Re: [PATCH v6 08/15] usb: phy-mxs: Add implementation of nofity_suspend and notify_resume

[Peter Chen <peter.chen@freescale.com>]

On Fri, Dec 13, 2013 at 02:09:24PM -0600, Felipe Balbi wrote:
> On Fri, Dec 13, 2013 at 02:31:42PM +0800, Peter Chen wrote:
> > On Fri, Dec 13, 2013 at 12:32 PM, Felipe Balbi <balbi@ti.com> wrote:
> > > On Fri, Dec 13, 2013 at 09:23:38AM +0800, Peter Chen wrote:
> > >> Implementation of notify_suspend and notify_resume will be different
> > >> according to mxs_phy_data->flags.
> > >>
> > >> Signed-off-by: Peter Chen <peter.chen@freescale.com>
> > >> ---
> > >>  drivers/usb/phy/phy-mxs-usb.c |   55 ++++++++++++++++++++++++++++++++++++++---
> > >>  1 files changed, 51 insertions(+), 4 deletions(-)
> > >>
> > >> diff --git a/drivers/usb/phy/phy-mxs-usb.c b/drivers/usb/phy/phy-mxs-usb.c
> > >> index 0ef930a..e3df53f 100644
> > >> --- a/drivers/usb/phy/phy-mxs-usb.c
> > >> +++ b/drivers/usb/phy/phy-mxs-usb.c
> > >> @@ -166,8 +166,8 @@ static int mxs_phy_suspend(struct usb_phy *x, int suspend)
> > >>  static int mxs_phy_on_connect(struct usb_phy *phy,
> > >>               enum usb_device_speed speed)
> > >>  {
> > >> -     dev_dbg(phy->dev, "%s speed device has connected\n",
> > >> -             (speed == USB_SPEED_HIGH) ? "high" : "non-high");
> > >> +     dev_dbg(phy->dev, "%s device has connected\n",
> > >> +             (speed == USB_SPEED_HIGH) ? "HS" : "FS/LS");
> > >
> > > unrelated.
> > >
> > >> @@ -179,8 +179,8 @@ static int mxs_phy_on_connect(struct usb_phy *phy,
> > >>  static int mxs_phy_on_disconnect(struct usb_phy *phy,
> > >>               enum usb_device_speed speed)
> > >>  {
> > >> -     dev_dbg(phy->dev, "%s speed device has disconnected\n",
> > >> -             (speed == USB_SPEED_HIGH) ? "high" : "non-high");
> > >> +     dev_dbg(phy->dev, "%s device has disconnected\n",
> > >> +             (speed == USB_SPEED_HIGH) ? "HS" : "FS/LS");
> > >
> > > unrelated.
> > >
> > 
> > Marek suggested using that string, I will added it at another patch.
> > 
> > >> @@ -189,6 +189,48 @@ static int mxs_phy_on_disconnect(struct usb_phy *phy,
> > >>       return 0;
> > >>  }
> > >>
> > >> +static int mxs_phy_on_suspend(struct usb_phy *phy,
> > >> +             enum usb_device_speed speed)
> > >> +{
> > >> +     struct mxs_phy *mxs_phy = to_mxs_phy(phy);
> > >> +
> > >> +     dev_dbg(phy->dev, "%s device has suspended\n",
> > >> +             (speed == USB_SPEED_HIGH) ? "HS" : "FS/LS");
> > >> +
> > >> +     /* delay 4ms to wait bus entering idle */
> > >> +     usleep_range(4000, 5000);
> > >> +
> > >> +     if (mxs_phy->data->flags & MXS_PHY_ABNORMAL_IN_SUSPEND) {
> > >> +             writel_relaxed(0xffffffff, phy->io_priv + HW_USBPHY_PWD);
> > >> +             writel_relaxed(0, phy->io_priv + HW_USBPHY_PWD);
> > >> +     }
> > >> +
> > >> +     if (speed == USB_SPEED_HIGH)
> > >> +             writel_relaxed(BM_USBPHY_CTRL_ENHOSTDISCONDETECT,
> > >> +                             phy->io_priv + HW_USBPHY_CTRL_CLR);
> > >
> > > why only on HS ? So if !HS and !ABNORMAL, this is no-op.
> > >
> > >> +static int mxs_phy_on_resume(struct usb_phy *phy,
> > >> +             enum usb_device_speed speed)
> > >> +{
> > >> +     dev_dbg(phy->dev, "%s device has resumed\n",
> > >> +             (speed == USB_SPEED_HIGH) ? "HS" : "FS/LS");
> > >> +
> > >> +     if (speed == USB_SPEED_HIGH) {
> > >> +             /* Make sure the device has switched to High-Speed mode */
> > >> +             udelay(500);
> > >> +             writel_relaxed(BM_USBPHY_CTRL_ENHOSTDISCONDETECT,
> > >> +                             phy->io_priv + HW_USBPHY_CTRL_SET);
> > >> +     }
> > >
> > > likewise, if !HS it's a no-op.
> > >
> > 
> > Correct,  this operation is only needed for HS.
> > 
> > >> @@ -235,6 +277,11 @@ static int mxs_phy_probe(struct platform_device *pdev)
> > >>
> > >>       platform_set_drvdata(pdev, mxs_phy);
> > >>
> > >> +     if (mxs_phy->data->flags & MXS_PHY_SENDING_SOF_TOO_FAST) {
> > >> +             mxs_phy->phy.notify_suspend = mxs_phy_on_suspend;
> > >> +             mxs_phy->phy.notify_resume = mxs_phy_on_resume;
> > >> +     }
> > >
> > > hmm, and seems like you only need notify_* on a buggy device. Sorry
> > > Peter but you don't have enough arguments to make me agree with this
> > > (and previous) patch.
> > >
> > > You gotta find a better way to handle this using normal phy
> > > suspend/resume calls.
> > >
> > 
> > Like I explained at previous patch, it needs to be notified during
> > ehci suspend/resume.
> > I admit it is a SoC bug, but all SoCs have bugs, hmm.
> > Software needs the solution to workaround it which breaks the standard USB spec.
> 
> Then I think what you need is a real notification mechanism. usbcore
> already notifies about buses and devices being added and removed,
> perhaps you can convince Greg to accept suspend/resume notifications.
> 
> With that, you can (conditionally) make this driver listen to usbcore
> notifications. That'll be more work, but I guess it's best in the long
> run as we won't need to keep on adding callbacks to the USB PHY
> structure just because another buggy device showed up on the market.
> 

Okay, I will add this notification to .set_suspend now, it can work most of
cases except disconnect during the resume signal.

Besides notification API add, how about other patches, eg add .set_wakeup API?
If you think there are no big problems, I will send v7 version.

-- 

Best Regards,
Peter Chen