linux/drivers/hwmon/max31790.c
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   1/*
   2 * max31790.c - Part of lm_sensors, Linux kernel modules for hardware
   3 *             monitoring.
   4 *
   5 * (C) 2015 by Il Han <corone.il.han@gmail.com>
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License as published by
   9 * the Free Software Foundation; either version 2 of the License, or
  10 * (at your option) any later version.
  11 *
  12 * This program is distributed in the hope that it will be useful,
  13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 * GNU General Public License for more details.
  16 */
  17
  18#include <linux/err.h>
  19#include <linux/hwmon.h>
  20#include <linux/i2c.h>
  21#include <linux/init.h>
  22#include <linux/jiffies.h>
  23#include <linux/module.h>
  24#include <linux/slab.h>
  25
  26/* MAX31790 registers */
  27#define MAX31790_REG_GLOBAL_CONFIG      0x00
  28#define MAX31790_REG_FAN_CONFIG(ch)     (0x02 + (ch))
  29#define MAX31790_REG_FAN_DYNAMICS(ch)   (0x08 + (ch))
  30#define MAX31790_REG_FAN_FAULT_STATUS2  0x10
  31#define MAX31790_REG_FAN_FAULT_STATUS1  0x11
  32#define MAX31790_REG_TACH_COUNT(ch)     (0x18 + (ch) * 2)
  33#define MAX31790_REG_PWM_DUTY_CYCLE(ch) (0x30 + (ch) * 2)
  34#define MAX31790_REG_PWMOUT(ch)         (0x40 + (ch) * 2)
  35#define MAX31790_REG_TARGET_COUNT(ch)   (0x50 + (ch) * 2)
  36
  37/* Fan Config register bits */
  38#define MAX31790_FAN_CFG_RPM_MODE       0x80
  39#define MAX31790_FAN_CFG_TACH_INPUT_EN  0x08
  40#define MAX31790_FAN_CFG_TACH_INPUT     0x01
  41
  42/* Fan Dynamics register bits */
  43#define MAX31790_FAN_DYN_SR_SHIFT       5
  44#define MAX31790_FAN_DYN_SR_MASK        0xE0
  45#define SR_FROM_REG(reg)                (((reg) & MAX31790_FAN_DYN_SR_MASK) \
  46                                         >> MAX31790_FAN_DYN_SR_SHIFT)
  47
  48#define FAN_RPM_MIN                     120
  49#define FAN_RPM_MAX                     7864320
  50
  51#define RPM_FROM_REG(reg, sr)           (((reg) >> 4) ? \
  52                                         ((60 * (sr) * 8192) / ((reg) >> 4)) : \
  53                                         FAN_RPM_MAX)
  54#define RPM_TO_REG(rpm, sr)             ((60 * (sr) * 8192) / ((rpm) * 2))
  55
  56#define NR_CHANNEL                      6
  57
  58/*
  59 * Client data (each client gets its own)
  60 */
  61struct max31790_data {
  62        struct i2c_client *client;
  63        struct mutex update_lock;
  64        bool valid; /* zero until following fields are valid */
  65        unsigned long last_updated; /* in jiffies */
  66
  67        /* register values */
  68        u8 fan_config[NR_CHANNEL];
  69        u8 fan_dynamics[NR_CHANNEL];
  70        u16 fault_status;
  71        u16 tach[NR_CHANNEL * 2];
  72        u16 pwm[NR_CHANNEL];
  73        u16 target_count[NR_CHANNEL];
  74};
  75
  76static struct max31790_data *max31790_update_device(struct device *dev)
  77{
  78        struct max31790_data *data = dev_get_drvdata(dev);
  79        struct i2c_client *client = data->client;
  80        struct max31790_data *ret = data;
  81        int i;
  82        int rv;
  83
  84        mutex_lock(&data->update_lock);
  85
  86        if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
  87                rv = i2c_smbus_read_byte_data(client,
  88                                MAX31790_REG_FAN_FAULT_STATUS1);
  89                if (rv < 0)
  90                        goto abort;
  91                data->fault_status = rv & 0x3F;
  92
  93                rv = i2c_smbus_read_byte_data(client,
  94                                MAX31790_REG_FAN_FAULT_STATUS2);
  95                if (rv < 0)
  96                        goto abort;
  97                data->fault_status |= (rv & 0x3F) << 6;
  98
  99                for (i = 0; i < NR_CHANNEL; i++) {
 100                        rv = i2c_smbus_read_word_swapped(client,
 101                                        MAX31790_REG_TACH_COUNT(i));
 102                        if (rv < 0)
 103                                goto abort;
 104                        data->tach[i] = rv;
 105
 106                        if (data->fan_config[i]
 107                            & MAX31790_FAN_CFG_TACH_INPUT) {
 108                                rv = i2c_smbus_read_word_swapped(client,
 109                                        MAX31790_REG_TACH_COUNT(NR_CHANNEL
 110                                                                + i));
 111                                if (rv < 0)
 112                                        goto abort;
 113                                data->tach[NR_CHANNEL + i] = rv;
 114                        } else {
 115                                rv = i2c_smbus_read_word_swapped(client,
 116                                                MAX31790_REG_PWMOUT(i));
 117                                if (rv < 0)
