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/hwmon.h> 14#include <linux/module.h> 15#include <linux/io.h> 16#include <linux/of.h> 17#include <linux/i2c.h> 18#include <linux/regmap.h> 19#include <linux/regulator/driver.h> 20#include <linux/regulator/machine.h> 21#include <linux/regulator/of_regulator.h> 22#include <linux/platform_device.h> 23 24#include <linux/mfd/max5970.h> 25 26struct max5970_regulator { 27 int num_switches, mon_rng, irng, shunt_micro_ohms, lim_uA; 28 struct regmap *regmap; 29}; 30 31enum max597x_regulator_id { 32 MAX597X_sw0, 33 MAX597X_sw1, 34}; 35 36static int max5970_read_adc(struct regmap *regmap, int reg, long *val) 37{ 38 u8 reg_data[2]; 39 int ret; 40 41 ret = regmap_bulk_read(regmap, reg, ®_data[0], 2); 42 if (ret < 0) 43 return ret; 44 45 *val = (reg_data[0] << 2) | (reg_data[1] & 3); 46 47 return 0; 48} 49 50static int max5970_read(struct device *dev, enum hwmon_sensor_types type, 51 u32 attr, int channel, long *val) 52{ 53 struct regulator_dev **rdevs = dev_get_drvdata(dev); 54 struct max5970_regulator *ddata = rdev_get_drvdata(rdevs[channel]); 55 struct regmap *regmap = ddata->regmap; 56 int ret; 57 58 switch (type) { 59 case hwmon_curr: 60 switch (attr) { 61 case hwmon_curr_input: 62 ret = max5970_read_adc(regmap, MAX5970_REG_CURRENT_H(channel), val); 63 if (ret < 0) 64 return ret; 65 /* 66 * Calculate current from ADC value, IRNG range & shunt resistor value. 67 * ddata->irng holds the voltage corresponding to the maximum value the 68 * 10-bit ADC can measure. 69 * To obtain the output, multiply the ADC value by the IRNG range (in 70 * millivolts) and then divide it by the maximum value of the 10-bit ADC. 71 */ 72 *val = (*val * ddata->irng) >> 10; 73 /* Convert the voltage meansurement across shunt resistor to current */ 74 *val = (*val * 1000) / ddata->shunt_micro_ohms; 75 return 0; 76 default: 77 return -EOPNOTSUPP; 78 } 79 80 case hwmon_in: 81 switch (attr) { 82 case hwmon_in_input: 83 ret = max5970_read_adc(regmap, MAX5970_REG_VOLTAGE_H(channel), val); 84 if (ret < 0) 85 return ret; 86 /* 87 * Calculate voltage from ADC value and MON range. 88 * ddata->mon_rng holds the voltage corresponding to the maximum value the 89 * 10-bit ADC can measure. 90 * To obtain the output, multiply the ADC value by the MON range (in 91 * microvolts) and then divide it by the maximum value of the 10-bit ADC. 92 */ 93 *val = mul_u64_u32_shr(*val, ddata->mon_rng, 10); 94 /* uV to mV */ 95 *val = *val / 1000; 96 return 0; 97 default: 98 return -EOPNOTSUPP; 99 } 100 default: 101 return -EOPNOTSUPP; 102 } 103} 104 105static umode_t max5970_is_visible(const void *data, 106 enum hwmon_sensor_types type, 107 u32 attr, int channel) 108{ 109 struct regulator_dev **rdevs = (struct regulator_dev **)data; 110 struct max5970_regulator *ddata; 111 112 if (channel >= MAX5970_NUM_SWITCHES || !rdevs[channel]) 113 return 0; 114 115 ddata = rdev_get_drvdata(rdevs[channel]); 116 117 if (channel >= ddata->num_switches) 118 return 0; 119 120 switch (type) { 121 case hwmon_in: 122 switch (attr) { 123 case hwmon_in_input: 124 return 0444; 125 default: 126 break; 127 } 128 break; 129 case hwmon_curr: 130 switch (attr) { 131 case hwmon_curr_input: 132 /* Current measurement requires knowledge of the shunt resistor value. */ 133 if (ddata->shunt_micro_ohms) 134 return 0444; 135 break; 136 default: 137 break; 138 } 139 break; 140 default: 141 break; 142 } 143 return 0; 144} 145 146static const struct hwmon_ops max5970_hwmon_ops = { 147 .is_visible = max5970_is_visible, 148 .read = max5970_read, 149}; 150 151static const struct hwmon_channel_info *max5970_info[] = { 152 HWMON_CHANNEL_INFO(in, HWMON_I_INPUT, HWMON_I_INPUT), 153 HWMON_CHANNEL_INFO(curr, HWMON_C_INPUT, HWMON_C_INPUT), 154 NULL 155}; 156 157static const struct hwmon_chip_info max5970_chip_info = { 158 .ops = &max5970_hwmon_ops, 159 .info = max5970_info, 160}; 161 162static int max597x_uvp_ovp_check_mode(struct regulator_dev *rdev, int severity) 163{ 164 int ret, reg; 165 166 /* Status1 register contains the soft strap values sampled at POR */ 167 ret = regmap_read(rdev->regmap, MAX5970_REG_STATUS1, ®); 168 if (ret) 169 return ret; 170 171 /* Check soft straps match requested mode */ 172 if (severity == REGULATOR_SEVERITY_PROT) { 173 if (STATUS1_PROT(reg) != STATUS1_PROT_SHUTDOWN) 174 return -EOPNOTSUPP; 175 176 return 0; 177 } 178 if (STATUS1_PROT(reg) == STATUS1_PROT_SHUTDOWN) 179 return -EOPNOTSUPP; 180 181 return 0; 182} 183 184static int max597x_set_vp(struct regulator_dev *rdev, int lim_uV, int severity, 185 bool enable, bool overvoltage) 186{ 187 int off_h, off_l, reg, ret; 188 struct max5970_regulator *data = rdev_get_drvdata(rdev); 189 int channel = rdev_get_id(rdev); 190 191 if (overvoltage) { 192 if (severity == REGULATOR_SEVERITY_WARN) { 193 off_h = MAX5970_REG_CH_OV_WARN_H(channel); 194 off_l = MAX5970_REG_CH_OV_WARN_L(channel); 195 } else { 196 off_h = MAX5970_REG_CH_OV_CRIT_H(channel); 197 off_l = MAX5970_REG_CH_OV_CRIT_L(channel); 198 } 199 } else { 200 if (severity == REGULATOR_SEVERITY_WARN) { 201 off_h = MAX5970_REG_CH_UV_WARN_H(channel); 202 off_l = MAX5970_REG_CH_UV_WARN_L(channel); 203 } else { 204 off_h = MAX5970_REG_CH_UV_CRIT_H(channel); 205 off_l = MAX5970_REG_CH_UV_CRIT_L(channel); 206 } 207 } 208 209 if (enable) 210 /* reg = ADC_MASK * (lim_uV / 1000000) / (data->mon_rng / 1000000) */ 211 reg = ADC_MASK * lim_uV / data->mon_rng; 212 else 213 reg = 0; 214 215 ret = regmap_write(rdev->regmap, off_h, MAX5970_VAL2REG_H(reg)); 216 if (ret) 217 return ret; 218 219 ret = regmap_write(rdev->regmap, off_l, MAX5970_VAL2REG_L(reg)); 220 if (ret) 221 return ret; 222 223 return 0; 224} 225 226static int max597x_set_uvp(struct regulator_dev *rdev, int lim_uV, int severity, 227 bool enable) 228{ 229 int ret; 230 231 /* 232 * MAX5970 has enable control as a special value in limit reg. Can't 233 * set limit but keep feature disabled or enable W/O given limit. 