[PATCH v4 1/2] dt-bindings: remoteproc: mediatek: Make l1tcm reg exclusive to mt819x

[Nícolas F. R. A. Prado]

Commit ca23ecfdbd44 ("remoteproc/mediatek: support L1TCM") added support
for the l1tcm memory region on the MT8192 SCP, adding a new da_to_va
callback that handles l1tcm while keeping the old one for
back-compatibility with MT8183. However, since the mt8192 compatible was
missing from the dt-binding, the accompanying dt-binding commit
503c64cc42f1 ("dt-bindings: remoteproc: mediatek: add L1TCM memory region")
mistakenly added this reg as if it were for mt8183. And later
it became common to all platforms as their compatibles were added.

Fix the dt-binding so that the l1tcm reg can, and must, be present only
on the supported platforms: mt8192 and mt8195.

Fixes: 503c64cc42f1 ("dt-bindings: remoteproc: mediatek: add L1TCM memory region")
Signed-off-by: Nícolas F. R. A. Prado <nfraprado at collabora.com>

---
The if:then: branches became rather long since it seems that it's not
possible to override the properties in them, only add new ones. That is,
I couldn't leave the items definition for all three regs in the global
reg-names and just decrease minItems and maxItems to 2 for
mt8183/mt8186.

Also I had to add a description to the global reg-names, since it
couldn't be neither missing nor empty.

Let me know if there are better ways to achieve this.

Changes in v4:
- Reworked presence of l1tcm reg to be if:then: based and present only
  on mt8192/mt8195
- Rewrote commit message
- Added Fixes tag

Changes in v3:
- Made the cfg reg required again. After looking again into the mtk-scp
  driver, only l1tcm is optional.
- Added mention that a dtbs_check warning gets fixed by patch in commit
  message.

 .../bindings/remoteproc/mtk,scp.yaml          | 69 ++++++++++++++-----
 1 file changed, 50 insertions(+), 19 deletions(-)

diff --git a/Documentation/devicetree/bindings/remoteproc/mtk,scp.yaml b/Documentation/devicetree/bindings/remoteproc/mtk,scp.yaml
index 823a236242de..e1793a85e610 100644
--- a/Documentation/devicetree/bindings/remoteproc/mtk,scp.yaml
+++ b/Documentation/devicetree/bindings/remoteproc/mtk,scp.yaml
@@ -23,15 +23,12 @@ properties:
 
   reg:
     description:
-      Should contain the address ranges for memory regions SRAM, CFG, and
-      L1TCM.
-    maxItems: 3
+      Should contain the address ranges for memory regions SRAM, CFG, and,
+      on some platforms, L1TCM.
 
   reg-names:
-    items:
-      - const: sram
-      - const: cfg
-      - const: l1tcm
+    description:
+      Register names depend on the platform.
 
   clocks:
     description:
@@ -50,16 +47,50 @@ required:
   - reg
   - reg-names
 
-if:
-  properties:
-    compatible:
-      enum:
-        - mediatek,mt8183-scp
-        - mediatek,mt8192-scp
-then:
-  required:
-    - clocks
-    - clock-names
+allOf:
+  - if:
+      properties:
+        compatible:
+          enum:
+            - mediatek,mt8183-scp
+            - mediatek,mt8192-scp
+    then:
+      required:
+        - clocks
+        - clock-names
+
+  - if:
+      properties:
+        compatible:
+          enum:
+            - mediatek,mt8183-scp
+            - mediatek,mt8186-scp
+    then:
+      properties:
+        reg:
+          minItems: 2
+          maxItems: 2
+        reg-names:
+          items:
+            - const: sram
+            - const: cfg
+
+  - if:
+      properties:
+        compatible:
+          enum:
+            - mediatek,mt8192-scp
+            - mediatek,mt8195-scp
+    then:
+      properties:
+        reg:
+          minItems: 3
+          maxItems: 3
+        reg-names:
+          items:
+            - const: sram
+            - const: cfg
+            - const: l1tcm
 
 additionalProperties:
   type: object
@@ -79,10 +110,10 @@ additionalProperties:
 
 examples:
   - |
-    #include <dt-bindings/clock/mt8183-clk.h>
+    #include <dt-bindings/clock/mt8192-clk.h>
 
     scp at 10500000 {
-        compatible = "mediatek,mt8183-scp";
+        compatible = "mediatek,mt8192-scp";
         reg = <0x10500000 0x80000>,
               <0x10700000 0x8000>,
               <0x10720000 0xe0000>;
-- 
2.36.0