drivers/hwmon/emc2305.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Hardware monitoring driver for EMC2305 fan controller
   4  *
   5  * Copyright (C) 2022 Nvidia Technologies Ltd.
   6  */
   7
   8 #include <linux/err.h>
   9 #include <linux/hwmon.h>
  10 #include <linux/i2c.h>
  11 #include <linux/module.h>
  12 #include <linux/platform_data/emc2305.h>
  13 #include <linux/thermal.h>
  14
  15 #define EMC2305_REG_DRIVE_FAIL_STATUS   0x27
  16 #define EMC2305_REG_VENDOR              0xfe
  17 #define EMC2305_FAN_MAX                 0xff
  18 #define EMC2305_FAN_MIN                 0x00
  19 #define EMC2305_FAN_MAX_STATE           10
  20 #define EMC2305_DEVICE                  0x34
  21 #define EMC2305_VENDOR                  0x5d
  22 #define EMC2305_REG_PRODUCT_ID          0xfd
  23 #define EMC2305_TACH_REGS_UNUSE_BITS    3
  24 #define EMC2305_TACH_CNT_MULTIPLIER     0x02
  25 #define EMC2305_TACH_RANGE_MIN          480
  26
  27 #define EMC2305_PWM_DUTY2STATE(duty, max_state, pwm_max) \
  28         DIV_ROUND_CLOSEST((duty) * (max_state), (pwm_max))
  29 #define EMC2305_PWM_STATE2DUTY(state, max_state, pwm_max) \
  30         DIV_ROUND_CLOSEST((state) * (pwm_max), (max_state))
  31
  32 /*
  33  * Factor by equations [2] and [3] from data sheet; valid for fans where the number of edges
  34  * equal (poles * 2 + 1).
  35  */
  36 #define EMC2305_RPM_FACTOR              3932160
  37
  38 #define EMC2305_REG_FAN_DRIVE(n)        (0x30 + 0x10 * (n))
  39 #define EMC2305_REG_FAN_MIN_DRIVE(n)    (0x38 + 0x10 * (n))
  40 #define EMC2305_REG_FAN_TACH(n)         (0x3e + 0x10 * (n))
  41
  42 enum emc230x_product_id {
  43         EMC2305 = 0x34,
  44         EMC2303 = 0x35,
  45         EMC2302 = 0x36,
  46         EMC2301 = 0x37,
  47 };
  48
  49 static const struct i2c_device_id emc2305_ids[] = {
  50         { "emc2305" },
  51         { "emc2303" },
  52         { "emc2302" },
  53         { "emc2301" },
  54         { }
  55 };
  56 MODULE_DEVICE_TABLE(i2c, emc2305_ids);
  57
  58 /**
  59  * struct emc2305_cdev_data - device-specific cooling device state
  60  * @cdev: cooling device
  61  * @cur_state: cooling current state
  62  * @last_hwmon_state: last cooling state updated by hwmon subsystem
  63  * @last_thermal_state: last cooling state updated by thermal subsystem
  64  *
  65  * The 'last_hwmon_state' and 'last_thermal_state' fields are provided to support fan low limit
  66  * speed feature. The purpose of this feature is to provides ability to limit fan speed
  67  * according to some system wise considerations, like absence of some replaceable units (PSU or
  68  * line cards), high system ambient temperature, unreliable transceivers temperature sensing or
  69  * some other factors which indirectly impacts system's airflow
  70  * Fan low limit feature is supported through 'hwmon' interface: 'hwmon' 'pwm' attribute is
  71  * used for setting low limit for fan speed in case 'thermal' subsystem is configured in
  72  * kernel. In this case setting fan speed through 'hwmon' will never let the 'thermal'
  73  * subsystem to select a lower duty cycle than the duty cycle selected with the 'pwm'
  74  * attribute.
