[PATCH v3 12/14] dt-bindings: msm/dp: Add bindings for HDCP registers

[Sean Paul <sean@poorly.run>]

From: Sean Paul <seanpaul@chromium.org>

This patch adds the bindings for the MSM DisplayPort HDCP registers
which are required to write the HDCP key into the display controller as
well as the registers to enable HDCP authentication/key
exchange/encryption.

We'll use a new compatible string for this since the fields are optional.

Cc: Rob Herring <robh@kernel.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210913175747.47456-13-sean@poorly.run #v1
Link: https://patchwork.freedesktop.org/patch/msgid/20210915203834.1439-13-sean@poorly.run #v2

Changes in v2:
-Drop register range names (Stephen)
-Fix yaml errors (Rob)
Changes in v3:
-Add new compatible string for dp-hdcp
-Add descriptions to reg
-Add minItems/maxItems to reg
-Make reg depend on the new hdcp compatible string
---

Disclaimer: I really don't know if this is the right way to approach
this. I tried using examples from other bindings, but feedback would be
very much welcome on how I could add the optional register ranges.


 .../bindings/display/msm/dp-controller.yaml   | 34 ++++++++++++++++---
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/msm/dp-controller.yaml b/Documentation/devicetree/bindings/display/msm/dp-controller.yaml
index 64d8d9e5e47a..a176f97b2f4c 100644
--- a/Documentation/devicetree/bindings/display/msm/dp-controller.yaml
+++ b/Documentation/devicetree/bindings/display/msm/dp-controller.yaml
@@ -17,9 +17,10 @@ properties:
   compatible:
     enum:
       - qcom,sc7180-dp
+      - qcom,sc7180-dp-hdcp
 
-  reg:
-    maxItems: 1
+  # See compatible-specific constraints below.
+  reg: true
 
   interrupts:
     maxItems: 1
@@ -89,6 +90,29 @@ required:
   - power-domains
   - ports
 
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: qcom,sc7180-dp-hdcp
+    then:
+      properties:
+        reg:
+          minItems: 3
+          maxItems: 3
+          items:
+            - description: Registers for base DP functionality
+            - description: (Optional) Registers for HDCP device key injection
+            - description: (Optional) Registers for HDCP TrustZone interaction
+    else:
+      properties:
+        reg:
+          minItems: 1
+          maxItems: 1
+          items:
+            - description: Registers for base DP functionality
+
 additionalProperties: false
 
 examples:
@@ -99,8 +123,10 @@ examples:
     #include <dt-bindings/power/qcom-rpmpd.h>
 
     displayport-controller@ae90000 {
-        compatible = "qcom,sc7180-dp";
-        reg = <0xae90000 0x1400>;
+        compatible = "qcom,sc7180-dp-hdcp";
+        reg = <0 0x0ae90000 0 0x1400>,
+              <0 0x0aed1000 0 0x174>,
+              <0 0x0aee1000 0 0x2c>;
         interrupt-parent = <&mdss>;
         interrupts = <12>;
         clocks = <&dispcc DISP_CC_MDSS_AHB_CLK>,
-- 
Sean Paul, Software Engineer, Google / Chromium OS