From: Jun Li <jun.li@nxp.com>
To: Ramneek Mehresh <ramneek.mehresh@freescale.com>,
        Felipe Balbi <balbi@ti.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC: "stern@rowland.harvard.edu" <stern@rowland.harvard.edu>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>
Subject: RE: [PATCH 0/7][v4] Add OTG support for FSL socs
Thread-Topic: [PATCH 0/7][v4] Add OTG support for FSL socs
Thread-Index: AQHRPOWIo2KIMiU280am0Ikf1Gw/sJ7X/dgQgACA8QCAACX1wA==
Date: Wed, 23 Dec 2015 16:31:33 +0000
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> -----Original Message-----
> From: Ramneek Mehresh [mailto:ramneek.mehresh@freescale.com]
> Sent: Wednesday, December 23, 2015 8:20 PM
> To: Jun Li <jun.li@nxp.com>; Felipe Balbi <balbi@ti.com>; linux-
> kernel@vger.kernel.org
> Cc: stern@rowland.harvard.edu; gregkh@linuxfoundation.org; linux-
> usb@vger.kernel.org
> Subject: RE: [PATCH 0/7][v4] Add OTG support for FSL socs
> 
> 
> 
> > -----Original Message-----
> > From: Jun Li [mailto:jun.li@nxp.com]
> > Sent: Wednesday, December 23, 2015 10:36 AM
> > To: Felipe Balbi <balbi@ti.com>; Mehresh Ramneek-B31383
> > <ramneek.mehresh@freescale.com>; linux-kernel@vger.kernel.org
> > Cc: stern@rowland.harvard.edu; gregkh@linuxfoundation.org; linux-
> > usb@vger.kernel.org
> > Subject: RE: [PATCH 0/7][v4] Add OTG support for FSL socs
> >
> > Hi
> >
> > > -----Original Message-----
> > > From: linux-usb-owner@vger.kernel.org [mailto:linux-usb-
> > > owner@vger.kernel.org] On Behalf Of Felipe Balbi
> > > Sent: Wednesday, December 23, 2015 2:21 AM
> > > To: Ramneek Mehresh <ramneek.mehresh@freescale.com>; linux-
> > > kernel@vger.kernel.org
> > > Cc: stern@rowland.harvard.edu; gregkh@linuxfoundation.org; linux-
> > > usb@vger.kernel.org
> > > Subject: RE: [PATCH 0/7][v4] Add OTG support for FSL socs
> > >
> > >
> > > Hi,
> > >
> > > Ramneek Mehresh <ramneek.mehresh@freescale.com> writes:
> > > >> -----Original Message-----
> > > >> From: Felipe Balbi [mailto:balbi@ti.com]
> > > >> Sent: Saturday, October 10, 2015 3:04 AM
> > > >> To: Mehresh Ramneek-B31383 <ramneek.mehresh@freescale.com>;
> > linux-
> > > >> kernel@vger.kernel.org
> > > >> Cc: stern@rowland.harvard.edu; gregkh@linuxfoundation.org; linux-
> > > >> usb@vger.kernel.org; Mehresh Ramneek-B31383
> > > >> <ramneek.mehresh@freescale.com>
> > > >> Subject: Re: [PATCH 0/7][v4] Add OTG support for FSL socs
> > > >>
> > > >> Felipe Balbi <balbi@ti.com> writes:
> > > >>
> > > >> > Hi,
> > > >> >
> > > >> > Ramneek Mehresh <ramneek.mehresh@freescale.com> writes:
> > > >> >> Add support for otg for all freescale socs having internal usb
> phy.
> > > >> >>
> > > >> >> Ramneek Mehresh (7):
> > > >> >>   usb:fsl:otg: Make fsl otg driver as tristate
> > > >> >>   usb:fsl:otg: Add controller version based ULPI and UTMI phy
> > > >> >>   usb:fsl:otg: Add support to add/remove usb host driver
> > > >> >>   usb:fsl:otg: Signal host drv when host is otg
> > > >> >>   usb:fsl:otg: Modify otg_event to start host drv
> > > >> >>   usb:fsl:otg: Combine host/gadget start/resume for ID change
> > > >> >>   usb:fsl:otg: Add host-gadget drv sync delay
> > > >> >
> > > >> > Unless Alan's okay with the host side changes, I can't accept
> > > >> > any of these. However, I must say some of the flags you add
> > > >> > here already exist in some way, shape or form. For example,
> > > >> > look at
> > > is_b_host flag.
> > > >>
> > > >
> > > > Could you please be more specific...which flag you think that I
> > > >should remove/I'm re-defining. The flags I'm defining are:
> > > >
> > > > have_hcd : defined in fsl specific structure for fsl specific
> > > > use-case
> > > >
> > > > had_hcd: defined in fsl specific structure for fsl specific
> > > > use-case
> > > >
> > > > is_otg : defined in include/linux/usb.h
> > > >
> > > > Are you suggesting using otg_port or is_b_host instead of is_otg?
> > > >
> > > > As I understand, is_b_host is specifically to check if an otg B
> > > > device is in host mode...correct?  I just need a flag to check if
> > > > a controller is capable of otg operations? That's why defined
> "is_otg"
> > > > flag. Please suggest.
> > >
> > > no, I don't know why I made that comment. You could use otg_port,
> > > but that wouldn't look very clean. Can you resend with Alan's ack,
> > > then I'll move this series into testing/next.
> > >
> > > --
> > > balbi
> >
> > Can you directly put the change_hcd_work in its phy driver(phy-fsl-
> usb.c)?
> > Then add/remove hcd will not through ehci_fsl_drv_suspend/resume, With
> > this, you can make it work without a new flag "is_otg".
> >
> change_hcd_work() changes host controller mode, and hence, should be in
> host controller driver. 

Reasonable, but most of OTG stuff not belong to phy actully,
I see phy-msm-usb.c directly do hcd add/remove for OTG. 

> To move this to phy driver (just to avoid usage of
> a single flag) won't be a good idea.

I just saw you simply still use the suspend/resume method, but the
change_hcd_work actually has nothing to do with it now, then add a
flag to return for it, also the flag in your usage is not to indicate
if the host capable/enabled otg, but something like
is_host_role_to_be_changed_for_otg(test and then clear).

Meanwhile you add another 2 flags in ehci_fsl(have_hcd, add_hcd) also for
OTG host add/remove, so I am thinking if all those can be simplified. 

> In this case, I'll also have to move some host controller specific flags
> to phy drv which won't be correct.

> 
> > Li Jun

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