drivers/regulator/max8973-regulator.c

   1 /*
   2  * max8973-regulator.c -- Maxim max8973
   3  *
   4  * Regulator driver for MAXIM 8973 DC-DC step-down switching regulator.
   5  *
   6  * Copyright (c) 2012, NVIDIA Corporation.
   7  *
   8  * Author: Laxman Dewangan <ldewangan@nvidia.com>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation version 2.
  13  *
  14  * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
  15  * whether express or implied; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  22  * 02111-1307, USA
  23  */
  24
  25 #include <linux/kernel.h>
  26 #include <linux/module.h>
  27 #include <linux/init.h>
  28 #include <linux/err.h>
  29 #include <linux/of.h>
  30 #include <linux/platform_device.h>
  31 #include <linux/regulator/driver.h>
  32 #include <linux/regulator/machine.h>
  33 #include <linux/regulator/max8973-regulator.h>
  34 #include <linux/regulator/of_regulator.h>
  35 #include <linux/gpio.h>
  36 #include <linux/of_gpio.h>
  37 #include <linux/i2c.h>
  38 #include <linux/slab.h>
  39 #include <linux/regmap.h>
  40
  41 /* Register definitions */
  42 #define MAX8973_VOUT                                    0x0
  43 #define MAX8973_VOUT_DVS                                0x1
  44 #define MAX8973_CONTROL1                                0x2
  45 #define MAX8973_CONTROL2                                0x3
  46 #define MAX8973_CHIPID1                                 0x4
  47 #define MAX8973_CHIPID2                                 0x5
  48
  49 #define MAX8973_MAX_VOUT_REG                            2
  50
  51 /* MAX8973_VOUT */
  52 #define MAX8973_VOUT_ENABLE                             BIT(7)
  53 #define MAX8973_VOUT_MASK                               0x7F
  54
  55 /* MAX8973_VOUT_DVS */
  56 #define MAX8973_DVS_VOUT_MASK                           0x7F
  57
  58 /* MAX8973_CONTROL1 */
  59 #define MAX8973_SNS_ENABLE                              BIT(7)
  60 #define MAX8973_FPWM_EN_M                               BIT(6)
  61 #define MAX8973_NFSR_ENABLE                             BIT(5)
  62 #define MAX8973_AD_ENABLE                               BIT(4)
  63 #define MAX8973_BIAS_ENABLE                             BIT(3)
  64 #define MAX8973_FREQSHIFT_9PER                          BIT(2)
  65
  66 #define MAX8973_RAMP_12mV_PER_US                        0x0
  67 #define MAX8973_RAMP_25mV_PER_US                        0x1
  68 #define MAX8973_RAMP_50mV_PER_US                        0x2
  69 #define MAX8973_RAMP_200mV_PER_US                       0x3
  70
  71 /* MAX8973_CONTROL2 */
  72 #define MAX8973_WDTMR_ENABLE                            BIT(6)
  73 #define MAX8973_DISCH_ENBABLE                           BIT(5)
  74 #define MAX8973_FT_ENABLE                               BIT(4)
  75
  76 #define MAX8973_CKKADV_TRIP_DISABLE                     0xC
  77 #define MAX8973_CKKADV_TRIP_75mV_PER_US                 0x0
  78 #define MAX8973_CKKADV_TRIP_150mV_PER_US                0x4
  79 #define MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS        0x8
  80 #define MAX8973_CONTROL_CLKADV_TRIP_MASK                0x00030000
  81
  82 #define MAX8973_INDUCTOR_MIN_30_PER                     0x0
  83 #define MAX8973_INDUCTOR_NOMINAL                        0x1
  84 #define MAX8973_INDUCTOR_PLUS_30_PER                    0x2
  85 #define MAX8973_INDUCTOR_PLUS_60_PER                    0x3
  86 #define MAX8973_CONTROL_INDUCTOR_VALUE_MASK             0x00300000
  87
  88 #define MAX8973_MIN_VOLATGE                             606250
  89 #define MAX8973_MAX_VOLATGE                             1400000
  90 #define MAX8973_VOLATGE_STEP                            6250
  91 #define MAX8973_BUCK_N_VOLTAGE                          0x80
  92
  93 /* Maxim 8973 chip information */
  94 struct max8973_chip {
  95         struct device *dev;
  96         struct regulator_desc desc;
  97         struct regmap *regmap;
  98         bool enable_external_control;
  99         int enable_gpio;
 100         int dvs_gpio;
 101         int lru_index[MAX8973_MAX_VOUT_REG];
 102         int curr_vout_val[MAX8973_MAX_VOUT_REG];
 103         int curr_vout_reg;
 104         int curr_gpio_val;
 105         struct regulator_ops ops;
 106 };
 107
 108 /*
 109  * find_voltage_set_register: Find new voltage configuration register (VOUT).
