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08e0b98123
The SpacemiT K1 SoC reuses the Marvell PXA910-compatible PWM controller with one notable difference: the addition of a resets property. To make the device tree pass schema validation (make dtbs_check W=3), this patch updates the binding to accept spacemit,k1-pwm as a compatible string, when used in conjunction with the fallback marvell,pxa910-pwm. Support for the optional resets property is also added, as it is required by the K1 integration but was not present in the original Marvell bindings. Since the PWM reset line may be deasserted during the early bootloader stage, making the resets property optional avoids potential double-deassertion, which could otherwise cause flickering on displays that use PWM for backlight control. Additionally, this patch adjusts the required value of the #pwm-cells property for the new compatible string: - For "spacemit,k1-pwm", #pwm-cells must be set to 3. - For existing Marvell compatibles, #pwm-cells remains 1. Background of #pwm-cells change is by an ongoing community discussion about increasing the #pwm-cells value from 1 to 3 for all Marvell PXA PWM devices. These devices are currently the only ones whose bindings do not pass the line index as the first argument. See [1] for further details. [1] https://lore.kernel.org/all/cover.1738842938.git.u.kleine-koenig@baylibre.com/ Reviewed-by: Rob Herring (Arm) <robh@kernel.org> # v2 Signed-off-by: Guodong Xu <guodong@riscstar.com> Link: https://lore.kernel.org/r/20250429085048.1310409-2-guodong@riscstar.com Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
72 lines
1.3 KiB
YAML
72 lines
1.3 KiB
YAML
# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/pwm/marvell,pxa-pwm.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: Marvell PXA PWM
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maintainers:
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- Duje Mihanović <duje.mihanovic@skole.hr>
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allOf:
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- $ref: pwm.yaml#
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- if:
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properties:
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compatible:
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contains:
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const: spacemit,k1-pwm
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then:
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properties:
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"#pwm-cells":
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const: 3
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else:
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properties:
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"#pwm-cells":
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const: 1
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description: |
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Used for specifying the period length in nanoseconds.
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properties:
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compatible:
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oneOf:
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- enum:
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- marvell,pxa250-pwm
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- marvell,pxa270-pwm
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- marvell,pxa168-pwm
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- marvell,pxa910-pwm
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- items:
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- const: spacemit,k1-pwm
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- const: marvell,pxa910-pwm
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reg:
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# Length should be 0x10
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maxItems: 1
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"#pwm-cells":
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description: Number of cells in a pwm specifier.
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clocks:
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maxItems: 1
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resets:
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maxItems: 1
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required:
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- compatible
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- reg
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- clocks
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additionalProperties: false
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examples:
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- |
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#include <dt-bindings/clock/pxa-clock.h>
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pwm0: pwm@40b00000 {
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compatible = "marvell,pxa250-pwm";
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reg = <0x40b00000 0x10>;
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#pwm-cells = <1>;
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clocks = <&clks CLK_PWM0>;
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};
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