drivers/regulator/max597x-regulator.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Device driver for regulators in MAX5970 and MAX5978 IC
   4  *
   5  * Copyright (c) 2022 9elements GmbH
   6  *
   7  * Author: Patrick Rudolph <patrick.rudolph@9elements.com>
   8  */
   9
  10 #include <linux/bitops.h>
  11 #include <linux/device.h>
  12 #include <linux/err.h>
  13 #include <linux/module.h>
  14 #include <linux/io.h>
  15 #include <linux/of.h>
  16 #include <linux/i2c.h>
  17 #include <linux/regmap.h>
  18 #include <linux/regulator/driver.h>
  19 #include <linux/regulator/machine.h>
  20 #include <linux/regulator/of_regulator.h>
  21 #include <linux/platform_device.h>
  22
  23 #include <linux/mfd/max597x.h>
  24
  25 struct max597x_regulator {
  26         int num_switches, mon_rng, irng, shunt_micro_ohms, lim_uA;
  27         struct regmap *regmap;
  28 };
  29
  30 enum max597x_regulator_id {
  31         MAX597X_SW0,
  32         MAX597X_SW1,
  33 };
  34
  35 static int max597x_uvp_ovp_check_mode(struct regulator_dev *rdev, int severity)
  36 {
  37         int ret, reg;
  38
  39         /* Status1 register contains the soft strap values sampled at POR */
  40         ret = regmap_read(rdev->regmap, MAX5970_REG_STATUS1, &reg);
  41         if (ret)
  42                 return ret;
  43
  44         /* Check soft straps match requested mode */
  45         if (severity == REGULATOR_SEVERITY_PROT) {
  46                 if (STATUS1_PROT(reg) != STATUS1_PROT_SHUTDOWN)
  47                         return -EOPNOTSUPP;
  48
  49                 return 0;
  50         }
  51         if (STATUS1_PROT(reg) == STATUS1_PROT_SHUTDOWN)
  52                 return -EOPNOTSUPP;
  53
  54         return 0;
  55 }
  56
  57 static int max597x_set_vp(struct regulator_dev *rdev, int lim_uV, int severity,
  58                           bool enable, bool overvoltage)
  59 {
  60         int off_h, off_l, reg, ret;
  61         struct max597x_regulator *data = rdev_get_drvdata(rdev);
  62         int channel = rdev_get_id(rdev);
  63
  64         if (overvoltage) {
  65                 if (severity == REGULATOR_SEVERITY_WARN) {
  66                         off_h = MAX5970_REG_CH_OV_WARN_H(channel);
  67                         off_l = MAX5970_REG_CH_OV_WARN_L(channel);
  68                 } else {
  69                         off_h = MAX5970_REG_CH_OV_CRIT_H(channel);
  70                         off_l = MAX5970_REG_CH_OV_CRIT_L(channel);
  71                 }
  72         } else {
  73                 if (severity == REGULATOR_SEVERITY_WARN) {
  74                         off_h = MAX5970_REG_CH_UV_WARN_H(channel);
  75                         off_l = MAX5970_REG_CH_UV_WARN_L(channel);
  76                 } else {
  77                         off_h = MAX5970_REG_CH_UV_CRIT_H(channel);
  78                         off_l = MAX5970_REG_CH_UV_CRIT_L(channel);
  79                 }
  80         }
  81
  82         if (enable)
  83                 /* reg = ADC_MASK * (lim_uV / 1000000) / (data->mon_rng / 1000000) */
  84                 reg = ADC_MASK * lim_uV / data->mon_rng;
  85         else
  86                 reg = 0;
  87
  88         ret = regmap_write(rdev->regmap, off_h, MAX5970_VAL2REG_H(reg));
  89         if (ret)
  90                 return ret;
  91
  92         ret = regmap_write(rdev->regmap, off_l, MAX5970_VAL2REG_L(reg));
  93         if (ret)
  94                 return ret;
  95
  96         return 0;
  97 }
  98
  99 static int max597x_set_uvp(struct regulator_dev *rdev, int lim_uV, int severity,
 100                            bool enable)
 101 {
 102         int ret;
 103
 104         /*
 105          * MAX5970 has enable control as a special value in limit reg. Can't
 106          * set limit but keep feature disabled or enable W/O given limit.