 110  * The finding of the new VOUT register will be based on the LRU mechanism.
 111  * Each VOUT register will have different voltage configured . This
 112  * Function will look if any of the VOUT register have requested voltage set
 113  * or not.
 114  *     - If it is already there then it will make that register as most
 115  *       recently used and return as found so that caller need not to set
 116  *       the VOUT register but need to set the proper gpios to select this
 117  *       VOUT register.
 118  *     - If requested voltage is not found then it will use the least
 119  *       recently mechanism to get new VOUT register for new configuration
 120  *       and will return not_found so that caller need to set new VOUT
 121  *       register and then gpios (both).
 122  */
 123 static bool find_voltage_set_register(struct max8973_chip *tps,
 124                 int req_vsel, int *vout_reg, int *gpio_val)
 125 {
 126         int i;
 127         bool found = false;
 128         int new_vout_reg = tps->lru_index[MAX8973_MAX_VOUT_REG - 1];
 129         int found_index = MAX8973_MAX_VOUT_REG - 1;
 130
 131         for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i) {
 132                 if (tps->curr_vout_val[tps->lru_index[i]] == req_vsel) {
 133                         new_vout_reg = tps->lru_index[i];
 134                         found_index = i;
 135                         found = true;
 136                         goto update_lru_index;
 137                 }
 138         }
 139
 140 update_lru_index:
 141         for (i = found_index; i > 0; i--)
 142                 tps->lru_index[i] = tps->lru_index[i - 1];
 143
 144         tps->lru_index[0] = new_vout_reg;
 145         *gpio_val = new_vout_reg;
 146         *vout_reg = MAX8973_VOUT + new_vout_reg;
 147         return found;
 148 }
 149
 150 static int max8973_dcdc_get_voltage_sel(struct regulator_dev *rdev)
 151 {
 152         struct max8973_chip *max = rdev_get_drvdata(rdev);
 153         unsigned int data;
 154         int ret;
 155
 156         ret = regmap_read(max->regmap, max->curr_vout_reg, &data);
 157         if (ret < 0) {
 158                 dev_err(max->dev, "register %d read failed, err = %d\n",
 159                         max->curr_vout_reg, ret);
 160                 return ret;
 161         }
 162         return data & MAX8973_VOUT_MASK;
 163 }
 164
 165 static int max8973_dcdc_set_voltage_sel(struct regulator_dev *rdev,
 166              unsigned vsel)
 167 {
 168         struct max8973_chip *max = rdev_get_drvdata(rdev);
 169         int ret;
 170         bool found = false;
 171         int vout_reg = max->curr_vout_reg;
 172         int gpio_val = max->curr_gpio_val;
 173
 174         /*
 175          * If gpios are available to select the VOUT register then least
 176          * recently used register for new configuration.