 118                                        goto abort;
 119                                data->pwm[i] = rv;
 120
 121                                rv = i2c_smbus_read_word_swapped(client,
 122                                                MAX31790_REG_TARGET_COUNT(i));
 123                                if (rv < 0)
 124                                        goto abort;
 125                                data->target_count[i] = rv;
 126                        }
 127                }
 128
 129                data->last_updated = jiffies;
 130                data->valid = true;
 131        }
 132        goto done;
 133
 134abort:
 135        data->valid = false;
 136        ret = ERR_PTR(rv);
 137
 138done:
 139        mutex_unlock(&data->update_lock);
 140
 141        return ret;
 142}
 143
 144static const u8 tach_period[8] = { 1, 2, 4, 8, 16, 32, 32, 32 };
 145
 146static u8 get_tach_period(u8 fan_dynamics)
 147{
 148        return tach_period[SR_FROM_REG(fan_dynamics)];
 149}
 150
 151static u8 bits_for_tach_period(int rpm)
 152{
 153        u8 bits;
 154
 155        if (rpm < 500)
 156                bits = 0x0;
 157        else if (rpm < 1000)
 158                bits = 0x1;
 159        else if (rpm < 2000)
 160                bits = 0x2;
 161        else if (rpm < 4000)
 162                bits = 0x3;
 163        else if (rpm < 8000)
 164                bits = 0x4;
 165        else
 166                bits = 0x5;
 167
 168        return bits;
 169}
 170
 171static int max31790_read_fan(struct device *dev, u32 attr, int channel,
 172                             long *val)
 173{
 174        struct max31790_data *data = max31790_update_device(dev);
 175        int sr, rpm;
 176
 177        if (IS_ERR(data))
 178                return PTR_ERR(data);
 179
 180        switch (attr) {
 181        case hwmon_fan_input:
 182                sr = get_tach_period(data->fan_dynamics[channel]);
 183                rpm = RPM_FROM_REG(data->tach[channel], sr);
 184                *val = rpm;
 185                return 0;
 186        case hwmon_fan_target:
 187                sr = get_tach_period(data->fan_dynamics[channel]);
 188                rpm = RPM_FROM_REG(data->target_count[channel], sr);
 189                *val = rpm;
 190                return 0;
 191        case hwmon_fan_fault:
 192                *val = !!(data->fault_status & (1 << channel));
 193                return 0;
 194        default:
 195                return -EOPNOTSUPP;
 196        }
 197}
 198
 199static int max31790_write_fan(struct device *dev, u32 attr, int channel,
 200                              long val)
 201{
 202        struct max31790_data *data = dev_get_drvdata(dev);
 203        struct i2c_client *client = data->client;
 204        int target_count;
 205        int err = 0;
 206        u8 bits;
 207        int sr;
 208
 209        mutex_lock(&data->update_lock);
 210
 211        switch (attr) {
 212        case hwmon_fan_target:
 213                val = clamp_val(val, FAN_RPM_MIN, FAN_RPM_MAX);
 214                bits = bits_for_tach_period(val);
 215                data->fan_dynamics[channel] =
 216                        ((data->fan_dynamics[channel] &
 217                          ~MAX31790_FAN_DYN_SR_MASK) |
 218                         (bits << MAX31790_FAN_DYN_SR_SHIFT));
 219                err = i2c_smbus_write_byte_data(client,
 220                                        MAX31790_REG_FAN_DYNAMICS(channel),
 221                                        data->fan_dynamics[channel]);
 222                if (err < 0)
 223                        break;
 224
 225                sr = get_tach_period(data->fan_dynamics[channel]);
 226                target_count = RPM_TO_REG(val, sr);
 227                target_count = clamp_val(target_count, 0x1, 0x7FF);
 228
 229                data->target_count[channel] = target_count << 5;
 230
 231                err = i2c_smbus_write_word_swapped(client,
 232                                        MAX31790_REG_TARGET_COUNT(channel),
 233                                        data->target_count[channel]);
 234                break;
 235        default:
 236                err = -EOPNOTSUPP;
 237                break;
 238        }
 239
 240        mutex_unlock(&data->update_lock);
 241
 242        return err;
 243}
 244
 245static umode_t max31790_fan_is_visible(const void *_data, u32 attr, int channel)
 246{
 247        const struct max31790_data *data = _data;
 248        u8 fan_config = data->fan_config[channel % NR_CHANNEL];
 249
 250        switch (attr) {
 251        case hwmon_fan_input:
 252        case hwmon_fan_fault:
 253                if (channel < NR_CHANNEL ||
 254                    (fan_config & MAX31790_FAN_CFG_TACH_INPUT))
 255                        return S_IRUGO;
 256                return 0;
 257        case hwmon_fan_target:
 258                if (channel < NR_CHANNEL &&
 259                    !(fan_config & MAX31790_FAN_CFG_TACH_INPUT))
