kernel/drivers/regulator/pwm-regulator.c

   1 /*
   2  * Regulator driver for PWM Regulators
   3  *
   4  * Copyright (C) 2014 - STMicroelectronics Inc.
   5  *
   6  * Author: Lee Jones <lee.jones@linaro.org>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/err.h>
  16 #include <linux/regulator/driver.h>
  17 #include <linux/regulator/machine.h>
  18 #include <linux/regulator/of_regulator.h>
  19 #include <linux/of.h>
  20 #include <linux/of_device.h>
  21 #include <linux/pwm.h>
  22
  23 struct pwm_regulator_data {
  24         struct regulator_desc desc;
  25         struct pwm_voltages *duty_cycle_table;
  26         struct pwm_device *pwm;
  27         bool enabled;
  28         int state;
  29 };
  30
  31 struct pwm_voltages {
  32         unsigned int uV;
  33         unsigned int dutycycle;
  34 };
  35
  36 static int pwm_regulator_get_voltage_sel(struct regulator_dev *dev)
  37 {
  38         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
  39
  40         return drvdata->state;
  41 }
  42
  43 static int pwm_regulator_set_voltage_sel(struct regulator_dev *dev,
  44                                          unsigned selector)
  45 {
  46         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
  47         unsigned int pwm_reg_period;
  48         int dutycycle;
  49         int ret;
  50
  51         pwm_reg_period = pwm_get_period(drvdata->pwm);
  52
  53         dutycycle = (pwm_reg_period *
  54                     drvdata->duty_cycle_table[selector].dutycycle) / 100;
  55
  56         ret = pwm_config(drvdata->pwm, dutycycle, pwm_reg_period);
  57         if (ret) {
  58                 dev_err(&dev->dev, "Failed to configure PWM\n");
  59                 return ret;
  60         }
  61
  62         drvdata->state = selector;
  63
  64         if (!drvdata->enabled) {
  65                 ret = pwm_enable(drvdata->pwm);
  66                 if (ret) {
  67                         dev_err(&dev->dev, "Failed to enable PWM\n");
  68                         return ret;
  69                 }
  70                 drvdata->enabled = true;
  71         }
  72
  73         return 0;
  74 }
  75
  76 static int pwm_regulator_list_voltage(struct regulator_dev *dev,
  77                                       unsigned selector)
  78 {
  79         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
  80
  81         if (selector >= drvdata->desc.n_voltages)
  82                 return -EINVAL;
  83
  84         return drvdata->duty_cycle_table[selector].uV;
  85 }
  86
  87 static struct regulator_ops pwm_regulator_voltage_ops = {
  88         .set_voltage_sel = pwm_regulator_set_voltage_sel,
  89         .get_voltage_sel = pwm_regulator_get_voltage_sel,
  90         .list_voltage    = pwm_regulator_list_voltage,
  91         .map_voltage     = regulator_map_voltage_iterate,
  92 };
  93
  94 static const struct regulator_desc pwm_regulator_desc = {
  95         .name           = "pwm-regulator",
  96         .ops            = &pwm_regulator_voltage_ops,
  97         .type           = REGULATOR_VOLTAGE,
  98         .owner          = THIS_MODULE,
  99         .supply_name    = "pwm",
 100 };
 101
 102 static int pwm_regulator_probe(struct platform_device *pdev)
 103 {
 104         struct pwm_regulator_data *drvdata;
 105         struct property *prop;
 106         struct regulator_dev *regulator;
 107         struct regulator_config config = { };
 108         struct device_node *np = pdev->dev.of_node;
 109         int length, ret;
 110
 111         if (!np) {
 112                 dev_err(&pdev->dev, "Device Tree node missing\n");
 113                 return -EINVAL;
 114         }
 115
 116         drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
 117         if (!drvdata)
 118                 return -ENOMEM;
 119
 120         memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(pwm_regulator_desc));
 121
 122         /* determine the number of voltage-table */
 123         prop = of_find_property(np, "voltage-table", &length);
 124         if (!prop) {
 125                 dev_err(&pdev->dev, "No voltage-table\n");
 126                 return -EINVAL;
 127         }
 128
 129         if ((length < sizeof(*drvdata->duty_cycle_table)) ||
 130             (length % sizeof(*drvdata->duty_cycle_table))) {
 131                 dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
 132                         length);
 133                 return -EINVAL;
 134         }
 135
 136         drvdata->desc.n_voltages = length / sizeof(*drvdata->duty_cycle_table);
 137
 138         drvdata->duty_cycle_table = devm_kzalloc(&pdev->dev,
 139                                                  length, GFP_KERNEL);
 140         if (!drvdata->duty_cycle_table)
 141                 return -ENOMEM;
 142
 143         /* read voltage table from DT property */
 144         ret = of_property_read_u32_array(np, "voltage-table",
 145                                          (u32 *)drvdata->duty_cycle_table,
 146                                          length / sizeof(u32));
 147         if (ret < 0) {
 148                 dev_err(&pdev->dev, "read voltage-table failed\n");
 149                 return ret;
 150         }
 151
 152         config.init_data = of_get_regulator_init_data(&pdev->dev, np,
 153                                                       &drvdata->desc);
 154         if (!config.init_data)
 155                 return -ENOMEM;
 156
 157         config.of_node = np;
 158         config.dev = &pdev->dev;
 159         config.driver_data = drvdata;
 160
 161         drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
 162         if (IS_ERR(drvdata->pwm)) {
 163                 dev_err(&pdev->dev, "Failed to get PWM\n");
 164                 return PTR_ERR(drvdata->pwm);
 165         }
 166
 167         regulator = devm_regulator_register(&pdev->dev,
 168                                             &drvdata->desc, &config);
 169         if (IS_ERR(regulator)) {
 170                 dev_err(&pdev->dev, "Failed to register regulator %s\n",
 171                         drvdata->desc.name);
 172                 return PTR_ERR(regulator);
 173         }
 174
 175         return 0;
 176 }
 177
 178 static const struct of_device_id pwm_of_match[] = {
 179         { .compatible = "pwm-regulator" },
 180         { },
 181 };
 182 MODULE_DEVICE_TABLE(of, pwm_of_match);
 183
 184 static struct platform_driver pwm_regulator_driver = {
 185         .driver = {
 186                 .name           = "pwm-regulator",
 187                 .of_match_table = of_match_ptr(pwm_of_match),
 188         },
 189         .probe = pwm_regulator_probe,
 190 };
 191
 192 module_platform_driver(pwm_regulator_driver);
 193
 194 MODULE_LICENSE("GPL");
 195 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
 196 MODULE_DESCRIPTION("PWM Regulator Driver");
 197 MODULE_ALIAS("platform:pwm-regulator");