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Date:   Tue, 17 May 2022 13:31:54 -0500
From:   Rob Herring <robh@kernel.org>
To:     Chia-Wei Wang <chiawei_wang@aspeedtech.com>
Cc:     joel@jms.id.au, andrew@aj.id.au, jk@codeconstruct.com.au,
        a.kartashev@yadro.com, patrick.rudolph@9elements.com,
        dphadke@linux.microsoft.com, linux-aspeed@lists.ozlabs.org,
        openbmc@lists.ozlabs.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        ryan_chen@aspeedtech.com
Subject: Re: [PATCH v5 1/4] dt-bindings: aspeed: Add eSPI controller
Message-ID: <20220517183154.GA1352926-robh@kernel.org>
References: <20220516005412.4844-1-chiawei_wang@aspeedtech.com>
 <20220516005412.4844-2-chiawei_wang@aspeedtech.com>
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On Mon, May 16, 2022 at 08:54:09AM +0800, Chia-Wei Wang wrote:
> Add dt-bindings for Aspeed eSPI controller
> 
> Signed-off-by: Chia-Wei Wang <chiawei_wang@aspeedtech.com>
> ---
>  .../devicetree/bindings/soc/aspeed/espi.yaml  | 162 ++++++++++++++++++

bindings/spi/ includes SPI slaves. Is there a reason this doesn't fit 
there?

>  1 file changed, 162 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/soc/aspeed/espi.yaml
> 
> diff --git a/Documentation/devicetree/bindings/soc/aspeed/espi.yaml b/Documentation/devicetree/bindings/soc/aspeed/espi.yaml
> new file mode 100644
> index 000000000000..aa91ec8caf6a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/soc/aspeed/espi.yaml
> @@ -0,0 +1,162 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +# # Copyright (c) 2021 Aspeed Technology Inc.
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/soc/aspeed/espi.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: Aspeed eSPI Controller
> +
> +maintainers:
> +  - Chia-Wei Wang <chiawei_wang@aspeedtech.com>
> +  - Ryan Chen <ryan_chen@aspeedtech.com>
> +
> +description:
> +  Aspeed eSPI controller implements a slave side eSPI endpoint device
> +  supporting the four eSPI channels, namely peripheral, virtual wire,
> +  out-of-band, and flash.
> +
> +properties:
> +  compatible:
> +    items:
> +      - enum:
> +          - aspeed,ast2500-espi
> +          - aspeed,ast2600-espi
> +      - const: simple-mfd
> +      - const: syscon
> +
> +  reg:
> +    maxItems: 1
> +
> +  "#address-cells":
> +    const: 1
> +
> +  "#size-cells":
> +    const: 1
> +
> +  ranges: true
> +
> +patternProperties:
> +  "^espi-ctrl@[0-9a-f]+$":
> +    type: object
> +
> +    description: Control of the four basic eSPI channels
> +
> +    properties:
> +      compatible:
> +        items:
> +          - enum:
> +              - aspeed,ast2500-espi-ctrl
> +              - aspeed,ast2600-espi-ctrl
> +
> +      interrupts:
> +        maxItems: 1
> +
> +      clocks:
> +        maxItems: 1
> +
> +      perif,memcyc-enable:

What vendor is 'perif'?

> +        type: boolean
> +        description: Enable memory cycle over eSPI peripheral channel
> +
> +      perif,memcyc-src-addr:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description: The Host side address to be decoded into the memory cycle over eSPI peripheral channel
> +
> +      perif,memcyc-size:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description: The size of the memory region allocated for the memory cycle over eSPI peripheral channel
> +        minimum: 65536

This region is defined by the h/w or just some carveout of system 
memory? In the former, perhaps this should be part of 'reg'. In the 
latter case, use a /reserved-memory node and memory-region here.

> +
> +      perif,dma-mode:
> +        type: boolean
> +        description: Enable DMA support for eSPI peripheral channel
> +
> +      oob,dma-mode:

What vendor is 'oob'?

> +        type: boolean
> +        description: Enable DMA support for eSPI out-of-band channel
> +
> +      oob,dma-tx-desc-num:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        minimum: 2
> +        maximum: 1023
> +        description: The number of TX descriptors available for eSPI OOB DMA engine
> +
> +      oob,dma-rx-desc-num:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        minimum: 2
> +        maximum: 1023
> +        description: The number of RX descriptors available for eSPI OOB DMA engine
> +
> +      flash,dma-mode:
> +        type: boolean
> +        description: Enable DMA support for eSPI flash channel

Why does this need to be in DT. It's configuration.

> +
> +      flash,safs-mode:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        enum: [ 0, 1, 2 ]
> +        default: 0
> +        description: Slave-Attached-Sharing-Flash mode, 0->Mix, 1->SW, 2->HW
> +
> +    dependencies:
> +      perif,memcyc-src-addr: [ "perif,memcyc-enable" ]
> +      perif,memcyc-size: [ "perif,memcyc-enable" ]
> +      oob,dma-tx-desc-num: [ "oob,dma-mode" ]
> +      oob,dma-rx-desc-num: [ "oob,dma-mode" ]
> +
> +    required:
> +      - compatible
> +      - interrupts
> +      - clocks
> +
> +  "^espi-mmbi@[0-9a-f]+$":
> +    type: object
> +
> +    description: Control of the PCH-BMC data exchange over eSPI peripheral memory cycle
> +
> +    properties:
> +      compatible:
> +        const: aspeed,ast2600-espi-mmbi
> +
> +      interrupts:
> +        maxItems: 1
> +
> +    required:
> +      - compatible
> +      - interrupts
> +
> +required:
> +  - compatible
> +  - reg
> +  - "#address-cells"
> +  - "#size-cells"
> +  - ranges
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +    #include <dt-bindings/clock/ast2600-clock.h>
> +
> +    espi: espi@1e6ee000 {
> +        compatible = "aspeed,ast2600-espi", "simple-mfd", "syscon";
> +        reg = <0x1e6ee000 0x1000>;
> +
> +        #address-cells = <1>;
> +        #size-cells = <1>;
> +        ranges = <0x0 0x1e6ee000 0x1000>;
> +
> +        espi_ctrl: espi-ctrl@0 {
> +            compatible = "aspeed,ast2600-espi-ctrl";
> +            reg = <0x0 0x800>;
> +            interrupts = <GIC_SPI 42 IRQ_TYPE_LEVEL_HIGH>;
> +            clocks = <&syscon ASPEED_CLK_GATE_ESPICLK>;
> +        };
> +
> +        espi_mmbi: espi-mmbi@800 {
> +            compatible = "aspeed,ast2600-espi-mmbi";
> +            reg = <0x800 0x50>;
> +            interrupts = <GIC_SPI 108 IRQ_TYPE_LEVEL_HIGH>;
> +        };

Why do you need these child nodes? Are the subblocks somehow useful on 
their own or reuseable in another configuration? If not, looks like this 
could all be 1 node.

Rob