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

System Control and Power Interface (SCPI) Message Protocol

----------------------------------------------------------

Firmware implementing the SCPI described in ARM document number ARM DUI 0922B

("ARM Compute Subsystem SCP: Message Interface Protocols")[0] can be used

by Linux to initiate various system control and power operations.

Required properties:

- compatible : should be

	* "arm,scpi" : For implementations complying to SCPI v1.0 or above

	* "arm,scpi-pre-1.0" : For implementations complying to all

		unversioned releases prior to SCPI v1.0

- mboxes: List of phandle and mailbox channel specifiers

	  All the channels reserved by remote SCP firmware for use by

	  SCPI message protocol should be specified in any order

- shmem : List of phandle pointing to the shared memory(SHM) area between the

	  processors using these mailboxes for IPC, one for each mailbox

	  SHM can be any memory reserved for the purpose of this communication

	  between the processors.

See Documentation/devicetree/bindings/mailbox/mailbox.txt

for more details about the generic mailbox controller and

client driver bindings.

Clock bindings for the clocks based on SCPI Message Protocol

------------------------------------------------------------

This binding uses the common clock binding[1].

Container Node

==============

Required properties:

- compatible : should be "arm,scpi-clocks"

	       All the clocks provided by SCP firmware via SCPI message

	       protocol much be listed as sub-nodes under this node.

Sub-nodes

=========

Required properties:

- compatible : shall include one of the following

	"arm,scpi-dvfs-clocks" - all the clocks that are variable and index based.

		These clocks don't provide an entire range of values between the

		limits but only discrete points within the range. The firmware

		provides the mapping for each such operating frequency and the

		index associated with it. The firmware also manages the

		voltage scaling appropriately with the clock scaling.

	"arm,scpi-variable-clocks" - all the clocks that are variable and provide full

		range within the specified range. The firmware provides the

		range of values within a specified range.

Other required properties for all clocks(all from common clock binding):

- #clock-cells : Should be 1. Contains the Clock ID value used by SCPI commands.

- clock-output-names : shall be the corresponding names of the outputs.

- clock-indices: The identifying number for the clocks(i.e.clock_id) in the

	node. It can be non linear and hence provide the mapping of identifiers

	into the clock-output-names array.

Sensor bindings for the sensors based on SCPI Message Protocol

--------------------------------------------------------------

SCPI provides an API to access the various sensors on the SoC.

Required properties:

- compatible : should be "arm,scpi-sensors".

- #thermal-sensor-cells: should be set to 1. This property follows the

			 thermal device tree bindings[2].

			 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.

Power domain bindings for the power domains based on SCPI Message Protocol

------------------------------------------------------------

This binding uses the generic power domain binding[4].

PM domain providers

===================

Required properties:

 - #power-domain-cells : Should be 1. Contains the device or the power

			 domain ID value used by SCPI commands.

 - num-domains: Total number of power domains provided by SCPI. This is

		needed as the SCPI message protocol lacks a mechanism to

		query this information at runtime.

PM domain consumers

===================

Required properties:

 - power-domains : A phandle and PM domain specifier as defined by bindings of

                   the power controller specified by phandle.

[0] http://infocenter.arm.com/help/topic/com.arm.doc.dui0922b/index.html

[1] Documentation/devicetree/bindings/clock/clock-bindings.txt

[2] Documentation/devicetree/bindings/thermal/thermal*.yaml

[3] Documentation/devicetree/bindings/sram/sram.yaml

[4] Documentation/devicetree/bindings/power/power-domain.yaml

Example:

sram: sram@50000000 {

	compatible = "arm,juno-sram-ns", "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,juno-scp-shmem";

		reg = <0x0 0x200>;

	};

	cpu_scp_hpri: scp-shmem@200 {

		compatible = "arm,juno-scp-shmem";

		reg = <0x200 0x200>;

	};

};

mailbox: mailbox0@40000000 {

	....

