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 #include <linux/gpio/consumer.h>
  23
  24 struct pwm_continuous_reg_data {
  25         unsigned int min_uV_dutycycle;
  26         unsigned int max_uV_dutycycle;
  27         unsigned int dutycycle_unit;
  28 };
  29
  30 struct pwm_regulator_data {
  31         /*  Shared */
  32         struct pwm_device *pwm;
  33
  34         /* Voltage table */
  35         struct pwm_voltages *duty_cycle_table;
  36
  37         /* Continuous mode info */
  38         struct pwm_continuous_reg_data continuous;
  39
  40         /* regulator descriptor */
  41         struct regulator_desc desc;
  42
  43         /* Regulator ops */
  44         struct regulator_ops ops;
  45
  46         int state;
  47
  48         /* Enable GPIO */
  49         struct gpio_desc *enb_gpio;
  50 };
  51
  52 struct pwm_voltages {
  53         unsigned int uV;
  54         unsigned int dutycycle;
  55 };
  56
  57 /**
  58  * Voltage table call-backs
  59  */
  60 static void pwm_regulator_init_state(struct regulator_dev *rdev)
  61 {
  62         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
  63         struct pwm_state pwm_state;
  64         unsigned int dutycycle;
  65         int i;
  66
  67         pwm_get_state(drvdata->pwm, &pwm_state);
  68         dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);
  69
  70         for (i = 0; i < rdev->desc->n_voltages; i++) {
  71                 if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) {
  72                         drvdata->state = i;
  73                         return;
  74                 }
  75         }
  76 }
  77
  78 static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
  79 {
  80         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
  81
  82         if (drvdata->state < 0)
  83                 pwm_regulator_init_state(rdev);
  84
  85         return drvdata->state;
  86 }
  87
  88 static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
  89                                          unsigned selector)
  90 {
  91         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
  92         struct pwm_state pstate;
  93         int ret;
  94
  95         pwm_init_state(drvdata->pwm, &pstate);
  96         pwm_set_relative_duty_cycle(&pstate,
  97                         drvdata->duty_cycle_table[selector].dutycycle, 100);
  98
  99         ret = pwm_apply_state(drvdata->pwm, &pstate);
 100         if (ret) {
 101                 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 102                 return ret;
 103         }
 104
 105         drvdata->state = selector;
 106
 107         return 0;
 108 }
 109
 110 static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
 111                                       unsigned selector)
 112 {
 113         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 114
 115         if (selector >= rdev->desc->n_voltages)
 116                 return -EINVAL;
 117
 118         return drvdata->duty_cycle_table[selector].uV;
 119 }
 120
 121 static int pwm_regulator_enable(struct regulator_dev *dev)
 122 {
 123         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 124
 125         if (drvdata->enb_gpio)
 126                 gpiod_set_value_cansleep(drvdata->enb_gpio, 1);
 127
 128         return pwm_enable(drvdata->pwm);
 129 }
 130
 131 static int pwm_regulator_disable(struct regulator_dev *dev)
 132 {
 133         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 134
 135         pwm_disable(drvdata->pwm);
 136
 137         if (drvdata->enb_gpio)
 138                 gpiod_set_value_cansleep(drvdata->enb_gpio, 0);
 139
 140         return 0;
 141 }
 142
 143 static int pwm_regulator_is_enabled(struct regulator_dev *dev)
 144 {
 145         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 146
 147         if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio))
 148                 return false;
 149
 150         return pwm_is_enabled(drvdata->pwm);
 151 }
 152
 153 static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
 154 {
 155         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 156         unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
 157         unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
 158         unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
 159         int min_uV = rdev->constraints->min_uV;
 160         int max_uV = rdev->constraints->max_uV;
 161         int diff_uV = max_uV - min_uV;
 162         struct pwm_state pstate;
 163         unsigned int diff_duty;
 164         unsigned int voltage;
 165
 166         pwm_get_state(drvdata->pwm, &pstate);
 167
 168         voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
 169
 170         /*
 171          * The dutycycle for min_uV might be greater than the one for max_uV.
 172          * This is happening when the user needs an inversed polarity, but the
 173          * PWM device does not support inversing it in hardware.
