From: Peter Chen <peter.chen@nxp.com>
To: Baolin Wang <baolin.wang@linaro.org>, Peter Chen <hzpeterchen@gmail.com>
CC: Felipe Balbi <balbi@kernel.org>, Greg KH <gregkh@linuxfoundation.org>,
        Sebastian Reichel <sre@kernel.org>,
        Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>,
        David Woodhouse <dwmw2@infradead.org>,
        Peter Chen <peter.chen@freescale.com>,
        Alan Stern <stern@rowland.harvard.edu>,
        "r.baldyga@samsung.com" <r.baldyga@samsung.com>,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
        Lee Jones <lee.jones@linaro.org>, "Mark Brown" <broonie@kernel.org>,
        Charles Keepax <ckeepax@opensource.wolfsonmicro.com>,
        "patches@opensource.wolfsonmicro.com" 
	<patches@opensource.wolfsonmicro.com>,
        Linux PM list <linux-pm@vger.kernel.org>,
        USB <linux-usb@vger.kernel.org>,
        "device-mainlining@lists.linuxfoundation.org" 
	<device-mainlining@lists.linuxfoundation.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v8 0/4] Introduce usb charger framework to deal with the
 usb gadget power negotation
Thread-Topic: [PATCH v8 0/4] Introduce usb charger framework to deal with the
 usb gadget power negotation
Thread-Index: AQHRhcnURUputCZIGEaEgiD/0HOB+59pvwGAgASx+gCAAAYzgIAAIG0AgAEA9/A=
Date: Tue, 29 Mar 2016 00:32:12 +0000
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References: <cover.1458822334.git.baolin.wang@linaro.org>
	<20160325070937.GA22398@peterchendt>
	<CAMz4kuJYBg4eortA35Dhr4-jPVhLzu9XhjpOcu0hDWq6FV09mw@mail.gmail.com>
	<20160328071351.GC3302@peterchendt>
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> 
> On 28 March 2016 at 15:13, Peter Chen <hzpeterchen@gmail.com> wrote:
> > On Mon, Mar 28, 2016 at 02:51:40PM +0800, Baolin Wang wrote:
> >> On 25 March 2016 at 15:09, Peter Chen <hzpeterchen@gmail.com> wrote:
> >> > On Thu, Mar 24, 2016 at 08:35:53PM +0800, Baolin Wang wrote:
> >> >> Currently the Linux kernel does not provide any standard
> >> >> integration of this feature that integrates the USB subsystem with
> >> >> the system power regulation provided by PMICs meaning that either
> >> >> vendors must add this in their kernels or USB gadget devices based
> >> >> on Linux (such as mobile phones) may not behave as they should. Thus
> provide a standard framework for doing this in kernel.
> >> >>
> >> >> Now introduce one user with wm831x_power to support and test the
> >> >> usb charger, which is pending testing. Moreover there may be other
> >> >> potential users will use it in future.
> >> >>
> >> >
> >> > I am afraid I still not find the user (udc driver) for this
> >> > framework, I would like to see how udc driver block the enumeration
> >> > until the charger detection has finished, or am I missing something?
> >>
> >> It is not for udc driver but for power users who want to negotiate
> >> with USB subsystem.
> >>
> >
> > Then, where is the code the test user to decide what kinds of USB
> > charger (SDP, CDP, DCP) is connecting now?
> 
> Users can choose to implement multiple ways to get the charger type In
> 'usb_charger_detect_type()' function.
> 
> >
 
Then, how you test your code? When we introduce an API, at least, there is one
user for it.

Peter