	#mbox-cells = <1>;

};

scpi_protocol: scpi@2e000000 {

	compatible = "arm,scpi";

	mboxes = <&mailbox 0 &mailbox 1>;

	shmem = <&cpu_scp_lpri &cpu_scp_hpri>;

	clocks {

		compatible = "arm,scpi-clocks";

		scpi_dvfs: scpi_clocks@0 {

			compatible = "arm,scpi-dvfs-clocks";

			#clock-cells = <1>;

			clock-indices = <0>, <1>, <2>;

			clock-output-names = "atlclk", "aplclk","gpuclk";

		};

		scpi_clk: scpi_clocks@3 {

			compatible = "arm,scpi-variable-clocks";

			#clock-cells = <1>;

			clock-indices = <3>, <4>;

			clock-output-names = "pxlclk0", "pxlclk1";

		};

	};

	scpi_sensors0: sensors {

		compatible = "arm,scpi-sensors";

		#thermal-sensor-cells = <1>;

	};

	scpi_devpd: scpi-power-domains {

		compatible = "arm,scpi-power-domains";

		num-domains = <2>;

		#power-domain-cells = <1>;

	};

};

cpu@0 {

	...

	reg = <0 0>;

	clocks = <&scpi_dvfs 0>;

};

hdlcd@7ff60000 {

	...

	reg = <0 0x7ff60000 0 0x1000>;

	clocks = <&scpi_clk 4>;

	power-domains = <&scpi_devpd 1>;

};

thermal-zones {

	soc_thermal {

		polling-delay-passive = <100>;

		polling-delay = <1000>;

				/* sensor         ID */

		thermal-sensors = <&scpi_sensors0 3>;

		...

	};

};

In the above example, the #clock-cells is set to 1 as required.

scpi_dvfs has 3 output clocks namely: atlclk, aplclk, and gpuclk with 0,

1 and 2 as clock-indices. scpi_clk has 2 output clocks namely: pxlclk0

and pxlclk1 with 3 and 4 as clock-indices.

The first consumer in the example is cpu@0 and it has '0' as the clock

specifier which points to the first entry in the output clocks of

scpi_dvfs i.e. "atlclk".

Similarly the second example is hdlcd@7ff60000 and it has pxlclk1 as input

clock. '4' in the clock specifier here points to the second entry

in the output clocks of scpi_clocks  i.e. "pxlclk1"

The thermal-sensors property in the soc_thermal node uses the

temperature sensor provided by SCP firmware to setup a thermal

zone. The ID "3" is the sensor identifier for the temperature sensor

as used by the firmware.

The num-domains property in scpi-power-domains domain specifies that

SCPI provides 2 power domains. The hdlcd node uses the power domain with

domain ID 1.

# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)

# Copyright 2021 ARM Ltd.

%YAML 1.2

---

$id: http://devicetree.org/schemas/firmware/arm,scpi.yaml#

$schema: http://devicetree.org/meta-schemas/core.yaml#

title: System Control and Power Interface (SCPI) Message Protocol bindings

maintainers:

  - Sudeep Holla <sudeep.holla@arm.com>

description: |

  Firmware implementing the SCPI described in ARM document number ARM DUI

  0922B ("ARM Compute Subsystem SCP: Message Interface Protocols")[0] can be

  used by Linux to initiate various system control and power operations.

  This binding is intended to define the interface the firmware implementing

  the SCPI provide for OSPM in the device tree.

  [0] http://infocenter.arm.com/help/topic/com.arm.doc.dui0922b/index.html

properties:

  $nodename:

    const: scpi

  compatible:

    description:

      SCPI compliant firmware complying to SCPI v1.0 and above OR

      SCPI compliant firmware complying to all unversioned releases

      prior to SCPI v1.0

    oneOf:

      - const: arm,scpi               # SCPI v1.0 and above

      - const: arm,scpi-pre-1.0       # Unversioned SCPI before v1.0

  mboxes:

    description:

      List of phandle and mailbox channel specifiers. All the channels reserved

      by remote SCP firmware for use by SCPI message protocol should be

      specified in any order.

    minItems: 1

  shmem:

    description:

      List of phandle pointing to the shared memory(SHM) area between the

      processors using these mailboxes for IPC, one for each mailbox SHM can

      be any memory reserved for the purpose of this communication between the

      processors.

    minItems: 1

  power-controller:

    type: object

    description:

      This sub-node represents SCPI power domain controller.