  75  * From other side, fan speed is to be updated in hardware through 'pwm' only in case the
  76  * requested fan speed is above last speed set by 'thermal' subsystem, otherwise requested fan
  77  * speed will be just stored with no PWM update.
  78  */
  79 struct emc2305_cdev_data {
  80         struct thermal_cooling_device *cdev;
  81         unsigned int cur_state;
  82         unsigned long last_hwmon_state;
  83         unsigned long last_thermal_state;
  84 };
  85
  86 /**
  87  * struct emc2305_data - device-specific data
  88  * @client: i2c client
  89  * @hwmon_dev: hwmon device
  90  * @max_state: maximum cooling state of the cooling device
  91  * @pwm_num: number of PWM channels
  92  * @pwm_separate: separate PWM settings for every channel
  93  * @pwm_min: array of minimum PWM per channel
  94  * @cdev_data: array of cooling devices data
  95  */
  96 struct emc2305_data {
  97         struct i2c_client *client;
  98         struct device *hwmon_dev;
  99         u8 max_state;
 100         u8 pwm_num;
 101         bool pwm_separate;
 102         u8 pwm_min[EMC2305_PWM_MAX];
 103         struct emc2305_cdev_data cdev_data[EMC2305_PWM_MAX];
 104 };
 105
 106 static char *emc2305_fan_name[] = {
 107         "emc2305_fan",
 108         "emc2305_fan1",
 109         "emc2305_fan2",
 110         "emc2305_fan3",
 111         "emc2305_fan4",
 112         "emc2305_fan5",
 113 };
 114
 115 static void emc2305_unset_tz(struct device *dev);
 116
 117 static int emc2305_get_max_channel(const struct emc2305_data *data)
 118 {
 119         return data->pwm_num;
 120 }
 121
 122 static int emc2305_get_cdev_idx(struct thermal_cooling_device *cdev)
 123 {
 124         struct emc2305_data *data = cdev->devdata;
 125         size_t len = strlen(cdev->type);
 126         int ret;
 127
 128         if (len <= 0)
 129                 return -EINVAL;
 130
 131         /*
 132          * Returns index of cooling device 0..4 in case of separate PWM setting.
 133          * Zero index is used in case of one common PWM setting.
 134          * If the mode is not set as pwm_separate, all PWMs are to be bound
 135          * to the common thermal zone and should work at the same speed
 136          * to perform cooling for the same thermal junction.
 137          * Otherwise, return specific channel that will be used in bound
 138          * related PWM to the thermal zone.
 139          */
 140         if (!data->pwm_separate)
 141                 return 0;
 142
 143         ret = cdev->type[len - 1];
 144         switch (ret) {
 145         case '1' ... '5':
 146                 return ret - '1';
 147         default:
 148                 break;
 149         }
 150         return -EINVAL;
 151 }
 152
 153 static int emc2305_get_cur_state(struct thermal_cooling_device *cdev, unsigned long *state)
 154 {
 155         int cdev_idx;
 156         struct emc2305_data *data = cdev->devdata;
 157
 158         cdev_idx = emc2305_get_cdev_idx(cdev);
 159         if (cdev_idx < 0)
 160                 return cdev_idx;
 161
 162         *state = data->cdev_data[cdev_idx].cur_state;
 163         return 0;
 164 }
 165
 166 static int emc2305_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state)
 167 {
 168         struct emc2305_data *data = cdev->devdata;
 169         *state = data->max_state;
 170         return 0;
 171 }
 172
 173 static int __emc2305_set_cur_state(struct emc2305_data *data, int cdev_idx, unsigned long state)
 174 {
 175         int ret;
 176         struct i2c_client *client = data->client;
 177         u8 val, i;
 178
 179         state = max_t(unsigned long, state, data->cdev_data[cdev_idx].last_hwmon_state);
 180
 181         val = EMC2305_PWM_STATE2DUTY(state, data->max_state, EMC2305_FAN_MAX);
 182
 183         data->cdev_data[cdev_idx].cur_state = state;
 184         if (data->pwm_separate) {
 185                 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(cdev_idx), val);
 186                 if (ret < 0)
 187                         return ret;
 188         } else {
 189                 /*
 190                  * Set the same PWM value in all channels
 191                  * if common PWM channel is used.
