Message-ID: <54491947.4010008@opensource.altera.com>
Date: Thu, 23 Oct 2014 10:05:43 -0500
From: Dinh Nguyen <dinguyen@opensource.altera.com>
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To: Paul Bolle <pebolle@tiscali.nl>
CC: <paulz@synopsys.com>, <balbi@ti.com>, <dinh.linux@gmail.com>,
        <linux-kernel@vger.kernel.org>, <swarren@wwwdotorg.org>,
        <b.zolnierkie@samsung.com>, <matthijs@stdin.nl>,
        <r.baldyga@samsung.com>, <jg1.han@samsung.com>,
        <sachin.kamat@linaro.org>, <ben-linux@fluff.org>,
        <dianders@chromium.org>, <kever.yang@rock-chips.com>,
        <linux-usb@vger.kernel.org>
Subject: Re: [PATCHv5 7/7] usb: dwc2: Update Kconfig to support dual-role
References: <1413831126-24193-1-git-send-email-dinguyen@opensource.altera.com>		 <1413831126-24193-8-git-send-email-dinguyen@opensource.altera.com>	 <1413834151.2010.19.camel@x41> <5446C668.3020609@opensource.altera.com> <1414009627.17121.15.camel@x220>
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On 10/22/2014 03:27 PM, Paul Bolle wrote:
> On Tue, 2014-10-21 at 15:47 -0500, Dinh Nguyen wrote:
>> On 10/20/2014 02:42 PM, Paul Bolle wrote:
>>> (Side note: drivers/usb/dwc2/Kconfig is sourced (in drivers/usb/Kconfig)
>>> even if USB is _not_ set. But USB_DCW2 still depends on USB. Why is
>>> that?)
>>
>> Because USB is for Host-Side support. DWC2 driver should only get built
>> for when USB is enabled. I think you're getting USB and USB_SUPPORT
>> mixed up.
> 
> No, I don't think I did. Because in drivers/usb/Kconfig we see  
>     if USB
> 
>     [...]
> 
>     endif
> 
>     [...]
> 
>     source "drivers/usb/dwc2/Kconfig"
> 
>     [...]

Well, CONFIG_USB enables the host stack that is needed by the DWC2
driver, without CONFIG_USB, the DWC2 driver will not be able to build.

> 
>> In addition, thanks to your comment, I realized that DWC2 should also be
>> available to build when USB_GADGET is enabled. A patch has been sent:
>>
>> http://marc.info/?l=linux-usb&m=141392377124818&w=2
> 
> I haven't checked, but doesn't this mean USB_DWC2 could just depend on
> USB_SUPPORT?
> 
I don't think so because USB_SUPPORT will not select USB or USB_GAGDGET,
and the DWC2 driver will need either 1 or both for it to build correctly.

Dinh

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