On Wed, Nov 9, 2016 at 9:19 PM, Joel Stanley [off-list ref] wrote:

On Thu, Nov 10, 2016 at 4:56 AM, Rob Herring [off-list ref] wrote:

quoted

On Thu, Nov 03, 2016 at 01:07:57AM +1030, Andrew Jeffery wrote:

quoted

The Aspeed SoC Display Controller is presented as a syscon device to
arbitrate access by display and pinmux drivers. Video pinmux
configuration on fifth generation SoCs depends on bits in both the
System Control Unit and the Display Controller.

Signed-off-by: Andrew Jeffery <redacted>
---
 Documentation/devicetree/bindings/mfd/aspeed-gfx.txt | 17 +++++++++++++++++

The register space can't be split to 2 nodes?

Do you mean splitting the GFX IP and enable register into two nodes?

We can't. Pinmux needs to check bit 6 and 7 in GFX064, which is in the
middle the IP block:

GFX060: CRT Control Register I
GFX064: CRT Control Register II
GFX068: CRT Status Register
GFX06C: CRT Misc Setting Register

Okay.

quoted

quoted

+The Aspeed SoC Display Controller primarily does as its name suggests, but also
+participates in pinmux requests on the g5 SoCs. It is therefore considered a
+syscon device.
+
+Required properties:
+- compatible:                "aspeed,ast2500-gfx", "syscon"

I think perhaps we should drop the syscon here and the driver should
just register as a syscon.

We want the regmap to be present whenever the GFX driver or pinmux is
loaded. If we register it in pinmux but chose to not build in that
driver, we lack the regmap. Same for the case where a user builds in
the GFX driver and not pinmux. I think this means we want the syscon
compatible string, unless my understanding is wrong?

Right.

Acked-by: Rob Herring <robh@kernel.org>

Rob