 174          */
 175         if (max_uV_duty < min_uV_duty) {
 176                 voltage = min_uV_duty - voltage;
 177                 diff_duty = min_uV_duty - max_uV_duty;
 178         } else {
 179                 voltage = voltage - min_uV_duty;
 180                 diff_duty = max_uV_duty - min_uV_duty;
 181         }
 182
 183         voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);
 184
 185         return voltage + min_uV;
 186 }
 187
 188 static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
 189                                      int req_min_uV, int req_max_uV,
 190                                      unsigned int *selector)
 191 {
 192         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 193         unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
 194         unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
 195         unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
 196         int min_uV = rdev->constraints->min_uV;
 197         int max_uV = rdev->constraints->max_uV;
 198         int diff_uV = max_uV - min_uV;
 199         struct pwm_state pstate;
 200         unsigned int diff_duty;
 201         unsigned int dutycycle;
 202         int ret;
 203
 204         pwm_init_state(drvdata->pwm, &pstate);
 205
 206         /*
 207          * The dutycycle for min_uV might be greater than the one for max_uV.
 208          * This is happening when the user needs an inversed polarity, but the
 209          * PWM device does not support inversing it in hardware.
 210          */
 211         if (max_uV_duty < min_uV_duty)
 212                 diff_duty = min_uV_duty - max_uV_duty;
 213         else
 214                 diff_duty = max_uV_duty - min_uV_duty;
 215
 216         dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
 217                                           diff_duty,
 218                                           diff_uV);
 219
 220         if (max_uV_duty < min_uV_duty)
 221                 dutycycle = min_uV_duty - dutycycle;
 222         else
 223                 dutycycle = min_uV_duty + dutycycle;
 224
 225         pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);
 226
 227         ret = pwm_apply_state(drvdata->pwm, &pstate);
 228         if (ret) {
 229                 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 230                 return ret;
 231         }
 232
 233         return 0;
 234 }
 235
 236 static struct regulator_ops pwm_regulator_voltage_table_ops = {
 237         .set_voltage_sel = pwm_regulator_set_voltage_sel,
 238         .get_voltage_sel = pwm_regulator_get_voltage_sel,
 239         .list_voltage    = pwm_regulator_list_voltage,
 240         .map_voltage     = regulator_map_voltage_iterate,
 241         .enable          = pwm_regulator_enable,
 242         .disable         = pwm_regulator_disable,
 243         .is_enabled      = pwm_regulator_is_enabled,
 244 };
 245
 246 static struct regulator_ops pwm_regulator_voltage_continuous_ops = {
 247         .get_voltage = pwm_regulator_get_voltage,
 248         .set_voltage = pwm_regulator_set_voltage,
 249         .enable          = pwm_regulator_enable,
 250         .disable         = pwm_regulator_disable,
 251         .is_enabled      = pwm_regulator_is_enabled,
 252 };
 253
 254 static struct regulator_desc pwm_regulator_desc = {
 255         .name           = "pwm-regulator",
 256         .type           = REGULATOR_VOLTAGE,
 257         .owner          = THIS_MODULE,
 258         .supply_name    = "pwm",
 259 };
 260
 261 static int pwm_regulator_init_table(struct platform_device *pdev,
 262                                     struct pwm_regulator_data *drvdata)
 263 {
 264         struct device_node *np = pdev->dev.of_node;
 265         struct pwm_voltages *duty_cycle_table;
 266         unsigned int length = 0;
 267         int ret;
 268
 269         of_find_property(np, "voltage-table", &length);
 270
 271         if ((length < sizeof(*duty_cycle_table)) ||
 272             (length % sizeof(*duty_cycle_table))) {
 273                 dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
 274                         length);
 275                 return -EINVAL;
 276         }
 277
 278         duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
 279         if (!duty_cycle_table)
 280                 return -ENOMEM;
 281
 282         ret = of_property_read_u32_array(np, "voltage-table",
 283                                          (u32 *)duty_cycle_table,
 284                                          length / sizeof(u32));
 285         if (ret) {
 286                 dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret);
 287                 return ret;
 288         }
 289
 290         drvdata->state                  = -EINVAL;
 291         drvdata->duty_cycle_table       = duty_cycle_table;
 292         memcpy(&drvdata->ops, &pwm_regulator_voltage_table_ops,
