127 lines
3.9 KiB
YAML
127 lines
3.9 KiB
YAML
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# SPDX-License-Identifier: GPL-2.0
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/regulator/pwm-regulator.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: Bindings for the Generic PWM Regulator
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maintainers:
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- Brian Norris <briannorris@chromium.org>
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- Lee Jones <lee@kernel.org>
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- Alexandre Courbot <acourbot@nvidia.com>
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description: |
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Currently supports 2 modes of operation:
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Voltage Table:
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When in this mode, a voltage table (See below) of predefined voltage <=>
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duty-cycle values must be provided via DT. Limitations are that the
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regulator can only operate at the voltages supplied in the table.
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Intermediary duty-cycle values which would normally allow finer grained
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voltage selection are ignored and rendered useless. Although more control
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is given to the user if the assumptions made in continuous-voltage mode do
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not reign true.
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Continuous Voltage:
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This mode uses the regulator's maximum and minimum supplied voltages
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specified in the regulator-{min,max}-microvolt properties to calculate
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appropriate duty-cycle values. This allows for a much more fine grained
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solution when compared with voltage-table mode above. This solution does
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make an assumption that a %50 duty-cycle value will cause the regulator
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voltage to run at half way between the supplied max_uV and min_uV values.
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If voltage-table is provided, then the device will be used in Voltage Table
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Mode. If no voltage-table is provided, then the device will be used in
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Continuous Voltage Mode.
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allOf:
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- $ref: regulator.yaml#
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properties:
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compatible:
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const: pwm-regulator
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pwms:
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maxItems: 1
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voltage-table:
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description: Voltage and Duty-Cycle table.
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$ref: /schemas/types.yaml#/definitions/uint32-matrix
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items:
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items:
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- description: voltage in microvolts (uV)
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- description: duty-cycle in percent (%)
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enable-gpios:
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description: Regulator enable GPIO
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maxItems: 1
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# Optional properties for Continuous mode:
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pwm-dutycycle-unit:
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description:
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Integer value encoding the duty cycle unit. If not
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defined, <100> is assumed, meaning that
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pwm-dutycycle-range contains values expressed in
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percent.
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default: 100
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pwm-dutycycle-range:
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description:
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Should contain 2 entries. The first entry is encoding
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the dutycycle for regulator-min-microvolt and the
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second one the dutycycle for regulator-max-microvolt.
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Duty cycle values are expressed in pwm-dutycycle-unit.
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If not defined, <0 100> is assumed.
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$ref: /schemas/types.yaml#/definitions/uint32-array
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items:
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- description: the dutycycle for regulator-min-microvolt
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- description: the dutycycle for regulator-max-microvolt
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default: [ 0 100 ]
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required:
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- compatible
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- pwms
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unevaluatedProperties: false
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examples:
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- |
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#include <dt-bindings/gpio/gpio.h>
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// Continuous Voltage With Enable GPIO Example:
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regulator {
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compatible = "pwm-regulator";
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pwms = <&pwm1 0 8448 0>;
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enable-gpios = <&gpio0 23 GPIO_ACTIVE_HIGH>;
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regulator-min-microvolt = <1016000>;
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regulator-max-microvolt = <1114000>;
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regulator-name = "vdd_logic";
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/* unit == per-mille */
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pwm-dutycycle-unit = <1000>;
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/*
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* Inverted PWM logic, and the duty cycle range is limited
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* to 30%-70%.
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*/
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pwm-dutycycle-range = <700 300>; /* */
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};
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- |
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// Voltage Table Example:
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regulator {
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compatible = "pwm-regulator";
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pwms = <&pwm1 0 8448 0>;
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regulator-min-microvolt = <1016000>;
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regulator-max-microvolt = <1114000>;
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regulator-name = "vdd_logic";
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/* Voltage Duty-Cycle */
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voltage-table = <1114000 0>,
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<1095000 10>,
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<1076000 20>,
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<1056000 30>,
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<1036000 40>,
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<1016000 50>;
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};
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...
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