Re: [PATCH v4 1/4] usb: otg: Add ulpi viewport access ops

[Igor Grinberg <grinberg-UTxiZqZC01RS1MOuV/RT9w@public.gmane.org>]

Hi,

On 02/21/11 17:30, Matthieu CASTET wrote:

> Igor Grinberg a écrit :
>> Hi,
>>
>> On 02/21/11 11:04, Matthieu CASTET wrote:
>>
>>> Hi,
>>>
>>> Igor Grinberg a écrit :
>>>> Hi,
>>>>
>>>> On 02/18/11 05:42, Benoit Goby wrote:
>>>>> Add generic access ops for controllers with a ulpi viewport register
>>>>> (e.g. Chipidea/ARC based controllers).
>>>> I can see mxc, msm and langwell are using the same bits
>>>> (or at least some of them).
>>> They all use the Chipidea/ARC usb controllers.
>>
>> This means, that it is not generic, but Chipidea/ARC usb controller specific.
>> And it is common to some/many platforms.
> Yes
>>
>> Can it be utilized on platforms that have another kind of ulpi access register?
> I don't think so

I've looked into the IMX Reference Manual regarding the ulpi viewport register
and it looks like these access ops can be utilized on another kind of ulpi access registers,
as the same features are available in most (if not all) of ulpi access registers,
whether they are called viewport or otherwise.
This will require much more thinking and may be the right solution would be
multiple access ops files (e.g. drivers/usb/otg/ulpi_...port.c).
So for now, this patch is a good stuff to start from.

Benoit,

can you, please, address comments in my first reply?

Thanks.

>
>>
>>>> Is there some kind of specification for this ulpi viewport register?
>>> You can find the Chipidea/ARC datasheet in IMX35 datasheet ( got  0x0170  ULPI VIEWPORT) or a newer version (extra fields in some registers but miss 0x168-0x170) in
>>> http://www.nxp.com/documents/user_manual/UM10314.pdf
>>
>> I don't have the IMX35 datasheet which describes the USB OTG registers.
>> The one that can be downloaded from Freescale website, only describes
>> hardware and no ULPI viewport is mentioned there.
> From freescale.com I manage to download IMX35RM.pdf witch describe it (p2075).

Found it. Thanks.


-- 
Regards,
Igor.

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