 260                        return S_IRUGO | S_IWUSR;
 261                return 0;
 262        default:
 263                return 0;
 264        }
 265}
 266
 267static int max31790_read_pwm(struct device *dev, u32 attr, int channel,
 268                             long *val)
 269{
 270        struct max31790_data *data = max31790_update_device(dev);
 271        u8 fan_config;
 272
 273        if (IS_ERR(data))
 274                return PTR_ERR(data);
 275
 276        fan_config = data->fan_config[channel];
 277
 278        switch (attr) {
 279        case hwmon_pwm_input:
 280                *val = data->pwm[channel] >> 8;
 281                return 0;
 282        case hwmon_pwm_enable:
 283                if (fan_config & MAX31790_FAN_CFG_RPM_MODE)
 284                        *val = 2;
 285                else if (fan_config & MAX31790_FAN_CFG_TACH_INPUT_EN)
 286                        *val = 1;
 287                else
 288                        *val = 0;
 289                return 0;
 290        default:
 291                return -EOPNOTSUPP;
 292        }
 293}
 294
 295static int max31790_write_pwm(struct device *dev, u32 attr, int channel,
 296                              long val)
 297{
 298        struct max31790_data *data = dev_get_drvdata(dev);
 299        struct i2c_client *client = data->client;
 300        u8 fan_config;
 301        int err = 0;
 302
 303        mutex_lock(&data->update_lock);
 304
 305        switch (attr) {
 306        case hwmon_pwm_input:
 307                if (val < 0 || val > 255) {
 308                        err = -EINVAL;
 309                        break;
 310                }
 311                data->pwm[channel] = val << 8;
 312                err = i2c_smbus_write_word_swapped(client,
 313                                                   MAX31790_REG_PWMOUT(channel),
 314                                                   val);
 315                break;
 316        case hwmon_pwm_enable:
 317                fan_config = data->fan_config[channel];
 318                if (val == 0) {
 319                        fan_config &= ~(MAX31790_FAN_CFG_TACH_INPUT_EN |
 320                                        MAX31790_FAN_CFG_RPM_MODE);
 321                } else if (val == 1) {
 322                        fan_config = (fan_config |
 323                                      MAX31790_FAN_CFG_TACH_INPUT_EN) &
 324                                     ~MAX31790_FAN_CFG_RPM_MODE;
 325                } else if (val == 2) {
 326                        fan_config |= MAX31790_FAN_CFG_TACH_INPUT_EN |
 327                                      MAX31790_FAN_CFG_RPM_MODE;
 328                } else {
 329                        err = -EINVAL;
 330                        break;
 331                }
 332                data->fan_config[channel] = fan_config;
 333                err = i2c_smbus_write_byte_data(client,
 334                                        MAX31790_REG_FAN_CONFIG(channel),
 335                                        fan_config);
 336                break;
 337        default:
 338                err = -EOPNOTSUPP;
 339                break;
 340        }
 341
 342        mutex_unlock(&data->update_lock);
 343
 344        return err;
 345}
 346
 347static umode_t max31790_pwm_is_visible(const void *_data, u32 attr, int channel)
 348{
 349        const struct max31790_data *data = _data;
 350        u8 fan_config = data->fan_config[channel];
 351
 352        switch (attr) {
 353        case hwmon_pwm_input:
 354        case hwmon_pwm_enable:
 355                if (!(fan_config & MAX31790_FAN_CFG_TACH_INPUT))
 356                        return S_IRUGO | S_IWUSR;
 357                return 0;
 358        default:
 359                return 0;
 360        }
 361}
 362
 363static int max31790_read(struct device *dev, enum hwmon_sensor_types type,
 364                         u32 attr, int channel, long *val)
 365{
 366        switch (type) {
 367        case hwmon_fan:
 368                return max31790_read_fan(dev, attr, channel, val);
 369        case hwmon_pwm:
 370                return max31790_read_pwm(dev, attr, channel, val);
 371        default:
 372                return -EOPNOTSUPP;
 373        }
 374}
 375
 376static int max31790_write(struct device *dev, enum hwmon_sensor_types type,
 377                          u32 attr, int channel, long val)
 378{
 379        switch (type) {
 380        case hwmon_fan:
 381                return max31790_write_fan(dev, attr, channel, val);
 382        case hwmon_pwm:
 383                return max31790_write_pwm(dev, attr, channel, val);
 384        default:
 385                return -EOPNOTSUPP;
 386        }
 387}
 388
 389static umode_t max31790_is_visible(const void *data,
 390                                   enum hwmon_sensor_types type,
 391                                   u32 attr, int channel)
