Re: About some sensor drivers in mc5602 gspca driver

["Erik Andrén" <erik.andren@gmail.com>]

Erik Andrén wrote:
> 
> Dongsoo, Nathaniel Kim wrote:
>> Hello,
>>
>> It has been years I've working on linux multimedia drivers, but what a
>> shame I found that there were already sensor drivers that I've already
>> implemented. Precisely speaking, soc camera devices from Samsung named
>> s5k4aa* and s5k83a* were already in Linux kernel and even seems to
>> have been there for years.
>> But a thing that I'm curious is those drivers are totally mc602 and
>> gspca oriented. So some users who are intending to use those samsung
>> camera devices but not using gspca and mc5602 H/W have to figure out
>> another way.
>> As you know, the s5k* camera devices are actually ISP devices which
>> are made in SoC device and can be used independently with any kind of
>> ITU or MIPI supporting host devices.
>> However, I see that gspca and mc5602 have their own driver structure
>> so it seems to be tough to split out the sensor drivers from them.
>> So, how should we coordinate our drivers if a new s5k* driver is
>> getting adopted in the Linux kernel? different version of s5k* drivers
>> in gspca and subdev or gspca also is able to use subdev drivers?
>> I am very willing to contribute several drivers for s5k* soc camera
>> isp devices and in the middle of researching to prepare for
>> contribution those s5k* drivers popped up.
>> Please let me know whether it is arrangeable or not.
>> Cheers,
>>
> 
> Hi Nathaniel,
> The sensor sharing question pops up now and then and I'm sure that
> if you search the mailing list archive you can find several threads
> discussing this.
> IIRC the main problem is that in an usb webcam consisting of a
> sensor and an usb bridge. The sensor is often configured in a very
> specific way tied to the particular usb bridge. It is also common
> that much of the initialization is reverse engineered and that we
> may have little or no understanding what we're actually doing.
> (Often just mimicing a windows webcam driver).
> I think the conclusion reached now is that it's not worth the effort
> considering that the sensors usually don't need that much setup to
> get working. Of course this may need to be reevaluated from time to
> time. If someone could device a clever solution I would be all for
> trying to create some kind of driver sharing.
> 
> In the gspca-m5602-s5k* case everything is reverse-engineered, as I
> don't possess any datasheets of the ALi m5602 nor the s5k83a,
> s5k4aa. I would be much happy if you Samsung folks would be able to
> provide with me with datasheets for the s5k* sensors.
> 
> Best regards,
> Erik
> 
Resending due to UTF-8 fail.


>> Nate
>>
>