Re: eMPIA Silvercrest 2710

[Hans de Goede <hdegoede@redhat.com>]

Hi,


On 07/03/2009 08:21 AM, Mauro Carvalho Chehab wrote:
> Hi Joel,
>
> Em Fri, 7 Nov 2008 10:10:45 +0000
> Joel Jordan<zcacjxj@hotmail.com>  escreveu:
>
>
>>    Has there been any work done on the eMPIA Silvercrest EM2710 (device for webcams)?
>
> I borrowed a Silvercrest 1.3 Mpix camera, based on em2710 and mt9v011 with a
> friend, at the end of a conference that happened last week. After spending some
> spare time on it at the airplane while returning back home, I discovered how to
> enable stream on it.
>

My that webcam has done some interesting travelling (me -> Dough -> you), I'm glad
it finally ended at someone who has managed to get it to produce a picture under Linux.

> Basically, there were just a very few registers that was needing a different
> initialization, plus a driver to the sensor inside.
>
> Could you please test the latest development code and see if this works for you also?
>
> It is at:
> 	http://linuxtv.org/hg/v4l-dvb
>
> The driver is the em28xx. As the camera uses the generic vendor usb id
> (eb1a:2820), you'll need to force the driver to load the proper card
> parameters, by using card=71 at module probing. This can be done by calling:
>
> 	modprobe em28xx card=71
>
> Or by adding an options line on your /etc/modprobe.conf (or the equivalent file on your machine):
> 	options em28xx card=71
>
> You need to do one of the above procedures _before_ plug the camera, or
> otherwise it will take the generic entry that won't work.
>


Hmm, having to specify the card=71 parameter, sucks, that makes this a very non plug
and play / not just working experience for end users. Question would it be possible to
modify the em28xx driver to, when it sees the generic usb-id, setup the i2c controller
approriately and then check:
1) If there is anything at the i2c address of the mt9v011 sensor
2) Read a couple of identification registers (often sensors have special non changing
    registers for this)
3) If both the 1 and 2 test succeed set card to 71 itself ?

This is how we handle the problem of having one generic usb-id for a certain bridge, with
various different sensors used in different cams, I know the em28xx is a lot more complicated
as it does a lot more, but this may still work ?

Regards,

Hans