Re: [PATCH RFC v4 01/12] dt-bindings: clk: zte: Add zx297520v3 top clock and reset bindings

[Conor Dooley <conor@kernel.org>]

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On Tue, Jun 16, 2026 at 11:26:21PM +0300, Stefan Dösinger wrote:
> These SoCs have 3 clock and reset controllers: Top, Matrix and LSP. The
> separation of concerns between Top and Matrix and the interface between
> them is poorly defined in the hardware, so the bindings list all
> potential PLL clocks that might be passed between them.
> 
> Generally every device has two clocks (one work clock, and one that
> connects it to the bus, I call it PCLK), two reset bits (I don't know
> what the difference is - sometimes asserting one is enough to reset the
> device, sometimes both need to be asserted). PCLK and WCLK are
> controlled by individual gates. Some devices have a mux and/or a
> divider for their work clock. Some devices, like the GPIO controller,
> only have reset bits and no clocks.
> 
> The top clock controller is fed by a 26mhz external oscillator and has 4
> PLLs to generate other clock rates. ZTE's kernel mostly relies on the
> boot ROM to set up PLLs, but one LTE-Related PLL is not configured
> on some boards. Therefore my driver contains code to program PLLs. It
> produces identical settings as the boot ROM for the pre-programmed
> frequencies.
> 
> Not all clocks will have an explicit user in the end. I am defining a
> lot of them simply to shut them off. The boot loader sets up a few of
> the proprietary timers, which will send regular IRQs (although the
> kernel of course doesn't need to listen to them). I don't plan to add a
> driver for the proprietary timer as I see no use for them - the ARM arch
> timer works just fine. I will add a driver for the very similar
> proprietary watchdog though.
> 
> The clock list in this patch is pretty complete but not exhaustive.
> There are other bits that are enabled, but I couldn't deduce what they
> are controlling by trial and error. Some of them seem to do nothing.
> Others cause an instant hang of the board when disabled. It is quite
> likely that a handful more clocks will be added in the future, but not a
> large number.
> 
> Signed-off-by: Stefan Dösinger <stefandoesinger@gmail.com>
> ---
>  .../bindings/clock/zte,zx297520v3-topclk.yaml      |  70 ++++++++++++
>  MAINTAINERS                                        |   2 +
>  include/dt-bindings/clock/zte,zx297520v3-clk.h     | 118 +++++++++++++++++++++
>  3 files changed, 190 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/clock/zte,zx297520v3-topclk.yaml b/Documentation/devicetree/bindings/clock/zte,zx297520v3-topclk.yaml
> new file mode 100644
> index 000000000000..374f63891288
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/zte,zx297520v3-topclk.yaml
> @@ -0,0 +1,70 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/clock/zte,zx297520v3-topclk.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: ZTE zx297520v3 SoC top clock and reset controller
> +
> +maintainers:
> +  - Stefan Dösinger <stefandoesinger@gmail.com>
> +
> +description: |
> +  The zx297520v3's top clock controller generates clocks for core devices on the
> +  board like the main bus, USB and timers. In addition to clocks it has reset
> +  controls for peripherals, a global board reset and watchdog reset controls.
> +
> +  The controller has two clock inputs: a 26 MHz and a 32 KHz external
> +  oscillator. They need to be provided as input clocks. The controller provides
> +  clocks to the downstream Matrix clock controller.
> +
> +  All available clocks are defined as preprocessor macros in the
> +  'dt-bindings/clock/zte,zx297520v3-clk.h' header.
> +
> +properties:
> +  compatible:
> +    items:
> +      - const: zte,zx297520v3-topclk
> +      - const: syscon
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    items:
> +      - description: 26 MHz external oscillator
> +      - description: 32 KHz external oscillator
> +
> +  clock-names:
> +    items:
> +      - const: osc26m
> +      - const: osc32k
> +
> +  "#clock-cells":
> +    const: 1
> +
> +  "#reset-cells":
> +    const: 1
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - clock-names
> +  - '#clock-cells'
> +  - '#reset-cells'
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/zte,zx297520v3-clk.h>
> +
> +    clock-controller@13b000 {
> +        compatible = "zte,zx297520v3-topclk", "syscon";
> +        reg = <0x0013b000 0x400>;
> +        clocks = <&osc26m>, <&osc32k>;
> +        clock-names = "osc26m", "osc32k";
> +        #clock-cells = <1>;
> +        #reset-cells = <1>;
> +    };
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 8629ed2aa82f..0cc1ede3c80c 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -3867,8 +3867,10 @@ L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
>  S:	Odd fixes
>  F:	Documentation/arch/arm/zte/
>  F:	Documentation/devicetree/bindings/arm/zte.yaml
> +F:	Documentation/devicetree/zte,zx297520v3-*

Sashiko complaint here looks valid.

FWIW
/scripts/get_maintainer.pl --self-test=patterns
will catch these kinds of things.

pw-bot: changes-requested

Cheers,
Conor.

>  F:	arch/arm/boot/dts/zte/
>  F:	arch/arm/mach-zte/
> +F:	include/dt-bindings/clock/zte,zx297520v3-clk.h

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