Re: [PATCH v3 02/23] dt-bindings: ata: ahci-platform: Detach common AHCI bindings

Rob Herring
2022-05-17T19:11:45Z

On Thu, May 12, 2022 at 02:17:49AM +0300, Serge Semin wrote:
> In order to create a more sophisticated AHCI controller DT bindings let's
> divide the already available generic AHCI platform YAML schema into the
> platform part and a set of the common AHCI properties. The former part
> will be used to evaluate the AHCI DT nodes mainly compatible with the
> generic AHCI controller while the later schema will be used for more
> thorough AHCI DT nodes description. For instance such YAML schemas design
> will be useful for our DW AHCI SATA controller derivative with four clock
> sources, two reset lines, one system controller reference and specific
> max Rx/Tx DMA xfers size constraints.
>
> Note the phys and target-supply property requirement is preserved in the
> generic AHCI platform bindings because some platforms can lack of the
> explicitly specified PHYs or target device power regulators.
>
> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
>
> ---
>
> Folks, I don't really see why the phys/target-supply requirement has been
> added to the generic AHCI DT schema in the first place. Probably just to
> imply some meaning for the sub-nodes definition. Anyway in one of the
> further patches I am adding the DW AHCI SATA controller DT bindings which
> won't require having these properties specified in the sub-nodes, but will
> describe additional port-specific properties. That's why I get to keep the
> constraints in the ahci-platform.yaml schema instead of moving them to the
> common schema.
>
> Changelog v2:
> - This is a new patch created after rebasing v1 onto the 5.18-rc3 kernel.
>
> Changelog v3:
> - Replace Jens's email address with Damien's one in the list of the
> schema maintainers. (@Damien)
> ---
> .../devicetree/bindings/ata/ahci-common.yaml | 117 ++++++++++++++++++
> .../bindings/ata/ahci-platform.yaml | 68 +---------
> 2 files changed, 123 insertions(+), 62 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/ata/ahci-common.yaml
>
> diff --git a/Documentation/devicetree/bindings/ata/ahci-common.yaml b/Documentation/devicetree/bindings/ata/ahci-common.yaml
> new file mode 100644
> index 000000000000..620042ca12e7
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/ata/ahci-common.yaml
> @@ -0,0 +1,117 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/ata/ahci-common.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Common Properties for Serial ATA AHCI controllers
> +
> +maintainers:
> + - Hans de Goede <hdegoede@redhat.com>
> + - Damien Le Moal <damien.lemoal@opensource.wdc.com>
> +
> +description:
> + This document defines device tree properties for a common AHCI SATA
> + controller implementation. It's hardware interface is supposed to
> + conform to the technical standard defined by Intel (see Serial ATA
> + Advanced Host Controller Interface specification for details). The
> + document doesn't constitute a DT-node binding by itself but merely
> + defines a set of common properties for the AHCI-compatible devices.
> +
> +select: false
> +
> +allOf:
> + - $ref: sata-common.yaml#
> +
> +properties:
> + reg:
> + description:
> + Generic AHCI registers space conforming to the Serial ATA AHCI
> + specification.
> +
> + reg-names:
> + description: CSR space IDs
> +
> + interrupts:
> + description:
> + Generic AHCI state change interrupt. Can be implemented either as a
> + single line attached to the controller as a set of the dedicated signals
> + for the global and particular port events.
> +
> + clocks:
> + description:
> + List of all the reference clocks connected to the controller.
> +
> + clock-names:
> + description: Reference clocks IDs
> +
> + resets:
> + description:
> + List of the reset control lines to reset the controller clock
> + domains.
> +
> + reset-names:
> + description: Reset line IDs
> +
> + power-domains:
> + description:
> + List of the power domain the AHCI controller being a part of.

There's not really any point in listing all the above properties here,
because they all have to be listed in the device specific schemas.