 177          */
 178         if (gpio_is_valid(max->dvs_gpio))
 179                 found = find_voltage_set_register(max, vsel,
 180                                         &vout_reg, &gpio_val);
 181
 182         if (!found) {
 183                 ret = regmap_update_bits(max->regmap, vout_reg,
 184                                         MAX8973_VOUT_MASK, vsel);
 185                 if (ret < 0) {
 186                         dev_err(max->dev, "register %d update failed, err %d\n",
 187                                  vout_reg, ret);
 188                         return ret;
 189                 }
 190                 max->curr_vout_reg = vout_reg;
 191                 max->curr_vout_val[gpio_val] = vsel;
 192         }
 193
 194         /* Select proper VOUT register vio gpios */
 195         if (gpio_is_valid(max->dvs_gpio)) {
 196                 gpio_set_value_cansleep(max->dvs_gpio, gpio_val & 0x1);
 197                 max->curr_gpio_val = gpio_val;
 198         }
 199         return 0;
 200 }
 201
 202 static int max8973_dcdc_set_mode(struct regulator_dev *rdev, unsigned int mode)
 203 {
 204         struct max8973_chip *max = rdev_get_drvdata(rdev);
 205         int ret;
 206         int pwm;
 207
 208         /* Enable force PWM mode in FAST mode only. */
 209         switch (mode) {
 210         case REGULATOR_MODE_FAST:
 211                 pwm = MAX8973_FPWM_EN_M;
 212                 break;
 213
 214         case REGULATOR_MODE_NORMAL:
 215                 pwm = 0;
 216                 break;
 217
 218         default:
 219                 return -EINVAL;
 220         }
 221
 222         ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
 223                                 MAX8973_FPWM_EN_M, pwm);
 224         if (ret < 0)
 225                 dev_err(max->dev, "register %d update failed, err %d\n",
 226                                 MAX8973_CONTROL1, ret);
 227         return ret;
 228 }
 229
 230 static unsigned int max8973_dcdc_get_mode(struct regulator_dev *rdev)
 231 {
 232         struct max8973_chip *max = rdev_get_drvdata(rdev);
 233         unsigned int data;
 234         int ret;
 235
 236         ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data);
 237         if (ret < 0) {
 238                 dev_err(max->dev, "register %d read failed, err %d\n",
 239                                 MAX8973_CONTROL1, ret);
 240                 return ret;
 241         }
 242         return (data & MAX8973_FPWM_EN_M) ?
 243                 REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL;
 244 }
 245
 246 static const struct regulator_ops max8973_dcdc_ops = {
 247         .get_voltage_sel        = max8973_dcdc_get_voltage_sel,
 248         .set_voltage_sel        = max8973_dcdc_set_voltage_sel,
 249         .list_voltage           = regulator_list_voltage_linear,
 250         .set_mode               = max8973_dcdc_set_mode,
 251         .get_mode               = max8973_dcdc_get_mode,
 252 };
 253
 254 static int max8973_init_dcdc(struct max8973_chip *max,
 255                              struct max8973_regulator_platform_data *pdata)
 256 {
 257         int ret;
 258         uint8_t control1 = 0;
 259         uint8_t control2 = 0;
 260
 261         if (pdata->control_flags & MAX8973_CONTROL_REMOTE_SENSE_ENABLE)
 262                 control1 |= MAX8973_SNS_ENABLE;
 263
 264         if (!(pdata->control_flags & MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE))
 265                 control1 |= MAX8973_NFSR_ENABLE;
 266
 267         if (pdata->control_flags & MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE)
 268                 control1 |= MAX8973_AD_ENABLE;
 269
 270         if (pdata->control_flags & MAX8973_CONTROL_BIAS_ENABLE) {
 271                 control1 |= MAX8973_BIAS_ENABLE;
 272                 max->desc.enable_time = 20;
 273         } else {
 274                 max->desc.enable_time = 240;
 275         }
 276
 277         if (pdata->control_flags & MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE)
 278                 control1 |= MAX8973_FREQSHIFT_9PER;
 279
 280         /* Set ramp delay */
 281         if (pdata->reg_init_data &&
 282                         pdata->reg_init_data->constraints.ramp_delay) {
 283                 if (pdata->reg_init_data->constraints.ramp_delay < 25000)
