Re: [PATCH RFC 1/4] phy: Add new Exynos5 USB 3.0 PHY driver

[Vivek Gautam <gautamvivek1987@gmail.com>]

Hi Kishon,


On Tue, Dec 24, 2013 at 11:15 PM, Kishon Vijay Abraham I <kishon@ti.com> wrote:
> Hi,
>
>
> On Thursday 05 December 2013 01:44 PM, Vivek Gautam wrote:
>>
>> Hi Kishon,
>>
>>
>> On Wed, Dec 4, 2013 at 7:58 PM, Kishon Vijay Abraham I <kishon@ti.com>
>> wrote:
>>>
>>> Hi Vivek,
>>>
>>> On Wednesday 20 November 2013 09:14 PM, Kishon Vijay Abraham I wrote:
>>>>
>>>> Hi,
>>>>
>>>> On Wednesday 20 November 2013 03:02 PM, Vivek Gautam wrote:
>>>>>
>>>>> On Wed, Nov 20, 2013 at 2:34 PM, Kishon Vijay Abraham I <kishon@ti.com>
>>>>> wrote:
>>>>>>
>>>>>> On Wednesday 20 November 2013 02:27 PM, Vivek Gautam wrote:
>>>>>>>
>>>>>>> Hi Kishon,
>>>>>>>
>>>>>>>
>>>>>>> On Mon, Nov 11, 2013 at 4:41 PM, Kishon Vijay Abraham I
>>>>>>> <kishon@ti.com> wrote:
>>>>>>>>
>>>>>>>> Hi,
>>>>>>>
>>>>>>> sorry for the delayed response.
>>>>>>>
>>>>>>>>
>>>>>>>> On Wednesday 06 November 2013 05:37 AM, Jingoo Han wrote:
>>>>>>>>>
>>>>>>>>> On Wednesday, November 06, 2013 2:58 AM, Vivek Gautam wrote:
>>>>>>>>>>
>>>>>>>>>> On Tue, Nov 5, 2013 at 5:33 PM, Jingoo Han <jg1.han@samsung.com>
>>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> [.....]
>>>>>>>>>
>>>>>>>>>>> USB3.0 PHY consists of two blocks such as 3.0 block and 2.0
>>>>>>>>>>> block.
>>>>>>>>>>> This USB3.0 PHY can support UTMI+ and PIPE3 interface for 3.0
>>>>>>>>>>> block
>>>>>>>>>>> and 2.0 block, respectively.
>>>>>>>>>>>
>>>>>>>>>>> Conclusion:
>>>>>>>>>>>
>>>>>>>>>>>     1) USB2.0 PHY: USB2.0 HOST, USB2.0 Device
>>>>>>>>>>>                         Base address: 0x1213 0000
>>>>>>>>>>>
>>>>>>>>>>>     2) USB3.0 PHY: USB3.0 DRD (3.0 HOST & 3.0 Device)
>>>>>>>>>>>                         Base address: 0x1210 0000
>>>>>>>>>>>                         2.0 block(UTMI+) & 3.0 block(PIPE3)
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> And this is of course the PHY used by DWC3 controller, which works
>>>>>>>>>> at
>>>>>>>>>> both High speed as well as Super Speed.
>>>>>>>>>> Right ?
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Right.
>>>>>>>>>
>>>>>>>>> While 3.0 block(PIPE3) can be used for Super Speed, 2.0
>>>>>>>>> block(UTMI+)
>>>>>>>>> can be used for High speed.
>>>>>>>>
>>>>>>>>
>>>>>>>> It should then come under *single IP muliple PHY* category similar
>>>>>>>> to what
>>>>>>>> Sylwester has done.
>>>>>>>
>>>>>>>
>>>>>>> Do you mean that i should be including PHY IDs for UTMI+ phy and
>>>>>>> PIPE3
>>>>>>> phy present in this PHY block ?
>>>>>>> AFAICS the two phys (UTMI+ and PIPE3) do not really have separate
>>>>>>> registers to program, and that's the reason
>>>>>>> we program the entire PHY in a shot.
>>>>>>
>>>>>>
>>>>>> you mean you program the same set of bits for UTMI+ and PIPE3?
>>>>>
>>>>>
>>>>> No, looking closely into PHY datasheet as well as Exynos5250 manual, i
>>>>> can see that UTMI+ and PIPE3
>>>>> phys have separate bit settings. So i think we should be able to
>>>>> segregate the two PHYs (UTMI+ and PIPE3).
>>>>> Pardon me for my earlier observations.
>>>>
>>>>
>>>> no problem..
>>>>>
>>>>> Let me clarify more with our h/w team also on this and then i will
>>>>> confirm with this.
>>>
>>>
>>> Did you get more information on this?
>>
>>
>> Yes, i have been in contact with our hardware team.
>> The functionality of setting up UTMI+ and PIPE3 phys separately, and
>> thereby using only one functionality of the two
>> at some point of time (either high speed or super speed) hasn't been
>> tested so far.
>
>
> Irrespective of whether we are able to test the functionality separately or
> not, we should model it as multiple PHYs since you have separate bit
> settings for UTMI+ and PIPE3.
>
> (I'll review your next patch version shortly).

Thanks Kishon, i know i am disturbing you in the holiday season. :-)
But there's one concern, on Exynos5 platforms we have only one bit to
power control
the entire PHY (irrespective of the two PHYs present in the USB 3.0
PHY controller).
So anyways we won't be able to save anything on the power front even
if we program only
one PHY (UTMI/PIPE3).
Although there are PHY settings register bits which seem separate for
the two phys.
What do you suggest in that case ?
May be i am not able to understand you properly on the front of multiple PHYs

>
> Cheers
> Kishon
>
>
>> So i will be looking into this and try to find out proper init
>> sequences for the two available PHYs
>> separately and as soon as i get a working solution for this, i will
>> update.
>>
>>>
>>> Thanks
>>> Kishon
>>
>>
>>
>>
>



-- 
Best Regards
Vivek Gautam
Samsung R&D Institute, Bangalore
India