> +
> + ahci-supply:
> + description: Power regulator for AHCI controller
> +
> + target-supply:
> + description: Power regulator for SATA target device
> +
> + phy-supply:
> + description: Power regulator for SATA PHY
> +
> + phys:
> + description: Reference to the SATA PHY node
> + maxItems: 1
> +
> + phy-names:
> + maxItems: 1
> +
> + ports-implemented:
> + $ref: '/schemas/types.yaml#/definitions/uint32'
> + description:
> + Mask that indicates which ports the HBA supports. Useful if PI is not
> + programmed by the BIOS, which is true for some embedded SoC's.
> + maximum: 0x1f

The AHCI spec says there's a max of 32 ports, not 5.

https://www.intel.com/content/dam/www/public/us/en/documents/technical-specifications/serial-ata-ahci-spec-rev1-3-1.pdf

> +
> +patternProperties:
> + "^sata-port@[0-9a-f]+$":
> + type: object
> + description:
> + It is optionally possible to describe the ports as sub-nodes so
> + to enable each port independently when dealing with multiple PHYs.
> +
> + properties:
> + reg:
> + description: AHCI SATA port identifier
> + maxItems: 1
> +
> + phys:
> + description: Individual AHCI SATA port PHY
> + maxItems: 1
> +
> + phy-names:
> + description: AHCI SATA port PHY ID
> + maxItems: 1
> +
> + target-supply:
> + description: Power regulator for SATA port target device
> +
> + required:
> + - reg
> +
> + additionalProperties: true

If device specific bindings can add their own properties (as this
allows), then all the common sata-port properties needs to be its own
schema document. That way the device binding can reference it, define
extra properties and set 'unevaluatedProperties: false'.

If other properties aren't allowed, then you can just change this to
false. That's what we had before this change.

> +
> +required:
> + - reg
> + - interrupts
> +
> +additionalProperties: true
> +
> +...
> diff --git a/Documentation/devicetree/bindings/ata/ahci-platform.yaml b/Documentation/devicetree/bindings/ata/ahci-platform.yaml
> index 9304e4731965..76075d3c8987 100644
> --- a/Documentation/devicetree/bindings/ata/ahci-platform.yaml
> +++ b/Documentation/devicetree/bindings/ata/ahci-platform.yaml
> @@ -36,8 +36,7 @@ select:
> - compatible
>
> allOf:
> - - $ref: "sata-common.yaml#"
> -
> + - $ref: "ahci-common.yaml#"
>
> properties:
> compatible:
> @@ -69,90 +68,35 @@ properties:
> maxItems: 1
>
> clocks:
> - description:
> - Clock IDs array as required by the controller.
> minItems: 1
> maxItems: 3
>
> clock-names:
> - description:
> - Names of clocks corresponding to IDs in the clock property.
> minItems: 1
> maxItems: 3
>
> interrupts:
> maxItems: 1
>
> - ahci-supply:
> - description:
> - regulator for AHCI controller
> -
> - phy-supply:
> - description:
> - regulator for PHY power
> -
> - phys:
> - description:
> - List of all PHYs on this controller
> - maxItems: 1
> -
> - phy-names:
> - description:
> - Name specifier for the PHYs
> - maxItems: 1
> -
> - ports-implemented:
> - $ref: '/schemas/types.yaml#/definitions/uint32'
> - description: |
> - Mask that indicates which ports that the HBA supports
> - are available for software to use. Useful if PORTS_IMPL
> - is not programmed by the BIOS, which is true with
> - some embedded SoCs.
> - maximum: 0x1f
> -
> power-domains:
> maxItems: 1
>
> resets:
> maxItems: 1
>
> - target-supply:
> - description:
> - regulator for SATA target power
> -
> -required:
> - - compatible
> - - reg
> - - interrupts
> -
> patternProperties:
> "^sata-port@[0-9a-f]+$":
> type: object
> - additionalProperties: false
> - description:
> - Subnode with configuration of the Ports.
> -
> - properties:
> - reg:
> - maxItems: 1
> -
> - phys:
> - maxItems: 1
> -
> - phy-names:
> - maxItems: 1
> -
> - target-supply:
> - description:
> - regulator for SATA target power
> -
> - required:
> - - reg
>
> anyOf:
> - required: [ phys ]
> - required: [ target-supply ]
>
> +required:
> + - compatible
> + - reg
> + - interrupts
> +
> unevaluatedProperties: false
>
> examples:
> --
> 2.35.1
>
>