On Tue, Jun 20, 2023 at 10:12:14AM +0200, Krzysztof Kozlowski wrote:

On 20/06/2023 02:03, Nícolas F. R. A. Prado wrote:

quoted

The binding expects the first register space to be VDEC_SYS. But on
mt8183, which uses the stateless decoders, this space is used only for
controlling clocks and resets, which are better described as separate
clock-controller and reset-controller nodes.

In fact, in mt8173's devicetree there are already such separate
clock-controller nodes, which cause duplicate addresses between the
vdecsys node and the vcodec node. But for this SoC, since the stateful
decoder code makes other uses of the VDEC_SYS register space, it's not
straightforward to remove it.

In order to avoid the same address conflict to happen on mt8183,
since the only current use of the VDEC_SYS register space in
the driver is to read the status of a hardware controlled clock, remove
the VDEC_SYS register space from the binding and describe an extra
syscon that will be used to directly check the hardware status.

Also add reg-names to be able to tell that this new register schema is
used, so the driver can keep backward compatibility.

Signed-off-by: Nícolas F. R. A. Prado <redacted>

---
I dropped the tags from this commit since a syscon is now used instead
of an extra clock.

Changes in v3:
- Removed the active clock
- Added a mediatek,vdecsys syscon property

Changes in v2:
- Merged with patch 1 (media: dt-bindings: mediatek,vcodec: Allow single
  clock for mt8183) to avoid changing number of clocks twice
- Added maxItems to reg-names
- Constrained clocks for each compatible
- Reordered properties for each compatible

 .../media/mediatek,vcodec-decoder.yaml        | 30 +++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/Documentation/devicetree/bindings/media/mediatek,vcodec-decoder.yaml b/Documentation/devicetree/bindings/media/mediatek,vcodec-decoder.yaml
index 1e56ece44aee..2f625c50bbfe 100644
--- a/Documentation/devicetree/bindings/media/mediatek,vcodec-decoder.yaml
+++ b/Documentation/devicetree/bindings/media/mediatek,vcodec-decoder.yaml

@@ -21,8 +21,13 @@ properties:
       - mediatek,mt8183-vcodec-dec
 
   reg:
+    minItems: 11
     maxItems: 12
 
+  reg-names:
+    minItems: 11
+    maxItems: 11

maxItems: 12

quoted

+
   interrupts:
     maxItems: 1
 

@@ -60,6 +65,10 @@ properties:
     description:
       Describes point to scp.
 
+  mediatek,vdecsys:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description: Phandle to the vdecsys syscon node.
+
 required:
   - compatible
   - reg

@@ -79,8 +88,26 @@ allOf:
     then:
       required:
         - mediatek,scp
+        - mediatek,vdecsys
 
       properties:
+        reg:
+          maxItems: 11
+
+        reg-names:
+          items:
+            - const: misc
+            - const: ld
+            - const: top
+            - const: cm
+            - const: ad
+            - const: av
+            - const: pp
+            - const: hwd
+            - const: hwq
+            - const: hwb
+            - const: hwg
+
         clocks:
           minItems: 1
           maxItems: 1

@@ -101,6 +128,9 @@ allOf:
         - mediatek,vpu
 
       properties:
+        reg:
+          minItems: 12

What about reg-names here? They should be also defined and in sync with
regs.

That's intentional. As described in the commit message, mt8173 will keep having
the VDEC_SYS iospace, while mt8183 won't. And we use the presence of reg-names
to tell them apart.

So, mt8173 has 12 regs, no reg-names and no syscon, while mt8183 has 11 regs,
with reg-names and the syscon.

Thanks,
Nícolas

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