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/platform_device.h>
  30 #include <linux/regulator/driver.h>
  31 #include <linux/regulator/machine.h>
  32 #include <linux/regulator/max8973-regulator.h>
  33 #include <linux/gpio.h>
  34 #include <linux/i2c.h>
  35 #include <linux/slab.h>
  36 #include <linux/regmap.h>
  37
  38 /* Register definitions */
  39 #define MAX8973_VOUT                                    0x0
  40 #define MAX8973_VOUT_DVS                                0x1
  41 #define MAX8973_CONTROL1                                0x2
  42 #define MAX8973_CONTROL2                                0x3
  43 #define MAX8973_CHIPID1                                 0x4
  44 #define MAX8973_CHIPID2                                 0x5
  45
  46 #define MAX8973_MAX_VOUT_REG                            2
  47
  48 /* MAX8973_VOUT */
  49 #define MAX8973_VOUT_ENABLE                             BIT(7)
  50 #define MAX8973_VOUT_MASK                               0x7F
  51
  52 /* MAX8973_VOUT_DVS */
  53 #define MAX8973_DVS_VOUT_MASK                           0x7F
  54
  55 /* MAX8973_CONTROL1 */
  56 #define MAX8973_SNS_ENABLE                              BIT(7)
  57 #define MAX8973_FPWM_EN_M                               BIT(6)
  58 #define MAX8973_NFSR_ENABLE                             BIT(5)
  59 #define MAX8973_AD_ENABLE                               BIT(4)
  60 #define MAX8973_BIAS_ENABLE                             BIT(3)
  61 #define MAX8973_FREQSHIFT_9PER                          BIT(2)
  62
  63 #define MAX8973_RAMP_12mV_PER_US                        0x0
  64 #define MAX8973_RAMP_25mV_PER_US                        0x1
  65 #define MAX8973_RAMP_50mV_PER_US                        0x2
  66 #define MAX8973_RAMP_200mV_PER_US                       0x3
  67
  68 /* MAX8973_CONTROL2 */
  69 #define MAX8973_WDTMR_ENABLE                            BIT(6)
  70 #define MAX8973_DISCH_ENBABLE                           BIT(5)
  71 #define MAX8973_FT_ENABLE                               BIT(4)
  72
  73 #define MAX8973_CKKADV_TRIP_DISABLE                     0xC
  74 #define MAX8973_CKKADV_TRIP_75mV_PER_US                 0x0
  75 #define MAX8973_CKKADV_TRIP_150mV_PER_US                0x4
  76 #define MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS        0x8
  77 #define MAX8973_CONTROL_CLKADV_TRIP_MASK                0x00030000
  78
  79 #define MAX8973_INDUCTOR_MIN_30_PER                     0x0
  80 #define MAX8973_INDUCTOR_NOMINAL                        0x1
  81 #define MAX8973_INDUCTOR_PLUS_30_PER                    0x2
  82 #define MAX8973_INDUCTOR_PLUS_60_PER                    0x3
  83 #define MAX8973_CONTROL_INDUCTOR_VALUE_MASK             0x00300000
  84
  85 #define MAX8973_MIN_VOLATGE                             606250
  86 #define MAX8973_MAX_VOLATGE                             1400000
  87 #define MAX8973_VOLATGE_STEP                            6250
  88 #define MAX8973_BUCK_N_VOLTAGE                          0x80
  89
  90 /* Maxim 8973 chip information */
  91 struct max8973_chip {
  92         struct device *dev;
  93         struct regulator_desc desc;
  94         struct regulator_dev *rdev;
  95         struct regmap *regmap;
  96         bool enable_external_control;
  97         int dvs_gpio;
  98         int lru_index[MAX8973_MAX_VOUT_REG];
  99         int curr_vout_val[MAX8973_MAX_VOUT_REG];
 100         int curr_vout_reg;
 101         int curr_gpio_val;
 102         bool valid_dvs_gpio;
 103 };
 104
 105 /*
 106  * find_voltage_set_register: Find new voltage configuration register (VOUT).
