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
 168         /*
 169          * The dutycycle for min_uV might be greater than the one for max_uV.
 170          * This is happening when the user needs an inversed polarity, but the
 171          * PWM device does not support inversing it in hardware.
 172          */
 173         if (max_uV_duty < min_uV_duty) {
 174                 voltage = min_uV_duty - voltage;
 175                 diff_duty = min_uV_duty - max_uV_duty;
 176         } else {
 177                 voltage = voltage - min_uV_duty;
 178                 diff_duty = max_uV_duty - min_uV_duty;
 179         }
 180
 181         voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);
 182
 183         return voltage + min_uV;
 184 }
 185
 186 static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
 187                                      int req_min_uV, int req_max_uV,
 188                                      unsigned int *selector)
 189 {
 190         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 191         unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
 192         unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
 193         unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
 194         int min_uV = rdev->constraints->min_uV;
 195         int max_uV = rdev->constraints->max_uV;
 196         int diff_uV = max_uV - min_uV;
 197         struct pwm_state pstate;
 198         unsigned int diff_duty;
 199         unsigned int dutycycle;
 200         int ret;
 201
 202         pwm_init_state(drvdata->pwm, &pstate);
 203
 204         /*
 205          * The dutycycle for min_uV might be greater than the one for max_uV.
 206          * This is happening when the user needs an inversed polarity, but the
 207          * PWM device does not support inversing it in hardware.
 208          */
 209         if (max_uV_duty < min_uV_duty)
 210                 diff_duty = min_uV_duty - max_uV_duty;
 211         else
 212                 diff_duty = max_uV_duty - min_uV_duty;
 213
 214         dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
 215                                           diff_duty,
 216                                           diff_uV);
 217
 218         if (max_uV_duty < min_uV_duty)
 219                 dutycycle = min_uV_duty - dutycycle;
 220         else
 221                 dutycycle = min_uV_duty + dutycycle;
 222
 223         pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);
 224
 225         ret = pwm_apply_state(drvdata->pwm, &pstate);
 226         if (ret) {
 227                 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 228                 return ret;
 229         }
 230
 231         return 0;
 232 }
 233
 234 static struct regulator_ops pwm_regulator_voltage_table_ops = {
 235         .set_voltage_sel = pwm_regulator_set_voltage_sel,
 236         .get_voltage_sel = pwm_regulator_get_voltage_sel,
 237         .list_voltage    = pwm_regulator_list_voltage,
 238         .map_voltage     = regulator_map_voltage_iterate,
 239         .enable          = pwm_regulator_enable,
 240         .disable         = pwm_regulator_disable,
 241         .is_enabled      = pwm_regulator_is_enabled,
 242 };
 243
 244 static struct regulator_ops pwm_regulator_voltage_continuous_ops = {
 245         .get_voltage = pwm_regulator_get_voltage,
 246         .set_voltage = pwm_regulator_set_voltage,
 247         .enable          = pwm_regulator_enable,
 248         .disable         = pwm_regulator_disable,
 249         .is_enabled      = pwm_regulator_is_enabled,
 250 };
 251
 252 static struct regulator_desc pwm_regulator_desc = {
 253         .name           = "pwm-regulator",
 254         .type           = REGULATOR_VOLTAGE,
 255         .owner          = THIS_MODULE,
 256         .supply_name    = "pwm",
 257 };
 258
 259 static int pwm_regulator_init_table(struct platform_device *pdev,
 260                                     struct pwm_regulator_data *drvdata)
 261 {
 262         struct device_node *np = pdev->dev.of_node;
 263         struct pwm_voltages *duty_cycle_table;
 264         unsigned int length = 0;
 265         int ret;
 266
 267         of_find_property(np, "voltage-table", &length);
 268
 269         if ((length < sizeof(*duty_cycle_table)) ||
 270             (length % sizeof(*duty_cycle_table))) {
 271                 dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
 272                         length);
 273                 return -EINVAL;
 274         }
 275
 276         duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
 277         if (!duty_cycle_table)
 278                 return -ENOMEM;
 279
 280         ret = of_property_read_u32_array(np, "voltage-table",
 281                                          (u32 *)duty_cycle_table,
 282                                          length / sizeof(u32));
 283         if (ret) {