 284                         control1 |= MAX8973_RAMP_12mV_PER_US;
 285                 else if (pdata->reg_init_data->constraints.ramp_delay < 50000)
 286                         control1 |= MAX8973_RAMP_25mV_PER_US;
 287                 else if (pdata->reg_init_data->constraints.ramp_delay < 200000)
 288                         control1 |= MAX8973_RAMP_50mV_PER_US;
 289                 else
 290                         control1 |= MAX8973_RAMP_200mV_PER_US;
 291         } else {
 292                 control1 |= MAX8973_RAMP_12mV_PER_US;
 293                 max->desc.ramp_delay = 12500;
 294         }
 295
 296         if (!(pdata->control_flags & MAX8973_CONTROL_PULL_DOWN_ENABLE))
 297                 control2 |= MAX8973_DISCH_ENBABLE;
 298
 299         /*  Clock advance trip configuration */
 300         switch (pdata->control_flags & MAX8973_CONTROL_CLKADV_TRIP_MASK) {
 301         case MAX8973_CONTROL_CLKADV_TRIP_DISABLED:
 302                 control2 |= MAX8973_CKKADV_TRIP_DISABLE;
 303                 break;
 304
 305         case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US:
 306                 control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US;
 307                 break;
 308
 309         case MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US:
 310                 control2 |= MAX8973_CKKADV_TRIP_150mV_PER_US;
 311                 break;
 312
 313         case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US_HIST_DIS:
 314                 control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS;
 315                 break;
 316         }
 317
 318         /* Configure inductor value */
 319         switch (pdata->control_flags & MAX8973_CONTROL_INDUCTOR_VALUE_MASK) {
 320         case MAX8973_CONTROL_INDUCTOR_VALUE_NOMINAL:
 321                 control2 |= MAX8973_INDUCTOR_NOMINAL;
 322                 break;
 323
 324         case MAX8973_CONTROL_INDUCTOR_VALUE_MINUS_30_PER:
 325                 control2 |= MAX8973_INDUCTOR_MIN_30_PER;
 326                 break;
 327
 328         case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_30_PER:
 329                 control2 |= MAX8973_INDUCTOR_PLUS_30_PER;
 330                 break;
 331
 332         case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_60_PER:
 333                 control2 |= MAX8973_INDUCTOR_PLUS_60_PER;
 334                 break;
 335         }
 336
 337         ret = regmap_write(max->regmap, MAX8973_CONTROL1, control1);
 338         if (ret < 0) {
 339                 dev_err(max->dev, "register %d write failed, err = %d",
 340                                 MAX8973_CONTROL1, ret);
 341                 return ret;
 342         }
 343
 344         ret = regmap_write(max->regmap, MAX8973_CONTROL2, control2);
 345         if (ret < 0) {
 346                 dev_err(max->dev, "register %d write failed, err = %d",
 347                                 MAX8973_CONTROL2, ret);
 348                 return ret;
 349         }
 350
 351         /* If external control is enabled then disable EN bit */
 352         if (max->enable_external_control) {
 353                 ret = regmap_update_bits(max->regmap, MAX8973_VOUT,
 354                                                 MAX8973_VOUT_ENABLE, 0);
 355                 if (ret < 0)
 356                         dev_err(max->dev, "register %d update failed, err = %d",
 357                                 MAX8973_VOUT, ret);
 358         }
 359         return ret;
 360 }
 361
 362 static const struct regmap_config max8973_regmap_config = {
 363         .reg_bits               = 8,
 364         .val_bits               = 8,
 365         .max_register           = MAX8973_CHIPID2,
 366         .cache_type             = REGCACHE_RBTREE,
 367 };
 368
 369 static struct max8973_regulator_platform_data *max8973_parse_dt(
 370                 struct device *dev)
 371 {
 372         struct max8973_regulator_platform_data *pdata;
 373         struct device_node *np = dev->of_node;
 374         int ret;
 375         u32 pval;
 376
 377         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 378         if (!pdata)
 379                 return NULL;
 380
 381         pdata->enable_ext_control = of_property_read_bool(np,
 382                                                 "maxim,externally-enable");
