drivers/hwmon/mlxreg-fan.c

   1 // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
   2 //
   3 // Copyright (c) 2018 Mellanox Technologies. All rights reserved.
   4 // Copyright (c) 2018 Vadim Pasternak <vadimp@mellanox.com>
   5
   6 #include <linux/bitops.h>
   7 #include <linux/device.h>
   8 #include <linux/hwmon.h>
   9 #include <linux/module.h>
  10 #include <linux/platform_data/mlxreg.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/regmap.h>
  13 #include <linux/thermal.h>
  14
  15 #define MLXREG_FAN_MAX_TACHO            12
  16 #define MLXREG_FAN_MAX_STATE            10
  17 #define MLXREG_FAN_MIN_DUTY             51      /* 20% */
  18 #define MLXREG_FAN_MAX_DUTY             255     /* 100% */
  19 /*
  20  * Minimum and maximum FAN allowed speed in percent: from 20% to 100%. Values
  21  * MLXREG_FAN_MAX_STATE + x, where x is between 2 and 10 are used for
  22  * setting FAN speed dynamic minimum. For example, if value is set to 14 (40%)
  23  * cooling levels vector will be set to 4, 4, 4, 4, 4, 5, 6, 7, 8, 9, 10 to
  24  * introduce PWM speed in percent: 40, 40, 40, 40, 40, 50, 60. 70, 80, 90, 100.
  25  */
  26 #define MLXREG_FAN_SPEED_MIN                    (MLXREG_FAN_MAX_STATE + 2)
  27 #define MLXREG_FAN_SPEED_MAX                    (MLXREG_FAN_MAX_STATE * 2)
  28 #define MLXREG_FAN_SPEED_MIN_LEVEL              2       /* 20 percent */
  29 #define MLXREG_FAN_TACHO_SAMPLES_PER_PULSE_DEF  44
  30 #define MLXREG_FAN_TACHO_DIV_MIN                283
  31 #define MLXREG_FAN_TACHO_DIV_DEF                (MLXREG_FAN_TACHO_DIV_MIN * 4)
  32 #define MLXREG_FAN_TACHO_DIV_SCALE_MAX  64
  33 /*
  34  * FAN datasheet defines the formula for RPM calculations as RPM = 15/t-high.
  35  * The logic in a programmable device measures the time t-high by sampling the
  36  * tachometer every t-sample (with the default value 11.32 uS) and increment
  37  * a counter (N) as long as the pulse has not change:
  38  * RPM = 15 / (t-sample * (K + Regval)), where:
  39  * Regval: is the value read from the programmable device register;
  40  *  - 0xff - represents tachometer fault;
  41  *  - 0xfe - represents tachometer minimum value , which is 4444 RPM;
  42  *  - 0x00 - represents tachometer maximum value , which is 300000 RPM;
  43  * K: is 44 and it represents the minimum allowed samples per pulse;
  44  * N: is equal K + Regval;
  45  * In order to calculate RPM from the register value the following formula is
  46  * used: RPM = 15 / ((Regval + K) * 11.32) * 10^(-6)), which in  the
  47  * default case is modified to:
  48  * RPM = 15000000 * 100 / ((Regval + 44) * 1132);
  49  * - for Regval 0x00, RPM will be 15000000 * 100 / (44 * 1132) = 30115;
  50  * - for Regval 0xfe, RPM will be 15000000 * 100 / ((254 + 44) * 1132) = 4446;
  51  * In common case the formula is modified to:
  52  * RPM = 15000000 * 100 / ((Regval + samples) * divider).
