Re: [PATCH 2/8 v2] ARM: EXYNOS5: Add machine data for USB 2.0

[Joonyoung Shim <jy0922.shim@samsung.com>]

On 07/29/2012 10:11 PM, Arnd Bergmann wrote:
> On Saturday 28 July 2012, Vivek Gautam wrote:
>>> Can you pleae explain why this is done in the changelog?
>>>
>>> We try hard to do such mappings from the device driver instead,
>>> so I'm surprised that this is necessary fo rthe USB phy.
>>>
>> We are doing the mapping for device address in the driver, but this memory
>> mapping for USB PHY registers that need to be programmed by the software
>> is done here. This is similar to what we see for exynos4 also. Is it
>> something
>> that i can still change? Please suggest.
>
> Yes, I think the USB PHY handling for all exynos chips should be changed
> from an ad-hoc method to a more formal device driver. As I commented
> in another patch of this series, I think the main problem is that
> treat the USB PHY as a property of the "platform", which it really isn't.
>
> We have a bunch of other USB PHY drivers for other platforms that are
> inside of the drivers/usb hierarchy. For all I know, there is no formal
> USB PHY driver API yet, and it seems that it would be a good idea to
> introduce one now, but for now, just move the code to
> drivers/usb/phy/ and make it one file per different kind of PHY.
>

Totally agree. I think that two PHY drivers need for usb2.0 PHY and
usb3.0 PHY in drivers/usb/phy directory. First, let's make usb2.0 PHY
driver for samsung SoCs from phy control codes of arch/arm, then add to
support usb2.0 PHY for exynos5 and make usb3.0 PHY driver for exynos.

Thanks.