 192                  */
 193                 for (i = 0; i < data->pwm_num; i++) {
 194                         ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(i), val);
 195                         if (ret < 0)
 196                                 return ret;
 197                 }
 198         }
 199
 200         return 0;
 201 }
 202
 203 static int emc2305_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
 204 {
 205         int cdev_idx, ret;
 206         struct emc2305_data *data = cdev->devdata;
 207
 208         if (state > data->max_state)
 209                 return -EINVAL;
 210
 211         cdev_idx =  emc2305_get_cdev_idx(cdev);
 212         if (cdev_idx < 0)
 213                 return cdev_idx;
 214
 215         /* Save thermal state. */
 216         data->cdev_data[cdev_idx].last_thermal_state = state;
 217         ret = __emc2305_set_cur_state(data, cdev_idx, state);
 218         if (ret < 0)
 219                 return ret;
 220
 221         return 0;
 222 }
 223
 224 static const struct thermal_cooling_device_ops emc2305_cooling_ops = {
 225         .get_max_state = emc2305_get_max_state,
 226         .get_cur_state = emc2305_get_cur_state,
 227         .set_cur_state = emc2305_set_cur_state,
 228 };
 229
 230 static int emc2305_show_fault(struct device *dev, int channel)
 231 {
 232         struct emc2305_data *data = dev_get_drvdata(dev);
 233         struct i2c_client *client = data->client;
 234         int status_reg;
 235
 236         status_reg = i2c_smbus_read_byte_data(client, EMC2305_REG_DRIVE_FAIL_STATUS);
 237         if (status_reg < 0)
 238                 return status_reg;
 239
 240         return status_reg & (1 << channel) ? 1 : 0;
 241 }
 242
 243 static int emc2305_show_fan(struct device *dev, int channel)
 244 {
 245         struct emc2305_data *data = dev_get_drvdata(dev);
 246         struct i2c_client *client = data->client;
 247         int ret;
 248
 249         ret = i2c_smbus_read_word_swapped(client, EMC2305_REG_FAN_TACH(channel));
 250         if (ret <= 0)
 251                 return ret;
 252
 253         ret = ret >> EMC2305_TACH_REGS_UNUSE_BITS;
 254         ret = EMC2305_RPM_FACTOR / ret;
 255         if (ret <= EMC2305_TACH_RANGE_MIN)
 256                 return 0;
 257
 258         return ret * EMC2305_TACH_CNT_MULTIPLIER;
 259 }
 260
 261 static int emc2305_show_pwm(struct device *dev, int channel)
 262 {
 263         struct emc2305_data *data = dev_get_drvdata(dev);
 264         struct i2c_client *client = data->client;
 265
 266         return i2c_smbus_read_byte_data(client, EMC2305_REG_FAN_DRIVE(channel));
 267 }
 268
 269 static int emc2305_set_pwm(struct device *dev, long val, int channel)
 270 {
 271         struct emc2305_data *data = dev_get_drvdata(dev);
 272         struct i2c_client *client = data->client;
 273         int ret;
 274
 275         if (val < data->pwm_min[channel] || val > EMC2305_FAN_MAX)
 276                 return -EINVAL;
 277
 278         ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(channel), val);
 279         if (ret < 0)
 280                 return ret;
 281         data->cdev_data[channel].cur_state = EMC2305_PWM_DUTY2STATE(val, data->max_state,
 282                                                                     EMC2305_FAN_MAX);
 283         return 0;
 284 }
 285
 286 static int emc2305_set_single_tz(struct device *dev, int idx)
 287 {
 288         struct emc2305_data *data = dev_get_drvdata(dev);
 289         long pwm;
 290         int i, cdev_idx, ret;
 291
 292         cdev_idx = (idx) ? idx - 1 : 0;
 293         pwm = data->pwm_min[cdev_idx];
 294
 295         data->cdev_data[cdev_idx].cdev =
 296                 thermal_cooling_device_register(emc2305_fan_name[idx], data,
 297                                                 &emc2305_cooling_ops);
 298
 299         if (IS_ERR(data->cdev_data[cdev_idx].cdev)) {
 300                 dev_err(dev, "Failed to register cooling device %s\n", emc2305_fan_name[idx]);
 301                 return PTR_ERR(data->cdev_data[cdev_idx].cdev);
 302         }
 303         /* Set minimal PWM speed. */