  53  */
  54 #define MLXREG_FAN_GET_RPM(rval, d, s)  (DIV_ROUND_CLOSEST(15000000 * 100, \
  55                                          ((rval) + (s)) * (d)))
  56 #define MLXREG_FAN_GET_FAULT(val, mask) ((val) == (mask))
  57 #define MLXREG_FAN_PWM_DUTY2STATE(duty) (DIV_ROUND_CLOSEST((duty) *     \
  58                                          MLXREG_FAN_MAX_STATE,          \
  59                                          MLXREG_FAN_MAX_DUTY))
  60 #define MLXREG_FAN_PWM_STATE2DUTY(stat) (DIV_ROUND_CLOSEST((stat) *     \
  61                                          MLXREG_FAN_MAX_DUTY,           \
  62                                          MLXREG_FAN_MAX_STATE))
  63
  64 /*
  65  * struct mlxreg_fan_tacho - tachometer data (internal use):
  66  *
  67  * @connected: indicates if tachometer is connected;
  68  * @reg: register offset;
  69  * @mask: fault mask;
  70  * @prsnt: present register offset;
  71  */
  72 struct mlxreg_fan_tacho {
  73         bool connected;
  74         u32 reg;
  75         u32 mask;
  76         u32 prsnt;
  77 };
  78
  79 /*
  80  * struct mlxreg_fan_pwm - PWM data (internal use):
  81  *
  82  * @connected: indicates if PWM is connected;
  83  * @reg: register offset;
  84  */
  85 struct mlxreg_fan_pwm {
  86         bool connected;
  87         u32 reg;
  88 };
  89
  90 /*
  91  * struct mlxreg_fan - private data (internal use):
  92  *
  93  * @dev: basic device;
  94  * @regmap: register map of parent device;
  95  * @tacho: tachometer data;
  96  * @pwm: PWM data;
  97  * @tachos_per_drwr - number of tachometers per drawer;
  98  * @samples: minimum allowed samples per pulse;
  99  * @divider: divider value for tachometer RPM calculation;
 100  * @cooling: cooling device levels;
 101  * @cdev: cooling device;
 102  */
 103 struct mlxreg_fan {
 104         struct device *dev;
 105         void *regmap;
 106         struct mlxreg_core_platform_data *pdata;
 107         struct mlxreg_fan_tacho tacho[MLXREG_FAN_MAX_TACHO];
 108         struct mlxreg_fan_pwm pwm;
 109         int tachos_per_drwr;
 110         int samples;
 111         int divider;
 112         u8 cooling_levels[MLXREG_FAN_MAX_STATE + 1];
 113         struct thermal_cooling_device *cdev;
 114 };
 115
 116 static int
 117 mlxreg_fan_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
 118                 int channel, long *val)
 119 {
 120         struct mlxreg_fan *fan = dev_get_drvdata(dev);
 121         struct mlxreg_fan_tacho *tacho;
 122         u32 regval;
 123         int err;
 124
 125         switch (type) {
 126         case hwmon_fan:
 127                 tacho = &fan->tacho[channel];
 128                 switch (attr) {
 129                 case hwmon_fan_input:
 130                         /*
 131                          * Check FAN presence: FAN related bit in presence register is one,
 132                          * if FAN is physically connected, zero - otherwise.
 133                          */
 134                         if (tacho->prsnt && fan->tachos_per_drwr) {
 135                                 err = regmap_read(fan->regmap, tacho->prsnt, &regval);
 136                                 if (err)
 137                                         return err;
 138
 139                                 /*
 140                                  * Map channel to presence bit - drawer can be equipped with
 141                                  * one or few FANs, while presence is indicated per drawer.
