On Tue, Jul 26, 2016 at 8:44 PM, Minghsiu Tsai
[off-list ref] wrote:

On Tue, 2016-07-26 at 13:54 -0500, Rob Herring wrote:

quoted

On Fri, Jul 22, 2016 at 04:33:01PM +0800, Minghsiu Tsai wrote:

quoted

Add a DT binding documentation of MDP for the MT8173 SoC
from Mediatek

Signed-off-by: Minghsiu Tsai <minghsiu.tsai@mediatek.com>
---
 .../devicetree/bindings/media/mediatek-mdp.txt     |   96 ++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/mediatek-mdp.txt

diff --git a/Documentation/devicetree/bindings/media/mediatek-mdp.txt b/Documentation/devicetree/bindings/media/mediatek-mdp.txt
new file mode 100644
index 0000000..2dad031
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/mediatek-mdp.txt

@@ -0,0 +1,96 @@
+* Mediatek Media Data Path
+
+Media Data Path is used for scaling and color space conversion.
+
+Required properties (all function blocks):
+- compatible: "mediatek,<chip>-mdp"

What is this, ...

It is used to match platform driver.

Would structuring things like this work instead:

{
  compatible = "mediatek,<chip>-mdp";
  ranges = ...;
  {
    compatible = "mediatek,<chip>-mdp-rdma";
    ...
  };
  {
    compatible = "mediatek,<chip>-mdp-wdma";
    ...
  };
  ...
};

quoted

quoted

+        "mediatek,<chip>-mdp-<function>", one of

and this?

It is string format of HW block. <chip> could be "mt8173", and
<function> are "rdma", "rsz", "wdma", and "wrot".

quoted

quoted

+        "mediatek,<chip>-mdp-rdma"  - read DMA
+        "mediatek,<chip>-mdp-rsz"   - resizer
+        "mediatek,<chip>-mdp-wdma"  - write DMA
+        "mediatek,<chip>-mdp-wrot"  - write DMA with rotation

List what are valid values of <chip>.

<chip> - mt8173. There should be other chip added in future.
I will change the property as blow:

- compatible: "mediatek,<chip>-mdp"
        Should be one of
        "mediatek,<chip>-mdp-rdma"  - read DMA
        "mediatek,<chip>-mdp-rsz"   - resizer
        "mediatek,<chip>-mdp-wdma"  - write DMA
        "mediatek,<chip>-mdp-wrot"  - write DMA with rotation
        <chip> - could be 8173


If don't need <chip>, I also can change it as below. It is more clear.

Up to you. Depends on how many different chips you will have.

- compatible: "mediatek,mt8173-mdp"
        Should be one of
        "mediatek,mt8173-mdp-rdma"  - read DMA
        "mediatek,mt8173-mdp-rsz"   - resizer
        "mediatek,mt8173-mdp-wdma"  - write DMA
        "mediatek,mt8173-mdp-wrot"  - write DMA with rotation

quoted

quoted

+- reg: Physical base address and length of the function block register space
+- clocks: device clocks
+- power-domains: a phandle to the power domain.
+- mediatek,vpu: the node of video processor unit
+
+Required properties (DMA function blocks):
+- compatible: Should be one of
+        "mediatek,<chip>-mdp-rdma"
+        "mediatek,<chip>-mdp-wdma"
+        "mediatek,<chip>-mdp-wrot"
+- iommus: should point to the respective IOMMU block with master port as
+  argument, see Documentation/devicetree/bindings/iommu/mediatek,iommu.txt
+  for details.
+- mediatek,larb: must contain the local arbiters in the current Socs.

It is still not clear which properties apply to which compatible
strings.

I found out the document for larb.
I will change the property as below:

- mediatek,larb: must contain the local arbiters in the current Socs,
see
Documentation/devicetree/bindings/memory-controllers/mediatek,smi-larb.txt
  for details.

That's good, but not what I meant. You still have properties which
only apply to certain blocks, but are listed for all blocks like
mediatek,vpu for example.

Rob