dt-bindings: firmware: arm,scmi: Convert to json schema

Convert the old text format binding for System Control and Management Interface
(SCMI) Message Protocol into the new and shiny YAML format.

Cc: Cristian Marussi <[e-mail]>
Cc: Florian Fainelli <[e-mail]>
Cc: Jim Quinlan <[e-mail]>
Cc: Etienne Carriere <[e-mail]>
Cc: Peter Hilber <[e-mail]>
Signed-off-by: Sudeep Holla <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
[robh: Rework interrupts schema and if/then]
Signed-off-by: Rob Herring <[e-mail]>

Documentation/devicetree/bindings/arm/arm,scmi.txt

···
-System Control and Management Interface (SCMI) Message Protocol
-----------------------------------------------------------
-
-The SCMI is intended to allow agents such as OSPM to manage various functions
-that are provided by the hardware platform it is running on, including power
-and performance functions.
-
-This binding is intended to define the interface the firmware implementing
-the SCMI as described in ARM document number ARM DEN 0056A ("ARM System Control
-and Management Interface Platform Design Document")[0] provide for OSPM in
-the device tree.
-
-Required properties:
-
-The scmi node with the following properties shall be under the /firmware/ node.
-
-- compatible : shall be "arm,scmi" or "arm,scmi-smc" for smc/hvc transports
-- mboxes: List of phandle and mailbox channel specifiers. It should contain
-	  exactly one or two mailboxes, one for transmitting messages("tx")
-	  and another optional for receiving the notifications("rx") if
-	  supported.
-- shmem : List of phandle pointing to the shared memory(SHM) area as per
-	  generic mailbox client binding.
-- #address-cells : should be '1' if the device has sub-nodes, maps to
-	  protocol identifier for a given sub-node.
-- #size-cells : should be '0' as 'reg' property doesn't have any size
-	  associated with it.
-- arm,smc-id : SMC id required when using smc or hvc transports
-
-Optional properties:
-
-- mbox-names: shall be "tx" or "rx" depending on mboxes entries.
-
-- interrupts : when using smc or hvc transports, this optional
-	 property indicates that msg completion by the platform is indicated
-	 by an interrupt rather than by the return of the smc call. This
-	 should not be used except when the platform requires such behavior.
-
-- interrupt-names : if "interrupts" is present, interrupt-names must also
-	 be present and have the value "a2p".
-
-See Documentation/devicetree/bindings/mailbox/mailbox.txt for more details
-about the generic mailbox controller and client driver bindings.
-
-The mailbox is the only permitted method of calling the SCMI firmware.
-Mailbox doorbell is used as a mechanism to alert the presence of a
-messages and/or notification.
-
-Each protocol supported shall have a sub-node with corresponding compatible
-as described in the following sections. If the platform supports dedicated
-communication channel for a particular protocol, the 3 properties namely:
-mboxes, mbox-names and shmem shall be present in the sub-node corresponding
-to that protocol.
-
-Clock/Performance bindings for the clocks/OPPs based on SCMI Message Protocol
-------------------------------------------------------------
-
-This binding uses the common clock binding[1].
-
-Required properties:
-- #clock-cells : Should be 1. Contains the Clock ID value used by SCMI commands.
-
-Power domain bindings for the power domains based on SCMI Message Protocol
-------------------------------------------------------------
-
-This binding for the SCMI power domain providers uses the generic power
-domain binding[2].
-
-Required properties:
- - #power-domain-cells : Should be 1. Contains the device or the power
-			 domain ID value used by SCMI commands.
-
-Regulator bindings for the SCMI Regulator based on SCMI Message Protocol
-------------------------------------------------------------
-An SCMI Regulator is permanently bound to a well defined SCMI Voltage Domain,
-and should be always positioned as a root regulator.
-It does not support any current operation.
-
-SCMI Regulators are grouped under a 'regulators' node which in turn is a child
-of the SCMI Voltage protocol node inside the desired SCMI instance node.
-
-This binding uses the common regulator binding[6].
