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  */
  71 struct mlxreg_fan_tacho {
  72         bool connected;
  73         u32 reg;
  74         u32 mask;
  75 };
  76
  77 /*
  78  * struct mlxreg_fan_pwm - PWM data (internal use):
  79  *
  80  * @connected: indicates if PWM is connected;
  81  * @reg: register offset;
  82  */
  83 struct mlxreg_fan_pwm {
  84         bool connected;
  85         u32 reg;
  86 };
  87
  88 /*
  89  * struct mlxreg_fan - private data (internal use):
  90  *
  91  * @dev: basic device;
  92  * @regmap: register map of parent device;
  93  * @tacho: tachometer data;
  94  * @pwm: PWM data;
  95  * @samples: minimum allowed samples per pulse;
  96  * @divider: divider value for tachometer RPM calculation;
  97  * @cooling: cooling device levels;
  98  * @cdev: cooling device;
  99  */
 100 struct mlxreg_fan {
 101         struct device *dev;
 102         void *regmap;
 103         struct mlxreg_core_platform_data *pdata;
 104         struct mlxreg_fan_tacho tacho[MLXREG_FAN_MAX_TACHO];
 105         struct mlxreg_fan_pwm pwm;
 106         int samples;
 107         int divider;
 108         u8 cooling_levels[MLXREG_FAN_MAX_STATE + 1];
 109         struct thermal_cooling_device *cdev;
 110 };
 111
 112 static int
 113 mlxreg_fan_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
 114                 int channel, long *val)
 115 {
 116         struct mlxreg_fan *fan = dev_get_drvdata(dev);
 117         struct mlxreg_fan_tacho *tacho;
 118         u32 regval;
 119         int err;
 120
 121         switch (type) {
 122         case hwmon_fan:
 123                 tacho = &fan->tacho[channel];
 124                 switch (attr) {
 125                 case hwmon_fan_input:
 126                         err = regmap_read(fan->regmap, tacho->reg, &regval);
 127                         if (err)
 128                                 return err;
 129
 130                         if (MLXREG_FAN_GET_FAULT(regval, tacho->mask)) {
 131                                 /* FAN is broken - return zero for FAN speed. */
 132                                 *val = 0;
 133                                 return 0;
 134                         }
 135
 136                         *val = MLXREG_FAN_GET_RPM(regval, fan->divider,
 137                                                   fan->samples);
 138                         break;
 139
 140                 case hwmon_fan_fault:
 141                         err = regmap_read(fan->regmap, tacho->reg, &regval);
 142                         if (err)
 143                                 return err;
 144
 145                         *val = MLXREG_FAN_GET_FAULT(regval, tacho->mask);
 146                         break;
 147
 148                 default:
 149                         return -EOPNOTSUPP;
 150                 }
 151                 break;
 152
 153         case hwmon_pwm:
 154                 switch (attr) {
 155                 case hwmon_pwm_input:
 156                         err = regmap_read(fan->regmap, fan->pwm.reg, &regval);
 157                         if (err)
 158                                 return err;
 159
 160                         *val = regval;
 161                         break;
 162
 163                 default:
 164                         return -EOPNOTSUPP;
 165                 }
 166                 break;
 167
 168         default:
 169                 return -EOPNOTSUPP;
 170         }
 171
 172         return 0;
 173 }
 174
 175 static int
 176 mlxreg_fan_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
 177                  int channel, long val)
 178 {
 179         struct mlxreg_fan *fan = dev_get_drvdata(dev);
 180
 181         switch (type) {
 182         case hwmon_pwm:
 183                 switch (attr) {
 184                 case hwmon_pwm_input:
 185                         if (val < MLXREG_FAN_MIN_DUTY ||
 186                             val > MLXREG_FAN_MAX_DUTY)
 187                                 return -EINVAL;
 188                         return regmap_write(fan->regmap, fan->pwm.reg, val);
 189                 default:
 190                         return -EOPNOTSUPP;
 191                 }
 192                 break;
 193
 194         default:
 195                 return -EOPNOTSUPP;
 196         }
 197
 198         return -EOPNOTSUPP;
 199 }