 142                                  */
 143                                 if (BIT(channel / fan->tachos_per_drwr) & regval) {
 144                                         /* FAN is not connected - return zero for FAN speed. */
 145                                         *val = 0;
 146                                         return 0;
 147                                 }
 148                         }
 149
 150                         err = regmap_read(fan->regmap, tacho->reg, &regval);
 151                         if (err)
 152                                 return err;
 153
 154                         *val = MLXREG_FAN_GET_RPM(regval, fan->divider,
 155                                                   fan->samples);
 156                         break;
 157
 158                 case hwmon_fan_fault:
 159                         err = regmap_read(fan->regmap, tacho->reg, &regval);
 160                         if (err)
 161                                 return err;
 162
 163                         *val = MLXREG_FAN_GET_FAULT(regval, tacho->mask);
 164                         break;
 165
 166                 default:
 167                         return -EOPNOTSUPP;
 168                 }
 169                 break;
 170
 171         case hwmon_pwm:
 172                 switch (attr) {
 173                 case hwmon_pwm_input:
 174                         err = regmap_read(fan->regmap, fan->pwm.reg, &regval);
 175                         if (err)
 176                                 return err;
 177
 178                         *val = regval;
 179                         break;
 180
 181                 default:
 182                         return -EOPNOTSUPP;
 183                 }
 184                 break;
 185
 186         default:
 187                 return -EOPNOTSUPP;
 188         }
 189
 190         return 0;
 191 }
 192
 193 static int
 194 mlxreg_fan_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
 195                  int channel, long val)
 196 {
 197         struct mlxreg_fan *fan = dev_get_drvdata(dev);
 198
 199         switch (type) {
 200         case hwmon_pwm:
 201                 switch (attr) {
 202                 case hwmon_pwm_input:
 203                         if (val < MLXREG_FAN_MIN_DUTY ||
 204                             val > MLXREG_FAN_MAX_DUTY)
 205                                 return -EINVAL;
 206                         return regmap_write(fan->regmap, fan->pwm.reg, val);
 207                 default:
 208                         return -EOPNOTSUPP;
 209                 }
 210                 break;
 211
 212         default:
 213                 return -EOPNOTSUPP;
 214         }
 215
 216         return -EOPNOTSUPP;
 217 }
 218
 219 static umode_t
 220 mlxreg_fan_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
 221                       int channel)
 222 {
 223         switch (type) {
 224         case hwmon_fan:
 225                 if (!(((struct mlxreg_fan *)data)->tacho[channel].connected))
 226                         return 0;
 227
 228                 switch (attr) {
 229                 case hwmon_fan_input:
 230                 case hwmon_fan_fault:
 231                         return 0444;
 232                 default:
 233                         break;
 234                 }
 235                 break;
 236
 237         case hwmon_pwm:
 238                 if (!(((struct mlxreg_fan *)data)->pwm.connected))
 239                         return 0;
 240
 241                 switch (attr) {
 242                 case hwmon_pwm_input:
 243                         return 0644;
 244                 default:
 245                         break;
 246                 }
 247                 break;
 248
 249         default:
 250                 break;
 251         }
 252
 253         return 0;
 254 }
 255
 256 static const struct hwmon_channel_info *mlxreg_fan_hwmon_info[] = {
 257         HWMON_CHANNEL_INFO(fan,
 258                            HWMON_F_INPUT | HWMON_F_FAULT,
 259                            HWMON_F_INPUT | HWMON_F_FAULT,
 260                            HWMON_F_INPUT | HWMON_F_FAULT,
 261                            HWMON_F_INPUT | HWMON_F_FAULT,
 262                            HWMON_F_INPUT | HWMON_F_FAULT,
 263                            HWMON_F_INPUT | HWMON_F_FAULT,
 264                            HWMON_F_INPUT | HWMON_F_FAULT,
 265                            HWMON_F_INPUT | HWMON_F_FAULT,
 266                            HWMON_F_INPUT | HWMON_F_FAULT,
 267                            HWMON_F_INPUT | HWMON_F_FAULT,
 268                            HWMON_F_INPUT | HWMON_F_FAULT,
 269                            HWMON_F_INPUT | HWMON_F_FAULT),
 270         HWMON_CHANNEL_INFO(pwm,
 271                            HWMON_PWM_INPUT),
 272         NULL
 273 };
 274
 275 static const struct hwmon_ops mlxreg_fan_hwmon_hwmon_ops = {
