2009/8/9 Hans Verkuil <hverkuil@xxxxxxxxx>:
> On Sunday 09 August 2009 10:20:47 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.
>
> Basically any gspca driver that can set registers in the i2c device
> (as opposed to only replaying USB commands) can be modified so the i2c
> part can be split off into a regular sub-device driver. I've discussed
> this in the past with Hans de Goede and that is definitely the way to go.
>
>> 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.
>
> Looking at the code I'd say that it should be possible to implement an
> i2c_adapter in m5602_core.c, and when that's in place the various sensor
> drivers can be gradually split off into generic subdev drivers. Which is
> of course ever so much easier if the datasheets are available :-)
>
> For this particular bridge driver I strongly suggest that this approach
> is taken since there are already duplicate sensor drivers here (mt9m111).
>
> Regards,
>
> Hans
>
Hi Hans,
I didn't know that there already have been a discussion. I'll google
about that thread and go through.
And thanks to your mail, I could find that there already existing
duplicated drivers. I'll take that as a reference.
BTW, I was strongly appealing my boss to let me attend the
linuxplumber conf and I sense a slight possibility to go there. It's a
progress :-). I'm looking forward to having approval.
Cheers,
Nate
>>
>> Best regards,
>> Erik
>>
>> > Nate
>> >
>>
>>
>
>
>
> --
> Hans Verkuil - video4linux developer - sponsored by TANDBERG Telecom
>
--
=
DongSoo, Nathaniel Kim
Engineer
Mobile S/W Platform Lab.
Digital Media & Communications R&D Centre
Samsung Electronics CO., LTD.
e-mail : dongsoo.kim@xxxxxxxxx
dongsoo45.kim@xxxxxxxxxxx
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