drivers/regulator/pwm-regulator.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Regulator driver for PWM Regulators
   4  *
   5  * Copyright (C) 2014 - STMicroelectronics Inc.
   6  *
   7  * Author: Lee Jones <lee.jones@linaro.org>
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/init.h>
  12 #include <linux/err.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/regulator/driver.h>
  15 #include <linux/regulator/machine.h>
  16 #include <linux/regulator/of_regulator.h>
  17 #include <linux/of.h>
  18 #include <linux/pwm.h>
  19 #include <linux/gpio/consumer.h>
  20
  21 struct pwm_continuous_reg_data {
  22         unsigned int min_uV_dutycycle;
  23         unsigned int max_uV_dutycycle;
  24         unsigned int dutycycle_unit;
  25 };
  26
  27 struct pwm_regulator_data {
  28         /*  Shared */
  29         struct pwm_device *pwm;
  30
  31         /* Voltage table */
  32         struct pwm_voltages *duty_cycle_table;
  33
  34         /* Continuous mode info */
  35         struct pwm_continuous_reg_data continuous;
  36
  37         /* regulator descriptor */
  38         struct regulator_desc desc;
  39
  40         int state;
  41
  42         /* Enable GPIO */
  43         struct gpio_desc *enb_gpio;
  44 };
  45
  46 struct pwm_voltages {
  47         unsigned int uV;
  48         unsigned int dutycycle;
  49 };
  50
  51 /*
  52  * Voltage table call-backs
  53  */
  54 static void pwm_regulator_init_state(struct regulator_dev *rdev)
  55 {
  56         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
  57         struct pwm_state pwm_state;
  58         unsigned int dutycycle;
  59         int i;
  60
  61         pwm_get_state(drvdata->pwm, &pwm_state);
  62         dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);
  63
  64         for (i = 0; i < rdev->desc->n_voltages; i++) {
  65                 if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) {
  66                         drvdata->state = i;
  67                         return;
  68                 }
  69         }
  70 }
  71
  72 static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
  73 {
  74         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
  75
  76         if (drvdata->state < 0)
  77                 pwm_regulator_init_state(rdev);
  78
  79         return drvdata->state;
  80 }
  81
  82 static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
  83                                          unsigned selector)
  84 {
  85         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
  86         struct pwm_state pstate;
  87         int ret;
  88
  89         pwm_init_state(drvdata->pwm, &pstate);
  90         pwm_set_relative_duty_cycle(&pstate,
  91                         drvdata->duty_cycle_table[selector].dutycycle, 100);
  92
  93         ret = pwm_apply_might_sleep(drvdata->pwm, &pstate);
  94         if (ret) {
  95                 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
  96                 return ret;
  97         }
  98
  99         drvdata->state = selector;
 100
 101         return 0;
 102 }
 103
 104 static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
 105                                       unsigned selector)
 106 {
 107         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 108
 109         if (selector >= rdev->desc->n_voltages)
 110                 return -EINVAL;
 111
 112         return drvdata->duty_cycle_table[selector].uV;
 113 }
 114
 115 static int pwm_regulator_enable(struct regulator_dev *dev)
 116 {
 117         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 118
 119         gpiod_set_value_cansleep(drvdata->enb_gpio, 1);
 120
 121         return pwm_enable(drvdata->pwm);
 122 }
 123
 124 static int pwm_regulator_disable(struct regulator_dev *dev)
 125 {
 126         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 127
 128         pwm_disable(drvdata->pwm);
 129
 130         gpiod_set_value_cansleep(drvdata->enb_gpio, 0);
 131
 132         return 0;
 133 }
 134
 135 static int pwm_regulator_is_enabled(struct regulator_dev *dev)
 136 {
 137         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 138
 139         if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio))
 140                 return false;
 141
 142         return pwm_is_enabled(drvdata->pwm);
 143 }
 144
 145 static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
 146 {
 147         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 148         unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
 149         unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
 150         unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
 151         int min_uV = rdev->constraints->min_uV;
 152         int max_uV = rdev->constraints->max_uV;
 153         int diff_uV = max_uV - min_uV;
 154         struct pwm_state pstate;
 155         unsigned int diff_duty;
 156         unsigned int voltage;
 157
 158         pwm_get_state(drvdata->pwm, &pstate);
 159
 160         if (!pstate.enabled) {
 161                 if (pstate.polarity == PWM_POLARITY_INVERSED)
 162                         pstate.duty_cycle = pstate.period;
 163                 else
 164                         pstate.duty_cycle = 0;
 165         }
 166
 167         voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
 168         if (voltage < min(max_uV_duty, min_uV_duty) ||
 169             voltage > max(max_uV_duty, min_uV_duty))
 170                 return -ENOTRECOVERABLE;
 171
 172         /*
 173          * The dutycycle for min_uV might be greater than the one for max_uV.
 174          * This is happening when the user needs an inversed polarity, but the
 175          * PWM device does not support inversing it in hardware.