 107          */
 108         if ((lim_uV && !enable) || (!lim_uV && enable))
 109                 return -EINVAL;
 110
 111         ret = max597x_uvp_ovp_check_mode(rdev, severity);
 112         if (ret)
 113                 return ret;
 114
 115         return max597x_set_vp(rdev, lim_uV, severity, enable, false);
 116 }
 117
 118 static int max597x_set_ovp(struct regulator_dev *rdev, int lim_uV, int severity,
 119                            bool enable)
 120 {
 121         int ret;
 122
 123         /*
 124          * MAX5970 has enable control as a special value in limit reg. Can't
 125          * set limit but keep feature disabled or enable W/O given limit.
 126          */
 127         if ((lim_uV && !enable) || (!lim_uV && enable))
 128                 return -EINVAL;
 129
 130         ret = max597x_uvp_ovp_check_mode(rdev, severity);
 131         if (ret)
 132                 return ret;
 133
 134         return max597x_set_vp(rdev, lim_uV, severity, enable, true);
 135 }
 136
 137 static int max597x_set_ocp(struct regulator_dev *rdev, int lim_uA,
 138                            int severity, bool enable)
 139 {
 140         int val, reg;
 141         unsigned int vthst, vthfst;
 142
 143         struct max597x_regulator *data = rdev_get_drvdata(rdev);
 144         int rdev_id = rdev_get_id(rdev);
 145         /*
 146          * MAX5970 doesn't has enable control for ocp.
 147          * If limit is specified but enable is not set then hold the value in
 148          * variable & later use it when ocp needs to be enabled.
 149          */
 150         if (lim_uA != 0 && lim_uA != data->lim_uA)
 151                 data->lim_uA = lim_uA;
 152
 153         if (severity != REGULATOR_SEVERITY_PROT)
 154                 return -EINVAL;
 155
 156         if (enable) {
 157
 158                 /* Calc Vtrip threshold in uV. */
 159                 vthst =
 160                     div_u64(mul_u32_u32(data->shunt_micro_ohms, data->lim_uA),
 161                             1000000);
 162
 163                 /*
 164                  * As recommended in datasheed, add 20% margin to avoid
 165                  * spurious event & passive component tolerance.
 166                  */
 167                 vthst = div_u64(mul_u32_u32(vthst, 120), 100);
 168
 169                 /* Calc fast Vtrip threshold in uV */
 170                 vthfst = vthst * (MAX5970_FAST2SLOW_RATIO / 100);
 171
 172                 if (vthfst > data->irng) {
 173                         dev_err(&rdev->dev, "Current limit out of range\n");
 174                         return -EINVAL;
 175                 }
 176                 /* Fast trip threshold to be programmed */
 177                 val = div_u64(mul_u32_u32(0xFF, vthfst), data->irng);
 178         } else
 179                 /*
 180                  * Since there is no option to disable ocp, set limit to max
 181                  * value
 182                  */
 183                 val = 0xFF;
 184
 185         reg = MAX5970_REG_DAC_FAST(rdev_id);
 186
 187         return regmap_write(rdev->regmap, reg, val);
 188 }
 189
 190 static int max597x_get_status(struct regulator_dev *rdev)
 191 {
 192         int val, ret;
 193
 194         ret = regmap_read(rdev->regmap, MAX5970_REG_STATUS3, &val);
 195         if (ret)
 196                 return REGULATOR_FAILED_RETRY;
 197
 198         if (val & MAX5970_STATUS3_ALERT)
 199                 return REGULATOR_STATUS_ERROR;
 200
 201         ret = regulator_is_enabled_regmap(rdev);
 202         if (ret < 0)
 203                 return ret;
 204
 205         if (ret)
 206                 return REGULATOR_STATUS_ON;
 207
 208         return REGULATOR_STATUS_OFF;
 209 }
 210
 211 static const struct regulator_ops max597x_switch_ops = {
 212         .enable = regulator_enable_regmap,
