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

[Chen-Yu Tsai <wens@csie.org>]

On Wed, Dec 14, 2016 at 5:16 AM, Icenowy Zheng <icenowy@aosc.xyz> wrote:
>
>
> 14.12.2016, 04:29, "Simon Glass" <sjg@chromium.org>:
>> Hi,
>>
>> On 12 December 2016 at 19:36, Jernej Skrabec <jernej.skrabec@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?

ChenYu

>
>>
>>>  - TCON code is currently exactly the same as in driver for older
>>>    SoCs. Should I split it out into shared module? Also TV out code
>>>    seems to be similar, but I didn't manage to confirm that it works
>>>    as-is on H3.
>>>  - A80 SoC is mix of older display engine and newer HDMI controller,
>>>    so it doesn't really work with either of sunxi video drivers. Two
>>>    solutions I see here are either combine both driver into one massive
>>>    display driver or, much better, split everything by components
>>>    (TCON/DE/DE2/HDMI/TV) and instantiate compatible ones. I guess this
>>>    is not much different than adding support for DT in drivers. Note
>>>    that I don't have any A80 board, I'm just thinking ahead.
>>>
>>>  Best regards,
>>>  Jernej Skrabec
>>>
>>>  Jernej Skrabec (3):
>>>    sunxi: Add clocks for DE2/HDMI/TCON
>>>    sunxi: video: Add video driver for H3 SoC
>>>    sunxi: Enable H3 video driver in defconfigs
>>>
>>>   arch/arm/include/asm/arch-sunxi/clock_sun6i.h | 43 +
>>>   arch/arm/include/asm/arch-sunxi/cpu_sun4i.h | 8 +
>>>   arch/arm/include/asm/arch-sunxi/display2.h | 377 +++++++++
>>>   arch/arm/mach-sunxi/clock_sun6i.c | 28 +
>>>   board/sunxi/Kconfig | 4 +-
>>>   configs/orangepi_2_defconfig | 1 +
>>>   configs/orangepi_lite_defconfig | 1 +
>>>   configs/orangepi_one_defconfig | 1 +
>>>   configs/orangepi_pc_defconfig | 1 +
>>>   configs/orangepi_pc_plus_defconfig | 1 +
>>>   configs/orangepi_plus2e_defconfig | 1 +
>>>   configs/orangepi_plus_defconfig | 1 +
>>>   drivers/video/Makefile | 1 +
>>>   drivers/video/sunxi_display2.c | 1037 +++++++++++++++++++++++++
>>>   include/configs/sunxi-common.h | 17 +-
>>>   scripts/config_whitelist.txt | 1 +
>>>   16 files changed, 1516 insertions(+), 7 deletions(-)
>>>   create mode 100644 arch/arm/include/asm/arch-sunxi/display2.h
>>>   create mode 100644 drivers/video/sunxi_display2.c
>>>
>>>  --
>>>  2.10.2
>>
>> Regards,
>> Simon
>>
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