| Tom Rini | 53633a8 | 2024-02-29 12:33:36 -0500 | [diff] [blame] | 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 | |
| 7 | title: Generic PWM Regulator |
| 8 | |
| 9 | maintainers: |
| 10 | - Brian Norris <briannorris@chromium.org> |
| 11 | - Lee Jones <lee@kernel.org> |
| 12 | - Alexandre Courbot <acourbot@nvidia.com> |
| 13 | |
| 14 | description: | |
| 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 | |
| 38 | allOf: |
| 39 | - $ref: regulator.yaml# |
| 40 | |
| 41 | properties: |
| 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 | |
| 83 | required: |
| 84 | - compatible |
| 85 | - pwms |
| 86 | |
| 87 | unevaluatedProperties: false |
| 88 | |
| 89 | examples: |
| 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 | ... |