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         int state;
  44
  45         /* Enable GPIO */
  46         struct gpio_desc *enb_gpio;
  47 };
  48
  49 struct pwm_voltages {
  50         unsigned int uV;
  51         unsigned int dutycycle;
  52 };
  53
  54 /**
  55  * Voltage table call-backs
  56  */
  57 static void pwm_regulator_init_state(struct regulator_dev *rdev)
  58 {
  59         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
  60         struct pwm_state pwm_state;
  61         unsigned int dutycycle;
  62         int i;
  63
  64         pwm_get_state(drvdata->pwm, &pwm_state);
  65         dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);
  66
  67         for (i = 0; i < rdev->desc->n_voltages; i++) {
  68                 if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) {
  69                         drvdata->state = i;
  70                         return;
  71                 }
  72         }
  73 }
  74
  75 static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
  76 {
  77         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
  78
  79         if (drvdata->state < 0)
  80                 pwm_regulator_init_state(rdev);
  81
  82         return drvdata->state;
  83 }
  84
  85 static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
  86                                          unsigned selector)
  87 {
  88         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
  89         struct pwm_state pstate;
  90         int ret;
  91
  92         pwm_init_state(drvdata->pwm, &pstate);
  93         pwm_set_relative_duty_cycle(&pstate,
  94                         drvdata->duty_cycle_table[selector].dutycycle, 100);
  95
  96         ret = pwm_apply_state(drvdata->pwm, &pstate);
  97         if (ret) {
  98                 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
  99                 return ret;
 100         }
 101
 102         drvdata->state = selector;
 103
 104         return 0;
 105 }
 106
 107 static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
 108                                       unsigned selector)
 109 {
 110         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 111
 112         if (selector >= rdev->desc->n_voltages)
 113                 return -EINVAL;
 114
 115         return drvdata->duty_cycle_table[selector].uV;
 116 }
 117
 118 static int pwm_regulator_enable(struct regulator_dev *dev)
 119 {
 120         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 121
 122         gpiod_set_value_cansleep(drvdata->enb_gpio, 1);
 123
 124         return pwm_enable(drvdata->pwm);
 125 }
 126
 127 static int pwm_regulator_disable(struct regulator_dev *dev)
 128 {
 129         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 130
 131         pwm_disable(drvdata->pwm);
 132
 133         gpiod_set_value_cansleep(drvdata->enb_gpio, 0);
 134
 135         return 0;
 136 }
 137
 138 static int pwm_regulator_is_enabled(struct regulator_dev *dev)
 139 {
 140         struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 141
 142         if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio))
 143                 return false;
 144
 145         return pwm_is_enabled(drvdata->pwm);
 146 }
 147
 148 static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
 149 {
 150         struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 151         unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
 152         unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
 153         unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
 154         int min_uV = rdev->constraints->min_uV;
 155         int max_uV = rdev->constraints->max_uV;
 156         int diff_uV = max_uV - min_uV;
 157         struct pwm_state pstate;
 158         unsigned int diff_duty;
 159         unsigned int voltage;
 160
 161         pwm_get_state(drvdata->pwm, &pstate);
 162
 163         voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
 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                  = -EINVAL;
 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_find_property(np, "voltage-table", NULL))
 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                 ret = PTR_ERR(drvdata->pwm);
 360                 dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
 361                 return ret;
 362         }
 363
 364         if (init_data->constraints.boot_on || init_data->constraints.always_on)
 365                 gpio_flags = GPIOD_OUT_HIGH;
 366         else
 367                 gpio_flags = GPIOD_OUT_LOW;
 368         drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
 369                                                     gpio_flags);
 370         if (IS_ERR(drvdata->enb_gpio)) {
 371                 ret = PTR_ERR(drvdata->enb_gpio);
 372                 dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
 373                 return ret;
 374         }
 375
 376         ret = pwm_adjust_config(drvdata->pwm);
 377         if (ret)
 378                 return ret;
 379
 380         regulator = devm_regulator_register(&pdev->dev,
 381                                             &drvdata->desc, &config);
 382         if (IS_ERR(regulator)) {
 383                 ret = PTR_ERR(regulator);
 384                 dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
 385                         drvdata->desc.name, ret);
 386                 return ret;
 387         }
 388
 389         return 0;
 390 }
 391
 392 static const struct of_device_id pwm_of_match[] = {
 393         { .compatible = "pwm-regulator" },
 394         { },
 395 };
 396 MODULE_DEVICE_TABLE(of, pwm_of_match);
 397
 398 static struct platform_driver pwm_regulator_driver = {
 399         .driver = {
 400                 .name           = "pwm-regulator",
 401                 .of_match_table = of_match_ptr(pwm_of_match),
 402         },
 403         .probe = pwm_regulator_probe,
 404 };
 405
 406 module_platform_driver(pwm_regulator_driver);
 407
 408 MODULE_LICENSE("GPL");
 409 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
 410 MODULE_DESCRIPTION("PWM Regulator Driver");
 411 MODULE_ALIAS("platform:pwm-regulator");