 392{
 393        switch (type) {
 394        case hwmon_fan:
 395                return max31790_fan_is_visible(data, attr, channel);
 396        case hwmon_pwm:
 397                return max31790_pwm_is_visible(data, attr, channel);
 398        default:
 399                return 0;
 400        }
 401}
 402
 403static const u32 max31790_fan_config[] = {
 404        HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
 405        HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
 406        HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
 407        HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
 408        HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
 409        HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
 410        HWMON_F_INPUT | HWMON_F_FAULT,
 411        HWMON_F_INPUT | HWMON_F_FAULT,
 412        HWMON_F_INPUT | HWMON_F_FAULT,
 413        HWMON_F_INPUT | HWMON_F_FAULT,
 414        HWMON_F_INPUT | HWMON_F_FAULT,
 415        HWMON_F_INPUT | HWMON_F_FAULT,
 416        0
 417};
 418
 419static const struct hwmon_channel_info max31790_fan = {
 420        .type = hwmon_fan,
 421        .config = max31790_fan_config,
 422};
 423
 424static const u32 max31790_pwm_config[] = {
 425        HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
 426        HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
 427        HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
 428        HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
 429        HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
 430        HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
 431        0
 432};
 433
 434static const struct hwmon_channel_info max31790_pwm = {
 435        .type = hwmon_pwm,
 436        .config = max31790_pwm_config,
 437};
 438
 439static const struct hwmon_channel_info *max31790_info[] = {
 440        &max31790_fan,
 441        &max31790_pwm,
 442        NULL
 443};
 444
 445static const struct hwmon_ops max31790_hwmon_ops = {
 446        .is_visible = max31790_is_visible,
 447        .read = max31790_read,
 448        .write = max31790_write,
 449};
 450
 451static const struct hwmon_chip_info max31790_chip_info = {
 452        .ops = &max31790_hwmon_ops,
 453        .info = max31790_info,
 454};
 455
 456static int max31790_init_client(struct i2c_client *client,
 457                                struct max31790_data *data)
 458{
 459        int i, rv;
 460
 461        for (i = 0; i < NR_CHANNEL; i++) {
 462                rv = i2c_smbus_read_byte_data(client,
 463                                MAX31790_REG_FAN_CONFIG(i));
 464                if (rv < 0)
 465                        return rv;
 466                data->fan_config[i] = rv;
 467
 468                rv = i2c_smbus_read_byte_data(client,
 469                                MAX31790_REG_FAN_DYNAMICS(i));
 470                if (rv < 0)
 471                        return rv;
 472                data->fan_dynamics[i] = rv;
 473        }
 474
 475        return 0;
 476}
 477
 478static int max31790_probe(struct i2c_client *client,
 479                          const struct i2c_device_id *id)
 480{
 481        struct i2c_adapter *adapter = client->adapter;
 482        struct device *dev = &client->dev;
 483        struct max31790_data *data;
 484        struct device *hwmon_dev;
 485        int err;
 486
 487        if (!i2c_check_functionality(adapter,
 488                        I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 489                return -ENODEV;
 490
 491        data = devm_kzalloc(dev, sizeof(struct max31790_data), GFP_KERNEL);
 492        if (!data)
 493                return -ENOMEM;
 494
 495        data->client = client;
 496        mutex_init(&data->update_lock);
 497
 498        /*
 499         * Initialize the max31790 chip
 500         */
 501        err = max31790_init_client(client, data);
 502        if (err)
 503                return err;
 504
 505        hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 506                                                         data,
 507                                                         &max31790_chip_info,
 508                                                         NULL);
 509
 510        return PTR_ERR_OR_ZERO(hwmon_dev);
 511}
 512
 513static const struct i2c_device_id max31790_id[] = {
 514        { "max31790", 0 },
 515        { }
 516};
 517MODULE_DEVICE_TABLE(i2c, max31790_id);
 518
 519static struct i2c_driver max31790_driver = {
 520        .class          = I2C_CLASS_HWMON,
 521        .probe          = max31790_probe,
 522        .driver = {
 523                .name   = "max31790",
 524        },
 525        .id_table       = max31790_id,
 526};
 527
 528module_i2c_driver(max31790_driver);
 529
 530MODULE_AUTHOR("Il Han <corone.il.han@gmail.com>");
 531MODULE_DESCRIPTION("MAX31790 sensor driver");
 532MODULE_LICENSE("GPL");
 533