[PATCH v2 6/8] dt-bindings: firmware: arm,scpi: Convert to json schema
Sudeep Holla
sudeep.holla at arm.com
Wed Jun 2 09:05:57 PDT 2021
On Wed, Jun 02, 2021 at 10:58:00AM -0500, Rob Herring wrote:
> On Tue, Jun 01, 2021 at 11:49:02PM +0100, Sudeep Holla wrote:
> > Convert the old text format binding for System Control and Power Interface
> > (SCPI) Message Protocol into the new and shiny YAML format.
> >
> > Cc: Rob Herring <robh+dt at kernel.org>
> > Cc: Kevin Hilman <khilman at baylibre.com>
> > Cc: Neil Armstrong <narmstrong at baylibre.com>
> > Cc: Jerome Brunet <jbrunet at baylibre.com>
> > Cc: Viresh Kumar <viresh.kumar at linaro.org
> > Signed-off-by: Sudeep Holla <sudeep.holla at arm.com>
> > ---
> > .../devicetree/bindings/arm/arm,scpi.txt | 204 -------------
> > .../bindings/firmware/arm,scpi.yaml | 285 ++++++++++++++++++
> > MAINTAINERS | 2 +-
> > 3 files changed, 286 insertions(+), 205 deletions(-)
> > delete mode 100644 Documentation/devicetree/bindings/arm/arm,scpi.txt
> > create mode 100644 Documentation/devicetree/bindings/firmware/arm,scpi.yaml
>
> [...]
>
> > diff --git a/Documentation/devicetree/bindings/firmware/arm,scpi.yaml b/Documentation/devicetree/bindings/firmware/arm,scpi.yaml
> > new file mode 100644
> > index 000000000000..b44a5a7040fc
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/firmware/arm,scpi.yaml
> > @@ -0,0 +1,285 @@
> > +# 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 at 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:
> > + $nodename:
> > + const: scpi
> > +
> > + compatible:
> > + description: |
> > + SCPI compliant firmware complying to SCPI v1.0 and above OR
> > + SCPI compliant firmware complying to all unversioned releases
> > + prior to SCPI v1.0
> > + oneOf:
> > + - const: arm,scpi # SCPI v1.0 and above
> > + - const: arm,scpi-pre-1.0 # Unversioned SCPI before v1.0
> > +
> > + mboxes:
> > + description: |
> > + List of phandle and mailbox channel specifiers. All the channels reserved
> > + by remote SCP firmware for use by SCPI message protocol should be
> > + specified in any order.
> > + minItems: 1
> > +
> > + shmem:
> > + description: |
> > + List of phandle pointing to the shared memory(SHM) area between the
> > + processors using these mailboxes for IPC, one for each mailbox SHM can
> > + be any memory reserved for the purpose of this communication between the
> > + processors.
> > + minItems: 1
> > +
> > +additionalProperties:
> > + type: object
> > +
> > +patternProperties:
> > + "^(sensors|power-domains)(-[0-9a-f]+)?$":
>
> AFAICT, we only ever have 1 sensor and 1 power-domains node, so we don't
> need the numbering.
>
Right, I initially had clock too there and didn't notice the above 2 doesn't
need the numbering, will drop it.
> Also, these should each be their own entry rather that having the
> if/then schema mess below. You need an 'additionalProperties: false' in
> here too.
>
OK that sounds cleaner.
> > + type: object
> > + description: |
> > + Each sub-node represents one of the controller - power domains or sensors.
> > +
> > + properties:
> > + compatible:
> > + oneOf:
> > + - const: arm,scpi-sensors
> > + - const: arm,scpi-power-domains
> > +
> > + "^clocks(-[0-9a-f]+)?$":
> > + type: object
> > + description: |
> > + "arm,scpi-clocks" - This is the container node. Each 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-clocks
> > + - const: arm,scpi-dvfs-clocks
> > + - const: arm,scpi-variable-clocks
>
> This doesn't make sense. The first one is the parent node and the last 2
> are child nodes under it. The child nodes need to be defined in yet
> another level.
>
Agreed, I did that for SCMI regulators, will follow that here too.
> > +
> > +required:
> > + - compatible
> > + - mboxes
> > + - shmem
> > +
> > +allOf:
> > + - if:
> > + properties:
> > + compatible:
> > + contains:
> > + const: arm,scpi-sensors
> > + then:
> > + properties:
> > + '#thermal-sensor-cells':
> > + const: 1
> > +
> > + required:
> > + - '#thermal-sensor-cells'
> > +
> > + - if:
> > + properties:
> > + compatible:
> > + contains:
> > + const: arm,scpi-power-domains
> > + then:
> > + properties:
> > + '#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:
> > + - '#power-domain-cells'
> > + - num-domains
> > +
> > + - if:
> > + properties:
> > + compatible:
> > + contains:
> > + enum:
> > + - arm,scpi-dvfs-clocks
> > + - arm,scpi-variable-clocks
>
> This would never be true unless you removed the container 'clocks' node.
>
Understood. I should have tested removing properties in the example like
I did for SCMI. I must have show less interest for SCPI as it is old and
almost deprecated 😁. I will fix it.
--
Regards,
Sudeep
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