234 */ 235 if ((lim_uV && !enable) || (!lim_uV && enable)) 236 return -EINVAL; 237 238 ret = max597x_uvp_ovp_check_mode(rdev, severity); 239 if (ret) 240 return ret; 241 242 return max597x_set_vp(rdev, lim_uV, severity, enable, false); 243} 244 245static int max597x_set_ovp(struct regulator_dev *rdev, int lim_uV, int severity, 246 bool enable) 247{ 248 int ret; 249 250 /* 251 * MAX5970 has enable control as a special value in limit reg. Can't 252 * set limit but keep feature disabled or enable W/O given limit. 253 */ 254 if ((lim_uV && !enable) || (!lim_uV && enable)) 255 return -EINVAL; 256 257 ret = max597x_uvp_ovp_check_mode(rdev, severity); 258 if (ret) 259 return ret; 260 261 return max597x_set_vp(rdev, lim_uV, severity, enable, true); 262} 263 264static int max597x_set_ocp(struct regulator_dev *rdev, int lim_uA, 265 int severity, bool enable) 266{ 267 int val, reg; 268 unsigned int vthst, vthfst; 269 270 struct max5970_regulator *data = rdev_get_drvdata(rdev); 271 int rdev_id = rdev_get_id(rdev); 272 /* 273 * MAX5970 doesn't has enable control for ocp. 274 * If limit is specified but enable is not set then hold the value in 275 * variable & later use it when ocp needs to be enabled. 276 */ 277 if (lim_uA != 0 && lim_uA != data->lim_uA) 278 data->lim_uA = lim_uA; 279 280 if (severity != REGULATOR_SEVERITY_PROT) 281 return -EINVAL; 282 283 if (enable) { 284 285 /* Calc Vtrip threshold in uV. */ 286 vthst = 287 div_u64(mul_u32_u32(data->shunt_micro_ohms, data->lim_uA), 288 1000000); 289 290 /* 291 * As recommended in datasheed, add 20% margin to avoid 292 * spurious event & passive component tolerance. 293 */ 294 vthst = div_u64(mul_u32_u32(vthst, 120), 100); 295 296 /* Calc fast Vtrip threshold in uV */ 297 vthfst = vthst * (MAX5970_FAST2SLOW_RATIO / 100); 298 299 if (vthfst > data->irng) { 300 dev_err(&rdev->dev, "Current limit out of range\n"); 301 return -EINVAL; 302 } 303 /* Fast trip threshold to be programmed */ 304 val = div_u64(mul_u32_u32(0xFF, vthfst), data->irng); 305 } else 306 /* 307 * Since there is no option to disable ocp, set limit to max 308 * value 309 */ 310 val = 0xFF; 311 312 reg = MAX5970_REG_DAC_FAST(rdev_id); 313 314 return regmap_write(rdev->regmap, reg, val); 315} 316 317static int max597x_get_status(struct regulator_dev *rdev) 318{ 319 int val, ret; 320 321 ret = regmap_read(rdev->regmap, MAX5970_REG_STATUS3, &val); 322 if (ret) 323 return ret; 324 325 if (val & MAX5970_STATUS3_ALERT) 326 return REGULATOR_STATUS_ERROR; 327 328 ret = regulator_is_enabled_regmap(rdev); 329 if (ret < 0) 330 return ret; 331 332 if (ret) 333 return REGULATOR_STATUS_ON; 334 335 return REGULATOR_STATUS_OFF; 336} 337 338static const struct regulator_ops max597x_switch_ops = { 339 .enable = regulator_enable_regmap, 340 .disable = regulator_disable_regmap, 341 .is_enabled = regulator_is_enabled_regmap, 342 .get_status = max597x_get_status, 343 .set_over_voltage_protection = max597x_set_ovp, 344 .set_under_voltage_protection = max597x_set_uvp, 345 .set_over_current_protection = max597x_set_ocp, 346}; 347 348static int max597x_dt_parse(struct device_node *np, 349 const struct regulator_desc *desc, 350 struct regulator_config *cfg) 351{ 352 struct max5970_regulator *data = cfg->driver_data; 353 int ret = 0; 354 355 ret = 356 of_property_read_u32(np, "shunt-resistor-micro-ohms", 357 &data->shunt_micro_ohms); 358 if (ret < 0) 359 dev_err(cfg->dev, 360 "property 'shunt-resistor-micro-ohms' not found, err %d\n", 361 ret); 362 return ret; 363 364} 365 366#define MAX597X_SWITCH(_ID, _ereg, _chan, _supply) { \ 367 .name = #_ID, \ 368 .of_match = of_match_ptr(#_ID), \ 369 .ops = &max597x_switch_ops, \ 370 .regulators_node = of_match_ptr("regulators"), \ 371 .type = REGULATOR_VOLTAGE, \ 372 .id = MAX597X_##_ID, \ 373 .owner = THIS_MODULE, \ 374 .supply_name = _supply, \ 375 .enable_reg = _ereg, \ 376 .enable_mask = CHXEN((_chan)), \ 377 .of_parse_cb = max597x_dt_parse, \ 378} 379 380static const struct regulator_desc regulators[] = { 381 MAX597X_SWITCH(sw0, MAX5970_REG_CHXEN, 0, "vss1"), 382 MAX597X_SWITCH(sw1, MAX5970_REG_CHXEN, 1, "vss2"), 383}; 384 385static int max597x_regmap_read_clear(struct regmap *map, unsigned int reg, 386 unsigned int *val) 387{ 388 int ret; 389 390 ret = regmap_read(map, reg, val); 391 if (ret) 392 return ret; 393 394 if (*val) 395 return regmap_write(map, reg, 0); 396 397 return 0; 398} 399 400static int max597x_irq_handler(int irq, struct regulator_irq_data *rid, 401 unsigned long *dev_mask) 402{ 403 struct regulator_err_state *stat; 404 struct max5970_regulator *d = (struct max5970_regulator *)rid->data; 405 int val, ret, i; 406 407 ret = max597x_regmap_read_clear(d->regmap, MAX5970_REG_FAULT0, &val); 408 if (ret) 409 return REGULATOR_FAILED_RETRY; 410 411 *dev_mask = 0; 412 for (i = 0; i < d->num_switches; i++) { 413 stat = &rid->states[i]; 414 stat->notifs = 0; 415 stat->errors = 0; 416 } 417 418 for (i = 0; i < d->num_switches; i++) { 419 stat = &rid->states[i]; 420 421 if (val & UV_STATUS_CRIT(i)) { 422 *dev_mask |= 1 << i; 423 stat->notifs |= REGULATOR_EVENT_UNDER_VOLTAGE; 424 stat->errors |= REGULATOR_ERROR_UNDER_VOLTAGE; 425 } else if (val & UV_STATUS_WARN(i)) { 426 *dev_mask |= 1 << i; 427 stat->notifs |= REGULATOR_EVENT_UNDER_VOLTAGE_WARN; 428 stat->errors |= REGULATOR_ERROR_UNDER_VOLTAGE_WARN; 429 } 430 } 431 432 ret = max597x_regmap_read_clear(d->regmap, MAX5970_REG_FAULT1, &val); 433 if (ret) 434 return REGULATOR_FAILED_RETRY; 435 436 for (i = 0; i < d->num_switches; i++) { 437 stat = &rid->states[i]; 438 439 if (val & OV_STATUS_CRIT(i)) { 440 *dev_mask |= 1 << i; 441 stat->notifs |= REGULATOR_EVENT_REGULATION_OUT; 442 stat->errors |= REGULATOR_ERROR_REGULATION_OUT; 443 } else if (val & OV_STATUS_WARN(i)) { 444 *dev_mask |= 1 << i; 445 stat->notifs |= REGULATOR_EVENT_OVER_VOLTAGE_WARN; 446 stat->errors |= REGULATOR_ERROR_OVER_VOLTAGE_WARN; 447 } 448 } 449 450 ret = max597x_regmap_read_clear(d->regmap, MAX5970_REG_FAULT2, &val); 451 if (ret) 452 return REGULATOR_FAILED_RETRY; 453 454 for (i = 0; i < d->num_switches; i++) { 455 stat = &rid->states[i]; 456 457 if (val & OC_STATUS_WARN(i)) { 458 *dev_mask |= 1 << i; 459 stat->notifs |= REGULATOR_EVENT_OVER_CURRENT_WARN; 460 stat->errors |= REGULATOR_ERROR_OVER_CURRENT_WARN; 461 } 462 } 463 464 ret = regmap_read(d->regmap, MAX5970_REG_STATUS0, &val); 465 if (ret) 466 return REGULATOR_FAILED_RETRY; 467 468 for (i = 0; i < d->num_switches; i++) { 469 stat = &rid->states[i]; 470 471 if ((val & MAX5970_CB_IFAULTF(i)) 472 || (val & MAX5970_CB_IFAULTS(i))) { 473 *dev_mask |= 1 << i; 474 stat->notifs |= 475 REGULATOR_EVENT_OVER_CURRENT | 476 REGULATOR_EVENT_DISABLE; 477 stat->errors |= 478 REGULATOR_ERROR_OVER_CURRENT | REGULATOR_ERROR_FAIL; 479 480 /* Clear the sub-IRQ status */ 481 regulator_disable_regmap(stat->rdev); 482 } 483 } 484 return 0; 485} 486 487static int max597x_adc_range(struct regmap *regmap, const int ch, 488 u32 *irng, u32 *mon_rng) 489{ 490 unsigned int reg; 491 int ret; 492 493 /* Decode current ADC range */ 494 ret = regmap_read(regmap, MAX5970_REG_STATUS2, ®); 495 if (ret) 496 return ret; 497 switch (MAX5970_IRNG(reg, ch)) { 498 case 0: 499 *irng = 100000; /* 100 mV */ 500 break; 501 case 1: 502 *irng = 50000; /* 50 mV */ 503 break; 504 case 2: 505 *irng = 25000; /* 25 mV */ 506 break; 507 default: 508 return -EINVAL; 509 } 510 511 /* Decode current voltage monitor range */ 512 ret = regmap_read(regmap, MAX5970_REG_MON_RANGE, ®); 513 if (ret) 514 return ret; 515 516 *mon_rng = MAX5970_MON_MAX_RANGE_UV >> MAX5970_MON(reg, ch); 517 518 return 0; 519} 520 521static int max597x_setup_irq(struct device *dev, 522 int irq, 523 struct regulator_dev *rdevs[MAX5970_NUM_SWITCHES], 524 int num_switches, struct max5970_regulator *data) 525{ 526 struct regulator_irq_desc max597x_notif = { 527 .name = "max597x-irq", 528 .map_event = max597x_irq_handler, 529 .data = data, 530 }; 531 int errs = REGULATOR_ERROR_UNDER_VOLTAGE | 532 REGULATOR_ERROR_UNDER_VOLTAGE_WARN | 533 REGULATOR_ERROR_OVER_VOLTAGE_WARN | 534 REGULATOR_ERROR_REGULATION_OUT | 535 REGULATOR_ERROR_OVER_CURRENT | 536 REGULATOR_ERROR_OVER_CURRENT_WARN | REGULATOR_ERROR_FAIL; 537 void *irq_helper; 538 539 /* Register notifiers - can fail if IRQ is not given */ 540 irq_helper = devm_regulator_irq_helper(dev, &max597x_notif, 541 irq, 0, errs, NULL, 542 &rdevs[0], num_switches); 543 if (IS_ERR(irq_helper)) { 544 if (PTR_ERR(irq_helper) == -EPROBE_DEFER) 545 return -EPROBE_DEFER; 546 547 dev_warn(dev, "IRQ disabled %pe\n", irq_helper); 548 } 549 550 return 0; 551} 552 553static int