Re: [PATCH 43/47] adv7604: Control hot-plug detect through a GPIO

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Hans,

On Thursday 13 February 2014 10:47:44 Hans Verkuil wrote:
> On 02/11/14 13:03, Laurent Pinchart wrote:
> > On Tuesday 11 February 2014 11:09:31 Hans Verkuil wrote:
> >> On 02/05/14 17:42, Laurent Pinchart wrote:
> >>> Replace the ADV7604-specific hotplug notifier with a GPIO to control the
> >>> HPD pin directly instead of going through the bridge driver.
> >> 
> >> Hmm, that's not going to work for me. I don't have a GPIO pin here,
> >> instead it is a bit in a register that I have to set.
> > 
> > But that bit controls a GPIO, doesn't it ? In that case it should be
> > exposed as a GPIO controller.
> 
> I feel unhappy about losing this notifier for two reasons: first adding a
> GPIO controller just to toggle a bit adds 40 lines to my driver, and that
> doesn't sit well with me. It's basically completely unnecessary overhead.
> 
> The second reason is that in some cases you want to do something in addition
> to just toggling the hotplug pin. In particular for CEC support this could
> be quite useful.

As discuss over IRC, I'll keep the HPD notification and add optional GPIO 
support in v2.

> In fact, if the adv7604 supports the ARC feature (Audio Return Channel),
> then this is really needed because in that case the hotplug toggling would
> have to be done via CEC CDC commands. However, while this webpage claims
> that the ARC is supported, I can't find any other information about that.
> 
> http://www.analog.com/en/audiovideo-products/analoghdmidvi-interfaces/adv760
> 4/products/product.html
> 
> Lars-Peter, do you know anything about ARC support in the adv7604?

-- 
Regards,

Laurent Pinchart