[v2,0/3] Support for Apple SoCs' NCO blocks

Hi,

this is v2 of the common clock driver for NCO blocks on recent Apple SoCs.

Changes since v1:

 - drop apple,nchannels property from the binding, rely on size of the register
   range instead to gauge the number of channels
 - add a lock to guard set_rate from racing with clock disable/enable
 - add short "theory of operation" comment
 - incorporate minor changes from Rob's, Sven's and Stephen's review (thanks!)

Martin

v1: https://lore.kernel.org/linux-clk/20211214120213.15649-1-povik@protonmail.com/

Martin Povišer (3):
  dt-bindings: clock: Add Apple NCO
  clk: clk-apple-nco: Add driver for Apple NCO
  MAINTAINERS: Add clk-apple-nco under ARM/APPLE MACHINE

 .../devicetree/bindings/clock/apple,nco.yaml  |  62 ++++
 MAINTAINERS                                   |   1 +
 drivers/clk/Kconfig                           |   9 +
 drivers/clk/Makefile                          |   1 +
 drivers/clk/clk-apple-nco.c                   | 340 ++++++++++++++++++
 5 files changed, 413 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/clock/apple,nco.yaml
 create mode 100644 drivers/clk/clk-apple-nco.c

--
2.33.0

> Date: Tue, 18 Jan 2022 19:21:03 +0000
> From: Martin Povišer <povik+lin@protonmail.com>
> 
> The NCO block found on Apple SoCs is a programmable clock generator
> performing fractional division of a high frequency input clock.
> 
> Signed-off-by: Martin Povišer <povik+lin@protonmail.com>

Reviewed-by: Mark Kettenis <kettenis@openbsd.org>

> ---
>  .../devicetree/bindings/clock/apple,nco.yaml  | 62 +++++++++++++++++++
>  1 file changed, 62 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/clock/apple,nco.yaml
> 
> diff --git a/Documentation/devicetree/bindings/clock/apple,nco.yaml b/Documentation/devicetree/bindings/clock/apple,nco.yaml
> new file mode 100644
> index 000000000000..da56b64b8fff
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/apple,nco.yaml
> @@ -0,0 +1,62 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/clock/apple,nco.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Apple SoCs' NCO block
> +
> +maintainers:
> +  - Martin Povišer <povik+lin@protonmail.com>
> +
> +description: |
> +  The NCO (Numerically Controlled Oscillator) block found on Apple SoCs
> +  such as the t8103 (M1) is a programmable clock generator performing
> +  fractional division of a high frequency input clock.
> +
> +  It carries a number of independent channels and is typically used for
> +  generation of audio bitclocks.
> +
> +properties:
> +  compatible:
> +    items:
> +      - enum:
> +        - apple,t6000-nco
> +        - apple,t8103-nco
> +      - const: apple,nco
> +
> +  clocks:
> +    description:
> +      Specifies the reference clock from which the output clocks
> +      are derived through fractional division.
> +    maxItems: 1
> +
> +  '#clock-cells':
> +    const: 1
> +
> +  reg:
> +    maxItems: 1
> +
> +required:
> +  - compatible
> +  - clocks
> +  - '#clock-cells'
> +  - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    nco_clkref: clock-ref {
> +      compatible = "fixed-clock";
> +      #clock-cells = <0>;
> +      clock-frequency = <900000000>;
> +      clock-output-names = "nco-ref";
> +    };
> +
> +    nco: clock-controller@23b044000 {
> +      compatible = "apple,t8103-nco", "apple,nco";
> +      reg = <0x3b044000 0x14000>;
> +      #clock-cells = <1>;
> +      clocks = <&nco_clkref>;
> +    };
> --
> 2.33.0
> 
> 
>