On 10/06/2016 12:51 PM, Maxime Ripard wrote:
Hi Archit,
On Mon, Oct 03, 2016 at 04:40:57PM +0530, Archit Taneja wrote:
Hi Maxime,
On 09/30/2016 08:07 PM, Maxime Ripard wrote:
Some boards have an entirely passive RGB to VGA bridge, based on either
DACs or resistor ladders.
Those might or might not have an i2c bus routed to the VGA connector in
order to access the screen EDIDs.
Add a bridge that doesn't do anything but expose the modes available on the
screen, either based on the EDIDs if available, or based on the XGA
standards.
Acked-by: Rob Herring <robh@xxxxxxxxxx>
Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
---
.../bindings/display/bridge/rgb-to-vga-bridge.txt | 48 +++++
drivers/gpu/drm/bridge/Kconfig | 7 +
drivers/gpu/drm/bridge/Makefile | 1 +
drivers/gpu/drm/bridge/rgb-to-vga.c | 229 +++++++++++++++++++++
4 files changed, 285 insertions(+)
create mode 100644 Documentation/devicetree/bindings/display/bridge/rgb-to-vga-bridge.txt
create mode 100644 drivers/gpu/drm/bridge/rgb-to-vga.c
diff --git a/Documentation/devicetree/bindings/display/bridge/rgb-to-vga-bridge.txt b/Documentation/devicetree/bindings/display/bridge/rgb-to-vga-bridge.txt
new file mode 100644
index 000000000000..a8375bc1f9cb
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/bridge/rgb-to-vga-bridge.txt
@@ -0,0 +1,48 @@
+Dumb RGB to VGA bridge
+----------------------
+
+This binding is aimed for dumb RGB to VGA bridges that do not require
+any configuration.
+
+Required properties:
+
+- compatible: Must be "rgb-to-vga-bridge"
I'd talked to Laurent on IRC if he's okay with this. And I guess you to
had discussed it during XDC too. He's suggested that it'd be better to
have the compatible string as "simple-vga-dac".
I just wished this bikeshedding had taken place publicly and be
actually part of that discussion, but yeah, ok.
Sorry about that. I'd pinged him for an Ack, the discussion went
more than that :)
Some of the reasons behind having this:
- We don't need to specify "rgb" in the compatible string since most
simple VGA DACs can only work with an RGB input.
Ok.
- Also, with "dac" specified in the string, we don't need to
specifically mention "bridge" in the string. Also, bridge is a drm
specific term.
- "simple" is considered because it's an unconfigurable bridge, and it
might be misleading for other VGA DACs to not use "vga-dac".
All those "simple" bindings are just the biggest lie we ever
told. It's simple when you introduce it, and then grows into something
much more complicated than a non-simple implementation.
"simple" here is supposed to mean that it's an unconfigurable RGB to
VGA DAC. This isn't supposed to follow the simple-panel model, where
you add the "simple-panel" string in the compatible node, along with
you chip specific compatible string.
In other words, this driver shouldn't be touched again in the future :)
If someone wants to write a RGB to VGA driver which is even
slightly configurable, they'll need to write a new bridge driver.
Thanks,
Archit
What do you think about this? If you think it's good, would it be
possible for you to change this? I guess it's okay for the rest of
the patch to stay the same.
I'll update and respin the serie.
Thanks,
Maxime
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