 383         pdata->enable_gpio = of_get_named_gpio(np, "maxim,enable-gpio", 0);
 384         pdata->dvs_gpio = of_get_named_gpio(np, "maxim,dvs-gpio", 0);
 385
 386         ret = of_property_read_u32(np, "maxim,dvs-default-state", &pval);
 387         if (!ret)
 388                 pdata->dvs_def_state = pval;
 389
 390         if (of_property_read_bool(np, "maxim,enable-remote-sense"))
 391                 pdata->control_flags  |= MAX8973_CONTROL_REMOTE_SENSE_ENABLE;
 392
 393         if (of_property_read_bool(np, "maxim,enable-falling-slew-rate"))
 394                 pdata->control_flags  |=
 395                                 MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE;
 396
 397         if (of_property_read_bool(np, "maxim,enable-active-discharge"))
 398                 pdata->control_flags  |=
 399                                 MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE;
 400
 401         if (of_property_read_bool(np, "maxim,enable-frequency-shift"))
 402                 pdata->control_flags  |= MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE;
 403
 404         if (of_property_read_bool(np, "maxim,enable-bias-control"))
 405                 pdata->control_flags  |= MAX8973_BIAS_ENABLE;
 406
 407         return pdata;
 408 }
 409
 410 static int max8973_probe(struct i2c_client *client,
 411                          const struct i2c_device_id *id)
 412 {
 413         struct max8973_regulator_platform_data *pdata;
 414         struct regulator_init_data *ridata;
 415         struct regulator_config config = { };
 416         struct regulator_dev *rdev;
 417         struct max8973_chip *max;
 418         bool pdata_from_dt = false;
 419         int ret;
 420
 421         pdata = dev_get_platdata(&client->dev);
 422
 423         if (!pdata && client->dev.of_node) {
 424                 pdata = max8973_parse_dt(&client->dev);
 425                 pdata_from_dt = true;
 426         }
 427
 428         if (!pdata) {
 429                 dev_err(&client->dev, "No Platform data");
 430                 return -EIO;
 431         }
 432
 433         if ((pdata->dvs_gpio == -EPROBE_DEFER) ||
 434                 (pdata->enable_gpio == -EPROBE_DEFER))
 435                 return -EPROBE_DEFER;
 436
 437         max = devm_kzalloc(&client->dev, sizeof(*max), GFP_KERNEL);
 438         if (!max)
 439                 return -ENOMEM;
 440
 441         max->regmap = devm_regmap_init_i2c(client, &max8973_regmap_config);
 442         if (IS_ERR(max->regmap)) {
 443                 ret = PTR_ERR(max->regmap);
 444                 dev_err(&client->dev, "regmap init failed, err %d\n", ret);
 445                 return ret;
 446         }
 447
 448         i2c_set_clientdata(client, max);
 449         max->ops = max8973_dcdc_ops;
 450         max->dev = &client->dev;
 451         max->desc.name = id->name;
 452         max->desc.id = 0;
 453         max->desc.ops = &max->ops;
 454         max->desc.type = REGULATOR_VOLTAGE;
 455         max->desc.owner = THIS_MODULE;
 456         max->desc.min_uV = MAX8973_MIN_VOLATGE;
 457         max->desc.uV_step = MAX8973_VOLATGE_STEP;
 458         max->desc.n_voltages = MAX8973_BUCK_N_VOLTAGE;
 459
 460         max->dvs_gpio = (pdata->dvs_gpio) ? pdata->dvs_gpio : -EINVAL;
 461         max->enable_gpio = (pdata->enable_gpio) ? pdata->enable_gpio : -EINVAL;
 462         max->enable_external_control = pdata->enable_ext_control;
 463         max->curr_gpio_val = pdata->dvs_def_state;
 464         max->curr_vout_reg = MAX8973_VOUT + pdata->dvs_def_state;
 465
 466         if (gpio_is_valid(max->enable_gpio))
 467                 max->enable_external_control = true;
 468
 469         if (!pdata->enable_ext_control) {
 470                 max->desc.enable_reg = MAX8973_VOUT;
 471                 max->desc.enable_mask = MAX8973_VOUT_ENABLE;
 472                 max->ops.enable = regulator_enable_regmap;
 473                 max->ops.disable = regulator_disable_regmap;
 474                 max->ops.is_enabled = regulator_is_enabled_regmap;
 475         }
 476
 477         max->lru_index[0] = max->curr_vout_reg;
 478
 479         if (gpio_is_valid(max->dvs_gpio)) {
 480                 int gpio_flags;
 481                 int i;
 482
 483                 gpio_flags = (pdata->dvs_def_state) ?
