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

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Date:	Wed, 4 Dec 2013 13:37:11 +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 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. Have you
tested at existing platforms?

-- 

Best Regards,
Peter Chen

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