Hi, > -----Original Message----- > From: Baolin Wang [mailto:baolin.w...@linaro.org] > Sent: Friday, March 10, 2017 6:52 PM > To: Jun Li <jun...@nxp.com> > Cc: NeilBrown <ne...@suse.com>; Felipe Balbi <ba...@kernel.org>; Greg KH > <gre...@linuxfoundation.org>; Sebastian Reichel <s...@kernel.org>; Dmitry > Eremin-Solenikov <dbarysh...@gmail.com>; David Woodhouse > <dw...@infradead.org>; r...@kernel.org; Marek Szyprowski > <m.szyprow...@samsung.com>; Ruslan Bilovol <ruslan.bilo...@gmail.com>; > Peter Chen <peter.c...@freescale.com>; Alan Stern > <st...@rowland.harvard.edu>; grygorii.stras...@ti.com; Yoshihiro Shimoda > <yoshihiro.shimoda...@renesas.com>; Lee Jones <lee.jo...@linaro.org>; > Mark Brown <broo...@kernel.org>; John Stultz <john.stu...@linaro.org>; > Charles Keepax <ckee...@opensource.wolfsonmicro.com>; > patc...@opensource.wolfsonmicro.com; Linux PM list <linux- > p...@vger.kernel.org>; USB <linux-usb@vger.kernel.org>; device- > mainlin...@lists.linuxfoundation.org; LKML <linux-ker...@vger.kernel.org> > Subject: Re: [PATCH v19 0/4] Introduce usb charger framework to deal with > the usb gadget power negotation > > On 10 March 2017 at 16:27, Jun Li <jun...@nxp.com> wrote: > > Hi > > > >> -----Original Message----- > >> From: Baolin Wang [mailto:baolin.w...@linaro.org] > >> Sent: Friday, March 10, 2017 3:15 PM > >> To: Jun Li <jun...@nxp.com> > >> Cc: NeilBrown <ne...@suse.com>; Felipe Balbi <ba...@kernel.org>; Greg > >> KH <gre...@linuxfoundation.org>; Sebastian Reichel <s...@kernel.org>; > >> Dmitry Eremin-Solenikov <dbarysh...@gmail.com>; David Woodhouse > >> <dw...@infradead.org>; r...@kernel.org; Marek Szyprowski > >> <m.szyprow...@samsung.com>; Ruslan Bilovol > >> <ruslan.bilo...@gmail.com>; Peter Chen <peter.c...@freescale.com>; > >> Alan Stern <st...@rowland.harvard.edu>; grygorii.stras...@ti.com; > >> Yoshihiro Shimoda <yoshihiro.shimoda...@renesas.com>; Lee Jones > >> <lee.jo...@linaro.org>; Mark Brown <broo...@kernel.org>; John Stultz > >> <john.stu...@linaro.org>; Charles Keepax > >> <ckee...@opensource.wolfsonmicro.com>; > >> patc...@opensource.wolfsonmicro.com; Linux PM list <linux- > >> p...@vger.kernel.org>; USB <linux-usb@vger.kernel.org>; device- > >> mainlin...@lists.linuxfoundation.org; LKML > >> <linux-ker...@vger.kernel.org> > >> Subject: Re: [PATCH v19 0/4] Introduce usb charger framework to deal > >> with the usb gadget power negotation > >> > >> On 10 March 2017 at 14:30, Jun Li <jun...@nxp.com> wrote: > >> >> >> > > >> >> >> > Will generic phy need add extcon as well? > >> >> >> > >> >> >> Yes, will add a 'struct extcon_dev*' in 'struct usb_phy', which > >> >> >> will be common code. > >> >> >> > >> >> > > >> >> > I mean the common code need add 'struct extcon_dev' into both > >> >> > 'struct phy' and 'struct usb_phy', right? as some/new usb phy > >> >> > use that generic phy > >> >> driver. > >> >> > >> >> Ah, you remind me. Seems we need also add one 'struct extcon_dev' > >> >> into 'struct phy'. > >> >> > >> >> >> > > >> >> >> >> > > >> >> >> >> >> Secondly, I also agreed with Peter's comments: Not only > >> >> >> >> >> USB PHY to register an extcon, but also for the drivers > >> >> >> >> >> which can detect USB charger type, it may be USB > >> >> >> >> >> controller driver, USB type-c driver, pmic driver, and > >> >> >> >> >> these drivers may not have an extcon device since the > >> >> >> >> >> internal part can finish > >> the vbus detect. > >> >> >> >> > > >> >> >> >> > Whichever part can detect vbus, the driver for that part > >> >> >> >> > must be able to find the extcon and trigger a notification. > >> >> >> >> > Maybe one part can detect VBUS, another can measure the > >> >> >> >> > resistance on ID and a third can work through the state > >> >> >> >> > machine to determine if D+ and D- are shorted together. > >> >> >> >> > Somehow these three need to work together to determine > >> >> >> >> > what is > >> >> >> >> plugged > >> >> >> >> > in to the external connection port. Somewhere there much > >> >> >> >> > an > >> >> 'extcon' > >> >> >> >> > device which represents that port and which the three > >> >> >> >> > devices