 176          */
 177         if (max_uV_duty < min_uV_duty) {
 178                 voltage = min_uV_duty - voltage;
 179                 diff_duty = min_uV_duty - max_uV_duty;
 180         } else {
 181                 voltage = voltage - min_uV_duty;
 182                 diff_duty = max_uV_duty - min_uV_duty;
 183         }
 184
 185         voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);
 186
 187         return voltage + min_uV;
 188 }
 189
 190 static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
 191                                      int req_min_uV, int req_max_uV,
 192                                      unsigned int *selector)
 193 {
 194         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 195         unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
 196         unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
 197         unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
 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         unsigned int diff_duty;
 203         unsigned int dutycycle;
 204         int ret;
 205
 206         pwm_init_state(drvdata->pwm, &pstate);
 207
 208         /*
 209          * The dutycycle for min_uV might be greater than the one for max_uV.
 210          * This is happening when the user needs an inversed polarity, but the
 211          * PWM device does not support inversing it in hardware.
 212          */
 213         if (max_uV_duty < min_uV_duty)
 214                 diff_duty = min_uV_duty - max_uV_duty;
 215         else
 216                 diff_duty = max_uV_duty - min_uV_duty;
 217
 218         dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
 219                                           diff_duty,
 220                                           diff_uV);
 221
 222         if (max_uV_duty < min_uV_duty)
 223                 dutycycle = min_uV_duty - dutycycle;
 224         else
 225                 dutycycle = min_uV_duty + dutycycle;
 226
 227         pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);
 228
 229         ret = pwm_apply_might_sleep(drvdata->pwm, &pstate);
 230         if (ret) {
 231                 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 232                 return ret;
 233         }
 234
 235         return 0;
 236 }
 237
 238 static const struct regulator_ops pwm_regulator_voltage_table_ops = {
 239         .set_voltage_sel = pwm_regulator_set_voltage_sel,
 240         .get_voltage_sel = pwm_regulator_get_voltage_sel,
 241         .list_voltage    = pwm_regulator_list_voltage,
 242         .map_voltage     = regulator_map_voltage_iterate,
 243         .enable          = pwm_regulator_enable,
 244         .disable         = pwm_regulator_disable,
 245         .is_enabled      = pwm_regulator_is_enabled,
 246 };
 247
 248 static const struct regulator_ops pwm_regulator_voltage_continuous_ops = {
 249         .get_voltage = pwm_regulator_get_voltage,
 250         .set_voltage = pwm_regulator_set_voltage,
 251         .enable          = pwm_regulator_enable,
 252         .disable         = pwm_regulator_disable,
 253         .is_enabled      = pwm_regulator_is_enabled,
 254 };
 255
 256 static const struct regulator_desc pwm_regulator_desc = {
 257         .name           = "pwm-regulator",
 258         .type           = REGULATOR_VOLTAGE,
 259         .owner          = THIS_MODULE,
 260         .supply_name    = "pwm",
 261 };
 262
 263 static int pwm_regulator_init_table(struct platform_device *pdev,
 264                                     struct pwm_regulator_data *drvdata)
 265 {
 266         struct device_node *np = pdev->dev.of_node;
 267         struct pwm_voltages *duty_cycle_table;
 268         unsigned int length = 0;
 269         int ret;
 270
 271         of_find_property(np, "voltage-table", &length);
 272
 273         if ((length < sizeof(*duty_cycle_table)) ||
 274             (length % sizeof(*duty_cycle_table)))
 275                 return dev_err_probe(&pdev->dev, -EINVAL,
 276                                      "voltage-table length(%d) is invalid\n",
 277                                      length);
 278
 279         duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
 280         if (!duty_cycle_table)
 281                 return -ENOMEM;
 282
 283         ret = of_property_read_u32_array(np, "voltage-table",
 284                                          (u32 *)duty_cycle_table,
 285                                          length / sizeof(u32));
 286         if (ret)
 287                 return dev_err_probe(&pdev->dev, ret,
 288                                      "Failed to read voltage-table\n");
 289
 290         drvdata->state                  = -ENOTRECOVERABLE;
 291         drvdata->duty_cycle_table       = duty_cycle_table;
 292         drvdata->desc.ops = &pwm_regulator_voltage_table_ops;
 293         drvdata->desc.n_voltages        = length / sizeof(*duty_cycle_table);
 294
 295         return 0;
 296 }
 297
 298 static int pwm_regulator_init_continuous(struct platform_device *pdev,
 299                                          struct pwm_regulator_data *drvdata)
 300 {
 301         u32 dutycycle_range[2] = { 0, 100 };
 302         u32 dutycycle_unit = 100;
 303
 304         drvdata->desc.ops = &pwm_regulator_voltage_continuous_ops;
 305         drvdata->desc.continuous_voltage_range = true;
 306
 307         of_property_read_u32_array(pdev->dev.of_node,
 308                                    "pwm-dutycycle-range",
 309                                    dutycycle_range, 2);
 310         of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
 311                              &dutycycle_unit);
 312
 313         if (dutycycle_range[0] > dutycycle_unit ||
 314             dutycycle_range[1] > dutycycle_unit)
 315                 return -EINVAL;
 316
 317         drvdata->continuous.dutycycle_unit = dutycycle_unit;
 318         drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
 319         drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];
 320
 321         return 0;
 322 }
 323
 324 static int pwm_regulator_init_boot_on(struct platform_device *pdev,
 325                                       struct pwm_regulator_data *drvdata,
 326                                       const struct regulator_init_data *init_data)
 327 {
 328         struct pwm_state pstate;
 329
 330         if (!init_data->constraints.boot_on || drvdata->enb_gpio)
 331                 return 0;
 332
 333         pwm_get_state(drvdata->pwm, &pstate);
 334         if (pstate.enabled)
 335                 return 0;
 336
 337         /*
 338          * Update the duty cycle so the output does not change
 339          * when the regulator core enables the regulator (and
 340          * thus the PWM channel).
