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/delay.h>
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/err.h>
  17 #include <linux/regulator/driver.h>
  18 #include <linux/regulator/machine.h>
  19 #include <linux/regulator/of_regulator.h>
  20 #include <linux/of.h>
  21 #include <linux/of_device.h>
  22 #include <linux/pwm.h>
  23 #include <linux/gpio/consumer.h>
  24
  25 struct pwm_continuous_reg_data {
  26         unsigned int min_uV_dutycycle;
  27         unsigned int max_uV_dutycycle;
  28         unsigned int dutycycle_unit;
  29 };
  30
  31 struct pwm_regulator_data {
  32         /*  Shared */
  33         struct pwm_device *pwm;
  34
  35         /* Voltage table */
  36         struct pwm_voltages *duty_cycle_table;
  37
  38         /* Continuous mode info */
  39         struct pwm_continuous_reg_data continuous;
  40
  41         /* regulator descriptor */
  42         struct regulator_desc desc;
  43
  44         /* Regulator ops */
  45         struct regulator_ops ops;
  46
  47         int state;
  48
  49         /* Enable GPIO */
  50         struct gpio_desc *enb_gpio;
  51 };
  52
  53 struct pwm_voltages {
  54         unsigned int uV;
  55         unsigned int dutycycle;
  56 };
  57
  58 /**
  59  * Voltage table call-backs
  60  */
  61 static void pwm_regulator_init_state(struct regulator_dev *rdev)
  62 {
  63         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
  64         struct pwm_state pwm_state;
  65         unsigned int dutycycle;
  66         int i;
  67
  68         pwm_get_state(drvdata->pwm, &pwm_state);
  69         dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);
  70
  71         for (i = 0; i < rdev->desc->n_voltages; i++) {
  72                 if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) {
  73                         drvdata->state = i;
  74                         return;
  75                 }
  76         }
  77 }
  78
  79 static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
  80 {
  81         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
  82
  83         if (drvdata->state < 0)
  84                 pwm_regulator_init_state(rdev);
  85
  86         return drvdata->state;
  87 }
  88
  89 static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
  90                                          unsigned selector)
  91 {
  92         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
  93         struct pwm_state pstate;
  94         int ret;
  95
  96         pwm_init_state(drvdata->pwm, &pstate);
  97         pwm_set_relative_duty_cycle(&pstate,
  98                         drvdata->duty_cycle_table[selector].dutycycle, 100);
  99
 100         ret = pwm_apply_state(drvdata->pwm, &pstate);
 101         if (ret) {
 102                 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 103                 return ret;
 104         }
 105
 106         drvdata->state = selector;
 107
 108         return 0;
 109 }
 110
 111 static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
 112                                       unsigned selector)
 113 {
 114         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 115
 116         if (selector >= rdev->desc->n_voltages)
 117                 return -EINVAL;
 118
 119         return drvdata->duty_cycle_table[selector].uV;
 120 }
 121
 122 static int pwm_regulator_enable(struct regulator_dev *dev)
 123 {
 124         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 125
 126         if (drvdata->enb_gpio)
 127                 gpiod_set_value_cansleep(drvdata->enb_gpio, 1);
 128
 129         return pwm_enable(drvdata->pwm);
 130 }
 131
 132 static int pwm_regulator_disable(struct regulator_dev *dev)
 133 {
 134         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 135
 136         pwm_disable(drvdata->pwm);
 137
 138         if (drvdata->enb_gpio)
 139                 gpiod_set_value_cansleep(drvdata->enb_gpio, 0);
 140
 141         return 0;
 142 }
 143
 144 static int pwm_regulator_is_enabled(struct regulator_dev *dev)
 145 {
 146         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 147
 148         if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio))
 149                 return false;
 150
 151         return pwm_is_enabled(drvdata->pwm);
 152 }
 153
 154 static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
 155 {
 156         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 157         unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
 158         unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
 159         unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
 160         int min_uV = rdev->constraints->min_uV;
 161         int max_uV = rdev->constraints->max_uV;
 162         int diff_uV = max_uV - min_uV;
 163         struct pwm_state pstate;
 164         unsigned int diff_duty;
 165         unsigned int voltage;
 166
 167         pwm_get_state(drvdata->pwm, &pstate);
 168
 169         voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
 170
 171         /*
 172          * The dutycycle for min_uV might be greater than the one for max_uV.
 173          * This is happening when the user needs an inversed polarity, but the
 174          * PWM device does not support inversing it in hardware.