 304         if (data->pwm_separate) {
 305                 ret = emc2305_set_pwm(dev, pwm, cdev_idx);
 306                 if (ret < 0)
 307                         return ret;
 308         } else {
 309                 for (i = 0; i < data->pwm_num; i++) {
 310                         ret = emc2305_set_pwm(dev, pwm, i);
 311                         if (ret < 0)
 312                                 return ret;
 313                 }
 314         }
 315         data->cdev_data[cdev_idx].cur_state =
 316                 EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state,
 317                                        EMC2305_FAN_MAX);
 318         data->cdev_data[cdev_idx].last_hwmon_state =
 319                 EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state,
 320                                        EMC2305_FAN_MAX);
 321         return 0;
 322 }
 323
 324 static int emc2305_set_tz(struct device *dev)
 325 {
 326         struct emc2305_data *data = dev_get_drvdata(dev);
 327         int i, ret;
 328
 329         if (!data->pwm_separate)
 330                 return emc2305_set_single_tz(dev, 0);
 331
 332         for (i = 0; i < data->pwm_num; i++) {
 333                 ret = emc2305_set_single_tz(dev, i + 1);
 334                 if (ret)
 335                         goto thermal_cooling_device_register_fail;
 336         }
 337         return 0;
 338
 339 thermal_cooling_device_register_fail:
 340         emc2305_unset_tz(dev);
 341         return ret;
 342 }
 343
 344 static void emc2305_unset_tz(struct device *dev)
 345 {
 346         struct emc2305_data *data = dev_get_drvdata(dev);
 347         int i;
 348
 349         /* Unregister cooling device. */
 350         for (i = 0; i < EMC2305_PWM_MAX; i++)
 351                 if (data->cdev_data[i].cdev)
 352                         thermal_cooling_device_unregister(data->cdev_data[i].cdev);
 353 }
 354
 355 static umode_t
 356 emc2305_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, int channel)
 357 {
 358         int max_channel = emc2305_get_max_channel(data);
 359
 360         /* Don't show channels which are not physically connected. */
 361         if (channel >= max_channel)
 362                 return 0;
 363         switch (type) {
 364         case hwmon_fan:
 365                 switch (attr) {
 366                 case hwmon_fan_input:
 367                         return 0444;
 368                 case hwmon_fan_fault:
 369                         return 0444;
 370                 default:
 371                         break;
 372                 }
 373                 break;
 374         case hwmon_pwm:
 375                 switch (attr) {
 376                 case hwmon_pwm_input:
 377                         return 0644;
 378                 default:
 379                         break;
 380                 }
 381                 break;
 382         default:
 383                 break;
 384         }
 385
 386         return 0;
 387 };
 388
 389 static int
 390 emc2305_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long val)
 391 {
 392         struct emc2305_data *data = dev_get_drvdata(dev);
 393         int cdev_idx;
 394
 395         switch (type) {
 396         case hwmon_pwm:
 397                 switch (attr) {
 398                 case hwmon_pwm_input:
 399                         /* If thermal is configured - handle PWM limit setting. */
 400                         if (IS_REACHABLE(CONFIG_THERMAL)) {
 401                                 if (data->pwm_separate)
 402                                         cdev_idx = channel;
 403                                 else
 404                                         cdev_idx = 0;
 405                                 data->cdev_data[cdev_idx].last_hwmon_state =
 406                                         EMC2305_PWM_DUTY2STATE(val, data->max_state,
 407                                                                EMC2305_FAN_MAX);
 408                                 /*
 409                                  * Update PWM only in case requested state is not less than the
 410                                  * last thermal state.