 107  * The finding of the new VOUT register will be based on the LRU mechanism.
 108  * Each VOUT register will have different voltage configured . This
 109  * Function will look if any of the VOUT register have requested voltage set
 110  * or not.
 111  *     - If it is already there then it will make that register as most
 112  *       recently used and return as found so that caller need not to set
 113  *       the VOUT register but need to set the proper gpios to select this
 114  *       VOUT register.
 115  *     - If requested voltage is not found then it will use the least
 116  *       recently mechanism to get new VOUT register for new configuration
 117  *       and will return not_found so that caller need to set new VOUT
 118  *       register and then gpios (both).
 119  */
 120 static bool find_voltage_set_register(struct max8973_chip *tps,
 121                 int req_vsel, int *vout_reg, int *gpio_val)
 122 {
 123         int i;
 124         bool found = false;
 125         int new_vout_reg = tps->lru_index[MAX8973_MAX_VOUT_REG - 1];
 126         int found_index = MAX8973_MAX_VOUT_REG - 1;
 127
 128         for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i) {
 129                 if (tps->curr_vout_val[tps->lru_index[i]] == req_vsel) {
 130                         new_vout_reg = tps->lru_index[i];
 131                         found_index = i;
 132                         found = true;
 133                         goto update_lru_index;
 134                 }
 135         }
 136
 137 update_lru_index:
 138         for (i = found_index; i > 0; i--)
 139                 tps->lru_index[i] = tps->lru_index[i - 1];
 140
 141         tps->lru_index[0] = new_vout_reg;
 142         *gpio_val = new_vout_reg;
 143         *vout_reg = MAX8973_VOUT + new_vout_reg;
 144         return found;
 145 }
 146
 147 static int max8973_dcdc_get_voltage_sel(struct regulator_dev *rdev)
 148 {
 149         struct max8973_chip *max = rdev_get_drvdata(rdev);
 150         unsigned int data;
 151         int ret;
 152
 153         ret = regmap_read(max->regmap, max->curr_vout_reg, &data);
 154         if (ret < 0) {
 155                 dev_err(max->dev, "register %d read failed, err = %d\n",
 156                         max->curr_vout_reg, ret);
 157                 return ret;
 158         }
 159         return data & MAX8973_VOUT_MASK;
 160 }
 161
 162 static int max8973_dcdc_set_voltage_sel(struct regulator_dev *rdev,
 163              unsigned vsel)
 164 {
 165         struct max8973_chip *max = rdev_get_drvdata(rdev);
 166         int ret;
 167         bool found = false;
 168         int vout_reg = max->curr_vout_reg;
 169         int gpio_val = max->curr_gpio_val;
 170
 171         /*
 172          * If gpios are available to select the VOUT register then least
 173          * recently used register for new configuration.
 174          */
 175         if (max->valid_dvs_gpio)
 176                 found = find_voltage_set_register(max, vsel,
 177                                         &vout_reg, &gpio_val);
 178
 179         if (!found) {
 180                 ret = regmap_update_bits(max->regmap, vout_reg,
 181                                         MAX8973_VOUT_MASK, vsel);
 182                 if (ret < 0) {
 183                         dev_err(max->dev, "register %d update failed, err %d\n",
 184                                  vout_reg, ret);
 185                         return ret;
 186                 }
 187                 max->curr_vout_reg = vout_reg;
 188                 max->curr_vout_val[gpio_val] = vsel;
 189         }
 190
 191         /* Select proper VOUT register vio gpios */
 192         if (max->valid_dvs_gpio) {
 193                 gpio_set_value_cansleep(max->dvs_gpio, gpio_val & 0x1);
 194                 max->curr_gpio_val = gpio_val;
 195         }
 196         return 0;
 197 }
 198
 199 static int max8973_dcdc_set_mode(struct regulator_dev *rdev, unsigned int mode)
 200 {
 201         struct max8973_chip *max = rdev_get_drvdata(rdev);
 202         int ret;
 203         int pwm;
 204
 205         /* Enable force PWM mode in FAST mode only. */
 206         switch (mode) {
 207         case REGULATOR_MODE_FAST:
 208                 pwm = MAX8973_FPWM_EN_M;
 209                 break;
 210
 211         case REGULATOR_MODE_NORMAL:
 212                 pwm = 0;
 213                 break;
 214
 215         default:
 216                 return -EINVAL;
 217         }
 218
 219         ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
 220                                 MAX8973_FPWM_EN_M, pwm);
 221         if (ret < 0)
 222                 dev_err(max->dev, "register %d update failed, err %d\n",
 223                                 MAX8973_CONTROL1, ret);
 224         return ret;
 225 }
 226
 227 static unsigned int max8973_dcdc_get_mode(struct regulator_dev *rdev)
 228 {
 229         struct max8973_chip *max = rdev_get_drvdata(rdev);
 230         unsigned int data;
 231         int ret;
 232
 233         ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data);
 234         if (ret < 0) {
 235                 dev_err(max->dev, "register %d read failed, err %d\n",
 236                                 MAX8973_CONTROL1, ret);
 237                 return ret;
 238         }
 239         return (data & MAX8973_FPWM_EN_M) ?