 284                 dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret);
 285                 return ret;
 286         }
 287
 288         drvdata->state                  = -EINVAL;
 289         drvdata->duty_cycle_table       = duty_cycle_table;
 290         memcpy(&drvdata->ops, &pwm_regulator_voltage_table_ops,
 291                sizeof(drvdata->ops));
 292         drvdata->desc.ops = &drvdata->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         memcpy(&drvdata->ops, &pwm_regulator_voltage_continuous_ops,
 305                sizeof(drvdata->ops));
 306         drvdata->desc.ops = &drvdata->ops;
 307         drvdata->desc.continuous_voltage_range = true;
 308
 309         of_property_read_u32_array(pdev->dev.of_node,
 310                                    "pwm-dutycycle-range",
 311                                    dutycycle_range, 2);
 312         of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
 313                              &dutycycle_unit);
 314
 315         if (dutycycle_range[0] > dutycycle_unit ||
 316             dutycycle_range[1] > dutycycle_unit)
 317                 return -EINVAL;
 318
 319         drvdata->continuous.dutycycle_unit = dutycycle_unit;
 320         drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
 321         drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];
 322
 323         return 0;
 324 }
 325
 326 static int pwm_regulator_probe(struct platform_device *pdev)
 327 {
 328         const struct regulator_init_data *init_data;
 329         struct pwm_regulator_data *drvdata;
 330         struct regulator_dev *regulator;
 331         struct regulator_config config = { };
 332         struct device_node *np = pdev->dev.of_node;
 333         enum gpiod_flags gpio_flags;
 334         int ret;
 335
 336         if (!np) {
 337                 dev_err(&pdev->dev, "Device Tree node missing\n");
 338                 return -EINVAL;
 339         }
 340
 341         drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
 342         if (!drvdata)
 343                 return -ENOMEM;
 344
 345         memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));
 346
 347         if (of_find_property(np, "voltage-table", NULL))
 348                 ret = pwm_regulator_init_table(pdev, drvdata);
 349         else
 350                 ret = pwm_regulator_init_continuous(pdev, drvdata);
 351         if (ret)
 352                 return ret;
 353
 354         init_data = of_get_regulator_init_data(&pdev->dev, np,
 355                                                &drvdata->desc);
 356         if (!init_data)
 357                 return -ENOMEM;
 358
 359         config.of_node = np;
 360         config.dev = &pdev->dev;
 361         config.driver_data = drvdata;
 362         config.init_data = init_data;
 363
 364         drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
 365         if (IS_ERR(drvdata->pwm)) {
 366                 ret = PTR_ERR(drvdata->pwm);
 367                 dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
 368                 return ret;
 369         }
 370
 371         if (init_data->constraints.boot_on || init_data->constraints.always_on)
 372                 gpio_flags = GPIOD_OUT_HIGH;
 373         else
 374                 gpio_flags = GPIOD_OUT_LOW;
 375         drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
 376                                                     gpio_flags);
 377         if (IS_ERR(drvdata->enb_gpio)) {
 378                 ret = PTR_ERR(drvdata->enb_gpio);
 379                 dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
 380                 return ret;
 381         }
 382
 383         ret = pwm_adjust_config(drvdata->pwm);
 384         if (ret)
 385                 return ret;
 386
 387         regulator = devm_regulator_register(&pdev->dev,
 388                                             &drvdata->desc, &config);
 389         if (IS_ERR(regulator)) {
 390                 ret = PTR_ERR(regulator);
 391                 dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
 392                         drvdata->desc.name, ret);
 393                 return ret;
 394         }
 395
 396         return 0;
 397 }
 398
 399 static const struct of_device_id pwm_of_match[] = {
 400         { .compatible = "pwm-regulator" },
 401         { },
 402 };
 403 MODULE_DEVICE_TABLE(of, pwm_of_match);
 404
 405 static struct platform_driver pwm_regulator_driver = {
 406         .driver = {
 407                 .name           = "pwm-regulator",
 408                 .of_match_table = of_match_ptr(pwm_of_match),
 409         },
 410         .probe = pwm_regulator_probe,
 411 };
 412
 413 module_platform_driver(pwm_regulator_driver);
 414
 415 MODULE_LICENSE("GPL");
 416 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
 417 MODULE_DESCRIPTION("PWM Regulator Driver");
 418 MODULE_ALIAS("platform:pwm-regulator");