Hi Matthias,

On Mon, 2016-02-08 at 18:51 +0100, Matthias Brugger wrote:

On 22/01/16 04:38, Horng-Shyang Liao wrote:

quoted

Hi Rob,

On Wed, 2016-01-20 at 10:38 -0600, Rob Herring wrote:

quoted

On Wed, Jan 20, 2016 at 01:14:38PM +0800, hs.liao@mediatek.com wrote:

quoted

From: HS Liao <redacted>

This adds documentation for the MediaTek Global Command Engine (GCE) unit
found in MT8173 SoCs.

Signed-off-by: HS Liao <redacted>
---
  .../devicetree/bindings/soc/mediatek/gce.txt       |   33 ++++++++++++++++++++
  1 file changed, 33 insertions(+)
  create mode 100644 Documentation/devicetree/bindings/soc/mediatek/gce.txt

diff --git a/Documentation/devicetree/bindings/soc/mediatek/gce.txt b/Documentation/devicetree/bindings/soc/mediatek/gce.txt
new file mode 100644
index 0000000..878b11e
--- /dev/null
+++ b/Documentation/devicetree/bindings/soc/mediatek/gce.txt

@@ -0,0 +1,33 @@
+MediaTek GCE
+===============
+
+The Global Command Engine (GCE) is used to help read/write registers with
+critical time limitation, such as updating display configuration during the
+vblank. The GCE can be used to implement the Command Queue (CMDQ) driver.
+Currently, the GCE only supports display related hardwares, but we expect
+it can be extended to other hardwares for future requirements.

That's a hardware limitation or just s/w is only using it for display?
If the latter, that's not really relevant to this binding and should be
removed.

Just s/w is only using it for display.
I will remove it from next patch.

quoted

quoted

+
+Required properties:
+- compatible: Must be "mediatek,mt8173-gce"
+- reg: Address range of the GCE unit
+- interrupts: The interrupt signal from the GCE block
+- clock: Clocks according to the common clock binding
+- clock-names: Must be "gce" to stand for GCE clock
+
+Example:
+
+	gce: gce@10212000 {
+		compatible = "mediatek,mt8173-gce";
+		reg = <0 0x10212000 0 0x1000>;
+		interrupts = <GIC_SPI 135 IRQ_TYPE_LEVEL_LOW>;
+		clocks = <&infracfg CLK_INFRA_GCE>;
+		clock-names = "gce";
+	};
+
+	mmsys: clock-controller@14000000 {
+		compatible = "mediatek,mt8173-mmsys", "syscon";
+		reg = <0 0x14000000 0 0x1000>;
+		power-domains = <&scpsys MT8173_POWER_DOMAIN_MM>;
+		#clock-cells = <1>;
+		mediatek,gce = <&gce>;

Not documented.

It's just an example about how gce is used by display mmsys.
After I discussed with Mediatek display owner,
we think this can be moved to display device tree document.
Do you agree with this suggestion?
If so, I will remove it from next patch, too.

The problem is that mediatek,gce is not documented, but only 
mediatek,mt8173-gce.

How about this?

Required properties for a client device:
- mediatek,gce: Should point to the respective GCE block

Example for a client device:

mmsys: clock-controller@14000000 {
	compatible = "mediatek,mt8173-mmsys";
	mediatek,gce = <&gce>;
	...
};

Regards,
Matthias

Thanks,
HS Liao