xref: /linux/Documentation/devicetree/bindings/regulator/pwm-regulator.yaml (revision cdd5b5a9761fd66d17586e4f4ba6588c70e640ea) 
1# SPDX-License-Identifier: GPL-2.0
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/regulator/pwm-regulator.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: Generic PWM Regulator
8
9maintainers:
10  - Brian Norris <briannorris@chromium.org>
11  - Lee Jones <lee@kernel.org>
12  - Alexandre Courbot <acourbot@nvidia.com>
13
14description: |
15  Currently supports 2 modes of operation:
16
17  Voltage Table:
18    When in this mode, a voltage table (See below) of predefined voltage <=>
19    duty-cycle values must be provided via DT. Limitations are that the
20    regulator can only operate at the voltages supplied in the table.
21    Intermediary duty-cycle values which would normally allow finer grained
22    voltage selection are ignored and rendered useless.  Although more control
23    is given to the user if the assumptions made in continuous-voltage mode do
24    not reign true.
25
26  Continuous Voltage:
27    This mode uses the regulator's maximum and minimum supplied voltages
28    specified in the regulator-{min,max}-microvolt properties to calculate
29    appropriate duty-cycle values.  This allows for a much more fine grained
30    solution when compared with voltage-table mode above.  This solution does
31    make an assumption that a %50 duty-cycle value will cause the regulator
32    voltage to run at half way between the supplied max_uV and min_uV values.
33
34  If voltage-table is provided, then the device will be used in Voltage Table
35  Mode.  If no voltage-table is provided, then the device will be used in
36  Continuous Voltage Mode.
37
38allOf:
39  - $ref: regulator.yaml#
40
41properties:
42  compatible:
43    const: pwm-regulator
44
45  pwms:
46    maxItems: 1
47
48  voltage-table:
49    description: Voltage and Duty-Cycle table.
50    $ref: /schemas/types.yaml#/definitions/uint32-matrix
51    items:
52      items:
53        - description: voltage in microvolts (uV)
54        - description: duty-cycle in percent (%)
55
56  enable-gpios:
57    description: Regulator enable GPIO
58    maxItems: 1
59
60   # Optional properties for Continuous mode:
61  pwm-dutycycle-unit:
62    description:
63      Integer value encoding the duty cycle unit. If not
64        defined, <100> is assumed, meaning that
65        pwm-dutycycle-range contains values expressed in
66        percent.
67    $ref: /schemas/types.yaml#/definitions/uint32
68    default: 100
69
70  pwm-dutycycle-range:
71    description:
72      Should contain 2 entries. The first entry is encoding
73        the dutycycle for regulator-min-microvolt and the
74        second one the dutycycle for regulator-max-microvolt.
75        Duty cycle values are expressed in pwm-dutycycle-unit.
76        If not defined, <0 100> is assumed.
77    $ref: /schemas/types.yaml#/definitions/uint32-array
78    items:
79      - description: the dutycycle for regulator-min-microvolt
80      - description: the dutycycle for regulator-max-microvolt
81    default: [ 0 100 ]
82
83required:
84  - compatible
85  - pwms
86
87unevaluatedProperties: false
88
89examples:
90  - |
91    #include <dt-bindings/gpio/gpio.h>
92
93    // Continuous Voltage With Enable GPIO Example:
94    regulator {
95        compatible = "pwm-regulator";
96        pwms = <&pwm1 0 8448 0>;
97        enable-gpios = <&gpio0 23 GPIO_ACTIVE_HIGH>;
98        regulator-min-microvolt = <1016000>;
99        regulator-max-microvolt = <1114000>;
100        regulator-name = "vdd_logic";
101        /* unit == per-mille */
102        pwm-dutycycle-unit = <1000>;
103        /*
104        * Inverted PWM logic, and the duty cycle range is limited
105        * to 30%-70%.
106        */
107        pwm-dutycycle-range = <700 300>; /* */
108    };
109
110  - |
111    // Voltage Table Example:
112    regulator {
113        compatible = "pwm-regulator";
114        pwms = <&pwm1 0 8448 0>;
115        regulator-min-microvolt = <1016000>;
116        regulator-max-microvolt = <1114000>;
117        regulator-name = "vdd_logic";
118
119                /* Voltage Duty-Cycle */
120        voltage-table = <1114000 0>,
121            <1095000 10>,
122            <1076000 20>,
123            <1056000 30>,
124            <1036000 40>,
125            <1016000 50>;
126    };
127...
128