 200
 201 static umode_t
 202 mlxreg_fan_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
 203                       int channel)
 204 {
 205         switch (type) {
 206         case hwmon_fan:
 207                 if (!(((struct mlxreg_fan *)data)->tacho[channel].connected))
 208                         return 0;
 209
 210                 switch (attr) {
 211                 case hwmon_fan_input:
 212                 case hwmon_fan_fault:
 213                         return 0444;
 214                 default:
 215                         break;
 216                 }
 217                 break;
 218
 219         case hwmon_pwm:
 220                 if (!(((struct mlxreg_fan *)data)->pwm.connected))
 221                         return 0;
 222
 223                 switch (attr) {
 224                 case hwmon_pwm_input:
 225                         return 0644;
 226                 default:
 227                         break;
 228                 }
 229                 break;
 230
 231         default:
 232                 break;
 233         }
 234
 235         return 0;
 236 }
 237
 238 static const struct hwmon_channel_info *mlxreg_fan_hwmon_info[] = {
 239         HWMON_CHANNEL_INFO(fan,
 240                            HWMON_F_INPUT | HWMON_F_FAULT,
 241                            HWMON_F_INPUT | HWMON_F_FAULT,
 242                            HWMON_F_INPUT | HWMON_F_FAULT,
 243                            HWMON_F_INPUT | HWMON_F_FAULT,
 244                            HWMON_F_INPUT | HWMON_F_FAULT,
 245                            HWMON_F_INPUT | HWMON_F_FAULT,
 246                            HWMON_F_INPUT | HWMON_F_FAULT,
 247                            HWMON_F_INPUT | HWMON_F_FAULT,
 248                            HWMON_F_INPUT | HWMON_F_FAULT,
 249                            HWMON_F_INPUT | HWMON_F_FAULT,
 250                            HWMON_F_INPUT | HWMON_F_FAULT,
 251                            HWMON_F_INPUT | HWMON_F_FAULT),
 252         HWMON_CHANNEL_INFO(pwm,
 253                            HWMON_PWM_INPUT),
 254         NULL
 255 };
 256
 257 static const struct hwmon_ops mlxreg_fan_hwmon_hwmon_ops = {
 258         .is_visible = mlxreg_fan_is_visible,
 259         .read = mlxreg_fan_read,
 260         .write = mlxreg_fan_write,
 261 };
 262
 263 static const struct hwmon_chip_info mlxreg_fan_hwmon_chip_info = {
 264         .ops = &mlxreg_fan_hwmon_hwmon_ops,
 265         .info = mlxreg_fan_hwmon_info,
 266 };
 267
 268 static int mlxreg_fan_get_max_state(struct thermal_cooling_device *cdev,
 269                                     unsigned long *state)
 270 {
 271         *state = MLXREG_FAN_MAX_STATE;
 272         return 0;
 273 }
 274
 275 static int mlxreg_fan_get_cur_state(struct thermal_cooling_device *cdev,
 276                                     unsigned long *state)
 277
 278 {
 279         struct mlxreg_fan *fan = cdev->devdata;
 280         u32 regval;
 281         int err;
 282
 283         err = regmap_read(fan->regmap, fan->pwm.reg, &regval);
 284         if (err) {
 285                 dev_err(fan->dev, "Failed to query PWM duty\n");
 286                 return err;
 287         }
 288
 289         *state = MLXREG_FAN_PWM_DUTY2STATE(regval);
 290
 291         return 0;
 292 }
 293
 294 static int mlxreg_fan_set_cur_state(struct thermal_cooling_device *cdev,
 295                                     unsigned long state)
 296
 297 {
 298         struct mlxreg_fan *fan = cdev->devdata;
 299         unsigned long cur_state;
 300         int i, config = 0;
 301         u32 regval;
 302         int err;
 303
 304         /*
 305          * Verify if this request is for changing allowed FAN dynamical
 306          * minimum. If it is - update cooling levels accordingly and update
 307          * state, if current state is below the newly requested minimum state.
 308          * For example, if current state is 5, and minimal state is to be
 309          * changed from 4 to 6, fan->cooling_levels[0 to 5] will be changed all
 310          * from 4 to 6. And state 5 (fan->cooling_levels[4]) should be
 311          * overwritten.
 312          */
 313         if (state >= MLXREG_FAN_SPEED_MIN && state <= MLXREG_FAN_SPEED_MAX) {
 314                 /*
 315                  * This is configuration change, which is only supported through sysfs.
