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         struct regulator_ops ops;
 104 };
 105
 106 /*
 107  * find_voltage_set_register: Find new voltage configuration register (VOUT).
 108  * The finding of the new VOUT register will be based on the LRU mechanism.
 109  * Each VOUT register will have different voltage configured . This
 110  * Function will look if any of the VOUT register have requested voltage set
 111  * or not.
 112  *     - If it is already there then it will make that register as most
 113  *       recently used and return as found so that caller need not to set
 114  *       the VOUT register but need to set the proper gpios to select this
 115  *       VOUT register.
 116  *     - If requested voltage is not found then it will use the least
 117  *       recently mechanism to get new VOUT register for new configuration
 118  *       and will return not_found so that caller need to set new VOUT
 119  *       register and then gpios (both).
 120  */
 121 static bool find_voltage_set_register(struct max8973_chip *tps,
 122                 int req_vsel, int *vout_reg, int *gpio_val)
 123 {
 124         int i;
 125         bool found = false;
 126         int new_vout_reg = tps->lru_index[MAX8973_MAX_VOUT_REG - 1];
 127         int found_index = MAX8973_MAX_VOUT_REG - 1;
 128
 129         for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i) {
 130                 if (tps->curr_vout_val[tps->lru_index[i]] == req_vsel) {
 131                         new_vout_reg = tps->lru_index[i];
 132                         found_index = i;
 133                         found = true;
 134                         goto update_lru_index;
 135                 }
 136         }
 137
 138 update_lru_index:
 139         for (i = found_index; i > 0; i--)
 140                 tps->lru_index[i] = tps->lru_index[i - 1];
 141
 142         tps->lru_index[0] = new_vout_reg;
 143         *gpio_val = new_vout_reg;
 144         *vout_reg = MAX8973_VOUT + new_vout_reg;
 145         return found;
 146 }
 147
 148 static int max8973_dcdc_get_voltage_sel(struct regulator_dev *rdev)
 149 {
 150         struct max8973_chip *max = rdev_get_drvdata(rdev);
 151         unsigned int data;
 152         int ret;
 153
 154         ret = regmap_read(max->regmap, max->curr_vout_reg, &data);
 155         if (ret < 0) {
 156                 dev_err(max->dev, "register %d read failed, err = %d\n",
 157                         max->curr_vout_reg, ret);
 158                 return ret;
 159         }
 160         return data & MAX8973_VOUT_MASK;
 161 }
 162
 163 static int max8973_dcdc_set_voltage_sel(struct regulator_dev *rdev,
 164              unsigned vsel)
 165 {
 166         struct max8973_chip *max = rdev_get_drvdata(rdev);
 167         int ret;
 168         bool found = false;
 169         int vout_reg = max->curr_vout_reg;
 170         int gpio_val = max->curr_gpio_val;
 171
 172         /*
 173          * If gpios are available to select the VOUT register then least
 174          * recently used register for new configuration.
