drivers/power/regulator/pwm_regulator.c

   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         /*
  28          * the polarity of one PWM
  29          * 0: normal polarity
  30          * 1: inverted polarity
  31          */
  32         bool polarity;
  33         struct udevice *pwm;
  34         /* initialize voltage of regulator */
  35         int init_voltage;
  36         /* the maximum voltage of regulator */
  37         int max_voltage;
  38         /* the minimum voltage of regulator */
  39         int min_voltage;
  40         /* the current voltage of regulator */
  41         int volt_uV;
  42 };
  43
  44 static int pwm_regulator_enable(struct udevice *dev, bool enable)
  45 {
  46         struct pwm_regulator_info *priv = dev_get_priv(dev);
  47
  48         return pwm_set_enable(priv->pwm, priv->pwm_id, enable);
  49 }
  50
  51 static int pwm_voltage_to_duty_cycle_percentage(struct udevice *dev, int req_uV)
  52 {
  53         struct pwm_regulator_info *priv = dev_get_priv(dev);
  54         int min_uV = priv->min_voltage;
  55         int max_uV = priv->max_voltage;
  56         int diff = max_uV - min_uV;
  57
  58         return ((req_uV * 100) - (min_uV * 100)) / diff;
  59 }
  60
  61 static int pwm_regulator_get_voltage(struct udevice *dev)
  62 {
  63         struct pwm_regulator_info *priv = dev_get_priv(dev);
  64
  65         return priv->volt_uV;
  66 }
  67
  68 static int pwm_regulator_set_voltage(struct udevice *dev, int uvolt)
  69 {
  70         struct pwm_regulator_info *priv = dev_get_priv(dev);
  71         int duty_cycle;
  72         int ret = 0;
  73
  74         duty_cycle = pwm_voltage_to_duty_cycle_percentage(dev, uvolt);
  75
  76         ret = pwm_set_invert(priv->pwm, priv->pwm_id, priv->polarity);
  77         if (ret) {
  78                 dev_err(dev, "Failed to init PWM\n");
  79                 return ret;
  80         }
  81
  82         ret = pwm_set_config(priv->pwm, priv->pwm_id,
  83                         priv->period_ns, (priv->period_ns / 100) * duty_cycle);
  84         if (ret) {
  85                 dev_err(dev, "Failed to configure PWM\n");
  86                 return ret;
  87         }
  88
  89         priv->volt_uV = uvolt;
  90
  91         return ret;
  92 }
  93
  94 static int pwm_regulator_ofdata_to_platdata(struct udevice *dev)
  95 {
  96         struct pwm_regulator_info *priv = dev_get_priv(dev);
  97         struct fdtdec_phandle_args args;
  98         const void *blob = gd->fdt_blob;
  99         int node = dev_of_offset(dev);
 100         int ret;
 101
 102         ret = fdtdec_parse_phandle_with_args(blob, node, "pwms", "#pwm-cells",
 103                                              0, 0, &args);
 104         if (ret) {
 105                 debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret);
 106                 return ret;
 107         }
 108
 109         priv->period_ns = args.args[1];
 110         priv->polarity = args.args[2];
 111
 112         priv->init_voltage = fdtdec_get_int(blob, node,
 113                         "regulator-init-microvolt", -1);
 114         if (priv->init_voltage < 0) {
 115                 printf("Cannot find regulator pwm init_voltage\n");
 116                 return -EINVAL;
 117         }
 118
 119         ret = uclass_get_device_by_of_offset(UCLASS_PWM, args.node, &priv->pwm);
 120         if (ret) {
 121                 debug("%s: Cannot get PWM: ret=%d\n", __func__, ret);
 122                 return ret;
 123         }
 124
 125         return 0;
 126 }
 127
 128 static int pwm_regulator_probe(struct udevice *dev)
 129 {
 130         struct pwm_regulator_info *priv = dev_get_priv(dev);
 131         struct dm_regulator_uclass_platdata *uc_pdata;
 132
 133         uc_pdata = dev_get_uclass_platdata(dev);
 134
 135         uc_pdata->type = REGULATOR_TYPE_BUCK;
 136         uc_pdata->mode_count = 0;
 137         priv->max_voltage = uc_pdata->max_uV;
 138         priv->min_voltage = uc_pdata->min_uV;
 139
 140         if (priv->init_voltage)
 141                 pwm_regulator_set_voltage(dev, priv->init_voltage);
 142
 143         return 0;
 144 }
 145
 146 static const struct dm_regulator_ops pwm_regulator_ops = {
 147         .get_value  = pwm_regulator_get_voltage,
 148         .set_value  = pwm_regulator_set_voltage,
 149         .set_enable = pwm_regulator_enable,
 150 };
 151
 152 static const struct udevice_id pwm_regulator_ids[] = {
 153         { .compatible = "pwm-regulator" },
 154         { }
 155 };
 156
 157 U_BOOT_DRIVER(pwm_regulator) = {
 158         .name = "pwm_regulator",
 159         .id = UCLASS_REGULATOR,
 160         .ops = &pwm_regulator_ops,
 161         .probe = pwm_regulator_probe,
 162         .of_match = pwm_regulator_ids,
 163         .ofdata_to_platdata     = pwm_regulator_ofdata_to_platdata,
 164         .priv_auto_alloc_size   = sizeof(struct pwm_regulator_info),
 165 };