1 /* 2 * Copyright (C) 2016 Rockchip Electronics Co., Ltd 3 * 4 * Based on kernel drivers/regulator/pwm-regulator.c 5 * Copyright (C) 2014 - STMicroelectronics Inc. 6 * Author: Lee Jones <lee.jones@linaro.org> 7 * 8 * SPDX-License-Identifier: GPL-2.0+ 9 */ 10 11 #include <common.h> 12 #include <dm.h> 13 #include <errno.h> 14 #include <pwm.h> 15 #include <power/regulator.h> 16 #include <libfdt.h> 17 #include <fdt_support.h> 18 #include <fdtdec.h> 19 20 DECLARE_GLOBAL_DATA_PTR; 21 22 struct pwm_regulator_info { 23 /* pwm id corresponding to the PWM driver */ 24 int pwm_id; 25 /* the period of one PWM cycle */ 26 int period_ns; 27 struct udevice *pwm; 28 /* initialize voltage of regulator */ 29 unsigned int init_voltage; 30 /* the maximum voltage of regulator */ 31 unsigned int max_voltage; 32 /* the minimum voltage of regulator */ 33 unsigned int min_voltage; 34 /* the current voltage of regulator */ 35 unsigned int volt_uV; 36 }; 37 38 static int pwm_regulator_enable(struct udevice *dev, bool enable) 39 { 40 struct pwm_regulator_info *priv = dev_get_priv(dev); 41 42 return pwm_set_enable(priv->pwm, priv->pwm_id, enable); 43 } 44 45 static int pwm_voltage_to_duty_cycle_percentage(struct udevice *dev, int req_uV) 46 { 47 struct pwm_regulator_info *priv = dev_get_priv(dev); 48 int min_uV = priv->min_voltage; 49 int max_uV = priv->max_voltage; 50 int diff = max_uV - min_uV; 51 52 return 100 - (((req_uV * 100) - (min_uV * 100)) / diff); 53 } 54 55 static int pwm_regulator_get_voltage(struct udevice *dev) 56 { 57 struct pwm_regulator_info *priv = dev_get_priv(dev); 58 59 return priv->volt_uV; 60 } 61 62 static int pwm_regulator_set_voltage(struct udevice *dev, int uvolt) 63 { 64 struct pwm_regulator_info *priv = dev_get_priv(dev); 65 int duty_cycle; 66 int ret = 0; 67 68 duty_cycle = pwm_voltage_to_duty_cycle_percentage(dev, uvolt); 69 70 ret = pwm_set_config(priv->pwm, priv->pwm_id, 71 (priv->period_ns / 100) * duty_cycle, priv->period_ns); 72 if (ret) { 73 dev_err(dev, "Failed to configure PWM\n"); 74 return ret; 75 } 76 77 ret = pwm_set_enable(priv->pwm, priv->pwm_id, true); 78 if (ret) { 79 dev_err(dev, "Failed to enable PWM\n"); 80 return ret; 81 } 82 priv->volt_uV = uvolt; 83 return ret; 84 } 85 86 static int pwm_regulator_ofdata_to_platdata(struct udevice *dev) 87 { 88 struct pwm_regulator_info *priv = dev_get_priv(dev); 89 struct fdtdec_phandle_args args; 90 const void *blob = gd->fdt_blob; 91 int node = dev_of_offset(dev); 92 int ret; 93 94 ret = fdtdec_parse_phandle_with_args(blob, node, "pwms", "#pwm-cells", 95 0, 0, &args); 96 if (ret) { 97 debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret); 98 return ret; 99 } 100 /* TODO: pwm_id here from device tree if needed */ 101 102 priv->period_ns = args.args[1]; 103 104 priv->init_voltage = fdtdec_get_int(blob, node, 105 "regulator-init-microvolt", -1); 106 if (priv->init_voltage < 0) { 107 printf("Cannot find regulator pwm init_voltage\n"); 108 return -EINVAL; 109 } 110 111 ret = uclass_get_device_by_of_offset(UCLASS_PWM, args.node, &priv->pwm); 112 if (ret) { 113 debug("%s: Cannot get PWM: ret=%d\n", __func__, ret); 114 return ret; 115 } 116 117 return 0; 118 } 119 120 static int pwm_regulator_probe(struct udevice *dev) 121 { 122 struct pwm_regulator_info *priv = dev_get_priv(dev); 123 struct dm_regulator_uclass_platdata *uc_pdata; 124 125 uc_pdata = dev_get_uclass_platdata(dev); 126 127 uc_pdata->type = REGULATOR_TYPE_BUCK; 128 uc_pdata->mode_count = 0; 129 priv->max_voltage = uc_pdata->max_uV; 130 priv->min_voltage = uc_pdata->min_uV; 131 132 if (priv->init_voltage) 133 pwm_regulator_set_voltage(dev, priv->init_voltage); 134 135 pwm_regulator_enable(dev, 1); 136 137 return 0; 138 } 139 140 static const struct dm_regulator_ops pwm_regulator_ops = { 141 .get_value = pwm_regulator_get_voltage, 142 .set_value = pwm_regulator_set_voltage, 143 .set_enable = pwm_regulator_enable, 144 }; 145 146 static const struct udevice_id pwm_regulator_ids[] = { 147 { .compatible = "pwm-regulator" }, 148 { } 149 }; 150 151 U_BOOT_DRIVER(pwm_regulator) = { 152 .name = "pwm_regulator", 153 .id = UCLASS_REGULATOR, 154 .ops = &pwm_regulator_ops, 155 .probe = pwm_regulator_probe, 156 .of_match = pwm_regulator_ids, 157 .ofdata_to_platdata = pwm_regulator_ofdata_to_platdata, 158 .priv_auto_alloc_size = sizeof(struct pwm_regulator_info), 159 }; 160