1Bindings for the Generic PWM Regulator 2====================================== 3 4Currently supports 2 modes of operation: 5 6Voltage Table: When in this mode, a voltage table (See below) of 7 predefined voltage <=> duty-cycle values must be 8 provided via DT. Limitations are that the regulator can 9 only operate at the voltages supplied in the table. 10 Intermediary duty-cycle values which would normally 11 allow finer grained voltage selection are ignored and 12 rendered useless. Although more control is given to 13 the user if the assumptions made in continuous-voltage 14 mode do not reign true. 15 16Continuous Voltage: This mode uses the regulator's maximum and minimum 17 supplied voltages specified in the 18 regulator-{min,max}-microvolt properties to calculate 19 appropriate duty-cycle values. This allows for a much 20 more fine grained solution when compared with 21 voltage-table mode above. This solution does make an 22 assumption that a %50 duty-cycle value will cause the 23 regulator voltage to run at half way between the 24 supplied max_uV and min_uV values. 25 26Required properties: 27-------------------- 28- compatible: Should be "pwm-regulator" 29 30- pwms: PWM specification (See: ../pwm/pwm.txt) 31 32Only required for Voltage Table Mode: 33- voltage-table: Voltage and Duty-Cycle table consisting of 2 cells 34 First cell is voltage in microvolts (uV) 35 Second cell is duty-cycle in percent (%) 36 37Optional properties for Continuous mode: 38- pwm-dutycycle-unit: Integer value encoding the duty cycle unit. If not 39 defined, <100> is assumed, meaning that 40 pwm-dutycycle-range contains values expressed in 41 percent. 42 43- pwm-dutycycle-range: Should contain 2 entries. The first entry is encoding 44 the dutycycle for regulator-min-microvolt and the 45 second one the dutycycle for regulator-max-microvolt. 46 Duty cycle values are expressed in pwm-dutycycle-unit. 47 If not defined, <0 100> is assumed. 48 49NB: To be clear, if voltage-table is provided, then the device will be used 50in Voltage Table Mode. If no voltage-table is provided, then the device will 51be used in Continuous Voltage Mode. 52 53Optional properties: 54-------------------- 55- enable-gpios: GPIO to use to enable/disable the regulator 56 57Any property defined as part of the core regulator binding can also be used. 58(See: ../regulator/regulator.txt) 59 60Continuous Voltage With Enable GPIO Example: 61 pwm_regulator { 62 compatible = "pwm-regulator"; 63 pwms = <&pwm1 0 8448 0>; 64 enable-gpios = <&gpio0 23 GPIO_ACTIVE_HIGH>; 65 regulator-min-microvolt = <1016000>; 66 regulator-max-microvolt = <1114000>; 67 regulator-name = "vdd_logic"; 68 /* unit == per-mille */ 69 pwm-dutycycle-unit = <1000>; 70 /* 71 * Inverted PWM logic, and the duty cycle range is limited 72 * to 30%-70%. 73 */ 74 pwm-dutycycle-range = <700 300>; /* */ 75 }; 76 77Voltage Table Example: 78 pwm_regulator { 79 compatible = "pwm-regulator"; 80 pwms = <&pwm1 0 8448 0>; 81 regulator-min-microvolt = <1016000>; 82 regulator-max-microvolt = <1114000>; 83 regulator-name = "vdd_logic"; 84 85 /* Voltage Duty-Cycle */ 86 voltage-table = <1114000 0>, 87 <1095000 10>, 88 <1076000 20>, 89 <1056000 30>, 90 <1036000 40>, 91 <1016000 50>; 92 }; 93