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_state(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         voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
 161         if (voltage < min(max_uV_duty, min_uV_duty) ||
 162             voltage > max(max_uV_duty, min_uV_duty))
 163                 return -ENOTRECOVERABLE;
 164
 165         /*
 166          * The dutycycle for min_uV might be greater than the one for max_uV.
 167          * This is happening when the user needs an inversed polarity, but the
 168          * PWM device does not support inversing it in hardware.
 169          */
 170         if (max_uV_duty < min_uV_duty) {
 171                 voltage = min_uV_duty - voltage;
 172                 diff_duty = min_uV_duty - max_uV_duty;
 173         } else {
 174                 voltage = voltage - min_uV_duty;
 175                 diff_duty = max_uV_duty - min_uV_duty;
 176         }
 177
 178         voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);
 179
 180         return voltage + min_uV;
 181 }
 182
 183 static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
 184                                      int req_min_uV, int req_max_uV,
 185                                      unsigned int *selector)
 186 {
 187         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 188         unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
 189         unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
 190         unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
 191         int min_uV = rdev->constraints->min_uV;
 192         int max_uV = rdev->constraints->max_uV;
 193         int diff_uV = max_uV - min_uV;
 194         struct pwm_state pstate;
 195         unsigned int diff_duty;
 196         unsigned int dutycycle;
 197         int ret;
 198
 199         pwm_init_state(drvdata->pwm, &pstate);
 200
 201         /*
 202          * The dutycycle for min_uV might be greater than the one for max_uV.
 203          * This is happening when the user needs an inversed polarity, but the
 204          * PWM device does not support inversing it in hardware.
 205          */
 206         if (max_uV_duty < min_uV_duty)
 207                 diff_duty = min_uV_duty - max_uV_duty;
 208         else
 209                 diff_duty = max_uV_duty - min_uV_duty;
 210
 211         dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
 212                                           diff_duty,
 213                                           diff_uV);
 214
 215         if (max_uV_duty < min_uV_duty)
 216                 dutycycle = min_uV_duty - dutycycle;
 217         else
 218                 dutycycle = min_uV_duty + dutycycle;
 219
 220         pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);
 221
 222         ret = pwm_apply_state(drvdata->pwm, &pstate);
 223         if (ret) {
 224                 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 225                 return ret;
 226         }
 227
 228         return 0;
 229 }
 230
 231 static const struct regulator_ops pwm_regulator_voltage_table_ops = {
 232         .set_voltage_sel = pwm_regulator_set_voltage_sel,
 233         .get_voltage_sel = pwm_regulator_get_voltage_sel,
 234         .list_voltage    = pwm_regulator_list_voltage,
 235         .map_voltage     = regulator_map_voltage_iterate,
 236         .enable          = pwm_regulator_enable,
 237         .disable         = pwm_regulator_disable,
 238         .is_enabled      = pwm_regulator_is_enabled,
 239 };
 240
 241 static const struct regulator_ops pwm_regulator_voltage_continuous_ops = {
 242         .get_voltage = pwm_regulator_get_voltage,
 243         .set_voltage = pwm_regulator_set_voltage,
 244         .enable          = pwm_regulator_enable,
 245         .disable         = pwm_regulator_disable,
 246         .is_enabled      = pwm_regulator_is_enabled,
 247 };
 248
 249 static const struct regulator_desc pwm_regulator_desc = {
 250         .name           = "pwm-regulator",
 251         .type           = REGULATOR_VOLTAGE,
 252         .owner          = THIS_MODULE,
 253         .supply_name    = "pwm",
 254 };
 255
 256 static int pwm_regulator_init_table(struct platform_device *pdev,
 257                                     struct pwm_regulator_data *drvdata)
 258 {
 259         struct device_node *np = pdev->dev.of_node;
 260         struct pwm_voltages *duty_cycle_table;
 261         unsigned int length = 0;
 262         int ret;
 263
 264         of_find_property(np, "voltage-table", &length);
 265
 266         if ((length < sizeof(*duty_cycle_table)) ||
 267             (length % sizeof(*duty_cycle_table))) {
 268                 dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
 269                         length);
 270                 return -EINVAL;
 271         }
 272
 273         duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
 274         if (!duty_cycle_table)
 275                 return -ENOMEM;
 276
 277         ret = of_property_read_u32_array(np, "voltage-table",
 278                                          (u32 *)duty_cycle_table,
 279                                          length / sizeof(u32));