-
-Required properties:
- - reg : shall identify an existent SCMI Voltage Domain.
-
-Sensor bindings for the sensors based on SCMI Message Protocol
---------------------------------------------------------------
-SCMI provides an API to access the various sensors on the SoC.
-
-Required properties:
-- #thermal-sensor-cells: should be set to 1. This property follows the
-			 thermal device tree bindings[3].
-
-			 Valid cell values are raw identifiers (Sensor ID)
-			 as used by the firmware. Refer to  platform details
-			 for your implementation for the IDs to use.
-
-Reset signal bindings for the reset domains based on SCMI Message Protocol
-------------------------------------------------------------
-
-This binding for the SCMI reset domain providers uses the generic reset
-signal binding[5].
-
-Required properties:
- - #reset-cells : Should be 1. Contains the reset domain ID value used
-		  by SCMI commands.
-
-[0] http://infocenter.arm.com/help/topic/com.arm.doc.den0056a/index.html
-[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
-[2] Documentation/devicetree/bindings/power/power-domain.yaml
-[3] Documentation/devicetree/bindings/thermal/thermal*.yaml
-[4] Documentation/devicetree/bindings/sram/sram.yaml
-[5] Documentation/devicetree/bindings/reset/reset.txt
-[6] Documentation/devicetree/bindings/regulator/regulator.yaml
-
-Example:
-
-sram@50000000 {
-	compatible = "mmio-sram";
-	reg = <0x0 0x50000000 0x0 0x10000>;
-
-	#address-cells = <1>;
-	#size-cells = <1>;
-	ranges = <0 0x0 0x50000000 0x10000>;
-
-	cpu_scp_lpri: scp-shmem@0 {
-		compatible = "arm,scmi-shmem";
-		reg = <0x0 0x200>;
-	};
-
-	cpu_scp_hpri: scp-shmem@200 {
-		compatible = "arm,scmi-shmem";
-		reg = <0x200 0x200>;
-	};
-};
-
-mailbox@40000000 {
-	....
-	#mbox-cells = <1>;
-	reg = <0x0 0x40000000 0x0 0x10000>;
-};
-
-firmware {
-
-	...
-
-	scmi {
-		compatible = "arm,scmi";
-		mboxes = <&mailbox 0 &mailbox 1>;
-		mbox-names = "tx", "rx";
-		shmem = <&cpu_scp_lpri &cpu_scp_hpri>;
-		#address-cells = <1>;
-		#size-cells = <0>;
-
-		scmi_devpd: protocol@11 {
-			reg = <0x11>;
-			#power-domain-cells = <1>;
-		};
-
-		scmi_dvfs: protocol@13 {
-			reg = <0x13>;
-			#clock-cells = <1>;
-		};
-
-		scmi_clk: protocol@14 {
-			reg = <0x14>;
-			#clock-cells = <1>;
-		};
-
-		scmi_sensors0: protocol@15 {
-			reg = <0x15>;
-			#thermal-sensor-cells = <1>;
-		};
-
-		scmi_reset: protocol@16 {
-			reg = <0x16>;
-			#reset-cells = <1>;
-		};
-
-		scmi_voltage: protocol@17 {
-			reg = <0x17>;
-
-			regulators {
-				regulator_devX: regulator@0 {
-					reg = <0x0>;
-					regulator-max-microvolt = <3300000>;
-				};
-
-				regulator_devY: regulator@9 {
-					reg = <0x9>;
-					regulator-min-microvolt = <500000>;
-					regulator-max-microvolt = <4200000>;
-				};
-
-				...
-			};
-		};
-	};
-};
-
-cpu@0 {
-	...
-	reg = <0 0>;
-	clocks = <&scmi_dvfs 0>;
-};
-
-hdlcd@7ff60000 {
-	...