 293                sizeof(drvdata->ops));
 294         drvdata->desc.ops = &drvdata->ops;
 295         drvdata->desc.n_voltages        = length / sizeof(*duty_cycle_table);
 296
 297         return 0;
 298 }
 299
 300 static int pwm_regulator_init_continuous(struct platform_device *pdev,
 301                                          struct pwm_regulator_data *drvdata)
 302 {
 303         u32 dutycycle_range[2] = { 0, 100 };
 304         u32 dutycycle_unit = 100;
 305
 306         memcpy(&drvdata->ops, &pwm_regulator_voltage_continuous_ops,
 307                sizeof(drvdata->ops));
 308         drvdata->desc.ops = &drvdata->ops;
 309         drvdata->desc.continuous_voltage_range = true;
 310
 311         of_property_read_u32_array(pdev->dev.of_node,
 312                                    "pwm-dutycycle-range",
 313                                    dutycycle_range, 2);
 314         of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
 315                              &dutycycle_unit);
 316
 317         if (dutycycle_range[0] > dutycycle_unit ||
 318             dutycycle_range[1] > dutycycle_unit)
 319                 return -EINVAL;
 320
 321         drvdata->continuous.dutycycle_unit = dutycycle_unit;
 322         drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
 323         drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];
 324
 325         return 0;
 326 }
 327
 328 static int pwm_regulator_probe(struct platform_device *pdev)
 329 {
 330         const struct regulator_init_data *init_data;
 331         struct pwm_regulator_data *drvdata;
 332         struct regulator_dev *regulator;
 333         struct regulator_config config = { };
 334         struct device_node *np = pdev->dev.of_node;
 335         enum gpiod_flags gpio_flags;
 336         int ret;
 337
 338         if (!np) {
 339                 dev_err(&pdev->dev, "Device Tree node missing\n");
 340                 return -EINVAL;
 341         }
 342
 343         drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
 344         if (!drvdata)
 345                 return -ENOMEM;
 346
 347         memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));
 348
 349         if (of_find_property(np, "voltage-table", NULL))
 350                 ret = pwm_regulator_init_table(pdev, drvdata);
 351         else
 352                 ret = pwm_regulator_init_continuous(pdev, drvdata);
 353         if (ret)
 354                 return ret;
 355
 356         init_data = of_get_regulator_init_data(&pdev->dev, np,
 357                                                &drvdata->desc);
 358         if (!init_data)
 359                 return -ENOMEM;
 360
 361         config.of_node = np;
 362         config.dev = &pdev->dev;
 363         config.driver_data = drvdata;
 364         config.init_data = init_data;
 365
 366         drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
 367         if (IS_ERR(drvdata->pwm)) {
 368                 ret = PTR_ERR(drvdata->pwm);
 369                 dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
 370                 return ret;
 371         }
 372
 373         if (init_data->constraints.boot_on || init_data->constraints.always_on)
 374                 gpio_flags = GPIOD_OUT_HIGH;
 375         else
 376                 gpio_flags = GPIOD_OUT_LOW;
 377         drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
 378                                                     gpio_flags);
 379         if (IS_ERR(drvdata->enb_gpio)) {
 380                 ret = PTR_ERR(drvdata->enb_gpio);
 381                 dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
 382                 return ret;
 383         }
 384
 385         ret = pwm_adjust_config(drvdata->pwm);
 386         if (ret)
 387                 return ret;
 388
 389         regulator = devm_regulator_register(&pdev->dev,
 390                                             &drvdata->desc, &config);
 391         if (IS_ERR(regulator)) {
 392                 ret = PTR_ERR(regulator);
 393                 dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
 394                         drvdata->desc.name, ret);
 395                 return ret;
 396         }
 397
 398         return 0;
 399 }
 400
 401 static const struct of_device_id pwm_of_match[] = {
 402         { .compatible = "pwm-regulator" },
 403         { },
 404 };
 405 MODULE_DEVICE_TABLE(of, pwm_of_match);
 406
 407 static struct platform_driver pwm_regulator_driver = {
 408         .driver = {
 409                 .name           = "pwm-regulator",
 410                 .of_match_table = of_match_ptr(pwm_of_match),
 411         },
 412         .probe = pwm_regulator_probe,
 413 };
 414
 415 module_platform_driver(pwm_regulator_driver);
 416
 417 MODULE_LICENSE("GPL");
 418 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
 419 MODULE_DESCRIPTION("PWM Regulator Driver");
 420 MODULE_ALIAS("platform:pwm-regulator");