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 regulator_dev *rdev;
  97         struct regmap *regmap;
  98         bool enable_external_control;
  99         int dvs_gpio;
 100         int lru_index[MAX8973_MAX_VOUT_REG];
 101         int curr_vout_val[MAX8973_MAX_VOUT_REG];
 102         int curr_vout_reg;
 103         int curr_gpio_val;
 104         bool valid_dvs_gpio;
 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 (max->valid_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 (max->valid_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
 273         if (pdata->control_flags & MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE)
 274                 control1 |= MAX8973_FREQSHIFT_9PER;
 275
 276         /* Set ramp delay */
 277         if (pdata->reg_init_data &&
 278                         pdata->reg_init_data->constraints.ramp_delay) {
 279                 if (pdata->reg_init_data->constraints.ramp_delay < 25000)
 280                         control1 |= MAX8973_RAMP_12mV_PER_US;
 281                 else if (pdata->reg_init_data->constraints.ramp_delay < 50000)
 282                         control1 |= MAX8973_RAMP_25mV_PER_US;
 283                 else if (pdata->reg_init_data->constraints.ramp_delay < 200000)
 284                         control1 |= MAX8973_RAMP_50mV_PER_US;
 285                 else
 286                         control1 |= MAX8973_RAMP_200mV_PER_US;
 287         } else {
 288                 control1 |= MAX8973_RAMP_12mV_PER_US;
 289                 max->desc.ramp_delay = 12500;
 290         }
 291
 292         if (!(pdata->control_flags & MAX8973_CONTROL_PULL_DOWN_ENABLE))
 293                 control2 |= MAX8973_DISCH_ENBABLE;
 294
 295         /*  Clock advance trip configuration */
 296         switch (pdata->control_flags & MAX8973_CONTROL_CLKADV_TRIP_MASK) {
 297         case MAX8973_CONTROL_CLKADV_TRIP_DISABLED:
 298                 control2 |= MAX8973_CKKADV_TRIP_DISABLE;
 299                 break;
 300
 301         case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US:
 302                 control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US;
 303                 break;
 304
 305         case MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US:
 306                 control2 |= MAX8973_CKKADV_TRIP_150mV_PER_US;
 307                 break;
 308
 309         case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US_HIST_DIS:
 310                 control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS;
 311                 break;
 312         }
 313
 314         /* Configure inductor value */
 315         switch (pdata->control_flags & MAX8973_CONTROL_INDUCTOR_VALUE_MASK) {
 316         case MAX8973_CONTROL_INDUCTOR_VALUE_NOMINAL:
 317                 control2 |= MAX8973_INDUCTOR_NOMINAL;
 318                 break;
 319
 320         case MAX8973_CONTROL_INDUCTOR_VALUE_MINUS_30_PER:
 321                 control2 |= MAX8973_INDUCTOR_MIN_30_PER;
 322                 break;
 323
 324         case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_30_PER:
 325                 control2 |= MAX8973_INDUCTOR_PLUS_30_PER;
 326                 break;
 327
 328         case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_60_PER:
 329                 control2 |= MAX8973_INDUCTOR_PLUS_60_PER;
 330                 break;
 331         }
 332
 333         ret = regmap_write(max->regmap, MAX8973_CONTROL1, control1);
 334         if (ret < 0) {
 335                 dev_err(max->dev, "register %d write failed, err = %d",
 336                                 MAX8973_CONTROL1, ret);
 337                 return ret;
 338         }
 339
 340         ret = regmap_write(max->regmap, MAX8973_CONTROL2, control2);
 341         if (ret < 0) {
 342                 dev_err(max->dev, "register %d write failed, err = %d",
 343                                 MAX8973_CONTROL2, ret);
 344                 return ret;
 345         }
 346
 347         /* If external control is enabled then disable EN bit */
 348         if (max->enable_external_control) {
