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