 411                                  */
 412                                 if (data->cdev_data[cdev_idx].last_hwmon_state >=
 413                                     data->cdev_data[cdev_idx].last_thermal_state)
 414                                         return __emc2305_set_cur_state(data, cdev_idx,
 415                                                         data->cdev_data[cdev_idx].last_hwmon_state);
 416                                 return 0;
 417                         }
 418                         return emc2305_set_pwm(dev, val, channel);
 419                 default:
 420                         break;
 421                 }
 422                 break;
 423         default:
 424                 break;
 425         }
 426
 427         return -EOPNOTSUPP;
 428 };
 429
 430 static int
 431 emc2305_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long *val)
 432 {
 433         int ret;
 434
 435         switch (type) {
 436         case hwmon_fan:
 437                 switch (attr) {
 438                 case hwmon_fan_input:
 439                         ret = emc2305_show_fan(dev, channel);
 440                         if (ret < 0)
 441                                 return ret;
 442                         *val = ret;
 443                         return 0;
 444                 case hwmon_fan_fault:
 445                         ret = emc2305_show_fault(dev, channel);
 446                         if (ret < 0)
 447                                 return ret;
 448                         *val = ret;
 449                         return 0;
 450                 default:
 451                         break;
 452                 }
 453                 break;
 454         case hwmon_pwm:
 455                 switch (attr) {
 456                 case hwmon_pwm_input:
 457                         ret = emc2305_show_pwm(dev, channel);
 458                         if (ret < 0)
 459                                 return ret;
 460                         *val = ret;
 461                         return 0;
 462                 default:
 463                         break;
 464                 }
 465                 break;
 466         default:
 467                 break;
 468         }
 469
 470         return -EOPNOTSUPP;
 471 };
 472
 473 static const struct hwmon_ops emc2305_ops = {
 474         .is_visible = emc2305_is_visible,
 475         .read = emc2305_read,
 476         .write = emc2305_write,
 477 };
 478
 479 static const struct hwmon_channel_info * const emc2305_info[] = {
 480         HWMON_CHANNEL_INFO(fan,
 481                            HWMON_F_INPUT | HWMON_F_FAULT,
 482                            HWMON_F_INPUT | HWMON_F_FAULT,
 483                            HWMON_F_INPUT | HWMON_F_FAULT,
 484                            HWMON_F_INPUT | HWMON_F_FAULT,
 485                            HWMON_F_INPUT | HWMON_F_FAULT),
 486         HWMON_CHANNEL_INFO(pwm,
 487                            HWMON_PWM_INPUT,
 488                            HWMON_PWM_INPUT,
 489                            HWMON_PWM_INPUT,
 490                            HWMON_PWM_INPUT,
 491                            HWMON_PWM_INPUT),
 492         NULL
 493 };
 494
 495 static const struct hwmon_chip_info emc2305_chip_info = {
 496         .ops = &emc2305_ops,
 497         .info = emc2305_info,
 498 };
 499
 500 static int emc2305_identify(struct device *dev)
 501 {
 502         struct i2c_client *client = to_i2c_client(dev);
 503         struct emc2305_data *data = i2c_get_clientdata(client);
 504         int ret;
 505
 506         ret = i2c_smbus_read_byte_data(client, EMC2305_REG_PRODUCT_ID);
 507         if (ret < 0)
 508                 return ret;
 509
 510         switch (ret) {
 511         case EMC2305:
 512                 data->pwm_num = 5;
 513                 break;
 514         case EMC2303:
 515                 data->pwm_num = 3;