 213         .disable = regulator_disable_regmap,
 214         .is_enabled = regulator_is_enabled_regmap,
 215         .get_status = max597x_get_status,
 216         .set_over_voltage_protection = max597x_set_ovp,
 217         .set_under_voltage_protection = max597x_set_uvp,
 218         .set_over_current_protection = max597x_set_ocp,
 219 };
 220
 221 static int max597x_dt_parse(struct device_node *np,
 222                             const struct regulator_desc *desc,
 223                             struct regulator_config *cfg)
 224 {
 225         struct max597x_regulator *data = cfg->driver_data;
 226         int ret = 0;
 227
 228         ret =
 229             of_property_read_u32(np, "shunt-resistor-micro-ohms",
 230                                  &data->shunt_micro_ohms);
 231         if (ret < 0)
 232                 dev_err(cfg->dev,
 233                         "property 'shunt-resistor-micro-ohms' not found, err %d\n",
 234                         ret);
 235         return ret;
 236
 237 }
 238
 239 #define MAX597X_SWITCH(_ID, _ereg, _chan, _supply) {     \
 240         .name            = #_ID,                         \
 241         .of_match        = of_match_ptr(#_ID),           \
 242         .ops             = &max597x_switch_ops,          \
 243         .regulators_node = of_match_ptr("regulators"),   \
 244         .type            = REGULATOR_VOLTAGE,            \
 245         .id              = MAX597X_##_ID,                \
 246         .owner           = THIS_MODULE,                  \
 247         .supply_name     = _supply,                      \
 248         .enable_reg      = _ereg,                        \
 249         .enable_mask     = CHXEN((_chan)),               \
 250         .of_parse_cb     = max597x_dt_parse,             \
 251 }
 252
 253 static const struct regulator_desc regulators[] = {
 254         MAX597X_SWITCH(SW0, MAX5970_REG_CHXEN, 0, "vss1"),
 255         MAX597X_SWITCH(SW1, MAX5970_REG_CHXEN, 1, "vss2"),
 256 };
 257
 258 static int max597x_regmap_read_clear(struct regmap *map, unsigned int reg,
 259                                      unsigned int *val)
 260 {
 261         int ret;
 262
 263         ret = regmap_read(map, reg, val);
 264         if (ret)
 265                 return ret;
 266
 267         if (*val)
 268                 return regmap_write(map, reg, *val);
 269
 270         return 0;
 271 }
 272
 273 static int max597x_irq_handler(int irq, struct regulator_irq_data *rid,
 274                                unsigned long *dev_mask)
 275 {
 276         struct regulator_err_state *stat;
 277         struct max597x_regulator *d = (struct max597x_regulator *)rid->data;
 278         int val, ret, i;
 279
 280         ret = max597x_regmap_read_clear(d->regmap, MAX5970_REG_FAULT0, &val);
 281         if (ret)
 282                 return REGULATOR_FAILED_RETRY;
 283
 284         *dev_mask = 0;
 285         for (i = 0; i < d->num_switches; i++) {
 286                 stat = &rid->states[i];
 287                 stat->notifs = 0;
 288                 stat->errors = 0;
 289         }
 290
 291         for (i = 0; i < d->num_switches; i++) {
 292                 stat = &rid->states[i];
 293
 294                 if (val & UV_STATUS_CRIT(i)) {
 295                         *dev_mask |= 1 << i;
 296                         stat->notifs |= REGULATOR_EVENT_UNDER_VOLTAGE;
 297                         stat->errors |= REGULATOR_ERROR_UNDER_VOLTAGE;
 298                 } else if (val & UV_STATUS_WARN(i)) {
 299                         *dev_mask |= 1 << i;
 300                         stat->notifs |= REGULATOR_EVENT_UNDER_VOLTAGE_WARN;
 301                         stat->errors |= REGULATOR_ERROR_UNDER_VOLTAGE_WARN;
 302                 }
 303         }
 304
 305         ret = max597x_regmap_read_clear(d->regmap, MAX5970_REG_FAULT1, &val);