 276         .is_visible = mlxreg_fan_is_visible,
 277         .read = mlxreg_fan_read,
 278         .write = mlxreg_fan_write,
 279 };
 280
 281 static const struct hwmon_chip_info mlxreg_fan_hwmon_chip_info = {
 282         .ops = &mlxreg_fan_hwmon_hwmon_ops,
 283         .info = mlxreg_fan_hwmon_info,
 284 };
 285
 286 static int mlxreg_fan_get_max_state(struct thermal_cooling_device *cdev,
 287                                     unsigned long *state)
 288 {
 289         *state = MLXREG_FAN_MAX_STATE;
 290         return 0;
 291 }
 292
 293 static int mlxreg_fan_get_cur_state(struct thermal_cooling_device *cdev,
 294                                     unsigned long *state)
 295
 296 {
 297         struct mlxreg_fan *fan = cdev->devdata;
 298         u32 regval;
 299         int err;
 300
 301         err = regmap_read(fan->regmap, fan->pwm.reg, &regval);
 302         if (err) {
 303                 dev_err(fan->dev, "Failed to query PWM duty\n");
 304                 return err;
 305         }
 306
 307         *state = MLXREG_FAN_PWM_DUTY2STATE(regval);
 308
 309         return 0;
 310 }
 311
 312 static int mlxreg_fan_set_cur_state(struct thermal_cooling_device *cdev,
 313                                     unsigned long state)
 314
 315 {
 316         struct mlxreg_fan *fan = cdev->devdata;
 317         unsigned long cur_state;
 318         u32 regval;
 319         int i;
 320         int err;
 321
 322         /*
 323          * Verify if this request is for changing allowed FAN dynamical
 324          * minimum. If it is - update cooling levels accordingly and update
 325          * state, if current state is below the newly requested minimum state.
 326          * For example, if current state is 5, and minimal state is to be
 327          * changed from 4 to 6, fan->cooling_levels[0 to 5] will be changed all
 328          * from 4 to 6. And state 5 (fan->cooling_levels[4]) should be
 329          * overwritten.
 330          */
 331         if (state >= MLXREG_FAN_SPEED_MIN && state <= MLXREG_FAN_SPEED_MAX) {
 332                 state -= MLXREG_FAN_MAX_STATE;
 333                 for (i = 0; i < state; i++)
 334                         fan->cooling_levels[i] = state;
 335                 for (i = state; i <= MLXREG_FAN_MAX_STATE; i++)
 336                         fan->cooling_levels[i] = i;
 337
 338                 err = regmap_read(fan->regmap, fan->pwm.reg, &regval);
 339                 if (err) {
 340                         dev_err(fan->dev, "Failed to query PWM duty\n");
 341                         return err;
 342                 }
 343
 344                 cur_state = MLXREG_FAN_PWM_DUTY2STATE(regval);
 345                 if (state < cur_state)
 346                         return 0;
 347
 348                 state = cur_state;
 349         }
 350
 351         if (state > MLXREG_FAN_MAX_STATE)
 352                 return -EINVAL;
 353
 354         /* Normalize the state to the valid speed range. */
 355         state = fan->cooling_levels[state];
 356         err = regmap_write(fan->regmap, fan->pwm.reg,
 357                            MLXREG_FAN_PWM_STATE2DUTY(state));
 358         if (err) {
 359                 dev_err(fan->dev, "Failed to write PWM duty\n");
 360                 return err;
 361         }
 362         return 0;
 363 }
 364
 365 static const struct thermal_cooling_device_ops mlxreg_fan_cooling_ops = {
 366         .get_max_state  = mlxreg_fan_get_max_state,
 367         .get_cur_state  = mlxreg_fan_get_cur_state,
 368         .set_cur_state  = mlxreg_fan_set_cur_state,
 369 };
 370
 371 static int mlxreg_fan_connect_verify(struct mlxreg_fan *fan,
 372                                      struct mlxreg_core_data *data)
 373 {
 374         u32 regval;
 375         int err;
 376
 377         err = regmap_read(fan->regmap, data->capability, &regval);
 378         if (err) {
 379                 dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
 380                         data->capability);
 381                 return err;
 382         }
 383
 384         return !!(regval & data->bit);
 385 }
 386
 387 static int mlxreg_fan_speed_divider_get(struct mlxreg_fan *fan,
 388                                         struct mlxreg_core_data *data)
 389 {
 390         u32 regval;
 391         int err;
 392
 393         err = regmap_read(fan->regmap, data->capability, &regval);
 394         if (err) {
 395                 dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
 396                         data->capability);
 397                 return err;
 398         }
 399
 400         /*
 401          * Set divider value according to the capability register, in case it
 402          * contains valid value. Otherwise use default value. The purpose of
 403          * this validation is to protect against the old hardware, in which
 404          * this register can return zero.
