HDMI transmitter attachement

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

Hello,
I'm looking for advice about the design for a new driver.

the AM335x arm SoC includes a framebuffer, which outputs a parallel digital
video signal. A HDMI transmitter which will serialize this video signal
can be connected to the SoC, which then allows to connect external monitors.
The beaglebone black includes a TDA19988 HDMI transmitter.

A driver is needed for the TDA19988, to get the EDID from the monitor, and
also configure the transmitter appropriately. So, in addition to the
video output lines, the TDA19988 is connected to one of the I2C controller
of the AM335x (one the beaglebone black it's the I2C0 controller, but
other boards could use any of the AM335x's I2C controllers).
In addition, the TDA19988 can transmit a digital audio signal, which it
gets from the SoC's "multichannel audio serial port".

Now my question is how should the TDA19988 appears in the device tree ?
I could make it a child of the I2C controller, with the framebuffer and
audio drivers using ad-hoc callbacks to the TDA19988 driver.
Or I could make it a child of the framebuffer, the framebuffer driver
redirecting I2C requests to the I2C controller driver.

I think the second solution is less hackish and more flexible;
but I'd like to hear from people more familiar than I am with
video hardware and drivers.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--