 341          */
 342         if (pstate.polarity == PWM_POLARITY_INVERSED)
 343                 pstate.duty_cycle = pstate.period;
 344         else
 345                 pstate.duty_cycle = 0;
 346
 347         return pwm_apply_might_sleep(drvdata->pwm, &pstate);
 348 }
 349
 350 static int pwm_regulator_probe(struct platform_device *pdev)
 351 {
 352         const struct regulator_init_data *init_data;
 353         struct pwm_regulator_data *drvdata;
 354         struct regulator_dev *regulator;
 355         struct regulator_config config = { };
 356         struct device_node *np = pdev->dev.of_node;
 357         enum gpiod_flags gpio_flags;
 358         int ret;
 359
 360         if (!np)
 361                 return dev_err_probe(&pdev->dev, -EINVAL,
 362                                      "Device Tree node missing\n");
 363
 364         drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
 365         if (!drvdata)
 366                 return -ENOMEM;
 367
 368         memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));
 369
 370         if (of_property_present(np, "voltage-table"))
 371                 ret = pwm_regulator_init_table(pdev, drvdata);
 372         else
 373                 ret = pwm_regulator_init_continuous(pdev, drvdata);
 374         if (ret)
 375                 return ret;
 376
 377         init_data = of_get_regulator_init_data(&pdev->dev, np,
 378                                                &drvdata->desc);
 379         if (!init_data)
 380                 return -ENOMEM;
 381
 382         config.of_node = np;
 383         config.dev = &pdev->dev;
 384         config.driver_data = drvdata;
 385         config.init_data = init_data;
 386
 387         drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
 388         if (IS_ERR(drvdata->pwm))
 389                 return dev_err_probe(&pdev->dev, PTR_ERR(drvdata->pwm),
 390                                      "Failed to get PWM\n");
 391
 392         if (init_data->constraints.boot_on || init_data->constraints.always_on)
 393                 gpio_flags = GPIOD_OUT_HIGH;
 394         else
 395                 gpio_flags = GPIOD_OUT_LOW;
 396         drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
 397                                                     gpio_flags);
 398         if (IS_ERR(drvdata->enb_gpio)) {
 399                 ret = PTR_ERR(drvdata->enb_gpio);
 400                 return dev_err_probe(&pdev->dev, ret, "Failed to get enable GPIO\n");
 401         }
 402
 403         ret = pwm_adjust_config(drvdata->pwm);
 404         if (ret)
 405                 return ret;
 406
 407         ret = pwm_regulator_init_boot_on(pdev, drvdata, init_data);
 408         if (ret)
 409                 return dev_err_probe(&pdev->dev, ret,
 410                                      "Failed to apply boot_on settings\n");
 411
 412         regulator = devm_regulator_register(&pdev->dev,
 413                                             &drvdata->desc, &config);
 414         if (IS_ERR(regulator)) {
 415                 ret = PTR_ERR(regulator);
 416                 return dev_err_probe(&pdev->dev, ret,
 417                                      "Failed to register regulator %s\n",
 418                                      drvdata->desc.name);
 419         }
 420
 421         return 0;
 422 }
 423
 424 static const struct of_device_id __maybe_unused pwm_of_match[] = {
 425         { .compatible = "pwm-regulator" },
 426         { },
 427 };
 428 MODULE_DEVICE_TABLE(of, pwm_of_match);
 429
 430 static struct platform_driver pwm_regulator_driver = {
 431         .driver = {
 432                 .name           = "pwm-regulator",
 433                 .probe_type     = PROBE_PREFER_ASYNCHRONOUS,
 434                 .of_match_table = of_match_ptr(pwm_of_match),
 435         },
 436         .probe = pwm_regulator_probe,
 437 };
 438
 439 module_platform_driver(pwm_regulator_driver);
 440
 441 MODULE_LICENSE("GPL");
 442 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
 443 MODULE_DESCRIPTION("PWM Regulator Driver");
 444 MODULE_ALIAS("platform:pwm-regulator");