Re: [PATCH 1/2] dt-bindings: timer: add a binding for LiteX Timer

From: Krzysztof Kozlowski
Date: Mon Nov 21 2022 - 05:19:41 EST


On 21/11/2022 05:25, Icenowy Zheng wrote:
> The LiteX SoC generator has a timer core, which by default only
> generates a simple down counter.

Subject: drop second, redundant "bindings".

>
> Add a DT binding for it.
>
> Signed-off-by: Icenowy Zheng <uwu@xxxxxxxxxx>
> ---
> .../bindings/timer/litex,timer.yaml | 52 +++++++++++++++++++
> 1 file changed, 52 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/timer/litex,timer.yaml
>
> diff --git a/Documentation/devicetree/bindings/timer/litex,timer.yaml b/Documentation/devicetree/bindings/timer/litex,timer.yaml
> new file mode 100644
> index 000000000000..bece07586c6b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/timer/litex,timer.yaml
> @@ -0,0 +1,52 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/timer/litex,timer.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: LiteX Timer
> +
> +maintainers:
> + - Icenowy Zheng <uwu@xxxxxxxxxx>
> +
> +description: |
> + The LiteX Timer is a count-down timer that is defaultly embedded
> + into all LiteX SoCs, unless explicitly disabled. It's fed directly
> + by the system clock like other LiteX peripherals.
> +
> +properties:
> + compatible:
> + const: litex,timer

No model name/number? If it is part of Soc, then a SoC specific number
is expected usually.

> +
> + reg:
> + maxItems: 1
> +
> + interrupts:
> + maxItems: 1
> +
> + clocks:
> + maxItems: 1
> +
> + litex,width:
> + description:
> + The width of the timer's value, specified as the width argument
> + when creating an instance of litex.soc.cores.Timer.

This lacks type ($ref) and units in description, but more important -
why this is not part of compatible? Is it a width of register(s)?

And what is "instance of litex.soc.cores.Timer"? Is it configurable,
soft-core?

BTW, there is reg-io-width property.

> +
> +required:
> + - compatible
> + - reg
> + - interrupts
> + - clocks
> + - litex,width
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + timer@a0006000 {

Use 4 spaces for example indentation.

> + compatible = "litex,timer";
> + reg = <0xa0006000 0x20>;
> + clocks = <&sys_clk>;
> + interrupts = <17>;
> + litex,width = <32>;
> + };

Best regards,
Krzysztof