ok.

Thanks
Kishon
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