[PATCH v4 1/2] dt-bindings: clock: mediatek: Add SMI LARBs reset for MT8188

[Friday Yang]

On the MediaTek platform, some SMI LARBs are directly connected to
the SMI Common, while others are connected to the SMI Sub-Common,
which in turn is connected to the SMI Common. The hardware block
diagram can be described as follows.

             SMI-Common(Smart Multimedia Interface Common)
                 |
         +----------------+------------------+
         |                |                  |
         |                |                  |
         |                |                  |
         |                |                  |
         |                |                  |
       larb0       SMI-Sub-Common0     SMI-Sub-Common1
                   |      |     |      |             |
                  larb1  larb2 larb3  larb7       larb9

For previous discussion on the direction of the code modifications,
please refer to:
https://lore.kernel.org/all/CAFGrd9qZhObQXvm2_abqaX83xMLqxjQETB2=
wXpobDWU1CnvkA at mail.gmail.com/
https://lore.kernel.org/all/CAPDyKFpokXV2gJDgowbixTvOH_5VL3B5H8ey
hP+KJ5Fasm2rFg at mail.gmail.com/

On the MediaTek MT8188 SoC platform, we encountered power-off failures
and SMI bus hang issues during camera stress tests. The issue arises
because bus glitches are sometimes produced when MTCMOS powers on or
off. While this is fairly normal, the software must handle these
glitches to avoid mistaking them for transaction signals. What's
more, this issue emerged only after the initial upstreaming of this
binding. Without these patches, the SMI becomes unstable during camera
stress tests.

The software solutions can be summarized as follows:

1. Use CLAMP to disable the SMI sub-common port after turning off the
   LARB CG and before turning off the LARB MTCMOS.
2. Use CLAMP to disable/enable the SMI sub-common port.
3. Implement an AXI reset for SMI LARBs.

This patch add '#reset-cells' for the clock controller located in image,
camera and IPE subsystems.

Signed-off-by: Friday Yang <friday.yang at mediatek.com>
---
 .../bindings/clock/mediatek,mt8188-clock.yaml | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/Documentation/devicetree/bindings/clock/mediatek,mt8188-clock.yaml b/Documentation/devicetree/bindings/clock/mediatek,mt8188-clock.yaml
index 860570320545..2985c8c717d7 100644
--- a/Documentation/devicetree/bindings/clock/mediatek,mt8188-clock.yaml
+++ b/Documentation/devicetree/bindings/clock/mediatek,mt8188-clock.yaml
@@ -57,6 +57,27 @@ required:
   - reg
   - '#clock-cells'

+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - mediatek,mt8188-camsys-rawa
+              - mediatek,mt8188-camsys-rawb
+              - mediatek,mt8188-camsys-yuva
+              - mediatek,mt8188-camsys-yuvb
+              - mediatek,mt8188-imgsys-wpe1
+              - mediatek,mt8188-imgsys-wpe2
+              - mediatek,mt8188-imgsys-wpe3
+              - mediatek,mt8188-imgsys1-dip-nr
+              - mediatek,mt8188-imgsys1-dip-top
+              - mediatek,mt8188-ipesys
+
+    then:
+      required:
+        - '#reset-cells'
+
 additionalProperties: false

 examples:
--
2.46.0