[U-Boot] [PATCH 11/17] sunxi: video: Add support for VGA via external DACs connected to the LCD pins

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 30-12-14 03:21, Chen-Yu Tsai wrote:
> Hi Hans,
>
> On Tue, Dec 30, 2014 at 3:25 AM, Hans de Goede <hdegoede@redhat.com> wrote:
>> Hi,
>>
>>
>> On 29-12-14 14:51, Ian Campbell wrote:
>>>
>>> On Wed, 2014-12-24 at 20:06 +0100, Hans de Goede wrote:
>>>>
>>>> Add support for external DACs connected to the parallel LCD interface
>>>> driving
>>>> a VGA connector, such as found on the Olimex A13 boards.
>>>>
>>>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>>>
>>>
>>> Acked-by: Ian Campbell <ijc@hellion.org.uk>
>>>
>>>> ---
>>>>    board/sunxi/Kconfig           |  9 +++++++++
>>>>    drivers/video/sunxi_display.c | 14 ++++++++++++++
>>>>    2 files changed, 23 insertions(+)
>>>>
>>>> diff --git a/board/sunxi/Kconfig b/board/sunxi/Kconfig
>>>> index 7a8503b..3e42866 100644
>>>> --- a/board/sunxi/Kconfig
>>>> +++ b/board/sunxi/Kconfig
>>>> @@ -253,6 +253,15 @@ config VIDEO_HDMI
>>>>          ---help---
>>>>          Say Y here to add support for outputting video over HDMI.
>>>>
>>>> +config VIDEO_VGA_VIA_LCD
>>>> +       boolean "VGA via LCD controller support"
>>>> +       depends on VIDEO
>>>> +       default n
>>>> +       ---help---
>>>> +       Say Y here to add support for external DACs connected to the
>>>> parallel
>>>> +       LCD interface driving a VGA connector, such as found on the
>>>> +       Olimex A13 boards.
>>>
>>>
>>> But not unique to those boards I take it?
>>
>>
>> Actually sofar it is unique to those boards, both the normal and the Micro
>> variant (in theory we could see something similar on other boards one day).
>
> The Hummingbird A31 has the same setup, using an external DAC for the
> RGB signals, as it doesn't have the TV encoder. See:
>
>      http://linux-sunxi.org/Merrii_Hummingbird_A31#VGA_out

Interesting, it would be cool to see if this works with CONFIG_VIDEO_VGA_VIA_LCD=y
and something like "setenv video-mode sunxi:1024x768-24 at 60,monitor=vga" "saveenv"
with my sunxi-wip u-boot branch, I guess you need to add support for the enable gpio
for this to work, patches for this are welcome :)

Regards,

Hans