 280         if (ret) {
 281                 dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret);
 282                 return ret;
 283         }
 284
 285         drvdata->state                  = -ENOTRECOVERABLE;
 286         drvdata->duty_cycle_table       = duty_cycle_table;
 287         drvdata->desc.ops = &pwm_regulator_voltage_table_ops;
 288         drvdata->desc.n_voltages        = length / sizeof(*duty_cycle_table);
 289
 290         return 0;
 291 }
 292
 293 static int pwm_regulator_init_continuous(struct platform_device *pdev,
 294                                          struct pwm_regulator_data *drvdata)
 295 {
 296         u32 dutycycle_range[2] = { 0, 100 };
 297         u32 dutycycle_unit = 100;
 298
 299         drvdata->desc.ops = &pwm_regulator_voltage_continuous_ops;
 300         drvdata->desc.continuous_voltage_range = true;
 301
 302         of_property_read_u32_array(pdev->dev.of_node,
 303                                    "pwm-dutycycle-range",
 304                                    dutycycle_range, 2);
 305         of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
 306                              &dutycycle_unit);
 307
 308         if (dutycycle_range[0] > dutycycle_unit ||
 309             dutycycle_range[1] > dutycycle_unit)
 310                 return -EINVAL;
 311
 312         drvdata->continuous.dutycycle_unit = dutycycle_unit;
 313         drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
 314         drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];
 315
 316         return 0;
 317 }
 318
 319 static int pwm_regulator_probe(struct platform_device *pdev)
 320 {
 321         const struct regulator_init_data *init_data;
 322         struct pwm_regulator_data *drvdata;
 323         struct regulator_dev *regulator;
 324         struct regulator_config config = { };
 325         struct device_node *np = pdev->dev.of_node;
 326         enum gpiod_flags gpio_flags;
 327         int ret;
 328
 329         if (!np) {
 330                 dev_err(&pdev->dev, "Device Tree node missing\n");
 331                 return -EINVAL;
 332         }
 333
 334         drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
 335         if (!drvdata)
 336                 return -ENOMEM;
 337
 338         memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));
 339
 340         if (of_property_present(np, "voltage-table"))
 341                 ret = pwm_regulator_init_table(pdev, drvdata);
 342         else
 343                 ret = pwm_regulator_init_continuous(pdev, drvdata);
 344         if (ret)
 345                 return ret;
 346
 347         init_data = of_get_regulator_init_data(&pdev->dev, np,
 348                                                &drvdata->desc);
 349         if (!init_data)
 350                 return -ENOMEM;
 351
 352         config.of_node = np;
 353         config.dev = &pdev->dev;
 354         config.driver_data = drvdata;
 355         config.init_data = init_data;
 356
 357         drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
 358         if (IS_ERR(drvdata->pwm))
 359                 return dev_err_probe(&pdev->dev, PTR_ERR(drvdata->pwm),
 360                                      "Failed to get PWM\n");
 361
 362         if (init_data->constraints.boot_on || init_data->constraints.always_on)
 363                 gpio_flags = GPIOD_OUT_HIGH;
 364         else
 365                 gpio_flags = GPIOD_OUT_LOW;
 366         drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
 367                                                     gpio_flags);
 368         if (IS_ERR(drvdata->enb_gpio)) {
 369                 ret = PTR_ERR(drvdata->enb_gpio);
 370                 dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
 371                 return ret;
 372         }
 373
 374         ret = pwm_adjust_config(drvdata->pwm);
 375         if (ret)
 376                 return ret;
 377
 378         regulator = devm_regulator_register(&pdev->dev,
 379                                             &drvdata->desc, &config);
 380         if (IS_ERR(regulator)) {
 381                 ret = PTR_ERR(regulator);
 382                 dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
 383                         drvdata->desc.name, ret);
 384                 return ret;
 385         }
 386
 387         return 0;
 388 }
 389
 390 static const struct of_device_id __maybe_unused pwm_of_match[] = {
 391         { .compatible = "pwm-regulator" },
 392         { },
 393 };
 394 MODULE_DEVICE_TABLE(of, pwm_of_match);
 395
 396 static struct platform_driver pwm_regulator_driver = {
 397         .driver = {
 398                 .name           = "pwm-regulator",
 399                 .probe_type     = PROBE_PREFER_ASYNCHRONOUS,
 400                 .of_match_table = of_match_ptr(pwm_of_match),
 401         },
 402         .probe = pwm_regulator_probe,
 403 };
 404
 405 module_platform_driver(pwm_regulator_driver);
 406
 407 MODULE_LICENSE("GPL");
 408 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
 409 MODULE_DESCRIPTION("PWM Regulator Driver");
 410 MODULE_ALIAS("platform:pwm-regulator");