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         gpiod_set_value_cansleep(drvdata->enb_gpio, 1);
 126
 127         return pwm_enable(drvdata->pwm);
 128 }
 129
 130 static int pwm_regulator_disable(struct regulator_dev *dev)
 131 {
 132         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 133
 134         pwm_disable(drvdata->pwm);
 135
 136         gpiod_set_value_cansleep(drvdata->enb_gpio, 0);
 137
 138         return 0;
 139 }
 140
 141 static int pwm_regulator_is_enabled(struct regulator_dev *dev)
 142 {
 143         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 144
 145         if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio))
 146                 return false;
 147
 148         return pwm_is_enabled(drvdata->pwm);
 149 }
 150
 151 static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
 152 {
 153         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 154         unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
 155         unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
 156         unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
 157         int min_uV = rdev->constraints->min_uV;
 158         int max_uV = rdev->constraints->max_uV;
 159         int diff_uV = max_uV - min_uV;
 160         struct pwm_state pstate;
 161         unsigned int diff_duty;
 162         unsigned int voltage;
 163
 164         pwm_get_state(drvdata->pwm, &pstate);
 165
 166         voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
 167         if (voltage < min(max_uV_duty, min_uV_duty) ||
 168             voltage > max(max_uV_duty, min_uV_duty))
 169                 return -ENOTRECOVERABLE;
 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         int min_uV = rdev->constraints->min_uV;
 198         int max_uV = rdev->constraints->max_uV;
 199         int diff_uV = max_uV - min_uV;
 200         struct pwm_state pstate;
 201         unsigned int diff_duty;
 202         unsigned int dutycycle;
 203         int ret;
 204
 205         pwm_init_state(drvdata->pwm, &pstate);
 206
 207         /*
 208          * The dutycycle for min_uV might be greater than the one for max_uV.
 209          * This is happening when the user needs an inversed polarity, but the
 210          * PWM device does not support inversing it in hardware.
 211          */
 212         if (max_uV_duty < min_uV_duty)
 213                 diff_duty = min_uV_duty - max_uV_duty;
 214         else
 215                 diff_duty = max_uV_duty - min_uV_duty;
 216
 217         dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
 218                                           diff_duty,
 219                                           diff_uV);
 220
 221         if (max_uV_duty < min_uV_duty)
 222                 dutycycle = min_uV_duty - dutycycle;
 223         else
 224                 dutycycle = min_uV_duty + dutycycle;
 225
 226         pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);
 227
 228         ret = pwm_apply_state(drvdata->pwm, &pstate);
 229         if (ret) {
 230                 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 231                 return ret;
 232         }
 233
 234         return 0;
 235 }
 236
 237 static struct regulator_ops pwm_regulator_voltage_table_ops = {
 238         .set_voltage_sel = pwm_regulator_set_voltage_sel,
 239         .get_voltage_sel = pwm_regulator_get_voltage_sel,
 240         .list_voltage    = pwm_regulator_list_voltage,
 241         .map_voltage     = regulator_map_voltage_iterate,
 242         .enable          = pwm_regulator_enable,
 243         .disable         = pwm_regulator_disable,
 244         .is_enabled      = pwm_regulator_is_enabled,
 245 };
 246
 247 static struct regulator_ops pwm_regulator_voltage_continuous_ops = {
 248         .get_voltage = pwm_regulator_get_voltage,
 249         .set_voltage = pwm_regulator_set_voltage,
 250         .enable          = pwm_regulator_enable,
 251         .disable         = pwm_regulator_disable,
 252         .is_enabled      = pwm_regulator_is_enabled,
 253 };
 254
 255 static struct regulator_desc pwm_regulator_desc = {
 256         .name           = "pwm-regulator",
 257         .type           = REGULATOR_VOLTAGE,
 258         .owner          = THIS_MODULE,
 259         .supply_name    = "pwm",
 260 };
 261
 262 static int pwm_regulator_init_table(struct platform_device *pdev,
 263                                     struct pwm_regulator_data *drvdata)
 264 {
 265         struct device_node *np = pdev->dev.of_node;
 266         struct pwm_voltages *duty_cycle_table;
 267         unsigned int length = 0;
 268         int ret;
 269
 270         of_find_property(np, "voltage-table", &length);
 271
 272         if ((length < sizeof(*duty_cycle_table)) ||
 273             (length % sizeof(*duty_cycle_table))) {
 274                 dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
 275                         length);
 276                 return -EINVAL;
 277         }
 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                 dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret);
 288                 return ret;
