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sunxi: Enable VGA output on Hummingbird A31

Hans de Goede u-boot 1 version New

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  1. v1 Latest0 of 3 patches 0 repliesNew

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Cover letter [U-Boot] [PATCH 0/3] sunxi: Enable VGA output on Hummingbird A31

Hi,

Quoted 19 lines · Chen-Yu Tsai

Hi Hans, Ian,

This series enables the VGA output on the Hummingbird A31. The VGA output is driven from LCD0, through an external DAC that's powered up by toggling pin PH25.

Patch 1 allows selecting CONFIG_VIDEO_VGA_VIA_LCD on sun6i and sun8i. These 2 platforms do not have builtin TV encoders, and some vendor may use an external DAC to support VGA.

Patch 2 adds support for toggling a GPIO pin as part of the video init sequence to power up the DAC

Patch 3 updates the Hummingbird A31 defconfig to enable VGA output.

I have one question about the VGA_VIA_LCD code in general. The color depth is forced to 18. Is this necessary? Can we make it configurable? I haven't tried displaying pictures so I don't know if it makes a visible difference.

Quoted 8 lines

Also with the VGA output on my Hummingbird A31, I get greenish flashing pixels where it should be black, like in and between characters. Once booted in to the kernel this disappears, and I get a nice console with simplefb. Kind of weird.

Cheers
ChenYu

Thanks, applied to u-boot-sunxi/next (with the discussed fix), while at it I've also fixed the whitespace errors you pointed out in <CAGb2v65Y26fTjcoOcWUZLG0+BR+UrWJ4HCL5d1V7ovn6TA6WTw@mail.gmail.com>

Regards,

Hans

Quoted 14 lines

Chen-Yu Tsai (3):
sunxi: video: Allow external DACs for VGA on platforms without TV
encoders
sunxi: video: Add support for external DAC enable pin
sunxi: Hummingbird_A31_defconfig: Enable VGA output through external
DAC

  board/sunxi/Kconfig               | 10 +++++++++-
  configs/Hummingbird_A31_defconfig |  2 ++
  drivers/video/sunxi_display.c     | 18 ++++++++++++++++++
  3 files changed, 29 insertions(+), 1 deletion(-)

Read the cover letter in its thread