 240                 REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL;
 241 }
 242
 243 static struct regulator_ops max8973_dcdc_ops = {
 244         .get_voltage_sel        = max8973_dcdc_get_voltage_sel,
 245         .set_voltage_sel        = max8973_dcdc_set_voltage_sel,
 246         .list_voltage           = regulator_list_voltage_linear,
 247         .set_mode               = max8973_dcdc_set_mode,
 248         .get_mode               = max8973_dcdc_get_mode,
 249 };
 250
 251 static int max8973_init_dcdc(struct max8973_chip *max,
 252                              struct max8973_regulator_platform_data *pdata)
 253 {
 254         int ret;
 255         uint8_t control1 = 0;
 256         uint8_t control2 = 0;
 257
 258         if (pdata->control_flags & MAX8973_CONTROL_REMOTE_SENSE_ENABLE)
 259                 control1 |= MAX8973_SNS_ENABLE;
 260
 261         if (!(pdata->control_flags & MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE))
 262                 control1 |= MAX8973_NFSR_ENABLE;
 263
 264         if (pdata->control_flags & MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE)
 265                 control1 |= MAX8973_AD_ENABLE;
 266
 267         if (pdata->control_flags & MAX8973_CONTROL_BIAS_ENABLE)
 268                 control1 |= MAX8973_BIAS_ENABLE;
 269
 270         if (pdata->control_flags & MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE)
 271                 control1 |= MAX8973_FREQSHIFT_9PER;
 272
 273         /* Set ramp delay */
 274         if (pdata->reg_init_data &&
 275                         pdata->reg_init_data->constraints.ramp_delay) {
 276                 if (pdata->reg_init_data->constraints.ramp_delay < 25000)
 277                         control1 = MAX8973_RAMP_12mV_PER_US;
 278                 else if (pdata->reg_init_data->constraints.ramp_delay < 50000)
 279                         control1 = MAX8973_RAMP_25mV_PER_US;
 280                 else if (pdata->reg_init_data->constraints.ramp_delay < 200000)
 281                         control1 = MAX8973_RAMP_50mV_PER_US;
 282                 else
 283                         control1 = MAX8973_RAMP_200mV_PER_US;
 284         } else {
 285                 control1 = MAX8973_RAMP_12mV_PER_US;
 286                 max->desc.ramp_delay = 12500;
 287         }
 288
 289         if (!(pdata->control_flags & MAX8973_CONTROL_PULL_DOWN_ENABLE))
 290                 control2 |= MAX8973_DISCH_ENBABLE;
 291
 292         /*  Clock advance trip configuration */
 293         switch (pdata->control_flags & MAX8973_CONTROL_CLKADV_TRIP_MASK) {
 294         case MAX8973_CONTROL_CLKADV_TRIP_DISABLED:
 295                 control2 |= MAX8973_CKKADV_TRIP_DISABLE;
 296                 break;
 297
 298         case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US:
 299                 control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US;
 300                 break;
 301
 302         case MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US:
 303                 control2 |= MAX8973_CKKADV_TRIP_150mV_PER_US;
 304                 break;
 305
 306         case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US_HIST_DIS:
 307                 control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS;
 308                 break;
 309         }
 310
 311         /* Configure inductor value */
 312         switch (pdata->control_flags & MAX8973_CONTROL_INDUCTOR_VALUE_MASK) {
 313         case MAX8973_CONTROL_INDUCTOR_VALUE_NOMINAL:
 314                 control2 |= MAX8973_INDUCTOR_NOMINAL;
 315                 break;
 316
 317         case MAX8973_CONTROL_INDUCTOR_VALUE_MINUS_30_PER:
 318                 control2 |= MAX8973_INDUCTOR_MIN_30_PER;
 319                 break;
 320
 321         case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_30_PER:
 322                 control2 |= MAX8973_INDUCTOR_PLUS_30_PER;
 323                 break;
 324
 325         case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_60_PER:
