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d5992f1af1
The imx8m-clock.yaml binding covers the clock controller inside all of the i.MX8M Q/M/N/P SoCs. All of them have in common that they support two operating modes: nominal and overdrive mode. While the overdrive mode allows for higher frequencies for many IPs, the nominal mode needs a lower SoC voltage, thereby reducing heat generation and power usage. As increasing clock rates beyond the maximum permitted by the supplied SoC voltage can lead to difficult to debug issues, device tree consumers would benefit from knowing what mode is active to enforce the clock rate limits that come with it. To facilitate this, extend the clock controller bindings with an optional fsl,operating-mode property. This intentionally allows the absence of the property, because there is no default suitable for all boards: For i.MX8M Mini and Nano, the kernel SoC DTSIs has assigned-clock-rates that are all achievable in nominal mode. For i.MX8MP, there are some rates only validated for overdrive mode. But even for the i.MX8M Mini/Nano boards, we don't know what rates they may configure at runtime, so it has not been possible so far to infer from just the device tree what the mode is. Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de> Link: https://lore.kernel.org/r/20250218-imx8m-clk-v4-1-b7697dc2dcd0@pengutronix.de Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
134 lines
3.3 KiB
YAML
134 lines
3.3 KiB
YAML
# SPDX-License-Identifier: GPL-2.0
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/clock/imx8m-clock.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: NXP i.MX8M Family Clock Control Module
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maintainers:
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- Abel Vesa <abelvesa@kernel.org>
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- Peng Fan <peng.fan@nxp.com>
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description: |
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NXP i.MX8M Mini/Nano/Plus/Quad clock control module is an integrated clock
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controller, which generates and supplies to all modules.
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properties:
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compatible:
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enum:
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- fsl,imx8mm-ccm
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- fsl,imx8mn-ccm
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- fsl,imx8mp-ccm
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- fsl,imx8mq-ccm
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reg:
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maxItems: 1
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interrupts:
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maxItems: 2
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clocks:
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minItems: 6
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maxItems: 7
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clock-names:
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minItems: 6
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maxItems: 7
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'#clock-cells':
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const: 1
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description:
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The clock consumer should specify the desired clock by having the clock
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ID in its "clocks" phandle cell. See include/dt-bindings/clock/imx8m-clock.h
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for the full list of i.MX8M clock IDs.
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fsl,operating-mode:
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$ref: /schemas/types.yaml#/definitions/string
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enum: [nominal, overdrive]
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description:
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The operating mode of the SoC. This affects the maximum clock rates that
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can safely be configured by the clock controller.
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required:
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- compatible
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- reg
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- clocks
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- clock-names
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- '#clock-cells'
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allOf:
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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: fsl,imx8mq-ccm
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then:
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properties:
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clocks:
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items:
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- description: 32k osc
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- description: 25m osc
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- description: 27m osc
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- description: ext1 clock input
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- description: ext2 clock input
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- description: ext3 clock input
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- description: ext4 clock input
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clock-names:
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items:
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- const: ckil
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- const: osc_25m
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- const: osc_27m
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- const: clk_ext1
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- const: clk_ext2
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- const: clk_ext3
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- const: clk_ext4
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else:
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properties:
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clocks:
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items:
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- description: 32k osc
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- description: 24m osc
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- description: ext1 clock input
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- description: ext2 clock input
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- description: ext3 clock input
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- description: ext4 clock input
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clock-names:
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items:
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- const: osc_32k
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- const: osc_24m
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- const: clk_ext1
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- const: clk_ext2
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- const: clk_ext3
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- const: clk_ext4
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additionalProperties: false
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examples:
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# Clock Control Module node:
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- |
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clock-controller@30380000 {
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compatible = "fsl,imx8mm-ccm";
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reg = <0x30380000 0x10000>;
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#clock-cells = <1>;
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clocks = <&osc_32k>, <&osc_24m>, <&clk_ext1>, <&clk_ext2>,
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<&clk_ext3>, <&clk_ext4>;
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clock-names = "osc_32k", "osc_24m", "clk_ext1", "clk_ext2",
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"clk_ext3", "clk_ext4";
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fsl,operating-mode = "nominal";
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};
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- |
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clock-controller@30380000 {
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compatible = "fsl,imx8mq-ccm";
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reg = <0x30380000 0x10000>;
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#clock-cells = <1>;
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clocks = <&ckil>, <&osc_25m>, <&osc_27m>, <&clk_ext1>,
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<&clk_ext2>, <&clk_ext3>, <&clk_ext4>;
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clock-names = "ckil", "osc_25m", "osc_27m", "clk_ext1",
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"clk_ext2", "clk_ext3", "clk_ext4";
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};
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...
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