Re: How to implement i2c map device

[Hans Verkuil <hverkuil@xxxxxxxxx>]

Hi Scott,

On Thursday 26 April 2012 11:47:08 Scott Jiang wrote:
> Hi Laurent,
> 
> I'm writing a driver for adv7842 video decoder. This chip has 12 i2c
> register maps. IO map is fixed to 0x20 and others are configurable.
> I plan to use 0x20 as the subdevice addr to call
> v4l2_i2c_new_subdev_board, and call i2c_new_device and i2c_add_driver
> in i2c_probe to enumerate other i2c maps. Is it acceptable or any
> other suggestion?

You have to use i2c_new_dummy for all the non-fixed register maps.

But I can save you a lot more time: we (Cisco) have a adv7842 driver already 
that is working for the most part (at least the parts that we need).

I'll mail the driver to you separately. I intend to make it available in a 
public repository in the next few weeks.

> 
> By the way, HDMI support seems under discussion, is there any
> framework or guide now?

There are two parts to HDMI: the first is a better API for selecting timings. 
The latest RFC patch series was just posted this week:

http://www.spinics.net/lists/linux-media/msg46813.html

I'm hopeful that this will make kernel 3.5.

The second part is to add some missing HDMI-specific controls and two ioctls 
to set/get EDIDs. I'm preparing an RFC for that and I expect to post that next 
week.

There is one final part: CEC support. We have implemented it, but the API 
needs more discussions. How to present CEC support to userspace seems to be a 
controversial issue.

Regards,

	Hans

> 
> Thanks,
> Scott
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