-	reg = <0 0x7ff60000 0 0x1000>;
-	clocks = <&scmi_clk 4>;
-	power-domains = <&scmi_devpd 1>;
-	resets = <&scmi_reset 10>;
-};
-
-thermal-zones {
-	soc_thermal {
-		polling-delay-passive = <100>;
-		polling-delay = <1000>;
-					/* sensor ID */
-		thermal-sensors = <&scmi_sensors0 3>;
-		...
-	};
-};

Documentation/devicetree/bindings/firmware/arm,scmi.yaml

···
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright 2021 ARM Ltd.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/firmware/arm,scmi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: System Control and Management Interface (SCMI) Message Protocol bindings
+
+maintainers:
+  - Sudeep Holla <[e-mail]>
+
+description: |
+  The SCMI is intended to allow agents such as OSPM to manage various functions
+  that are provided by the hardware platform it is running on, including power
+  and performance functions.
+
+  This binding is intended to define the interface the firmware implementing
+  the SCMI as described in ARM document number ARM DEN 0056 ("ARM System Control
+  and Management Interface Platform Design Document")[0] provide for OSPM in
+  the device tree.
+
+  [0] https://developer.arm.com/documentation/den0056/latest
+
+properties:
+  $nodename:
+    const: scmi
+
+  compatible:
+    oneOf:
+      - description: SCMI compliant firmware with mailbox transport
+        items:
+          - const: arm,scmi
+      - description: SCMI compliant firmware with ARM SMC/HVC transport
+        items:
+          - const: arm,scmi-smc
+
+  interrupts:
+    description:
+      The interrupt that indicates message completion by the platform
+      rather than by the return of the smc call. This should not be used
+      except when the platform requires such behavior.
+    maxItems: 1
+
+  interrupt-names:
+    const: a2p
+
+  mbox-names:
+    description:
+      Specifies the mailboxes used to communicate with SCMI compliant
+      firmware.
+    items:
+      - const: tx
+      - const: rx
+
+  mboxes:
+    description:
+      List of phandle and mailbox channel specifiers. It should contain
+      exactly one or two mailboxes, one for transmitting messages("tx")
+      and another optional for receiving the notifications("rx") if supported.
+    minItems: 1
+    maxItems: 2
+
+  shmem:
+    description:
+      List of phandle pointing to the shared memory(SHM) area, for each
+      transport channel specified.
+    minItems: 1
+    maxItems: 2
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+  arm,smc-id:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      SMC id required when using smc or hvc transports
+
+  protocol@11:
+    type: object
+    properties:
+      reg:
+        const: 0x11
+
+      '#power-domain-cells':
+        const: 1
+
+    required:
+      - '#power-domain-cells'
+
+  protocol@13:
+    type: object
+    properties:
+      reg:
+        const: 0x13
+
+      '#clock-cells':
+        const: 1
+
+    required:
+      - '#clock-cells'
+
+  protocol@14:
+    type: object
+    properties:
+      reg:
+        const: 0x14
+
+      '#clock-cells':
+        const: 1
+
+    required:
+      - '#clock-cells'
+
+  protocol@15:
+    type: object
+    properties:
+      reg:
+        const: 0x15
+
+      '#thermal-sensor-cells':
+        const: 1
+
+    required:
+      - '#thermal-sensor-cells'
+
+  protocol@16:
+    type: object
+    properties:
+      reg:
+        const: 0x16
+
+      '#reset-cells':
+        const: 1
+
+    required:
+      - '#reset-cells'
+
+  protocol@17:
+    type: object
+    properties:
+      reg:
+        const: 0x17
+
+      regulators:
+        type: object
+        description:
+          The list of all regulators provided by this SCMI controller.
+
+        patternProperties:
+          '^regulators@[0-9a-f]+$':
+            type: object
+            $ref: "../regulator/regulator.yaml#"
+
+            properties:
+              reg:
+                maxItems: 1
+                description: Identifier for the voltage regulator.
+
+            required:
+              - reg
+
+additionalProperties: false
+
+patternProperties:
+  '^protocol@[0-9a-f]+$':
+    type: object
+    description:
+      Each sub-node represents a protocol supported. If the platform
+      supports a dedicated communication channel for a particular protocol,
+      then the corresponding transport properties must be present.