 289         }
 290
 291         drvdata->state                  = -ENOTRECOVERABLE;
 292         drvdata->duty_cycle_table       = duty_cycle_table;
 293         memcpy(&drvdata->ops, &pwm_regulator_voltage_table_ops,
 294                sizeof(drvdata->ops));
 295         drvdata->desc.ops = &drvdata->ops;
 296         drvdata->desc.n_voltages        = length / sizeof(*duty_cycle_table);
 297
 298         return 0;
 299 }
 300
 301 static int pwm_regulator_init_continuous(struct platform_device *pdev,
 302                                          struct pwm_regulator_data *drvdata)
 303 {
 304         u32 dutycycle_range[2] = { 0, 100 };
 305         u32 dutycycle_unit = 100;
 306
 307         memcpy(&drvdata->ops, &pwm_regulator_voltage_continuous_ops,
 308                sizeof(drvdata->ops));
 309         drvdata->desc.ops = &drvdata->ops;
 310         drvdata->desc.continuous_voltage_range = true;
 311
 312         of_property_read_u32_array(pdev->dev.of_node,
 313                                    "pwm-dutycycle-range",
 314                                    dutycycle_range, 2);
 315         of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
 316                              &dutycycle_unit);
 317
 318         if (dutycycle_range[0] > dutycycle_unit ||
 319             dutycycle_range[1] > dutycycle_unit)
 320                 return -EINVAL;
 321
 322         drvdata->continuous.dutycycle_unit = dutycycle_unit;
 323         drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
 324         drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];
 325
 326         return 0;
 327 }
 328
 329 static int pwm_regulator_probe(struct platform_device *pdev)
 330 {
 331         const struct regulator_init_data *init_data;
 332         struct pwm_regulator_data *drvdata;
 333         struct regulator_dev *regulator;
 334         struct regulator_config config = { };
 335         struct device_node *np = pdev->dev.of_node;
 336         enum gpiod_flags gpio_flags;
 337         int ret;
 338
 339         if (!np) {
 340                 dev_err(&pdev->dev, "Device Tree node missing\n");
 341                 return -EINVAL;
 342         }
 343
 344         drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
 345         if (!drvdata)
 346                 return -ENOMEM;
 347
 348         memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));
 349
 350         if (of_find_property(np, "voltage-table", NULL))
 351                 ret = pwm_regulator_init_table(pdev, drvdata);
 352         else
 353                 ret = pwm_regulator_init_continuous(pdev, drvdata);
 354         if (ret)
 355                 return ret;
 356
 357         init_data = of_get_regulator_init_data(&pdev->dev, np,
 358                                                &drvdata->desc);
 359         if (!init_data)
 360                 return -ENOMEM;
 361
 362         config.of_node = np;
 363         config.dev = &pdev->dev;
 364         config.driver_data = drvdata;
 365         config.init_data = init_data;
 366
 367         drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
 368         if (IS_ERR(drvdata->pwm)) {
 369                 ret = PTR_ERR(drvdata->pwm);
 370                 dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
 371                 return ret;
 372         }
 373
 374         if (init_data->constraints.boot_on || init_data->constraints.always_on)
 375                 gpio_flags = GPIOD_OUT_HIGH;
 376         else
 377                 gpio_flags = GPIOD_OUT_LOW;
 378         drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
 379                                                     gpio_flags);
 380         if (IS_ERR(drvdata->enb_gpio)) {
 381                 ret = PTR_ERR(drvdata->enb_gpio);
 382                 dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
 383                 return ret;
 384         }
 385
 386         ret = pwm_adjust_config(drvdata->pwm);
 387         if (ret)
 388                 return ret;
 389
 390         regulator = devm_regulator_register(&pdev->dev,
 391                                             &drvdata->desc, &config);
 392         if (IS_ERR(regulator)) {
 393                 ret = PTR_ERR(regulator);
 394                 dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
 395                         drvdata->desc.name, ret);
 396                 return ret;
 397         }
 398
 399         return 0;
 400 }
 401
 402 static const struct of_device_id pwm_of_match[] = {
 403         { .compatible = "pwm-regulator" },
 404         { },
 405 };
 406 MODULE_DEVICE_TABLE(of, pwm_of_match);
 407
 408 static struct platform_driver pwm_regulator_driver = {
 409         .driver = {
 410                 .name           = "pwm-regulator",
 411                 .of_match_table = of_match_ptr(pwm_of_match),
 412         },
 413         .probe = pwm_regulator_probe,
 414 };
 415
 416 module_platform_driver(pwm_regulator_driver);
 417
 418 MODULE_LICENSE("GPL");
 419 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
 420 MODULE_DESCRIPTION("PWM Regulator Driver");
 421 MODULE_ALIAS("platform:pwm-regulator");