USB OTG support on mx27pdk

[Michael Grzeschik]

Hi,

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.

Regards,
Michael

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