Re: [PATCH] dt-bindings: maxim-ds1302: Convert to dt schema

[Conor Dooley <conor@kernel.org>]

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On Wed, Sep 02, 2026 at 04:35:49PM -0700, Sudheendra Sampath wrote:
> Convert Maxim DS1302 real-time clock binding to DT schema.
> 
> Signed-off-by: Sudheendra Sampath <giveback4fun@gmail.com>
> ---
>  .../devicetree/bindings/rtc/maxim-ds1302.txt  | 46 -----------
>  .../devicetree/bindings/rtc/maxim-ds1302.yaml | 81 +++++++++++++++++++
>  2 files changed, 81 insertions(+), 46 deletions(-)
>  delete mode 100644 Documentation/devicetree/bindings/rtc/maxim-ds1302.txt
>  create mode 100644 Documentation/devicetree/bindings/rtc/maxim-ds1302.yaml
> 
> diff --git a/Documentation/devicetree/bindings/rtc/maxim-ds1302.txt b/Documentation/devicetree/bindings/rtc/maxim-ds1302.txt
> deleted file mode 100644
> index ba470c56cdec..000000000000
> --- a/Documentation/devicetree/bindings/rtc/maxim-ds1302.txt
> +++ /dev/null
> @@ -1,46 +0,0 @@
> -* Maxim/Dallas Semiconductor DS-1302 RTC
> -
> -Simple device which could be used to store date/time between reboots.
> -
> -The device uses the standard MicroWire half-duplex transfer timing.
> -Master output is set on low clock and sensed by the RTC on the rising
> -edge. Master input is set by the RTC on the trailing edge and is sensed
> -by the master on low clock.
> -
> -Required properties:
> -
> -- compatible : Should be "maxim,ds1302"
> -
> -Required SPI properties:
> -
> -- reg : Should be address of the device chip select within
> -  the controller.
> -
> -- spi-max-frequency : DS-1302 has 500 kHz if powered at 2.2V,
> -  and 2MHz if powered at 5V.
> -
> -- spi-3wire : The device has a shared signal IN/OUT line.
> -
> -- spi-lsb-first : DS-1302 requires least significant bit first
> -  transfers.
> -
> -- spi-cs-high: DS-1302 has active high chip select line. This is
> -  required unless inverted in hardware.
> -
> -Example:
> -
> -spi@901c {
> -	#address-cells = <1>;
> -	#size-cells = <0>;
> -	compatible = "icpdas,lp8841-spi-rtc";
> -	reg = <0x901c 0x1>;
> -
> -	rtc@0 {
> -		compatible = "maxim,ds1302";
> -		reg = <0>;
> -		spi-max-frequency = <500000>;
> -		spi-3wire;
> -		spi-lsb-first;
> -		spi-cs-high;
> -	};
> -};
> diff --git a/Documentation/devicetree/bindings/rtc/maxim-ds1302.yaml b/Documentation/devicetree/bindings/rtc/maxim-ds1302.yaml
> new file mode 100644
> index 000000000000..3e6264464e10
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/rtc/maxim-ds1302.yaml

s/-/,/ as the filename should match the compatible.

> @@ -0,0 +1,81 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/rtc/maxim-ds1302.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Maxim/Dallas Semiconductor DS-1302 RTC
> +
> +maintainers:
> +  - Alexandre Belloni <alexandre.belloni@bootlin.com>

This should be the original author of the text binding, provided they're
still responsive.

> +
> +description: |
> +  Simple device which could be used to store date/time between reboots.
> +
> +  The device uses the standard MicroWire half-duplex transfer timing.
> +  Master output is set on low clock and sensed by the RTC on the rising
> +  edge. Master input is set by the RTC on the trailing edge and is sensed
> +  by the master on low clock.
> +
> +properties:
> +  compatible:
> +    items:
> +      # Maxim DS1302 Real-time Clock

This comment is obvious, just drop it.

> +      - const: maxim,ds1302
> +
> +  reg:
> +    maxItems: 1
> +
> +  spi-max-frequency:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: Maximum SPI clocking speed in Hz.

This should retain the comment about the voltages, rather than state the
obvious.

> +    enum:
> +      - 500000
> +      - 2000000
> +
> +  spi-3wire: true
> +
> +  spi-lsb-first: true
> +
> +  spi-cs-high: true
> +
> +required:
> +  - compatible
> +  - reg
> +  - spi-max-frequency
> +  - spi-3wire
> +  - spi-lsb-first
> +  - spi-cs-high
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    spi1 {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        rtc@0 {
> +            compatible = "maxim,ds1302";
> +            reg = <0>;
> +            spi-max-frequency = <500000>;
> +            spi-3wire;
> +            spi-lsb-first;
> +            spi-cs-high;
> +        };
> +    };
> +

> +  - |
> +    spi2 {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        rtc@2000 {
> +            compatible = "maxim,ds1302";
> +            reg = <0x2000>;
> +            spi-max-frequency = <2000000>;
> +            spi-3wire;
> +            spi-lsb-first;
> +            spi-cs-high;
> +        };
> +    };

Where did this additional example come from? The chip select looks
rather unlikely and the example has nothing meaningfully different in
it.
I think this should be dropped.

pw-bot: changes-requested

Thanks,
Conor.

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