 405          */
 406         if (regval > 0 && regval <= MLXREG_FAN_TACHO_DIV_SCALE_MAX)
 407                 fan->divider = regval * MLXREG_FAN_TACHO_DIV_MIN;
 408
 409         return 0;
 410 }
 411
 412 static int mlxreg_fan_config(struct mlxreg_fan *fan,
 413                              struct mlxreg_core_platform_data *pdata)
 414 {
 415         struct mlxreg_core_data *data = pdata->data;
 416         int tacho_num = 0, tacho_avail = 0, i;
 417         bool configured = false;
 418         int err;
 419
 420         fan->samples = MLXREG_FAN_TACHO_SAMPLES_PER_PULSE_DEF;
 421         fan->divider = MLXREG_FAN_TACHO_DIV_DEF;
 422         for (i = 0; i < pdata->counter; i++, data++) {
 423                 if (strnstr(data->label, "tacho", sizeof(data->label))) {
 424                         if (tacho_num == MLXREG_FAN_MAX_TACHO) {
 425                                 dev_err(fan->dev, "too many tacho entries: %s\n",
 426                                         data->label);
 427                                 return -EINVAL;
 428                         }
 429
 430                         if (data->capability) {
 431                                 err = mlxreg_fan_connect_verify(fan, data);
 432                                 if (err < 0)
 433                                         return err;
 434                                 else if (!err) {
 435                                         tacho_num++;
 436                                         continue;
 437                                 }
 438                         }
 439
 440                         fan->tacho[tacho_num].reg = data->reg;
 441                         fan->tacho[tacho_num].mask = data->mask;
 442                         fan->tacho[tacho_num].prsnt = data->reg_prsnt;
 443                         fan->tacho[tacho_num++].connected = true;
 444                         tacho_avail++;
 445                 } else if (strnstr(data->label, "pwm", sizeof(data->label))) {
 446                         if (fan->pwm.connected) {
 447                                 dev_err(fan->dev, "duplicate pwm entry: %s\n",
 448                                         data->label);
 449                                 return -EINVAL;
 450                         }
 451                         fan->pwm.reg = data->reg;
 452                         fan->pwm.connected = true;
 453                 } else if (strnstr(data->label, "conf", sizeof(data->label))) {
 454                         if (configured) {
 455                                 dev_err(fan->dev, "duplicate conf entry: %s\n",
 456                                         data->label);
 457                                 return -EINVAL;
 458                         }
 459                         /* Validate that conf parameters are not zeros. */
 460                         if (!data->mask && !data->bit && !data->capability) {
 461                                 dev_err(fan->dev, "invalid conf entry params: %s\n",
 462                                         data->label);
 463                                 return -EINVAL;
 464                         }
 465                         if (data->capability) {
 466                                 err = mlxreg_fan_speed_divider_get(fan, data);
 467                                 if (err)
 468                                         return err;
 469                         } else {
 470                                 if (data->mask)
 471                                         fan->samples = data->mask;
 472                                 if (data->bit)
 473                                         fan->divider = data->bit;
 474                         }
 475                         configured = true;
