[RFC/PATCH 02/13] media: s5p-csis: Add device tree support

[Sylwester Nawrocki]

On 07/31/2012 01:05 PM, Laurent Pinchart wrote:
>>>>> What about CSI receivers that can reroute the lanes internally ? We
>>>>> would
>>>>> need to specify lane indices for each lane then, maybe with something
>>>>> like
>>>>>
>>>>> clock-lane =<0>;
>>>>> data-lanes =<2 3 1>;
>>>>
>>>> Sounds good to me. And the clock-lane could be made optional, as not all
>>>> devices would need it.
>>>>
>>>> However, as far as I can see, there is currently no generic API for
>>>> handling this kind of data structure. E.g. number of cells for the
>>>> "interrupts" property is specified with an additional
>>>> "#interrupt-cells" property.
>>>>
>>>> It would have been much easier to handle something like:
>>>>
>>>> data-lanes = <2>, <3>, <1>;
>>>>
>>>> i.e. an array of the lane indexes.
>>>
>>> I'm fine with that.
>>
>> ...on a second thought: shouldn't this be handled by pinctrl? Or is it
>> some CSI-2 module internal lane switching, not the global SoC pin function
>> configuration?
> 
> On the hardware I came across, it's handled by the CSI2 receiver, not the SoC 
> pinmux feature.

Same here. Is there any hardware known to mux those MIPI-CSI
D-PHY high speed differential signals with general purpose IO pins ?

Or are there mostly dedicated pins used ?

However, if there are cases the lane configuration is done solely at CSI2
receiver level, there seems little point in involving the pinctrl API.

--

Regards,
Sylwester