Re: [RFT 0/3] usb: usb3503: Fix probing on Arndale board (missing phy)

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Hello,

On 2015-10-07 02:30, Krzysztof Kozlowski wrote:
Introduction
============
This patchset tries to fix probing of usb3503 on Arndale board
if the Samsung PHY driver is probed later (or built as a module).

*The patchset was not tested on Arndale board.*
I don't have that board. Please test it and say if the usb3503 deferred probe
works fine and the issue is solved.

The patchset was tested on Odroid U3 board (which is different!)
in a simulated environment. It is not sufficient testing.


Difference
==========
The usb3503 device driver can be used as a I2C device (on Odroid U3)
or as a platform device connected through phy (on Arndale). In the second
case the necessary phy reference has to be obtained and enabled.

For some details please look also at thread [0][1].

[0] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-June/348524.html
[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-June/348875.html


I'm not sure that this is the correct approach. usb3503 chip is simply connected to Exynos USB2 phy, so it visible on the USB bus. The real driver that controls USB2
PHY is Exynos EHCI driver and USB3503 should not mess around it.

In my opinion all that is needed in case of Arndale board is forcing reset of usb3503 chip after successful EHCI and USB2 PHY initialization (for some reason
initialization of usb3503 chip must be done after usb host initialization).
However I have no idea which driver should trigger this reset. Right now I didn't find any good solution for additional control for devices which are on autoprobed
bus like usb.

Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland

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