Re: [PATCH v6 1/3] dt-bindings: pwm: Add Xilinx AXI Timer

Rob Herring
2021-08-31T20:11:40Z

On Thu, Aug 26, 2021 at 05:18:28PM -0400, Sean Anderson wrote:
> This adds a binding for the Xilinx LogiCORE IP AXI Timer. This device is a
> "soft" block, so it has some parameters which would not be configurable in
> most hardware. This binding is usually automatically generated by Xilinx's
> tools, so the names and values of some properties should be kept as they
> are, if possible. In addition, this binding is already in the kernel at
> arch/microblaze/boot/dts/system.dts, and in user software such as QEMU.
>
> The existing driver uses the clock-frequency property, or alternatively the
> /cpus/timebase-frequency property as its frequency input. Because these
> properties are deprecated, they have not been included with this schema.
> All new bindings should use the clocks/clock-names properties to specify
> the parent clock.
>
> Because we need to init timer devices so early in boot, we determine if we
> should use the PWM driver or the clocksource/clockevent driver by the
> presence/absence, respectively, of #pwm-cells. Because both counters are
> used by the PWM, there is no need for a separate property specifying which
> counters are to be used for the PWM.
>
> Signed-off-by: Sean Anderson <sean.anderson@seco.com>
> ---
>
> Changes in v6:
> - Fix incorrect schema id
> - Enumerate possible counter widths
>
> Changes in v5:
> - Update commit message to reflect revisions
> - Fix indentation lint
> - Add example for timer binding
> - Remove xlnx,axi-timer-2.0 compatible string
> - Move schema into the timer directory
>
> Changes in v4:
> - Remove references to generate polarity so this can get merged
> - Predicate PWM driver on the presence of #pwm-cells
> - Make some properties optional for clocksource drivers
>
> Changes in v3:
> - Mark all boolean-as-int properties as deprecated
> - Add xlnx,pwm and xlnx,gen?-active-low properties.
> - Make newer replacement properties mutually-exclusive with what they
> replace
> - Add an example with non-deprecated properties only.
>
> Changes in v2:
> - Use 32-bit addresses for example binding
>
> .../bindings/timer/xlnx,xps-timer.yaml | 90 +++++++++++++++++++
> 1 file changed, 90 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/timer/xlnx,xps-timer.yaml
>
> diff --git a/Documentation/devicetree/bindings/timer/xlnx,xps-timer.yaml b/Documentation/devicetree/bindings/timer/xlnx,xps-timer.yaml
> new file mode 100644
> index 000000000000..5be353a642aa
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/timer/xlnx,xps-timer.yaml
> @@ -0,0 +1,90 @@
> +# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/timer/xlnx,xps-timer.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Xilinx LogiCORE IP AXI Timer Device Tree Binding
> +
> +maintainers:
> + - Sean Anderson <sean.anderson@seco.com>
> +
> +properties:
> + compatible:
> + contains:
> + const: xlnx,xps-timer-1.00.a
> +
> + clocks:
> + maxItems: 1
> +
> + clock-names:
> + const: s_axi_aclk
> +
> + interrupts:
> + maxItems: 1
> +
> + reg:
> + maxItems: 1
> +
> + xlnx,count-width:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + enum: [8, 16, 32]
> + default: 32
> + description:
> + The width of the counter(s), in bits.
> +
> + xlnx,one-timer-only:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + enum: [ 0, 1 ]
> + description:
> + Whether only one timer is present in this block.
> +
> +required:
> + - compatible
> + - reg
> + - xlnx,one-timer-only
> +
> +allOf:
> + - if:
> + required:
> + - '#pwm-cells'
> + then:
> + allOf:
> + - required:
> + - clocks
> + - properties:
> + xlnx,one-timer-only:
> + const: 0
> + else:
> + required:
> + - interrupts
> + - if:
> + required:
> + - clocks
> + then:
> + required:
> + - clock-names
> +
> +additionalProperties: true

This needs to be false. What else do you expect to be present?

> +
> +examples:
> + - |
> + timer@800e0000 {
> + clock-names = "s_axi_aclk";
> + clocks = <&zynqmp_clk 71>;
> + compatible = "xlnx,xps-timer-1.00.a";
> + reg = <0x800e0000 0x10000>;
> + interrupts = <0 39 2>;
> + xlnx,count-width = <16>;
> + xlnx,one-timer-only = <0x0>;
> + };
> +
> + timer@800f0000 {
> + #pwm-cells = <0>;
> + clock-names = "s_axi_aclk";
> + clocks = <&zynqmp_clk 71>;
> + compatible = "xlnx,xps-timer-1.00.a";
> + reg = <0x800e0000 0x10000>;
> + xlnx,count-width = <32>;
> + xlnx,one-timer-only = <0x0>;
> + };
> --
> 2.25.1
>
>