[U-Boot] [linux-sunxi] Re: [RFC PATCH 0/3] sunxi: video: Add support for HDMI output on H3

[Maxime Ripard]

Hi,

On Wed, Dec 14, 2016 at 11:37:38AM +0200, Alexander Graf wrote:
> 
> 
> > Am 14.12.2016 um 11:25 schrieb Maxime Ripard <maxime.ripard at free-electrons.com>:
> > 
> >> On Wed, Dec 14, 2016 at 11:02:33AM +0800, Chen-Yu Tsai wrote:
> >>> On Wed, Dec 14, 2016 at 5:16 AM, Icenowy Zheng <icenowy at aosc.xyz> wrote:
> >>> 
> >>> 
> >>> 14.12.2016, 04:29, "Simon Glass" <sjg at chromium.org>:
> >>>> Hi,
> >>>> 
> >>>>> On 12 December 2016 at 19:36, Jernej Skrabec <jernej.skrabec at siol.net> wrote:
> >>>>> This patch series add support for HDMI output. Support for other,
> >>>>> newer, SoCs, which also uses DE2 and same or similar HDMI controller
> >>>>> and PHY can be easily added later (A83T/A64/H5/R40). Current driver
> >>>>> can also be easily extended with TV out support, just like video
> >>>>> driver for older Allwinner SoCs.
> >>>>> 
> >>>>> While driver works, I would like to get few opinions first.
> >>>>> - From what I understand, drivers which supports DT are preferred.
> >>>>>   Would it be better to rewrite this driver to support device tree?
> >>>> 
> >>>> Yes I think so, and in fact it should use driver model also.
> >>>> 
> >>>> The rockchip driver provides a reasonable example of how to split the
> >>>> driver up as you suggest below. The VIDEO driver provides the
> >>>> top-level video interface, DISPLAY drivers provide display output for
> >>>> the video, and you have PANEL as well for receiving the display
> >>>> output. VIDCONSOLE works automatically to display text.
> >>>> 
> >>>> I actually took a bit of a look at this a few weeks ago so am happy to
> >>>> help with review or discussions.
> >>> 
> >>> Yes, I think go to Driver Model is also valuable, as Allwinner's display parts
> >>> are really in reusable components.
> >>> 
> >>> In addition, Driver Model provides the possibility to use EFI GOP, which can
> >>> be a more standardized replacement of SimpleFB, especially for OSes other
> >>> than Linux. (For example, Windows, if we can really get it running ;-) )
> >> 
> >> We're going to use EFI now? Doesn't EFI mean we have to leave another bit
> >> of firmware in memory running under the OS? What about PSCI and ATF on
> >> ARMv8?
> > 
> > Until EFI on A64 on U-boot is a real thing, I don't really care to be
> > honest.
> 
> How is it not a real thing today?

Sorry, I missed it...

But still, the point remains. If it needs the DT and the device model
to be enabled and working properly, since that's not a feature that
worked before (on the previous SoC), I don't see why we should hold it
off. If and when someone is interested, and if and when we have a DT
bindings in Linux, then we will take care of this.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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