 175          */
 176         if (gpio_is_valid(max->dvs_gpio))
 177                 found = find_voltage_set_register(max, vsel,
 178                                         &vout_reg, &gpio_val);
 179
 180         if (!found) {
 181                 ret = regmap_update_bits(max->regmap, vout_reg,
 182                                         MAX8973_VOUT_MASK, vsel);
 183                 if (ret < 0) {
 184                         dev_err(max->dev, "register %d update failed, err %d\n",
 185                                  vout_reg, ret);
 186                         return ret;
 187                 }
 188                 max->curr_vout_reg = vout_reg;
 189                 max->curr_vout_val[gpio_val] = vsel;
 190         }
 191
 192         /* Select proper VOUT register vio gpios */
 193         if (gpio_is_valid(max->dvs_gpio)) {
 194                 gpio_set_value_cansleep(max->dvs_gpio, gpio_val & 0x1);
 195                 max->curr_gpio_val = gpio_val;
 196         }
 197         return 0;
 198 }
 199
 200 static int max8973_dcdc_set_mode(struct regulator_dev *rdev, unsigned int mode)
 201 {
 202         struct max8973_chip *max = rdev_get_drvdata(rdev);
 203         int ret;
 204         int pwm;
 205
 206         /* Enable force PWM mode in FAST mode only. */
 207         switch (mode) {
 208         case REGULATOR_MODE_FAST:
 209                 pwm = MAX8973_FPWM_EN_M;
 210                 break;
 211
 212         case REGULATOR_MODE_NORMAL:
 213                 pwm = 0;
 214                 break;
 215
 216         default:
 217                 return -EINVAL;
 218         }
 219
 220         ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
 221                                 MAX8973_FPWM_EN_M, pwm);
 222         if (ret < 0)
 223                 dev_err(max->dev, "register %d update failed, err %d\n",
 224                                 MAX8973_CONTROL1, ret);
 225         return ret;
 226 }
 227
 228 static unsigned int max8973_dcdc_get_mode(struct regulator_dev *rdev)
 229 {
 230         struct max8973_chip *max = rdev_get_drvdata(rdev);
 231         unsigned int data;
 232         int ret;
 233
 234         ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data);
 235         if (ret < 0) {
 236                 dev_err(max->dev, "register %d read failed, err %d\n",
 237                                 MAX8973_CONTROL1, ret);
 238                 return ret;
 239         }
 240         return (data & MAX8973_FPWM_EN_M) ?
 241                 REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL;
 242 }
 243
 244 static const struct regulator_ops max8973_dcdc_ops = {
 245         .get_voltage_sel        = max8973_dcdc_get_voltage_sel,
 246         .set_voltage_sel        = max8973_dcdc_set_voltage_sel,
 247         .list_voltage           = regulator_list_voltage_linear,
 248         .set_mode               = max8973_dcdc_set_mode,
 249         .get_mode               = max8973_dcdc_get_mode,
 250 };
 251
 252 static int max8973_init_dcdc(struct max8973_chip *max,
 253                              struct max8973_regulator_platform_data *pdata)
 254 {
 255         int ret;
 256         uint8_t control1 = 0;
 257         uint8_t control2 = 0;
 258
 259         if (pdata->control_flags & MAX8973_CONTROL_REMOTE_SENSE_ENABLE)
 260                 control1 |= MAX8973_SNS_ENABLE;
 261
 262         if (!(pdata->control_flags & MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE))
 263                 control1 |= MAX8973_NFSR_ENABLE;
 264
 265         if (pdata->control_flags & MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE)
 266                 control1 |= MAX8973_AD_ENABLE;
 267
 268         if (pdata->control_flags & MAX8973_CONTROL_BIAS_ENABLE) {
 269                 control1 |= MAX8973_BIAS_ENABLE;
 270                 max->desc.enable_time = 20;
 271         } else {
 272                 max->desc.enable_time = 240;
 273         }
 274
 275         if (pdata->control_flags & MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE)
 276                 control1 |= MAX8973_FREQSHIFT_9PER;
 277
 278         /* Set ramp delay */
 279         if (pdata->reg_init_data &&
 280                         pdata->reg_init_data->constraints.ramp_delay) {
 281                 if (pdata->reg_init_data->constraints.ramp_delay < 25000)
 282                         control1 |= MAX8973_RAMP_12mV_PER_US;