max597x_regulator_probe(struct platform_device *pdev) 554{ 555 struct max5970_data *max597x; 556 struct regmap *regmap = dev_get_regmap(pdev->dev.parent, NULL); 557 struct max5970_regulator *data; 558 struct i2c_client *i2c = to_i2c_client(pdev->dev.parent); 559 struct regulator_config config = { }; 560 struct regulator_dev *rdev; 561 struct regulator_dev **rdevs = NULL; 562 struct device *hwmon_dev; 563 int num_switches; 564 int ret, i; 565 566 if (!regmap) 567 return -EPROBE_DEFER; 568 569 max597x = devm_kzalloc(&i2c->dev, sizeof(struct max5970_data), GFP_KERNEL); 570 if (!max597x) 571 return -ENOMEM; 572 573 rdevs = devm_kcalloc(&i2c->dev, MAX5970_NUM_SWITCHES, sizeof(struct regulator_dev *), 574 GFP_KERNEL); 575 if (!rdevs) 576 return -ENOMEM; 577 578 i2c_set_clientdata(i2c, max597x); 579 580 if (of_device_is_compatible(i2c->dev.of_node, "maxim,max5978")) 581 max597x->num_switches = MAX5978_NUM_SWITCHES; 582 else if (of_device_is_compatible(i2c->dev.of_node, "maxim,max5970")) 583 max597x->num_switches = MAX5970_NUM_SWITCHES; 584 else 585 return -ENODEV; 586 587 num_switches = max597x->num_switches; 588 589 for (i = 0; i < num_switches; i++) { 590 data = 591 devm_kzalloc(&i2c->dev, sizeof(struct max5970_regulator), 592 GFP_KERNEL); 593 if (!data) 594 return -ENOMEM; 595 596 data->num_switches = num_switches; 597 data->regmap = regmap; 598 599 ret = max597x_adc_range(regmap, i, &max597x->irng[i], &max597x->mon_rng[i]); 600 if (ret < 0) 601 return ret; 602 603 data->irng = max597x->irng[i]; 604 data->mon_rng = max597x->mon_rng[i]; 605 606 config.dev = &i2c->dev; 607 config.driver_data = (void *)data; 608 config.regmap = data->regmap; 609 rdev = devm_regulator_register(&i2c->dev, 610 ®ulators[i], &config); 611 if (IS_ERR(rdev)) { 612 dev_err(&i2c->dev, "failed to register regulator %s\n", 613 regulators[i].name); 614 return PTR_ERR(rdev); 615 } 616 rdevs[i] = rdev; 617 max597x->shunt_micro_ohms[i] = data->shunt_micro_ohms; 618 } 619 620 if (IS_REACHABLE(CONFIG_HWMON)) { 621 hwmon_dev = devm_hwmon_device_register_with_info(&i2c->dev, "max5970", rdevs, 622 &max5970_chip_info, NULL); 623 if (IS_ERR(hwmon_dev)) { 624 return dev_err_probe(&i2c->dev, PTR_ERR(hwmon_dev), 625 "Unable to register hwmon device\n"); 626 } 627 } 628 629 if (i2c->irq) { 630 ret = 631 max597x_setup_irq(&i2c->dev, i2c->irq, rdevs, num_switches, 632 data); 633 if (ret) { 634 dev_err(&i2c->dev, "IRQ setup failed"); 635 return ret; 636 } 637 } 638 639 return ret; 640} 641 642static struct platform_driver max597x_regulator_driver = { 643 .driver = { 644 .name = "max5970-regulator", 645 .probe_type = PROBE_PREFER_ASYNCHRONOUS, 646 }, 647 .probe = max597x_regulator_probe, 648}; 649 650module_platform_driver(max597x_regulator_driver); 651 652 653MODULE_AUTHOR("Patrick Rudolph <patrick.rudolph@9elements.com>"); 654MODULE_DESCRIPTION("MAX5970_hot-swap controller driver"); 655MODULE_LICENSE("GPL v2"); 656