 316                  * For configuration non-zero value is to be returned to avoid thermal
 317                  * statistics update.
 318                  */
 319                 config = 1;
 320                 state -= MLXREG_FAN_MAX_STATE;
 321                 for (i = 0; i < state; i++)
 322                         fan->cooling_levels[i] = state;
 323                 for (i = state; i <= MLXREG_FAN_MAX_STATE; i++)
 324                         fan->cooling_levels[i] = i;
 325
 326                 err = regmap_read(fan->regmap, fan->pwm.reg, &regval);
 327                 if (err) {
 328                         dev_err(fan->dev, "Failed to query PWM duty\n");
 329                         return err;
 330                 }
 331
 332                 cur_state = MLXREG_FAN_PWM_DUTY2STATE(regval);
 333                 if (state < cur_state)
 334                         return config;
 335
 336                 state = cur_state;
 337         }
 338
 339         if (state > MLXREG_FAN_MAX_STATE)
 340                 return -EINVAL;
 341
 342         /* Normalize the state to the valid speed range. */
 343         state = fan->cooling_levels[state];
 344         err = regmap_write(fan->regmap, fan->pwm.reg,
 345                            MLXREG_FAN_PWM_STATE2DUTY(state));
 346         if (err) {
 347                 dev_err(fan->dev, "Failed to write PWM duty\n");
 348                 return err;
 349         }
 350         return config;
 351 }
 352
 353 static const struct thermal_cooling_device_ops mlxreg_fan_cooling_ops = {
 354         .get_max_state  = mlxreg_fan_get_max_state,
 355         .get_cur_state  = mlxreg_fan_get_cur_state,
 356         .set_cur_state  = mlxreg_fan_set_cur_state,
 357 };
 358
 359 static int mlxreg_fan_connect_verify(struct mlxreg_fan *fan,
 360                                      struct mlxreg_core_data *data)
 361 {
 362         u32 regval;
 363         int err;
 364
 365         err = regmap_read(fan->regmap, data->capability, &regval);
 366         if (err) {
 367                 dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
 368                         data->capability);
 369                 return err;
 370         }
 371
 372         return !!(regval & data->bit);
 373 }
 374
 375 static int mlxreg_fan_speed_divider_get(struct mlxreg_fan *fan,
 376                                         struct mlxreg_core_data *data)
 377 {
 378         u32 regval;
 379         int err;
 380
 381         err = regmap_read(fan->regmap, data->capability, &regval);
 382         if (err) {
 383                 dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
 384                         data->capability);
 385                 return err;
 386         }
 387
 388         /*
 389          * Set divider value according to the capability register, in case it
 390          * contains valid value. Otherwise use default value. The purpose of
 391          * this validation is to protect against the old hardware, in which
 392          * this register can return zero.
 393          */
 394         if (regval > 0 && regval <= MLXREG_FAN_TACHO_DIV_SCALE_MAX)
 395                 fan->divider = regval * MLXREG_FAN_TACHO_DIV_MIN;
 396
 397         return 0;
 398 }
 399
 400 static int mlxreg_fan_config(struct mlxreg_fan *fan,
 401                              struct mlxreg_core_platform_data *pdata)
 402 {
 403         struct mlxreg_core_data *data = pdata->data;
 404         bool configured = false;
 405         int tacho_num = 0, i;
 406         int err;
 407
 408         fan->samples = MLXREG_FAN_TACHO_SAMPLES_PER_PULSE_DEF;
 409         fan->divider = MLXREG_FAN_TACHO_DIV_DEF;
 410         for (i = 0; i < pdata->counter; i++, data++) {
 411                 if (strnstr(data->label, "tacho", sizeof(data->label))) {
 412                         if (tacho_num == MLXREG_FAN_MAX_TACHO) {
 413                                 dev_err(fan->dev, "too many tacho entries: %s\n",
 414                                         data->label);
 415                                 return -EINVAL;
 416                         }
 417
 418                         if (data->capability) {
 419                                 err = mlxreg_fan_connect_verify(fan, data);
 420                                 if (err < 0)
 421                                         return err;
 422                                 else if (!err) {
 423                                         tacho_num++;
 424                                         continue;
 425                                 }
 426                         }
 427
 428                         fan->tacho[tacho_num].reg = data->reg;