can find and can interact with. > >> >> >> >> > I think it makes sense for the usb_phy to be the connection > point. > >> >> >> >> > Each of the devices can get to the phy, and the phy can > >> >> >> >> > get to the > >> >> >> extcon. > >> >> >> >> > It doesn't matter very much if the usb phy driver creates > >> >> >> >> > the extcon, or if something else creates the extcon and > >> >> >> >> > the phy driver performs a lookup to find it (e.g. based on > devicetree info). > >> >> >> >> > > >> >> >> >> > The point is that there is obviously an external physical > >> >> >> >> > connection, and so there should be an 'extcon' device that > >> >> represents it. > >> >> >> >> > >> >> >> >> Peter & Jun, is it OK for you every phy has one extcon > >> >> >> >> device to receive VBUS notification, especially for > >> >> >> >> detecting the charger type by > >> >> >> software? > >> >> >> >> > >> >> >> > > >> >> >> > My understanding is phy/usb_phy as the connection point, will > >> >> >> > send the notification to PMIC driver which actually control > >> >> >> > the charge current, also this will be done in your common > >> >> >> > framework, > >> right? > >> >> >> > >> >> >> Not in USB charger framework. If we are all agree every usb_phy > >> >> >> can register one extcon device, can get correct charger type > >> >> >> and send out correct vbus_draw information, then we don't need > >> >> >> USB charger framework as Neil suggested. So this will be okay > >> >> >> for your case (especially for detecting the charger type by > software) ? > >> >> > > >> >> > In my case, charger detection is done by controller driver and I > >> >> > need do charger type detection internally, and only pass the > >> >> > current draw info via phy which will send out, this seems ok for > >> >> > me, but I think it will be good if you or someone can show us an > >> >> > example user based on the > >> >> design Neil suggested. > >> >> > Will you work out that common code if this USB charger framework > >> >> > is not > >> >> needed? > >> >> > >> >> I will add a 'struct extcon_dev*' in 'struct usb_phy' and struct > >> >> phy“. Others are already ready if everyone has no complain about > >> >> current design, except > >> > > >> > Only adding extcon_dev into usb_phy/phy and all others are ready? > >> > My understanding you will also do: > >> > - We need find a central place to send the notification(phy common > part). > >> > >> That will include these implementation when adding extcon_dev. > >> > > > > OK, thanks. > > > >> > - If the extcon_dev is directly added in usb_phy/phy, PMIC needs > >> > some > >> API to findup it. > >> > >> PMIC can find extcon device by phandle. > > > > extcon_dev(not a reference pointer) is directly added in usb_phy/phy, > > not via devicetree, how PMIC find it by phandle? > > From my understanding, here we should add one pointer (extcon_dev *), > since usb phy is not one external connect device.
Agreed. > > > > >> > >> > > >> >> my one concern. (I am afraid if it is enough to send out vbus draw > >> >> information from USB phy driver, for example you will miss super > >> >> speed (900mA), which need get the speed information from gadget > >> >> driver.) > >> >> > >> > > >> > Can we handle this in USB(so has super speed information) and just > >> > send out 900mA directly? > >> > >> From Neil's suggestion, we only have one place to send out current > >> information from usb phy, so I have this concern and doubt if we > >> still need the USB charger framework. > > > > So if put it in phy/usb_phy, this is a problem, that only one place > > should have the infor of both speed and usb state, how about put it at > > usb_gadget, then, e.g. send the notification in > usb_gadget_vbus_connect()? > > That is same what USB charger did, from this point, we need USB charger to > send out vbus draw information according to speed and usb state. But I > should listen to other guys suggestion. Peter and Felipe, what do you think? So now the only to do work is to find a common place to send the notification out (based on gadget speed and sate). Li Jun > > -- > Baolin.wang > Best Regards
