Re: [PATCH v3 6/7] dt-bindings: clock: meson: add A1 CPU clock controller bindings

Jerome Brunet
2024-06-10T10:04:11Z

On Wed 15 May 2024 at 21:47, Dmitry Rokosov <ddrokosov@salutedevices.com> wrote:

> Add the documentation and dt bindings for Amlogic A1 CPU clock
> controller.
>
> This controller consists of the general 'cpu_clk' and two main parents:
> 'cpu fixed clock' and 'syspll'. The 'cpu fixed clock' is an internal
> fixed clock, while the 'syspll' serves as an external input from the A1
> PLL clock controller.
>
> Signed-off-by: Dmitry Rokosov <ddrokosov@salutedevices.com>
> Reviewed-by: Rob Herring <robh@kernel.org>
> ---
> .../bindings/clock/amlogic,a1-cpu-clkc.yaml | 64 +++++++++++++++++++
> .../dt-bindings/clock/amlogic,a1-cpu-clkc.h | 19 ++++++
> 2 files changed, 83 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/clock/amlogic,a1-cpu-clkc.yaml
> create mode 100644 include/dt-bindings/clock/amlogic,a1-cpu-clkc.h
>
> diff --git a/Documentation/devicetree/bindings/clock/amlogic,a1-cpu-clkc.yaml b/Documentation/devicetree/bindings/clock/amlogic,a1-cpu-clkc.yaml
> new file mode 100644
> index 000000000000..f4958b315ed4
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/amlogic,a1-cpu-clkc.yaml
> @@ -0,0 +1,64 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/clock/amlogic,a1-cpu-clkc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Amlogic A1 CPU Clock Control Unit
> +
> +maintainers:
> + - Neil Armstrong <neil.armstrong@linaro.org>
> + - Jerome Brunet <jbrunet@baylibre.com>
> + - Dmitry Rokosov <ddrokosov@salutedevices.com>
> +
> +properties:
> + compatible:
> + const: amlogic,a1-cpu-clkc
> +
> + '#clock-cells':
> + const: 1
> +
> + reg:
> + maxItems: 1
> +
> + clocks:
> + items:
> + - description: input fixed pll div2
> + - description: input fixed pll div3
> + - description: input sys pll
> + - description: input oscillator (usually at 24MHz)

According to the documentation, fdiv5 is also an input of the CPU clock
tree.

That is typically the kind of things we'd prefer to get right from the
beginning to avoid modifying the bindings later.

> +
> + clock-names:
> + items:
> + - const: fclk_div2
> + - const: fclk_div3
> + - const: sys_pll
> + - const: xtal
> +
> +required:
> + - compatible
> + - '#clock-cells'
> + - reg
> + - clocks
> + - clock-names
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + #include <dt-bindings/clock/amlogic,a1-pll-clkc.h>
> + apb {
> + #address-cells = <2>;
> + #size-cells = <2>;
> +
> + clock-controller@fd000000 {
> + compatible = "amlogic,a1-cpu-clkc";
> + reg = <0 0xfd000080 0 0x8>;

If reg is <0 0xfd000080 0 0x8> then node name should be clock-controller@fd000080

> + #clock-cells = <1>;
> + clocks = <&clkc_pll CLKID_FCLK_DIV2>,
> + <&clkc_pll CLKID_FCLK_DIV3>,
> + <&clkc_pll CLKID_SYS_PLL>,
> + <&xtal>;
> + clock-names = "fclk_div2", "fclk_div3", "sys_pll", "xtal";
> + };
> + };
> diff --git a/include/dt-bindings/clock/amlogic,a1-cpu-clkc.h b/include/dt-bindings/clock/amlogic,a1-cpu-clkc.h
> new file mode 100644
> index 000000000000..1d321c6eddb7
> --- /dev/null
> +++ b/include/dt-bindings/clock/amlogic,a1-cpu-clkc.h
> @@ -0,0 +1,19 @@
> +/* SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause */
> +/*
> + * Copyright (c) 2024, SaluteDevices. All Rights Reserved.
> + * Author: Dmitry Rokosov <ddrokosov@salutedevices.com>
> + */
> +
> +#ifndef __A1_CPU_CLKC_H
> +#define __A1_CPU_CLKC_H
> +
> +#define CLKID_CPU_FSOURCE_SEL0 0
> +#define CLKID_CPU_FSOURCE_DIV0 1
> +#define CLKID_CPU_FSEL0 2
> +#define CLKID_CPU_FSOURCE_SEL1 3
> +#define CLKID_CPU_FSOURCE_DIV1 4
> +#define CLKID_CPU_FSEL1 5
> +#define CLKID_CPU_FCLK 6
> +#define CLKID_CPU_CLK 7
> +
> +#endif /* __A1_CPU_CLKC_H */

--
Jerome