 326                 control2 |= MAX8973_INDUCTOR_PLUS_60_PER;
 327                 break;
 328         }
 329
 330         ret = regmap_write(max->regmap, MAX8973_CONTROL1, control1);
 331         if (ret < 0) {
 332                 dev_err(max->dev, "register %d write failed, err = %d",
 333                                 MAX8973_CONTROL1, ret);
 334                 return ret;
 335         }
 336
 337         ret = regmap_write(max->regmap, MAX8973_CONTROL2, control2);
 338         if (ret < 0) {
 339                 dev_err(max->dev, "register %d write failed, err = %d",
 340                                 MAX8973_CONTROL2, ret);
 341                 return ret;
 342         }
 343
 344         /* If external control is enabled then disable EN bit */
 345         if (max->enable_external_control) {
 346                 ret = regmap_update_bits(max->regmap, MAX8973_VOUT,
 347                                                 MAX8973_VOUT_ENABLE, 0);
 348                 if (ret < 0)
 349                         dev_err(max->dev, "register %d update failed, err = %d",
 350                                 MAX8973_VOUT, ret);
 351         }
 352         return ret;
 353 }
 354
 355 static const struct regmap_config max8973_regmap_config = {
 356         .reg_bits               = 8,
 357         .val_bits               = 8,
 358         .max_register           = MAX8973_CHIPID2,
 359         .cache_type             = REGCACHE_RBTREE,
 360 };
 361
 362 static int max8973_probe(struct i2c_client *client,
 363                          const struct i2c_device_id *id)
 364 {
 365         struct max8973_regulator_platform_data *pdata;
 366         struct regulator_config config = { };
 367         struct regulator_dev *rdev;
 368         struct max8973_chip *max;
 369         int ret;
 370
 371         pdata = client->dev.platform_data;
 372         if (!pdata) {
 373                 dev_err(&client->dev, "No Platform data");
 374                 return -EIO;
 375         }
 376
 377         max = devm_kzalloc(&client->dev, sizeof(*max), GFP_KERNEL);
 378         if (!max) {
 379                 dev_err(&client->dev, "Memory allocation for max failed\n");
 380                 return -ENOMEM;
 381         }
 382
 383         max->regmap = devm_regmap_init_i2c(client, &max8973_regmap_config);
 384         if (IS_ERR(max->regmap)) {
 385                 ret = PTR_ERR(max->regmap);
 386                 dev_err(&client->dev, "regmap init failed, err %d\n", ret);
 387                 return ret;
 388         }
 389
 390         i2c_set_clientdata(client, max);
 391         max->dev = &client->dev;
 392         max->desc.name = id->name;
 393         max->desc.id = 0;
 394         max->desc.ops = &max8973_dcdc_ops;
 395         max->desc.type = REGULATOR_VOLTAGE;
 396         max->desc.owner = THIS_MODULE;
 397         max->desc.min_uV = MAX8973_MIN_VOLATGE;
 398         max->desc.uV_step = MAX8973_VOLATGE_STEP;
 399         max->desc.n_voltages = MAX8973_BUCK_N_VOLTAGE;
 400
 401         if (!pdata->enable_ext_control) {
 402                 max->desc.enable_reg = MAX8973_VOUT;
 403                 max->desc.enable_mask = MAX8973_VOUT_ENABLE;
 404                 max8973_dcdc_ops.enable = regulator_enable_regmap;
 405                 max8973_dcdc_ops.disable = regulator_disable_regmap;
 406                 max8973_dcdc_ops.is_enabled = regulator_is_enabled_regmap;
 407         }
 408
 409         max->enable_external_control = pdata->enable_ext_control;
 410         max->dvs_gpio = pdata->dvs_gpio;
 411         max->curr_gpio_val = pdata->dvs_def_state;
 412         max->curr_vout_reg = MAX8973_VOUT + pdata->dvs_def_state;
 413         max->lru_index[0] = max->curr_vout_reg;
 414         max->valid_dvs_gpio = false;
 415
 416         if (gpio_is_valid(max->dvs_gpio)) {
 417                 int gpio_flags;
 418                 int i;
 419
 420                 gpio_flags = (pdata->dvs_def_state) ?