 306         if (ret)
 307                 return REGULATOR_FAILED_RETRY;
 308
 309         for (i = 0; i < d->num_switches; i++) {
 310                 stat = &rid->states[i];
 311
 312                 if (val & OV_STATUS_CRIT(i)) {
 313                         *dev_mask |= 1 << i;
 314                         stat->notifs |= REGULATOR_EVENT_REGULATION_OUT;
 315                         stat->errors |= REGULATOR_ERROR_REGULATION_OUT;
 316                 } else if (val & OV_STATUS_WARN(i)) {
 317                         *dev_mask |= 1 << i;
 318                         stat->notifs |= REGULATOR_EVENT_OVER_VOLTAGE_WARN;
 319                         stat->errors |= REGULATOR_ERROR_OVER_VOLTAGE_WARN;
 320                 }
 321         }
 322
 323         ret = max597x_regmap_read_clear(d->regmap, MAX5970_REG_FAULT2, &val);
 324         if (ret)
 325                 return REGULATOR_FAILED_RETRY;
 326
 327         for (i = 0; i < d->num_switches; i++) {
 328                 stat = &rid->states[i];
 329
 330                 if (val & OC_STATUS_WARN(i)) {
 331                         *dev_mask |= 1 << i;
 332                         stat->notifs |= REGULATOR_EVENT_OVER_CURRENT_WARN;
 333                         stat->errors |= REGULATOR_ERROR_OVER_CURRENT_WARN;
 334                 }
 335         }
 336
 337         ret = regmap_read(d->regmap, MAX5970_REG_STATUS0, &val);
 338         if (ret)
 339                 return REGULATOR_FAILED_RETRY;
 340
 341         for (i = 0; i < d->num_switches; i++) {
 342                 stat = &rid->states[i];
 343
 344                 if ((val & MAX5970_CB_IFAULTF(i))
 345                     || (val & MAX5970_CB_IFAULTS(i))) {
 346                         *dev_mask |= 1 << i;
 347                         stat->notifs |=
 348                             REGULATOR_EVENT_OVER_CURRENT |
 349                             REGULATOR_EVENT_DISABLE;
 350                         stat->errors |=
 351                             REGULATOR_ERROR_OVER_CURRENT | REGULATOR_ERROR_FAIL;
 352
 353                         /* Clear the sub-IRQ status */
 354                         regulator_disable_regmap(stat->rdev);
 355                 }
 356         }
 357         return 0;
 358 }
 359
 360 static const struct regmap_config max597x_regmap_config = {
 361         .reg_bits = 8,
 362         .val_bits = 8,
 363         .max_register = MAX_REGISTERS,
 364 };
 365
 366 static int max597x_adc_range(struct regmap *regmap, const int ch,
 367                              u32 *irng, u32 *mon_rng)
 368 {
 369         unsigned int reg;
 370         int ret;
 371
 372         /* Decode current ADC range */
 373         ret = regmap_read(regmap, MAX5970_REG_STATUS2, &reg);
 374         if (ret)
 375                 return ret;
 376         switch (MAX5970_IRNG(reg, ch)) {
 377         case 0:
 378                 *irng = 100000; /* 100 mV */
 379                 break;
 380         case 1:
 381                 *irng = 50000;  /* 50 mV */
 382                 break;
 383         case 2:
 384                 *irng = 25000;  /* 25 mV */
 385                 break;
 386         default:
 387                 return -EINVAL;
 388         }
 389
 390         /* Decode current voltage monitor range */
 391         ret = regmap_read(regmap, MAX5970_REG_MON_RANGE, &reg);
 392         if (ret)
 393                 return ret;
 394
 395         *mon_rng = MAX5970_MON_MAX_RANGE_UV >> MAX5970_MON(reg, ch);
 396
 397         return 0;
 398 }
 399
 400 static int max597x_setup_irq(struct device *dev,
 401                              int irq,
 402                              struct regulator_dev *rdevs[MAX5970_NUM_SWITCHES],
 403                              int num_switches, struct max597x_regulator *data)
 404 {
 405         struct regulator_irq_desc max597x_notif = {