    properties:

      compatible:

        const: arm,scpi-power-domains

      '#power-domain-cells':

        const: 1

      num-domains:

        $ref: /schemas/types.yaml#/definitions/uint32

        description:

          Total number of power domains provided by SCPI. This is needed as

          the SCPI message protocol lacks a mechanism to query this

          information at runtime.

    required:

      - compatible

      - '#power-domain-cells'

      - num-domains

    additionalProperties: false

  sensors:

    type: object

    description: |

      This sub-node represents SCPI sensors controller.

    properties:

      compatible:

        const: arm,scpi-sensors

      '#thermal-sensor-cells':

        const: 1

    required:

      - compatible

      - '#thermal-sensor-cells'

    additionalProperties: false

  clocks:

    type: object

    description:

      This is the container node. Each sub-node represents one of the types

      of clock controller - indexed or full range.

    properties:

      compatible:

        const: arm,scpi-clocks

    patternProperties:

      "^clocks-[0-9a-f]+$":

        type: object

        description: |

          This sub-node represents one of the types of clock controller

          - indexed or full range.

          "arm,scpi-dvfs-clocks" - all the clocks that are variable and index

          based. These clocks don't provide an entire range of values between

          the limits but only discrete points within the range. The firmware

          provides the mapping for each such operating frequency and the index

          associated with it. The firmware also manages the voltage scaling

          appropriately with the clock scaling.

          "arm,scpi-variable-clocks" - all the clocks that are variable and

          provide full range within the specified range. The firmware provides

          the range of values within a specified range.

        properties:

          compatible:

            oneOf:

              - const: arm,scpi-dvfs-clocks

              - const: arm,scpi-variable-clocks

          '#clock-cells':

            const: 1

          clock-output-names: true

          clock-indices:

            $ref: /schemas/types.yaml#/definitions/uint32-array

            description:

              The identifying number for the clocks(i.e.clock_id) in the node.

              It can be non linear and hence provide the mapping of identifiers

              into the clock-output-names array.

        required:

          - compatible

          - '#clock-cells'

          - clock-output-names

          - clock-indices

        additionalProperties: false

    required:

      - compatible

    additionalProperties: false

additionalProperties: false

required:

  - compatible

  - mboxes

  - shmem

examples:

  - |

    firmware {

        scpi {

            compatible = "arm,scpi";

            mboxes = <&mhuA 1>;

            shmem = <&cpu_scp_hpri>; /* HP-NonSecure */

            scpi_devpd: power-controller {

                compatible = "arm,scpi-power-domains";

                num-domains = <2>;

                #power-domain-cells = <1>;

            };

            clocks {

                compatible = "arm,scpi-clocks";

                scpi_dvfs: clocks-0 {

                    compatible = "arm,scpi-dvfs-clocks";

                    #clock-cells = <1>;

                    clock-indices = <0>, <1>, <2>;

                    clock-output-names = "atlclk", "aplclk","gpuclk";

                };

                scpi_clk: clocks-1 {

                    compatible = "arm,scpi-variable-clocks";

                    #clock-cells = <1>;

                    clock-indices = <3>, <4>;

                    clock-output-names = "pxlclk0", "pxlclk1";

                };

            };

            scpi_sensors: sensors {

                compatible = "arm,scpi-sensors";

                #thermal-sensor-cells = <1>;

            };

        };

    };

    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_lpri: scp-sram-section@0 {

                compatible = "arm,scp-shmem";

                reg = <0x0 0x200>;

            };

            cpu_scp_hpri: scp-sram-section@200 {

                compatible = "arm,scp-shmem";

                reg = <0x200 0x200>;

            };

        };

    };

...

R:	Cristian Marussi <cristian.marussi@arm.com>

L:	linux-arm-kernel@lists.infradead.org

S:	Maintained

F:	Documentation/devicetree/bindings/arm/arm,sc[mp]i.txt

F:	Documentation/devicetree/bindings/firmware/arm,sc[mp]i.yaml

F:	drivers/clk/clk-sc[mp]i.c

F:	drivers/cpufreq/sc[mp]i-cpufreq.c

F:	drivers/firmware/arm_scmi/