On Wed, Oct 19, 2016 at 3:02 PM, Maxime Ripard <
maxime.rip...@free-electrons.com> wrote:

> Hi,
>
> On Mon, Oct 17, 2016 at 11:33:45PM +0200, Jarosław Nieć wrote:
> > BTW Implementing general cec-over-gpio driver could be also quite
> > useful for lot of projects.
>
> Rockchip has such a driver already. It's not upstream at the moment,
> but your point is valid :)
>

Are you refering to this driver?
https://github.com/tyeo098/MK908-Kernel-NAND/tree/master/drivers/video/rockchip/hdmi/softcec
Or maybe something new was written?
This old one doesn't look too good. Lot of very ineffective sleeps
and of course lack of support to this new framework.


> > > > 2) CEC driver requires HDMI physical address to be provided. This
> address
> > > > can be passed from userspace (but userspace need to know it), or
> driver
> > > can
> > > > obtain it on its own.
> > > > Right now I left providing of this parameter to userspace, but it
> will be
> > > > good to have option of obtaining it. Normally we can read this value
> from
> > > > EDID that is read using HDMI I2C.
> > > > AFAIK currently there is no Display Engine HDMI support in mainline
> > > kernel,
> > > > so there is no HDMI I2C interface implemented.
> > > > Are there any plans to support HDMI in Display Engine in near future?
> > >
> > > I started working on it. I'm still at the point where I try to get the
> > > EDIDs, but I shouldn't be very far now.
> >
> > I'm very happy to hear that :)
> > Are you planing to provide any interface to EDID or HDMI address to other
> > modules?
> > CEC framework already contains some code to parse EDID
> > https://github.com/linux-sunxi/linux-sunxi/blob/sunxi-
> next/include/media/cec-edid.h
>
> The EDIDs are exposed to the userspace already through a sysfs
> file. Did you need them in the kernel too?


Truly I don't know what I need :)
CEC framework supports 2 types of CEC adapters. First one that doesn't know
its HDMI physical address and second one that knows it, because it analyzed
EDID on its own.
In case of first adapters userplane should pass this address to adapter so
it can use it.
Unfortunately right now there is no large support in userplane for new
framework.
The most popular libcec doesn't support framework and I don't know how they
are
planing to obtain and pass this address to adapter.
Maybe they will read this sysfs file. Who knows.
https://github.com/Pulse-Eight/libcec/issues/67

Thats why to make this cec driver "more independent" and I wanted to somehow
get address from EDID.
But as for now I don't think this is very important and we shouldn't worry
about that.

Jarek

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