 476                 } else {
 477                         dev_err(fan->dev, "invalid label: %s\n", data->label);
 478                         return -EINVAL;
 479                 }
 480         }
 481
 482         if (pdata->capability) {
 483                 int drwr_avail;
 484                 u32 regval;
 485
 486                 /* Obtain the number of FAN drawers, supported by system. */
 487                 err = regmap_read(fan->regmap, pdata->capability, &regval);
 488                 if (err) {
 489                         dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
 490                                 pdata->capability);
 491                         return err;
 492                 }
 493
 494                 drwr_avail = hweight32(regval);
 495                 if (!tacho_avail || !drwr_avail || tacho_avail < drwr_avail) {
 496                         dev_err(fan->dev, "Configuration is invalid: drawers num %d tachos num %d\n",
 497                                 drwr_avail, tacho_avail);
 498                         return -EINVAL;
 499                 }
 500
 501                 /* Set the number of tachometers per one drawer. */
 502                 fan->tachos_per_drwr = tacho_avail / drwr_avail;
 503         }
 504
 505         /* Init cooling levels per PWM state. */
 506         for (i = 0; i < MLXREG_FAN_SPEED_MIN_LEVEL; i++)
 507                 fan->cooling_levels[i] = MLXREG_FAN_SPEED_MIN_LEVEL;
 508         for (i = MLXREG_FAN_SPEED_MIN_LEVEL; i <= MLXREG_FAN_MAX_STATE; i++)
 509                 fan->cooling_levels[i] = i;
 510
 511         return 0;
 512 }
 513
 514 static int mlxreg_fan_probe(struct platform_device *pdev)
 515 {
 516         struct mlxreg_core_platform_data *pdata;
 517         struct device *dev = &pdev->dev;
 518         struct mlxreg_fan *fan;
 519         struct device *hwm;
 520         int err;
 521
 522         pdata = dev_get_platdata(dev);
 523         if (!pdata) {
 524                 dev_err(dev, "Failed to get platform data.\n");
 525                 return -EINVAL;
 526         }
 527
 528         fan = devm_kzalloc(dev, sizeof(*fan), GFP_KERNEL);
 529         if (!fan)
 530                 return -ENOMEM;
 531
 532         fan->dev = dev;
 533         fan->regmap = pdata->regmap;
 534
 535         err = mlxreg_fan_config(fan, pdata);
 536         if (err)
 537                 return err;
 538
 539         hwm = devm_hwmon_device_register_with_info(dev, "mlxreg_fan",
 540                                                    fan,
 541                                                    &mlxreg_fan_hwmon_chip_info,
 542                                                    NULL);
 543         if (IS_ERR(hwm)) {
 544                 dev_err(dev, "Failed to register hwmon device\n");
 545                 return PTR_ERR(hwm);
 546         }
 547
 548         if (IS_REACHABLE(CONFIG_THERMAL)) {
 549                 fan->cdev = devm_thermal_of_cooling_device_register(dev,
 550                         NULL, "mlxreg_fan", fan, &mlxreg_fan_cooling_ops);
 551                 if (IS_ERR(fan->cdev)) {
 552                         dev_err(dev, "Failed to register cooling device\n");
 553                         return PTR_ERR(fan->cdev);
 554                 }
 555         }
 556
 557         return 0;
 558 }
 559
 560 static struct platform_driver mlxreg_fan_driver = {
 561         .driver = {
 562             .name = "mlxreg-fan",
 563         },
 564         .probe = mlxreg_fan_probe,
 565 };
 566
 567 module_platform_driver(mlxreg_fan_driver);
 568
 569 MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
 570 MODULE_DESCRIPTION("Mellanox FAN driver");
 571 MODULE_LICENSE("GPL");
 572 MODULE_ALIAS("platform:mlxreg-fan");