 484                                 GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
 485                 ret = devm_gpio_request_one(&client->dev, max->dvs_gpio,
 486                                 gpio_flags, "max8973-dvs");
 487                 if (ret) {
 488                         dev_err(&client->dev,
 489                                 "gpio_request for gpio %d failed, err = %d\n",
 490                                 max->dvs_gpio, ret);
 491                         return ret;
 492                 }
 493
 494                 /*
 495                  * Initialize the lru index with vout_reg id
 496                  * The index 0 will be most recently used and
 497                  * set with the max->curr_vout_reg */
 498                 for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i)
 499                         max->lru_index[i] = i;
 500                 max->lru_index[0] = max->curr_vout_reg;
 501                 max->lru_index[max->curr_vout_reg] = 0;
 502         }
 503
 504         if (pdata_from_dt)
 505                 pdata->reg_init_data = of_get_regulator_init_data(&client->dev,
 506                                         client->dev.of_node, &max->desc);
 507
 508         ret = max8973_init_dcdc(max, pdata);
 509         if (ret < 0) {
 510                 dev_err(max->dev, "Max8973 Init failed, err = %d\n", ret);
 511                 return ret;
 512         }
 513
 514         config.dev = &client->dev;
 515         config.init_data = pdata->reg_init_data;
 516         config.driver_data = max;
 517         config.of_node = client->dev.of_node;
 518         config.regmap = max->regmap;
 519
 520         if (gpio_is_valid(max->enable_gpio)) {
 521                 ridata = pdata->reg_init_data;
 522                 config.ena_gpio_flags = GPIOF_OUT_INIT_LOW;
 523                 if (ridata && (ridata->constraints.always_on ||
 524                         ridata->constraints.boot_on))
 525                         config.ena_gpio_flags = GPIOF_OUT_INIT_HIGH;
 526                 config.ena_gpio = max->enable_gpio;
 527         }
 528
 529         /* Register the regulators */
 530         rdev = devm_regulator_register(&client->dev, &max->desc, &config);
 531         if (IS_ERR(rdev)) {
 532                 ret = PTR_ERR(rdev);
 533                 dev_err(max->dev, "regulator register failed, err %d\n", ret);
 534                 return ret;
 535         }
 536
 537         return 0;
 538 }
 539
 540 static const struct i2c_device_id max8973_id[] = {
 541         {.name = "max8973",},
 542         {},
 543 };
 544
 545 MODULE_DEVICE_TABLE(i2c, max8973_id);
 546
 547 static struct i2c_driver max8973_i2c_driver = {
 548         .driver = {
 549                 .name = "max8973",
 550                 .owner = THIS_MODULE,
 551         },
 552         .probe = max8973_probe,
 553         .id_table = max8973_id,
 554 };
 555
 556 static int __init max8973_init(void)
 557 {
 558         return i2c_add_driver(&max8973_i2c_driver);
 559 }
 560 subsys_initcall(max8973_init);
 561
 562 static void __exit max8973_cleanup(void)
 563 {
 564         i2c_del_driver(&max8973_i2c_driver);
 565 }
 566 module_exit(max8973_cleanup);
 567
 568 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
 569 MODULE_DESCRIPTION("MAX8973 voltage regulator driver");
 570 MODULE_LICENSE("GPL v2");