LXR linux/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 */
  72struct 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 */
  85struct 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 */
 103struct 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
 116static int
 117mlxreg_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
 193static int
 194mlxreg_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
 219static umode_t
 220mlxreg_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
 256static 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
 275static 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
 281static 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
 286static 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
 293static 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
 312static 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
 365static 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
 371static 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
 387static 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
 412static 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
 514static 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
 560static struct platform_driver mlxreg_fan_driver = {
 561        .driver = {
 562            .name = "mlxreg-fan",
 563        },
 564        .probe = mlxreg_fan_probe,
 565};
 566
 567module_platform_driver(mlxreg_fan_driver);
 568
 569MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
 570MODULE_DESCRIPTION("Mellanox FAN driver");
 571MODULE_LICENSE("GPL");
 572MODULE_ALIAS("platform:mlxreg-fan");
 573