linux-kernel - Re: [PATCH v2 1/2] dt-bindings: iio: dac: add MCP4821

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Message-ID: <CAMknhBGR7WS46J+MeqY51RhMb78AoUO6URaFxw2M83P29fqzdQ@mail.gmail.com>
Date: Sun, 17 Dec 2023 19:25:26 -0600
From: David Lechner <dlechner@...libre.com>
To: Anshul Dalal <anshulusr@...il.com>
Cc: linux-kernel@...r.kernel.org, linux-iio@...r.kernel.org, 
	Jonathan Cameron <jic23@...nel.org>, devicetree@...r.kernel.org, 
	Conor Dooley <conor+dt@...nel.org>, Lars-Peter Clausen <lars@...afoo.de>, Rob Herring <robh+dt@...nel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, 
	linux-kernel-mentees@...ts.linuxfoundation.org, 
	Shuah Khan <skhan@...uxfoundation.org>, Conor Dooley <conor.dooley@...rochip.com>
Subject: Re: [PATCH v2 1/2] dt-bindings: iio: dac: add MCP4821

On Sun, Dec 17, 2023 at 12:11 PM Anshul Dalal <anshulusr@...il.com> wrote:
>
> Adds support for MCP48xx series of DACs.
>
> Datasheet: https://ww1.microchip.com/downloads/en/DeviceDoc/22244B.pdf #MCP48x1
> Datasheet: https://ww1.microchip.com/downloads/en/DeviceDoc/20002249B.pdf #MCP48x2
> Reviewed-by: Conor Dooley <conor.dooley@...rochip.com>
> Signed-off-by: Anshul Dalal <anshulusr@...il.com>
>
> ---
>
> Changes for v2:
> - Changed order in device table to numerical
> - Made vdd_supply required
> - Added 'Reviewed-by: Conor Dooley'
>
> Previous versions:
> v1: https://lore.kernel.org/lkml/20231117073040.685860-1-anshulusr@gmail.com/
> ---
>  .../bindings/iio/dac/microchip,mcp4821.yaml   | 64 +++++++++++++++++++
>  1 file changed, 64 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/dac/microchip,mcp4821.yaml
>
> diff --git a/Documentation/devicetree/bindings/iio/dac/microchip,mcp4821.yaml b/Documentation/devicetree/bindings/iio/dac/microchip,mcp4821.yaml
> new file mode 100644
> index 000000000000..97da9f9ef450
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/dac/microchip,mcp4821.yaml
> @@ -0,0 +1,64 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/dac/microchip,mcp4821.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Microchip MCP4821 and similar DACs
> +
> +description: |
> +  Supports MCP48x1 (single channel) and MCP48x2 (dual channel) series of DACs.
> +  Device supports simplex communication over SPI in Mode 0,1 and Mode 1,1.

It seems like SPI modes usually only have one number in them, i.e.
mode 1 and mode 3 in this case, I'm guessing.

> +
> +  +---------+--------------+-------------+
> +  | Device  |  Resolution  |   Channels  |
> +  |---------|--------------|-------------|
> +  | MCP4801 |     8-bit    |      1      |
> +  | MCP4802 |     8-bit    |      2      |
> +  | MCP4811 |    10-bit    |      1      |
> +  | MCP4812 |    10-bit    |      2      |
> +  | MCP4821 |    12-bit    |      1      |
> +  | MCP4822 |    12-bit    |      2      |
> +  +---------+--------------+-------------+
> +
> +  Datasheet:
> +    MCP48x1: https://ww1.microchip.com/downloads/en/DeviceDoc/22244B.pdf
> +    MCP48x2: https://ww1.microchip.com/downloads/en/DeviceDoc/20002249B.pdf
> +
> +maintainers:
> +  - Anshul Dalal <anshulusr@...il.com>
> +
> +properties:
> +  compatible:
> +    enum:
> +      - microchip,mcp4801
> +      - microchip,mcp4802
> +      - microchip,mcp4811
> +      - microchip,mcp4812
> +      - microchip,mcp4821
> +      - microchip,mcp4822
> +
> +  reg:
> +    maxItems: 1
> +
> +  vdd-supply: true

What about the SHDN and LDAC pins? It seems like all should have an
ldac-gpios property and MCP48x1 should have a shdn-gpios property for
these.

> +
> +required:
> +  - compatible
> +  - reg
> +  - vdd-supply
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    spi {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        dac@0 {
> +            compatible = "microchip,mcp4821";
> +            reg = <0>;
> +            vdd-supply = <&vdd_regulator>;
> +        };
> +    };
> --
> 2.43.0
>
>