+
+    properties:
+      reg:
+        maxItems: 1
+
+      mbox-names:
+        items:
+          - const: tx
+          - const: rx
+
+      mboxes:
+        minItems: 1
+        maxItems: 2
+
+      shmem:
+        minItems: 1
+        maxItems: 2
+
+    required:
+      - reg
+
+required:
+  - compatible
+  - shmem
+
+if:
+  properties:
+    compatible:
+      contains:
+        const: arm,scmi
+then:
+  properties:
+    interrupts: false
+    interrupt-names: false
+
+  required:
+    - mboxes
+
+else:
+  if:
+    properties:
+      compatible:
+        contains:
+          const: arm,scmi-smc
+  then:
+    required:
+      - arm,smc-id
+
+examples:
+  - |
+    firmware {
+        scmi {
+            compatible = "arm,scmi";
+            mboxes = <&mhuB 0 0>,
+                     <&mhuB 0 1>;
+            mbox-names = "tx", "rx";
+            shmem = <&cpu_scp_lpri0>,
+                    <&cpu_scp_lpri1>;
+
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            scmi_devpd: protocol@11 {
+                reg = <0x11>;
+                #power-domain-cells = <1>;
+            };
+
+            scmi_dvfs: protocol@13 {
+                reg = <0x13>;
+                #clock-cells = <1>;
+
+                mboxes = <&mhuB 1 0>,
+                         <&mhuB 1 1>;
+                mbox-names = "tx", "rx";
+                shmem = <&cpu_scp_hpri0>,
+                        <&cpu_scp_hpri1>;
+            };
+
+            scmi_clk: protocol@14 {
+                reg = <0x14>;
+                #clock-cells = <1>;
+            };
+
+            scmi_sensors: protocol@15 {
+                reg = <0x15>;
+                #thermal-sensor-cells = <1>;
+            };
+
+            scmi_reset: protocol@16 {
+                reg = <0x16>;
+                #reset-cells = <1>;
+            };
+
+            scmi_voltage: protocol@17 {
+                reg = <0x17>;
+                regulators {
+                    #address-cells = <1>;
+                    #size-cells = <0>;
+
+                    regulator_devX: regulator@0 {
+                        reg = <0x0>;
+                        regulator-max-microvolt = <3300000>;
+                    };
+
+                    regulator_devY: regulator@9 {
+                        reg = <0x9>;
+                        regulator-min-microvolt = <500000>;
+                        regulator-max-microvolt = <4200000>;
+                    };
+                };
+            };
+        };
+    };
+
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        sram@50000000 {
+            compatible = "mmio-sram";
+            reg = <0x0 0x50000000 0x0 0x10000>;
+
+            #address-cells = <1>;
+            #size-cells = <1>;
+            ranges = <0 0x0 0x50000000 0x10000>;
+
+            cpu_scp_lpri0: scp-sram-section@0 {
+                compatible = "arm,scmi-shmem";
+                reg = <0x0 0x80>;
+            };
+
+            cpu_scp_lpri1: scp-sram-section@80 {
+                compatible = "arm,scmi-shmem";
+                reg = <0x80 0x80>;
+            };
+
+            cpu_scp_hpri0: scp-sram-section@100 {
+                compatible = "arm,scmi-shmem";
+                reg = <0x100 0x80>;
+            };
+
+            cpu_scp_hpri2: scp-sram-section@180 {
+                compatible = "arm,scmi-shmem";
+                reg = <0x180 0x80>;
+            };
+        };
+    };
+
+  - |
+    firmware {
+        scmi {
+            compatible = "arm,scmi-smc";
+            shmem = <&cpu_scp_lpri0 &cpu_scp_lpri1>;
+            arm,smc-id = <0xc3000001>;
+
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            scmi_devpd1: protocol@11 {
+                reg = <0x11>;
+                #power-domain-cells = <1>;
+            };
+
+        };
+    };
+
+...