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