 406                 .name = "max597x-irq",
 407                 .map_event = max597x_irq_handler,
 408                 .data = data,
 409         };
 410         int errs = REGULATOR_ERROR_UNDER_VOLTAGE |
 411             REGULATOR_ERROR_UNDER_VOLTAGE_WARN |
 412             REGULATOR_ERROR_OVER_VOLTAGE_WARN |
 413             REGULATOR_ERROR_REGULATION_OUT |
 414             REGULATOR_ERROR_OVER_CURRENT |
 415             REGULATOR_ERROR_OVER_CURRENT_WARN | REGULATOR_ERROR_FAIL;
 416         void *irq_helper;
 417
 418         /* Register notifiers - can fail if IRQ is not given */
 419         irq_helper = devm_regulator_irq_helper(dev, &max597x_notif,
 420                                                irq, 0, errs, NULL,
 421                                                &rdevs[0], num_switches);
 422         if (IS_ERR(irq_helper)) {
 423                 if (PTR_ERR(irq_helper) == -EPROBE_DEFER)
 424                         return -EPROBE_DEFER;
 425
 426                 dev_warn(dev, "IRQ disabled %pe\n", irq_helper);
 427         }
 428
 429         return 0;
 430 }
 431
 432 static int max597x_regulator_probe(struct platform_device *pdev)
 433 {
 434
 435
 436         struct max597x_data *max597x = dev_get_drvdata(pdev->dev.parent);
 437         struct max597x_regulator *data;
 438
 439         struct regulator_config config = { };
 440         struct regulator_dev *rdev;
 441         struct regulator_dev *rdevs[MAX5970_NUM_SWITCHES];
 442         int num_switches = max597x->num_switches;
 443         int ret, i;
 444
 445         for (i = 0; i < num_switches; i++) {
 446                 data =
 447                     devm_kzalloc(max597x->dev, sizeof(struct max597x_regulator),
 448                                  GFP_KERNEL);
 449                 if (!data)
 450                         return -ENOMEM;
 451
 452                 data->num_switches = num_switches;
 453                 data->regmap = max597x->regmap;
 454
 455                 ret = max597x_adc_range(data->regmap, i, &max597x->irng[i], &max597x->mon_rng[i]);
 456                 if (ret < 0)
 457                         return ret;
 458
 459                 data->irng = max597x->irng[i];
 460                 data->mon_rng = max597x->mon_rng[i];
 461
 462                 config.dev = max597x->dev;
 463                 config.driver_data = (void *)data;
 464                 config.regmap = data->regmap;
 465                 rdev = devm_regulator_register(max597x->dev,
 466                                                &regulators[i], &config);
 467                 if (IS_ERR(rdev)) {
 468                         dev_err(max597x->dev, "failed to register regulator %s\n",
 469                                 regulators[i].name);
 470                         return PTR_ERR(rdev);
 471                 }
 472                 rdevs[i] = rdev;
 473                 max597x->shunt_micro_ohms[i] = data->shunt_micro_ohms;
 474         }
 475
 476         if (max597x->irq) {
 477                 ret =
 478                     max597x_setup_irq(max597x->dev, max597x->irq, rdevs, num_switches,
 479                                       data);
 480                 if (ret) {
 481                         dev_err(max597x->dev, "IRQ setup failed");
 482                         return ret;
 483                 }
 484         }
 485
 486         return ret;
 487 }
 488
 489 static struct platform_driver max597x_regulator_driver = {
 490         .driver = {
 491                 .name = "max597x-regulator",
 492         },
 493         .probe = max597x_regulator_probe,
 494 };
 495
 496 module_platform_driver(max597x_regulator_driver);
 497
 498
 499 MODULE_AUTHOR("Patrick Rudolph <patrick.rudolph@9elements.com>");
 500 MODULE_DESCRIPTION("MAX5970_hot-swap controller driver");
 501 MODULE_LICENSE("GPL v2");