 175          */
 176         if (max_uV_duty < min_uV_duty) {
 177                 voltage = min_uV_duty - voltage;
 178                 diff_duty = min_uV_duty - max_uV_duty;
 179         } else {
 180                 voltage = voltage - min_uV_duty;
 181                 diff_duty = max_uV_duty - min_uV_duty;
 182         }
 183
 184         voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);
 185
 186         return voltage + min_uV;
 187 }
 188
 189 static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
 190                                      int req_min_uV, int req_max_uV,
 191                                      unsigned int *selector)
 192 {
 193         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 194         unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
 195         unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
 196         unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
 197         unsigned int ramp_delay = rdev->constraints->ramp_delay;
 198         int min_uV = rdev->constraints->min_uV;
 199         int max_uV = rdev->constraints->max_uV;
 200         int diff_uV = max_uV - min_uV;
 201         struct pwm_state pstate;
 202         int old_uV = pwm_regulator_get_voltage(rdev);
 203         unsigned int diff_duty;
 204         unsigned int dutycycle;
 205         int ret;
 206
 207         pwm_init_state(drvdata->pwm, &pstate);
 208
 209         /*
 210          * The dutycycle for min_uV might be greater than the one for max_uV.
 211          * This is happening when the user needs an inversed polarity, but the
 212          * PWM device does not support inversing it in hardware.
 213          */
 214         if (max_uV_duty < min_uV_duty)
 215                 diff_duty = min_uV_duty - max_uV_duty;
 216         else
 217                 diff_duty = max_uV_duty - min_uV_duty;
 218
 219         dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
 220                                           diff_duty,
 221                                           diff_uV);
 222
 223         if (max_uV_duty < min_uV_duty)
 224                 dutycycle = min_uV_duty - dutycycle;
 225         else
 226                 dutycycle = min_uV_duty + dutycycle;
 227
 228         pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);
 229
 230         ret = pwm_apply_state(drvdata->pwm, &pstate);
 231         if (ret) {
 232                 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 233                 return ret;
 234         }
 235
 236         if ((ramp_delay == 0) || !pwm_regulator_is_enabled(rdev))
 237                 return 0;
 238
 239         /* Ramp delay is in uV/uS. Adjust to uS and delay */
 240         ramp_delay = DIV_ROUND_UP(abs(req_min_uV - old_uV), ramp_delay);
 241         usleep_range(ramp_delay, ramp_delay + DIV_ROUND_UP(ramp_delay, 10));
 242
 243         return 0;
 244 }
 245
 246 static struct regulator_ops pwm_regulator_voltage_table_ops = {
 247         .set_voltage_sel = pwm_regulator_set_voltage_sel,
 248         .get_voltage_sel = pwm_regulator_get_voltage_sel,
 249         .list_voltage    = pwm_regulator_list_voltage,
 250         .map_voltage     = regulator_map_voltage_iterate,
 251         .enable          = pwm_regulator_enable,
 252         .disable         = pwm_regulator_disable,
 253         .is_enabled      = pwm_regulator_is_enabled,
 254 };
 255
 256 static struct regulator_ops pwm_regulator_voltage_continuous_ops = {
 257         .get_voltage = pwm_regulator_get_voltage,
 258         .set_voltage = pwm_regulator_set_voltage,
 259         .enable          = pwm_regulator_enable,
 260         .disable         = pwm_regulator_disable,
 261         .is_enabled      = pwm_regulator_is_enabled,
 262 };
 263
 264 static struct regulator_desc pwm_regulator_desc = {
 265         .name           = "pwm-regulator",
 266         .type           = REGULATOR_VOLTAGE,
 267         .owner          = THIS_MODULE,
 268         .supply_name    = "pwm",
 269 };
 270
 271 static int pwm_regulator_init_table(struct platform_device *pdev,
 272                                     struct pwm_regulator_data *drvdata)
 273 {
 274         struct device_node *np = pdev->dev.of_node;
 275         struct pwm_voltages *duty_cycle_table;
 276         unsigned int length = 0;
 277         int ret;
 278
 279         of_find_property(np, "voltage-table", &length);
 280
 281         if ((length < sizeof(*duty_cycle_table)) ||
 282             (length % sizeof(*duty_cycle_table))) {
 283                 dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
 284                         length);
 285                 return -EINVAL;
 286         }
 287
 288         duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
 289         if (!duty_cycle_table)
 290                 return -ENOMEM;
 291
 292         ret = of_property_read_u32_array(np, "voltage-table",
 293                                          (u32 *)duty_cycle_table,
 294                                          length / sizeof(u32));
 295         if (ret) {
 296                 dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret);