 429                         fan->tacho[tacho_num].mask = data->mask;
 430                         fan->tacho[tacho_num++].connected = true;
 431                 } else if (strnstr(data->label, "pwm", sizeof(data->label))) {
 432                         if (fan->pwm.connected) {
 433                                 dev_err(fan->dev, "duplicate pwm entry: %s\n",
 434                                         data->label);
 435                                 return -EINVAL;
 436                         }
 437                         fan->pwm.reg = data->reg;
 438                         fan->pwm.connected = true;
 439                 } else if (strnstr(data->label, "conf", sizeof(data->label))) {
 440                         if (configured) {
 441                                 dev_err(fan->dev, "duplicate conf entry: %s\n",
 442                                         data->label);
 443                                 return -EINVAL;
 444                         }
 445                         /* Validate that conf parameters are not zeros. */
 446                         if (!data->mask && !data->bit && !data->capability) {
 447                                 dev_err(fan->dev, "invalid conf entry params: %s\n",
 448                                         data->label);
 449                                 return -EINVAL;
 450                         }
 451                         if (data->capability) {
 452                                 err = mlxreg_fan_speed_divider_get(fan, data);
 453                                 if (err)
 454                                         return err;
 455                         } else {
 456                                 if (data->mask)
 457                                         fan->samples = data->mask;
 458                                 if (data->bit)
 459                                         fan->divider = data->bit;
 460                         }
 461                         configured = true;
 462                 } else {
 463                         dev_err(fan->dev, "invalid label: %s\n", data->label);
 464                         return -EINVAL;
 465                 }
 466         }
 467
 468         /* Init cooling levels per PWM state. */
 469         for (i = 0; i < MLXREG_FAN_SPEED_MIN_LEVEL; i++)
 470                 fan->cooling_levels[i] = MLXREG_FAN_SPEED_MIN_LEVEL;
 471         for (i = MLXREG_FAN_SPEED_MIN_LEVEL; i <= MLXREG_FAN_MAX_STATE; i++)
 472                 fan->cooling_levels[i] = i;
 473
 474         return 0;
 475 }
 476
 477 static int mlxreg_fan_probe(struct platform_device *pdev)
 478 {
 479         struct mlxreg_core_platform_data *pdata;
 480         struct device *dev = &pdev->dev;
 481         struct mlxreg_fan *fan;
 482         struct device *hwm;
 483         int err;
 484
 485         pdata = dev_get_platdata(dev);
 486         if (!pdata) {
 487                 dev_err(dev, "Failed to get platform data.\n");
 488                 return -EINVAL;
 489         }
 490
 491         fan = devm_kzalloc(dev, sizeof(*fan), GFP_KERNEL);
 492         if (!fan)
 493                 return -ENOMEM;
 494
 495         fan->dev = dev;
 496         fan->regmap = pdata->regmap;
 497
 498         err = mlxreg_fan_config(fan, pdata);
 499         if (err)
 500                 return err;
 501
 502         hwm = devm_hwmon_device_register_with_info(dev, "mlxreg_fan",
 503                                                    fan,
 504                                                    &mlxreg_fan_hwmon_chip_info,
 505                                                    NULL);
 506         if (IS_ERR(hwm)) {
 507                 dev_err(dev, "Failed to register hwmon device\n");
 508                 return PTR_ERR(hwm);
 509         }
 510
 511         if (IS_REACHABLE(CONFIG_THERMAL)) {
 512                 fan->cdev = devm_thermal_of_cooling_device_register(dev,
 513                         NULL, "mlxreg_fan", fan, &mlxreg_fan_cooling_ops);
 514                 if (IS_ERR(fan->cdev)) {
 515                         dev_err(dev, "Failed to register cooling device\n");
 516                         return PTR_ERR(fan->cdev);
 517                 }
 518         }
 519
 520         return 0;
 521 }
 522
 523 static struct platform_driver mlxreg_fan_driver = {
 524         .driver = {
 525             .name = "mlxreg-fan",
 526         },
 527         .probe = mlxreg_fan_probe,
 528 };
 529
 530 module_platform_driver(mlxreg_fan_driver);
 531
 532 MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
 533 MODULE_DESCRIPTION("Mellanox FAN driver");
 534 MODULE_LICENSE("GPL");
 535 MODULE_ALIAS("platform:mlxreg-fan");