Re: [PATCH RESEND v10 2/3] dt-bindings: hwmon: Support Aspeed g6 PWM TACH Control

[Rob Herring]

On Tue, Nov 07, 2023 at 06:50:24PM +0800, Billy Tsai wrote:
> Document the compatible for aspeed,ast2600-pwm-tach device, which can
> support up to 16 PWM outputs and 16 fan tach input.
> 
> Signed-off-by: Billy Tsai <billy_tsai@xxxxxxxxxxxxxx>
> ---
>  .../bindings/hwmon/aspeed,g6-pwm-tach.yaml    | 69 +++++++++++++++++++
>  1 file changed, 69 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/hwmon/aspeed,g6-pwm-tach.yaml
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/aspeed,g6-pwm-tach.yaml b/Documentation/devicetree/bindings/hwmon/aspeed,g6-pwm-tach.yaml
> new file mode 100644
> index 000000000000..c615fb10705c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/aspeed,g6-pwm-tach.yaml
> @@ -0,0 +1,69 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +# Copyright (C) 2023 Aspeed, Inc.
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/hwmon/aspeed,g6-pwm-tach.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: ASPEED G6 PWM and Fan Tach controller
> +
> +maintainers:
> +  - Billy Tsai <billy_tsai@xxxxxxxxxxxxxx>
> +
> +description: |
> +  The ASPEED PWM controller can support up to 16 PWM outputs.
> +  The ASPEED Fan Tacho controller can support up to 16 fan tach input.
> +  They are independent hardware blocks, which are different from the
> +  previous version of the ASPEED chip.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - aspeed,ast2600-pwm-tach
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 1
> +
> +  resets:
> +    maxItems: 1
> +
> +  "#pwm-cells":
> +    const: 3
> +
> +patternProperties:
> +  "^fan-[0-9]+$":
> +    $ref: fan-common.yaml#
> +    unevaluatedProperties: false
> +    required:
> +      - tach-ch
> +
> +required:
> +  - reg
> +  - clocks
> +  - resets
> +  - "#pwm-cells"
> +  - compatible
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/aspeed-clock.h>
> +    pwm_tach: pwm-tach-controller@1e610000 {
> +      compatible = "aspeed,ast2600-pwm-tach";
> +      reg = <0x1e610000 0x100>;
> +      clocks = <&syscon ASPEED_CLK_AHB>;
> +      resets = <&syscon ASPEED_RESET_PWM>;
> +      #pwm-cells = <3>;
> +
> +      fan-0 {

I assume there's a PWM connection here? How do you know which PWM? You 
said the tach channel is independent, so it is not that.

It should not be 0 from 'fan-0' because that's just a meaningless index. 

You either need 'pwms' here or you can use 'reg' and the reg value is 
the PWM channel.

> +        tach-ch = /bits/ 8 <0x0>;
> +      };
> +
> +      fan-1 {
> +        tach-ch = /bits/ 8 <0x1 0x2>;
> +      };
> +    };
> -- 
> 2.25.1
>