linux-kernel - Re: [PATCH 4/4] usb: chipidea: msm: Use USB PHY API to control PHY state

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Message-ID: <20131204133858.GC1573@shlinux1.ap.freescale.net>
Date:	Wed, 4 Dec 2013 21:38:59 +0800
From:	Peter Chen <peter.chen@...escale.com>
To:	"Ivan T. Ivanov" <iivanov@...sol.com>
CC:	<alexander.shishkin@...ux.intel.com>, <gregkh@...uxfoundation.org>,
	<rob.herring@...xeda.com>, <pawel.moll@....com>,
	<mark.rutland@....com>, <swarren@...dotorg.org>,
	<ijc+devicetree@...lion.org.uk>, <davidb@...eaurora.org>,
	<linux-usb@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 4/4] usb: chipidea: msm: Use USB PHY API to control PHY
 state

On Wed, Dec 04, 2013 at 11:35:54AM +0200, Ivan T. Ivanov wrote:
> 
> Hi Peter, 
> 
> On Wed, 2013-12-04 at 13:37 +0800, Peter Chen wrote: 
> > On Mon, Nov 11, 2013 at 04:36:09PM +0200, Ivan T. Ivanov wrote:
> > > 
> > > Hi Peter,
> > > 
> > > On Mon, 2013-11-11 at 21:59 +0800, Peter Chen wrote: 
> > > > On Mon, Nov 11, 2013 at 03:35:37PM +0200, Ivan T. Ivanov wrote:
> > > > > From: "Ivan T. Ivanov" <iivanov@...sol.com>
> > > > > 
> > > > > PHY drivers keep track of the current state of the hardware,
> > > > > so don't change PHY settings under it.
> > > > > 
> > > > > Signed-off-by: Ivan T. Ivanov <iivanov@...sol.com>
> > > > > ---
> > > > >  drivers/usb/chipidea/ci_hdrc_msm.c |    9 ++-------
> > > > >  1 file changed, 2 insertions(+), 7 deletions(-)
> > > > > 
> > > > > diff --git a/drivers/usb/chipidea/ci_hdrc_msm.c b/drivers/usb/chipidea/ci_hdrc_msm.c
> > > > > index e9624f3..338b209 100644
> > > > > --- a/drivers/usb/chipidea/ci_hdrc_msm.c
> > > > > +++ b/drivers/usb/chipidea/ci_hdrc_msm.c
> > > > > @@ -20,13 +20,11 @@
> > > > >  static void ci_hdrc_msm_notify_event(struct ci_hdrc *ci, unsigned event)
> > > > >  {
> > > > >  	struct device *dev = ci->gadget.dev.parent;
> > > > > -	int val;
> > > > >  
> > > > >  	switch (event) {
> > > > >  	case CI_HDRC_CONTROLLER_RESET_EVENT:
> > > > >  		dev_dbg(dev, "CI_HDRC_CONTROLLER_RESET_EVENT received\n");
> > > > > -		writel(0, USB_AHBBURST);
> > > > > -		writel(0, USB_AHBMODE);
> > > > > +		usb_phy_init(ci->transceiver);
> > > > 
> > > > It will reset the PHY,  but your comment is "don't change PHY settings under it"
> > > 
> > > :-). This function is exported by PHY drivers, so they will know how
> > > to handle this change.
> > > 
> > > > 
> > > > >  		break;
> > > > >  	case CI_HDRC_CONTROLLER_STOPPED_EVENT:
> > > > >  		dev_dbg(dev, "CI_HDRC_CONTROLLER_STOPPED_EVENT received\n");
> > > > > @@ -34,10 +32,7 @@ static void ci_hdrc_msm_notify_event(struct ci_hdrc *ci, unsigned event)
> > > > >  		 * Put the transceiver in non-driving mode. Otherwise host
> > > > >  		 * may not detect soft-disconnection.
> > > > >  		 */
> > > > > -		val = usb_phy_io_read(ci->transceiver, ULPI_FUNC_CTRL);
> > > > > -		val &= ~ULPI_FUNC_CTRL_OPMODE_MASK;
> > > > > -		val |= ULPI_FUNC_CTRL_OPMODE_NONDRIVING;
> > > > > -		usb_phy_io_write(ci->transceiver, val, ULPI_FUNC_CTRL);
> > > > > +		usb_phy_notify_disconnect(ci->transceiver, USB_SPEED_UNKNOWN);
> > > > 
> > > > Where you have implemented .notify_disconnect?
> > > > I have not found it at your phy driver.
> > > 
> > > Yep, I will post PHY driver changes shortly. Meanwhile this should
> > > not break existing board file based platforms, because not of them
> > > could be compiled (HTC Dream, Halibut Board) and DT based platforms 
> > > are sill work in progress.
> > > 
> > 
> > Hi Ivan, I am going to apply this msm chipidea patchset, but the change
> > in this file is different with its original meaning. 
> 
> What did you mean?
> 
> CI_HDRC_CONTROLLER_RESET_EVENT -> usb_phy_init()
> Take wherever actions are needed to put device in known state. ?

At current code, it only sets two AHB parameters which should be only related
to controller but your patch init the whole PHY, look at msm_otg_reset,
it does many other things, like phy reset, controller reset, etc.

Does the partial otg fsm at msm_otg_sm_work will be called or not? If it is
not called, then, it is OK you just use msm_otg_reset here.

> 
> CI_HDRC_CONTROLLER_STOPPED_EVENT -> usb_phy_notify_disconnect() 
> Emitted after ci->driver->disconnect(&ci->gadget);

I just see your [PATCH v4 14/15] usb: phy: msm: Handle disconnect events,
then, it is ok now. By the way, do I need to wait your phy patches are queued,
otherwise, it may not work?

> 
> Probably I am missing something.
> 
> 
> > Have you
> > tested at existing platforms?
> 
> 
> I have 8074 based DragonBoard which I used for testing. 
> CV Test Suite engine "Chapter 9 tests" are passing except
> "Halt Endpoint Test". 

I mean with your patch, the old non-dt platform can work or not?

-- 

Best Regards,
Peter Chen

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