 283                 else if (pdata->reg_init_data->constraints.ramp_delay < 50000)
 284                         control1 |= MAX8973_RAMP_25mV_PER_US;
 285                 else if (pdata->reg_init_data->constraints.ramp_delay < 200000)
 286                         control1 |= MAX8973_RAMP_50mV_PER_US;
 287                 else
 288                         control1 |= MAX8973_RAMP_200mV_PER_US;
 289         } else {
 290                 control1 |= MAX8973_RAMP_12mV_PER_US;
 291                 max->desc.ramp_delay = 12500;
 292         }
 293
 294         if (!(pdata->control_flags & MAX8973_CONTROL_PULL_DOWN_ENABLE))
 295                 control2 |= MAX8973_DISCH_ENBABLE;
 296
 297         /*  Clock advance trip configuration */
 298         switch (pdata->control_flags & MAX8973_CONTROL_CLKADV_TRIP_MASK) {
 299         case MAX8973_CONTROL_CLKADV_TRIP_DISABLED:
 300                 control2 |= MAX8973_CKKADV_TRIP_DISABLE;
 301                 break;
 302
 303         case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US:
 304                 control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US;
 305                 break;
 306
 307         case MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US:
 308                 control2 |= MAX8973_CKKADV_TRIP_150mV_PER_US;
 309                 break;
 310
 311         case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US_HIST_DIS:
 312                 control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS;
 313                 break;
 314         }
 315
 316         /* Configure inductor value */
 317         switch (pdata->control_flags & MAX8973_CONTROL_INDUCTOR_VALUE_MASK) {
 318         case MAX8973_CONTROL_INDUCTOR_VALUE_NOMINAL:
 319                 control2 |= MAX8973_INDUCTOR_NOMINAL;
 320                 break;
 321
 322         case MAX8973_CONTROL_INDUCTOR_VALUE_MINUS_30_PER:
 323                 control2 |= MAX8973_INDUCTOR_MIN_30_PER;
 324                 break;
 325
 326         case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_30_PER:
 327                 control2 |= MAX8973_INDUCTOR_PLUS_30_PER;
 328                 break;
 329
 330         case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_60_PER:
 331                 control2 |= MAX8973_INDUCTOR_PLUS_60_PER;
 332                 break;
 333         }
 334
 335         ret = regmap_write(max->regmap, MAX8973_CONTROL1, control1);
 336         if (ret < 0) {
 337                 dev_err(max->dev, "register %d write failed, err = %d",
 338                                 MAX8973_CONTROL1, ret);
 339                 return ret;
 340         }
 341
 342         ret = regmap_write(max->regmap, MAX8973_CONTROL2, control2);
 343         if (ret < 0) {
 344                 dev_err(max->dev, "register %d write failed, err = %d",
 345                                 MAX8973_CONTROL2, ret);
 346                 return ret;
 347         }
 348
 349         /* If external control is enabled then disable EN bit */
 350         if (max->enable_external_control) {
 351                 ret = regmap_update_bits(max->regmap, MAX8973_VOUT,
 352                                                 MAX8973_VOUT_ENABLE, 0);
 353                 if (ret < 0)
 354                         dev_err(max->dev, "register %d update failed, err = %d",
 355                                 MAX8973_VOUT, ret);
 356         }
 357         return ret;
 358 }
 359
 360 static const struct regmap_config max8973_regmap_config = {
 361         .reg_bits               = 8,
 362         .val_bits               = 8,
 363         .max_register           = MAX8973_CHIPID2,
 364         .cache_type             = REGCACHE_RBTREE,
 365 };
 366
 367 static int max8973_probe(struct i2c_client *client,
 368                          const struct i2c_device_id *id)
 369 {
 370         struct max8973_regulator_platform_data *pdata;
 371         struct regulator_config config = { };
 372         struct regulator_dev *rdev;
 373         struct max8973_chip *max;
 374         int ret;
 375
 376         pdata = dev_get_platdata(&client->dev);
 377
 378         if (!pdata && !client->dev.of_node) {
 379                 dev_err(&client->dev, "No Platform data");
 380                 return -EIO;
 381         }
 382
 383         max = devm_kzalloc(&client->dev, sizeof(*max), GFP_KERNEL);
 384         if (!max)
 385                 return -ENOMEM;
 386
