dt-bindings: remoteproc: st,stm32-rproc: Rework reset declarations

With the introduction of the SCMI (System Control and Management
Interface), it is now possible to use the SCMI to handle the
hold boot instead of a dedicated SMC call.

As consequence two configurations are possible:
- without SCMI server on OP-TEE:
  use the Linux rcc reset service and use syscon for the MCU hold boot
- With SCMI server on OP-TEE:
  use the SCMI reset service for both the MCU reset and the MCU hold boot.

This patch:
- make optional and deprecated the use of the property st,syscfg-tz
  which was used to check if the trusted Zone was enable to use scm call,
  to manage the hold boot. The reset controller phandle is used instead
  to select the configurations.
- make st,syscfg-holdboot optional
- adds properties check on resets definitions.
- adds an example of the SCMI reset service usage.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230512093926.661509-2-arnaud.pouliquen@foss.st.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml

@@ -25,7 +25,14 @@ properties:
     maxItems: 3
 
   resets:
-    maxItems: 1
+    minItems: 1
+    maxItems: 2
+
+  reset-names:
+    items:
+      - const: mcu_rst
+      - const: hold_boot
+    minItems: 1
 
   st,syscfg-holdboot:
     description: remote processor reset hold boot
@@ -37,6 +44,7 @@ properties:
           - description: The field mask of the hold boot
 
   st,syscfg-tz:
+    deprecated: true
     description:
       Reference to the system configuration which holds the RCC trust zone mode
     $ref: /schemas/types.yaml#/definitions/phandle-array
@@ -135,22 +143,48 @@ required:
   - compatible
   - reg
   - resets
-  - st,syscfg-holdboot
-  - st,syscfg-tz
+
+allOf:
+  - if:
+      properties:
+        reset-names:
+          not:
+            contains:
+              const: hold_boot
+    then:
+      required:
+        - st,syscfg-holdboot
+    else:
+      properties:
+        st,syscfg-holdboot: false
 
 additionalProperties: false
 
 examples:
   - |
     #include <dt-bindings/reset/stm32mp1-resets.h>
-    m4_rproc: m4@10000000 {
+    m4@10000000 {
       compatible = "st,stm32mp1-m4";
       reg = <0x10000000 0x40000>,
             <0x30000000 0x40000>,
             <0x38000000 0x10000>;
       resets = <&rcc MCU_R>;
+      reset-names = "mcu_rst";
+      /* Hold boot managed using system config*/
       st,syscfg-holdboot = <&rcc 0x10C 0x1>;
-      st,syscfg-tz = <&rcc 0x000 0x1>;
+      st,syscfg-rsc-tbl = <&tamp 0x144 0xFFFFFFFF>;
+      st,syscfg-m4-state = <&tamp 0x148 0xFFFFFFFF>;
+    };
+  - |
+    #include <dt-bindings/reset/stm32mp1-resets.h>
+    m4@10000000 {
+      compatible = "st,stm32mp1-m4";
+      reg = <0x10000000 0x40000>,
+            <0x30000000 0x40000>,
+            <0x38000000 0x10000>;
+      /* Hold boot managed using SCMI reset controller */
+      resets = <&scmi MCU_R>, <&scmi MCU_HOLD_BOOT_R>;
+      reset-names = "mcu_rst", "hold_boot";
       st,syscfg-rsc-tbl = <&tamp 0x144 0xFFFFFFFF>;
       st,syscfg-m4-state = <&tamp 0x148 0xFFFFFFFF>;
     };