 297                 return ret;
 298         }
 299
 300         drvdata->state                  = -EINVAL;
 301         drvdata->duty_cycle_table       = duty_cycle_table;
 302         memcpy(&drvdata->ops, &pwm_regulator_voltage_table_ops,
 303                sizeof(drvdata->ops));
 304         drvdata->desc.ops = &drvdata->ops;
 305         drvdata->desc.n_voltages        = length / sizeof(*duty_cycle_table);
 306
 307         return 0;
 308 }
 309
 310 static int pwm_regulator_init_continuous(struct platform_device *pdev,
 311                                          struct pwm_regulator_data *drvdata)
 312 {
 313         u32 dutycycle_range[2] = { 0, 100 };
 314         u32 dutycycle_unit = 100;
 315
 316         memcpy(&drvdata->ops, &pwm_regulator_voltage_continuous_ops,
 317                sizeof(drvdata->ops));
 318         drvdata->desc.ops = &drvdata->ops;
 319         drvdata->desc.continuous_voltage_range = true;
 320
 321         of_property_read_u32_array(pdev->dev.of_node,
 322                                    "pwm-dutycycle-range",
 323                                    dutycycle_range, 2);
 324         of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
 325                              &dutycycle_unit);
 326
 327         if (dutycycle_range[0] > dutycycle_unit ||
 328             dutycycle_range[1] > dutycycle_unit)
 329                 return -EINVAL;
 330
 331         drvdata->continuous.dutycycle_unit = dutycycle_unit;
 332         drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
 333         drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];
 334
 335         return 0;
 336 }
 337
 338 static int pwm_regulator_probe(struct platform_device *pdev)
 339 {
 340         const struct regulator_init_data *init_data;
 341         struct pwm_regulator_data *drvdata;
 342         struct regulator_dev *regulator;
 343         struct regulator_config config = { };
 344         struct device_node *np = pdev->dev.of_node;
 345         enum gpiod_flags gpio_flags;
 346         int ret;
 347
 348         if (!np) {
 349                 dev_err(&pdev->dev, "Device Tree node missing\n");
 350                 return -EINVAL;
 351         }
 352
 353         drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
 354         if (!drvdata)
 355                 return -ENOMEM;
 356
 357         memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));
 358
 359         if (of_find_property(np, "voltage-table", NULL))
 360                 ret = pwm_regulator_init_table(pdev, drvdata);
 361         else
 362                 ret = pwm_regulator_init_continuous(pdev, drvdata);
 363         if (ret)
 364                 return ret;
 365
 366         init_data = of_get_regulator_init_data(&pdev->dev, np,
 367                                                &drvdata->desc);
 368         if (!init_data)
 369                 return -ENOMEM;
 370
 371         config.of_node = np;
 372         config.dev = &pdev->dev;
 373         config.driver_data = drvdata;
 374         config.init_data = init_data;
 375
 376         drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
 377         if (IS_ERR(drvdata->pwm)) {
 378                 ret = PTR_ERR(drvdata->pwm);
 379                 dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
 380                 return ret;
 381         }
 382
 383         if (init_data->constraints.boot_on || init_data->constraints.always_on)
 384                 gpio_flags = GPIOD_OUT_HIGH;
 385         else
 386                 gpio_flags = GPIOD_OUT_LOW;
 387         drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
 388                                                     gpio_flags);
 389         if (IS_ERR(drvdata->enb_gpio)) {
 390                 ret = PTR_ERR(drvdata->enb_gpio);
 391                 dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
 392                 return ret;
 393         }
 394
 395         ret = pwm_adjust_config(drvdata->pwm);
 396         if (ret)
 397                 return ret;
 398
 399         regulator = devm_regulator_register(&pdev->dev,
 400                                             &drvdata->desc, &config);
 401         if (IS_ERR(regulator)) {
 402                 ret = PTR_ERR(regulator);
 403                 dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
 404                         drvdata->desc.name, ret);
 405                 return ret;
 406         }
 407
 408         return 0;
 409 }
 410
 411 static const struct of_device_id pwm_of_match[] = {
 412         { .compatible = "pwm-regulator" },
 413         { },
 414 };
 415 MODULE_DEVICE_TABLE(of, pwm_of_match);
 416
 417 static struct platform_driver pwm_regulator_driver = {
 418         .driver = {
 419                 .name           = "pwm-regulator",
 420                 .of_match_table = of_match_ptr(pwm_of_match),
 421         },
 422         .probe = pwm_regulator_probe,
 423 };
 424
 425 module_platform_driver(pwm_regulator_driver);
 426
 427 MODULE_LICENSE("GPL");
 428 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
 429 MODULE_DESCRIPTION("PWM Regulator Driver");
 430 MODULE_ALIAS("platform:pwm-regulator");