Re: [RFC, PATCH] gspca pac7302: add support for camera button

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

Hi,

On 11/16/2009 07:58 AM, Németh Márton wrote:
> Hi,
> Hans de Goede wrote:
>> Hi,
>>
>> Thanks for working on this! I think it would be great if we could
>> get support for camera buttons in general into gspca.
>>
>> I've not looked closely at your code yet, have you looked at
>> the camera button code in the gspca sn9c20x.c driver? Also I would really
>
> As you proposed I had a look on sn9c20x. It seems that sn9c20x uses register read
> via USB control message. The pac7302 uses interrupt endpoint. So it looks like
> quite different to me. Currently I see the common point in the connection
> to input subsystem only.
>

Ah you are right, oops, most camera's use an interrupt end point so I assumed
sn9c20x would be the same, my bad.

>> like to see as much of the button handling code as possible go into
>> the gspca core. AFAIK many many camera's use an usb interrupt ep for this, so
>> I would like to see the setting up and cleanup of this interrupt ep be in
>> the core (as said before see the sn9c20x driver for another driver which
>> does such things).
>
> Unfortunately I do not know how the USB descriptors of other webcams look like.
> I have access to two webcams which are handled by gspca:
>

No problem, just put all the input code in pac7302.c for now, we will abstract it
later when we add support for the button on other camera's too.

<snip>

> Comparing these two endpoints shows the common and different points:
> Common: interface class, endpoint direction, endpoint type.
> Different: interface number, sub class, protocol, endpoint address, max
>             packet size, interval.
>
> Maybe the second example is not a good one because I don't know whether
> the interrupt endpoint is used for buttons or not.
>
> Do you have access to webcams equipped with button? Could you please
> send the device descriptor (lsusb -v) about these devices in order
> the common points can be identified for interrupt endpoints?
>

As the author/maintainer of quite a few drivers and libv4l author I have
build up quite a test camera collection, I'll send you the lsusb -v output
of a few in a private mail. But as said before, for now I think you can just put
the input code inside pac7302.c, then later on we can try to abstract it.

Regards,

Hans
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