 387         max->regmap = devm_regmap_init_i2c(client, &max8973_regmap_config);
 388         if (IS_ERR(max->regmap)) {
 389                 ret = PTR_ERR(max->regmap);
 390                 dev_err(&client->dev, "regmap init failed, err %d\n", ret);
 391                 return ret;
 392         }
 393
 394         i2c_set_clientdata(client, max);
 395         max->ops = max8973_dcdc_ops;
 396         max->dev = &client->dev;
 397         max->desc.name = id->name;
 398         max->desc.id = 0;
 399         max->desc.ops = &max->ops;
 400         max->desc.type = REGULATOR_VOLTAGE;
 401         max->desc.owner = THIS_MODULE;
 402         max->desc.min_uV = MAX8973_MIN_VOLATGE;
 403         max->desc.uV_step = MAX8973_VOLATGE_STEP;
 404         max->desc.n_voltages = MAX8973_BUCK_N_VOLTAGE;
 405
 406         if (!pdata || !pdata->enable_ext_control) {
 407                 max->desc.enable_reg = MAX8973_VOUT;
 408                 max->desc.enable_mask = MAX8973_VOUT_ENABLE;
 409                 max->ops.enable = regulator_enable_regmap;
 410                 max->ops.disable = regulator_disable_regmap;
 411                 max->ops.is_enabled = regulator_is_enabled_regmap;
 412         }
 413
 414         if (pdata) {
 415                 max->dvs_gpio = (pdata->dvs_gpio) ? pdata->dvs_gpio : -EINVAL;
 416                 max->enable_external_control = pdata->enable_ext_control;
 417                 max->curr_gpio_val = pdata->dvs_def_state;
 418                 max->curr_vout_reg = MAX8973_VOUT + pdata->dvs_def_state;
 419         } else {
 420                 max->dvs_gpio = -EINVAL;
 421                 max->curr_vout_reg = MAX8973_VOUT;
 422         }
 423
 424         max->lru_index[0] = max->curr_vout_reg;
 425
 426         if (gpio_is_valid(max->dvs_gpio)) {
 427                 int gpio_flags;
 428                 int i;
 429
 430                 gpio_flags = (pdata->dvs_def_state) ?
 431                                 GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
 432                 ret = devm_gpio_request_one(&client->dev, max->dvs_gpio,
 433                                 gpio_flags, "max8973-dvs");
 434                 if (ret) {
 435                         dev_err(&client->dev,
 436                                 "gpio_request for gpio %d failed, err = %d\n",
 437                                 max->dvs_gpio, ret);
 438                         return ret;
 439                 }
 440
 441                 /*
 442                  * Initialize the lru index with vout_reg id
 443                  * The index 0 will be most recently used and
 444                  * set with the max->curr_vout_reg */
 445                 for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i)
 446                         max->lru_index[i] = i;
 447                 max->lru_index[0] = max->curr_vout_reg;
 448                 max->lru_index[max->curr_vout_reg] = 0;
 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                                            &max->desc);
 463         config.driver_data = max;
 464         config.of_node = client->dev.of_node;
 465         config.regmap = max->regmap;
 466
 467         /* Register the regulators */
 468         rdev = devm_regulator_register(&client->dev, &max->desc, &config);
 469         if (IS_ERR(rdev)) {
 470                 ret = PTR_ERR(rdev);
 471                 dev_err(max->dev, "regulator register failed, err %d\n", ret);
 472                 return ret;
 473         }
 474
 475         return 0;
 476 }
 477
 478 static const struct i2c_device_id max8973_id[] = {
 479         {.name = "max8973",},
 480         {},
 481 };
 482
 483 MODULE_DEVICE_TABLE(i2c, max8973_id);
 484
 485 static struct i2c_driver max8973_i2c_driver = {
 486         .driver = {
 487                 .name = "max8973",
 488                 .owner = THIS_MODULE,
 489         },
 490         .probe = max8973_probe,
 491         .id_table = max8973_id,
 492 };
 493
 494 static int __init max8973_init(void)
 495 {
 496         return i2c_add_driver(&max8973_i2c_driver);
 497 }
 498 subsys_initcall(max8973_init);
 499
 500 static void __exit max8973_cleanup(void)
 501 {
 502         i2c_del_driver(&max8973_i2c_driver);
 503 }
 504 module_exit(max8973_cleanup);
 505
 506 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
 507 MODULE_DESCRIPTION("MAX8973 voltage regulator driver");
 508 MODULE_LICENSE("GPL v2");