root/drivers/hwmon/mlxreg-fan.c

DEFINITIONS

1. mlxreg_fan_read
2. mlxreg_fan_write
3. mlxreg_fan_is_visible
4. mlxreg_fan_get_max_state
5. mlxreg_fan_get_cur_state
6. mlxreg_fan_set_cur_state
7. mlxreg_fan_connect_verify
8. mlxreg_fan_speed_divider_get
9. mlxreg_fan_config
10. mlxreg_fan_probe

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