 421                                 GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
 422                 ret = devm_gpio_request_one(&client->dev, max->dvs_gpio,
 423                                 gpio_flags, "max8973-dvs");
 424                 if (ret) {
 425                         dev_err(&client->dev,
 426                                 "gpio_request for gpio %d failed, err = %d\n",
 427                                 max->dvs_gpio, ret);
 428                         return ret;
 429                 }
 430                 max->valid_dvs_gpio = true;
 431
 432                 /*
 433                  * Initialize the lru index with vout_reg id
 434                  * The index 0 will be most recently used and
 435                  * set with the max->curr_vout_reg */
 436                 for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i)
 437                         max->lru_index[i] = i;
 438                 max->lru_index[0] = max->curr_vout_reg;
 439                 max->lru_index[max->curr_vout_reg] = 0;
 440         }
 441
 442         ret = max8973_init_dcdc(max, pdata);
 443         if (ret < 0) {
 444                 dev_err(max->dev, "Max8973 Init failed, err = %d\n", ret);
 445                 return ret;
 446         }
 447
 448         config.dev = &client->dev;
 449         config.init_data = pdata->reg_init_data;
 450         config.driver_data = max;
 451         config.of_node = client->dev.of_node;
 452         config.regmap = max->regmap;
 453
 454         /* Register the regulators */
 455         rdev = regulator_register(&max->desc, &config);
 456         if (IS_ERR(rdev)) {
 457                 ret = PTR_ERR(rdev);
 458                 dev_err(max->dev, "regulator register failed, err %d\n", ret);
 459                 return ret;
 460         }
 461
 462         max->rdev = rdev;
 463         return 0;
 464 }
 465
 466 static int max8973_remove(struct i2c_client *client)
 467 {
 468         struct max8973_chip *max = i2c_get_clientdata(client);
 469
 470         regulator_unregister(max->rdev);
 471         return 0;
 472 }
 473
 474 static const struct i2c_device_id max8973_id[] = {
 475         {.name = "max8973",},
 476         {},
 477 };
 478
 479 MODULE_DEVICE_TABLE(i2c, max8973_id);
 480
 481 static struct i2c_driver max8973_i2c_driver = {
 482         .driver = {
 483                 .name = "max8973",
 484                 .owner = THIS_MODULE,
 485         },
 486         .probe = max8973_probe,
 487         .remove = max8973_remove,
 488         .id_table = max8973_id,
 489 };
 490
 491 static int __init max8973_init(void)
 492 {
 493         return i2c_add_driver(&max8973_i2c_driver);
 494 }
 495 subsys_initcall(max8973_init);
 496
 497 static void __exit max8973_cleanup(void)
 498 {
 499         i2c_del_driver(&max8973_i2c_driver);
 500 }
 501 module_exit(max8973_cleanup);
 502
 503 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
 504 MODULE_DESCRIPTION("MAX8973 voltage regulator driver");
 505 MODULE_LICENSE("GPL v2");