drivers/regulator/st-pwm.c

   1 /*
   2  * Regulator driver for ST's 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 #define ST_PWM_REG_PERIOD 8448
  24
  25 struct st_pwm_regulator_pdata {
  26         const struct regulator_desc *desc;
  27         struct st_pwm_voltages *duty_cycle_table;
  28 };
  29
  30 struct st_pwm_regulator_data {
  31         const struct st_pwm_regulator_pdata *pdata;
  32         struct pwm_device *pwm;
  33         bool enabled;
  34         int state;
  35 };
  36
  37 struct st_pwm_voltages {
  38         unsigned int uV;
  39         unsigned int dutycycle;
  40 };
  41
  42 static int st_pwm_regulator_get_voltage_sel(struct regulator_dev *dev)
  43 {
  44         struct st_pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
  45
  46         return drvdata->state;
  47 }
  48
  49 static int st_pwm_regulator_set_voltage_sel(struct regulator_dev *dev,
  50                                             unsigned selector)
  51 {
  52         struct st_pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
  53         int dutycycle;
  54         int ret;
  55
  56         dutycycle = (ST_PWM_REG_PERIOD / 100) *
  57                 drvdata->pdata->duty_cycle_table[selector].dutycycle;
  58
  59         ret = pwm_config(drvdata->pwm, dutycycle, ST_PWM_REG_PERIOD);
  60         if (ret) {
  61                 dev_err(&dev->dev, "Failed to configure PWM\n");
  62                 return ret;
  63         }
  64
  65         drvdata->state = selector;
  66
  67         if (!drvdata->enabled) {
  68                 ret = pwm_enable(drvdata->pwm);
  69                 if (ret) {
  70                         dev_err(&dev->dev, "Failed to enable PWM\n");
  71                         return ret;
  72                 }
  73                 drvdata->enabled = true;
  74         }
  75
  76         return 0;
  77 }
  78
  79 static int st_pwm_regulator_list_voltage(struct regulator_dev *dev,
  80                                          unsigned selector)
  81 {
  82         struct st_pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
  83
  84         if (selector >= dev->desc->n_voltages)
  85                 return -EINVAL;
  86
  87         return drvdata->pdata->duty_cycle_table[selector].uV;
  88 }
  89
  90 static struct regulator_ops st_pwm_regulator_voltage_ops = {
  91         .set_voltage_sel = st_pwm_regulator_set_voltage_sel,
  92         .get_voltage_sel = st_pwm_regulator_get_voltage_sel,
  93         .list_voltage    = st_pwm_regulator_list_voltage,
  94         .map_voltage     = regulator_map_voltage_iterate,
  95 };
  96
  97 static struct st_pwm_voltages b2105_duty_cycle_table[] = {
  98         { .uV = 1114000, .dutycycle = 0,  },
  99         { .uV = 1095000, .dutycycle = 10, },
 100         { .uV = 1076000, .dutycycle = 20, },
 101         { .uV = 1056000, .dutycycle = 30, },
 102         { .uV = 1036000, .dutycycle = 40, },
 103         { .uV = 1016000, .dutycycle = 50, },
 104         /* WARNING: Values above 50% duty-cycle cause boot failures. */
 105 };
 106
 107 static const struct regulator_desc b2105_desc = {
 108         .name           = "b2105-pwm-regulator",
 109         .ops            = &st_pwm_regulator_voltage_ops,
 110         .type           = REGULATOR_VOLTAGE,
 111         .owner          = THIS_MODULE,
 112         .n_voltages     = ARRAY_SIZE(b2105_duty_cycle_table),
 113         .supply_name    = "pwm",
 114 };
 115
 116 static const struct st_pwm_regulator_pdata b2105_info = {
 117         .desc             = &b2105_desc,
 118         .duty_cycle_table = b2105_duty_cycle_table,
 119 };
 120
 121 static const struct of_device_id st_pwm_of_match[] = {
 122         { .compatible = "st,b2105-pwm-regulator", .data = &b2105_info, },
 123         { },
 124 };
 125 MODULE_DEVICE_TABLE(of, st_pwm_of_match);
 126
 127 static int st_pwm_regulator_probe(struct platform_device *pdev)
 128 {
 129         struct st_pwm_regulator_data *drvdata;
 130         struct regulator_dev *regulator;
 131         struct regulator_config config = { };
 132         struct device_node *np = pdev->dev.of_node;
 133         const struct of_device_id *of_match;
 134
 135         if (!np) {
 136                 dev_err(&pdev->dev, "Device Tree node missing\n");
 137                 return -EINVAL;
 138         }
 139
 140         drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
 141         if (!drvdata)
 142                 return -ENOMEM;
 143
 144         of_match = of_match_device(st_pwm_of_match, &pdev->dev);
 145         if (!of_match) {
 146                 dev_err(&pdev->dev, "failed to match of device\n");
 147                 return -ENODEV;
 148         }
 149         drvdata->pdata = of_match->data;
 150
 151         config.init_data = of_get_regulator_init_data(&pdev->dev, np);
 152         if (!config.init_data)
 153                 return -ENOMEM;
 154
 155         config.of_node = np;
 156         config.dev = &pdev->dev;
 157         config.driver_data = drvdata;
 158
 159         drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
 160         if (IS_ERR(drvdata->pwm)) {
 161                 dev_err(&pdev->dev, "Failed to get PWM\n");
 162                 return PTR_ERR(drvdata->pwm);
 163         }
 164
 165         regulator = devm_regulator_register(&pdev->dev,
 166                                             drvdata->pdata->desc, &config);
 167         if (IS_ERR(regulator)) {
 168                 dev_err(&pdev->dev, "Failed to register regulator %s\n",
 169                         drvdata->pdata->desc->name);
 170                 return PTR_ERR(regulator);
 171         }
 172
 173         return 0;
 174 }
 175
 176 static struct platform_driver st_pwm_regulator_driver = {
 177         .driver = {
 178                 .name           = "st-pwm-regulator",
 179                 .owner          = THIS_MODULE,
 180                 .of_match_table = of_match_ptr(st_pwm_of_match),
 181         },
 182         .probe = st_pwm_regulator_probe,
 183 };
 184
 185 module_platform_driver(st_pwm_regulator_driver);
 186
 187 MODULE_LICENSE("GPL");
 188 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
 189 MODULE_DESCRIPTION("ST PWM Regulator Driver");
 190 MODULE_ALIAS("platform:st_pwm-regulator");