Re: [PATCH v1 4/8] dt-bindings: timer: Add EcoNet HPT CPU Timer

[Krzysztof Kozlowski <krzk@kernel.org>]

On 21/03/2025 14:46, Caleb James DeLisle wrote:
> Add device tree binding documentation for the high-precision timer (HPT)
> in the EcoNet EN751221 SoC.
> 
> Signed-off-by: Caleb James DeLisle <cjd@cjdns.fr>

Previous patch was not tested, so was this one tested?

> ---
>  .../bindings/timer/econet,timer-hpt.yaml      | 58 +++++++++++++++++++
>  1 file changed, 58 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/timer/econet,timer-hpt.yaml
> 
> diff --git a/Documentation/devicetree/bindings/timer/econet,timer-hpt.yaml b/Documentation/devicetree/bindings/timer/econet,timer-hpt.yaml
> new file mode 100644
> index 000000000000..8b7ff9bce947
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/timer/econet,timer-hpt.yaml
> @@ -0,0 +1,58 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/timer/econet,timer-hpt.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: EcoNet High Precision Timer (HPT)
> +
> +maintainers:
> +  - Calev James DeLisle <cjd@cjdns.fr>
> +
> +description: |

Do not need '|' unless you need to preserve formatting.

> +  The EcoNet High Precision Timer (HPT) is a timer peripheral found in various
> +  EcoNet SoCs, including the EN751221 and EN751627 families. It provides per-VPE
> +  count/compare registers and a per-CPU control register, with a single interrupt
> +  line using a percpu-devid interrupt mechanism.
> +
> +properties:
> +  compatible:
> +    const: econet,timer-hpt

Soc components must have soc-based compatible and then filename matching
whatever you use as fallback.

> +
> +  reg:
> +    minItems: 1
> +    maxItems: 2

No, list items instead.

> +    description: |
> +      Physical base address and size of the timer's register space. On 34Kc
> +      processors, a single region is used. On 1004Kc processors, two regions are
> +      used, one for each core.

So different hardware, different compatible. That's why you need
soc-based compatibles. Follow standard SoC upstreaming rules and examples.

> +
> +  interrupts:
> +    maxItems: 1
> +    description: |

Do not need '|' unless you need to preserve formatting.

> +      The interrupt number for the timer.

Drop, redundant.


> This is a percpu-devid interrupt shared
> +      across CPUs.
> +
> +  clocks:
> +    maxItems: 1
> +    description: |
> +      A clock to get the frequency of the timer.

Drop description, redundant

> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - clocks
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    timer_hpt@1fbf0400 {

No underscores

Node names should be generic. See also an explanation and list of
examples (not exhaustive) in DT specification:
https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation

Look how other SoCs are calling this.

> +        compatible = "econet,timer-hpt";
> +        reg = <0x1fbf0400 0x100>;
> +        interrupt-parent = <&intc>;
> +        interrupts = <30>;
> +        clocks = <&hpt_clock>;
> +    };
> +...


Best regards,
Krzysztof