 516                 break;
 517         case EMC2302:
 518                 data->pwm_num = 2;
 519                 break;
 520         case EMC2301:
 521                 data->pwm_num = 1;
 522                 break;
 523         default:
 524                 return -ENODEV;
 525         }
 526
 527         return 0;
 528 }
 529
 530 static int emc2305_probe(struct i2c_client *client)
 531 {
 532         struct i2c_adapter *adapter = client->adapter;
 533         struct device *dev = &client->dev;
 534         struct emc2305_data *data;
 535         struct emc2305_platform_data *pdata;
 536         int vendor;
 537         int ret;
 538         int i;
 539
 540         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 541                 return -ENODEV;
 542
 543         vendor = i2c_smbus_read_byte_data(client, EMC2305_REG_VENDOR);
 544         if (vendor != EMC2305_VENDOR)
 545                 return -ENODEV;
 546
 547         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 548         if (!data)
 549                 return -ENOMEM;
 550
 551         i2c_set_clientdata(client, data);
 552         data->client = client;
 553
 554         ret = emc2305_identify(dev);
 555         if (ret)
 556                 return ret;
 557
 558         pdata = dev_get_platdata(&client->dev);
 559         if (pdata) {
 560                 if (!pdata->max_state || pdata->max_state > EMC2305_FAN_MAX_STATE)
 561                         return -EINVAL;
 562                 data->max_state = pdata->max_state;
 563                 /*
 564                  * Validate a number of active PWM channels. Note that
 565                  * configured number can be less than the actual maximum
 566                  * supported by the device.
 567                  */
 568                 if (!pdata->pwm_num || pdata->pwm_num > EMC2305_PWM_MAX)
 569                         return -EINVAL;
 570                 data->pwm_num = pdata->pwm_num;
 571                 data->pwm_separate = pdata->pwm_separate;
 572                 for (i = 0; i < EMC2305_PWM_MAX; i++)
 573                         data->pwm_min[i] = pdata->pwm_min[i];
 574         } else {
 575                 data->max_state = EMC2305_FAN_MAX_STATE;
 576                 data->pwm_separate = false;
 577                 for (i = 0; i < EMC2305_PWM_MAX; i++)
 578                         data->pwm_min[i] = EMC2305_FAN_MIN;
 579         }
 580
 581         data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "emc2305", data,
 582                                                                &emc2305_chip_info, NULL);
 583         if (IS_ERR(data->hwmon_dev))
 584                 return PTR_ERR(data->hwmon_dev);
 585
 586         if (IS_REACHABLE(CONFIG_THERMAL)) {
 587                 ret = emc2305_set_tz(dev);
 588                 if (ret != 0)
 589                         return ret;
 590         }
 591
 592         for (i = 0; i < data->pwm_num; i++) {
 593                 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_MIN_DRIVE(i),
 594                                                 data->pwm_min[i]);
 595                 if (ret < 0)
 596                         return ret;
 597         }
 598
 599         return 0;
 600 }
 601
 602 static void emc2305_remove(struct i2c_client *client)
 603 {
 604         struct device *dev = &client->dev;
 605
 606         if (IS_REACHABLE(CONFIG_THERMAL))
 607                 emc2305_unset_tz(dev);
 608 }
 609
 610 static struct i2c_driver emc2305_driver = {
 611         .driver = {
 612                 .name = "emc2305",
 613         },
 614         .probe = emc2305_probe,
 615         .remove   = emc2305_remove,
 616         .id_table = emc2305_ids,
 617 };
 618
 619 module_i2c_driver(emc2305_driver);
 620
 621 MODULE_AUTHOR("Nvidia");
 622 MODULE_DESCRIPTION("Microchip EMC2305 fan controller driver");
 623 MODULE_LICENSE("GPL");