 349                 ret = regmap_update_bits(max->regmap, MAX8973_VOUT,
 350                                                 MAX8973_VOUT_ENABLE, 0);
 351                 if (ret < 0)
 352                         dev_err(max->dev, "register %d update failed, err = %d",
 353                                 MAX8973_VOUT, ret);
 354         }
 355         return ret;
 356 }
 357
 358 static const struct regmap_config max8973_regmap_config = {
 359         .reg_bits               = 8,
 360         .val_bits               = 8,
 361         .max_register           = MAX8973_CHIPID2,
 362         .cache_type             = REGCACHE_RBTREE,
 363 };
 364
 365 static int max8973_probe(struct i2c_client *client,
 366                          const struct i2c_device_id *id)
 367 {
 368         struct max8973_regulator_platform_data *pdata;
 369         struct regulator_config config = { };
 370         struct regulator_dev *rdev;
 371         struct max8973_chip *max;
 372         int ret;
 373
 374         pdata = dev_get_platdata(&client->dev);
 375
 376         if (!pdata && !client->dev.of_node) {
 377                 dev_err(&client->dev, "No Platform data");
 378                 return -EIO;
 379         }
 380
 381         max = devm_kzalloc(&client->dev, sizeof(*max), GFP_KERNEL);
 382         if (!max) {
 383                 dev_err(&client->dev, "Memory allocation for max failed\n");
 384                 return -ENOMEM;
 385         }
 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;
 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                 max->valid_dvs_gpio = true;
 441
 442                 /*
 443                  * Initialize the lru index with vout_reg id
 444                  * The index 0 will be most recently used and
 445                  * set with the max->curr_vout_reg */
 446                 for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i)
 447                         max->lru_index[i] = i;
 448                 max->lru_index[0] = max->curr_vout_reg;
 449                 max->lru_index[max->curr_vout_reg] = 0;
 450         } else {
 451                 max->valid_dvs_gpio = false;
 452         }
 453
 454         if (pdata) {
 455                 ret = max8973_init_dcdc(max, pdata);
 456                 if (ret < 0) {
 457                         dev_err(max->dev, "Max8973 Init failed, err = %d\n", ret);
 458                         return ret;
 459                 }
 460         }
 461
 462         config.dev = &client->dev;
 463         config.init_data = pdata ? pdata->reg_init_data :
 464                 of_get_regulator_init_data(&client->dev, client->dev.of_node);
 465         config.driver_data = max;
 466         config.of_node = client->dev.of_node;
 467         config.regmap = max->regmap;
 468
 469         /* Register the regulators */
 470         rdev = devm_regulator_register(&client->dev, &max->desc, &config);
 471         if (IS_ERR(rdev)) {
 472                 ret = PTR_ERR(rdev);
 473                 dev_err(max->dev, "regulator register failed, err %d\n", ret);
 474                 return ret;
 475         }
 476
 477         max->rdev = rdev;
 478         return 0;
 479 }
 480
 481 static const struct i2c_device_id max8973_id[] = {
 482         {.name = "max8973",},
 483         {},
 484 };
 485
 486 MODULE_DEVICE_TABLE(i2c, max8973_id);
 487
 488 static struct i2c_driver max8973_i2c_driver = {
 489         .driver = {
 490                 .name = "max8973",
 491                 .owner = THIS_MODULE,
 492         },
 493         .probe = max8973_probe,
 494         .id_table = max8973_id,
 495 };
 496
 497 static int __init max8973_init(void)
 498 {
 499         return i2c_add_driver(&max8973_i2c_driver);
 500 }
 501 subsys_initcall(max8973_init);
 502
 503 static void __exit max8973_cleanup(void)
 504 {
 505         i2c_del_driver(&max8973_i2c_driver);
 506 }
 507 module_exit(max8973_cleanup);
 508
 509 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
 510 MODULE_DESCRIPTION("MAX8973 voltage regulator driver");
 511 MODULE_LICENSE("GPL v2");