USB OTG support on mx27pdk

[Peter Chen]

> 
> On Wed, Apr 16, 2014 at 09:53:34AM -0300, Fabio Estevam wrote:
> > On Wed, Apr 16, 2014 at 8:58 AM, Alexander Shiyan <shc_work at mail.ru>
> wrote:
> >
> > > I can tell immediately without further testing,
> > > this will not work without the USB support in the bootoader because
> > > we do not have DT support for ULPI.
> >
> > The generic nop usb phy should work just fine.
> >
> > I have tried Uwe's suggestion from a previous post and reverted:
> >
> > commit cd0b42c2a6d2a74244f0053f8960f5dad5842278
> > Author: Chris Ruehl <chris.ruehl at gtsys.com.hk>
> > Date:   Fri Jan 10 13:51:30 2014 +0800
> >
> >     usb: chipidea: put hw_phymode_configure before ci_usb_phy_init
> >
> >     hw_phymode_configure configures the PORTSC registers and allow the
> >     following phy_inits to operate on the right parameters. This fix a
> problem
> >     where the UPLI (ISP1504) could not be detected, because the
> Viewport was not
> >     available and read the viewport return 0's only.
> >
> >     Signed-off-by: Chris Ruehl <chris.ruehl at gtsys.com.hk>
> >     Signed-off-by: Peter Chen <peter.chen at freescale.com>
> >     Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> >
> >
> > Then USB OTG port detected the USB pen driver fine:
> >
> > usbcore: registered new interface driver usb-storage
> > 10024000.usb supply vbus not found, using dummy regulator
> > ci_hdrc ci_hdrc.0: EHCI Host Controller
> > ci_hdrc ci_hdrc.0: new USB bus registered, assigned bus number 1
> > ci_hdrc ci_hdrc.0: USB 2.0 started, EHCI 1.00
> > hub 1-0:1.0: USB hub found
> > hub 1-0:1.0: 1 port detected
> > ...
> > scsi 0:0:0:0: Direct-Access     ChipsBnk Flash Disk       2.00 PQ: 0
> ANSI: 2
> > sd 0:0:0:0: [sda] 1035200 512-byte logical blocks: (530 MB/505 MiB)
> > sd 0:0:0:0: [sda] Write Protect is off
> > sd 0:0:0:0: [sda] No Caching mode page found
> > sd 0:0:0:0: [sda] Assuming drive cache: write through
> >  sda: sda1
> > sd 0:0:0:0: [sda] Attached SCSI removable disk
> >
> > If I understand correctly commit cd0b42c2a was only needed because
> > Chris was trying to add DT support for ULPI, which never got merged
> > into mainline.
> >
> > If we use the generic nop usb phy instead, we should just revert this
> commit.
> >
> > Any objections?
> 
> Yes, when this patch got reverted it will probably break usb support
> on mx6 machines. We have seen different behaviour on several mxc/mxs
> machines regarding the order of PORTSC and phy configuration.
> 
> We will probably need to test all platforms before reordering this
> function call again and again for every machine using this driver.
> 

The below patch is intended to fix above issues for all platforms,
I have tested it at imx6 platform, if possible, have a test at imx25/imx27
please.

Peter