linux/drivers/hwmon/ltc2945.c
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   1/*
   2 * Driver for Linear Technology LTC2945 I2C Power Monitor
   3 *
   4 * Copyright (c) 2014 Guenter Roeck
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 */
  16
  17#include <linux/kernel.h>
  18#include <linux/module.h>
  19#include <linux/err.h>
  20#include <linux/slab.h>
  21#include <linux/i2c.h>
  22#include <linux/hwmon.h>
  23#include <linux/hwmon-sysfs.h>
  24#include <linux/jiffies.h>
  25#include <linux/regmap.h>
  26
  27/* chip registers */
  28#define LTC2945_CONTROL                 0x00
  29#define LTC2945_ALERT                   0x01
  30#define LTC2945_STATUS                  0x02
  31#define LTC2945_FAULT                   0x03
  32#define LTC2945_POWER_H                 0x05
  33#define LTC2945_MAX_POWER_H             0x08
  34#define LTC2945_MIN_POWER_H             0x0b
  35#define LTC2945_MAX_POWER_THRES_H       0x0e
  36#define LTC2945_MIN_POWER_THRES_H       0x11
  37#define LTC2945_SENSE_H                 0x14
  38#define LTC2945_MAX_SENSE_H             0x16
  39#define LTC2945_MIN_SENSE_H             0x18
  40#define LTC2945_MAX_SENSE_THRES_H       0x1a
  41#define LTC2945_MIN_SENSE_THRES_H       0x1c
  42#define LTC2945_VIN_H                   0x1e
  43#define LTC2945_MAX_VIN_H               0x20
  44#define LTC2945_MIN_VIN_H               0x22
  45#define LTC2945_MAX_VIN_THRES_H         0x24
  46#define LTC2945_MIN_VIN_THRES_H         0x26
  47#define LTC2945_ADIN_H                  0x28
  48#define LTC2945_MAX_ADIN_H              0x2a
  49#define LTC2945_MIN_ADIN_H              0x2c
  50#define LTC2945_MAX_ADIN_THRES_H        0x2e
  51#define LTC2945_MIN_ADIN_THRES_H        0x30
  52#define LTC2945_MIN_ADIN_THRES_L        0x31
  53
  54/* Fault register bits */
  55
  56#define FAULT_ADIN_UV           (1 << 0)
  57#define FAULT_ADIN_OV           (1 << 1)
  58#define FAULT_VIN_UV            (1 << 2)
  59#define FAULT_VIN_OV            (1 << 3)
  60#define FAULT_SENSE_UV          (1 << 4)
  61#define FAULT_SENSE_OV          (1 << 5)
  62#define FAULT_POWER_UV          (1 << 6)
  63#define FAULT_POWER_OV          (1 << 7)
  64
  65/* Control register bits */
  66
  67#define CONTROL_MULT_SELECT     (1 << 0)
  68#define CONTROL_TEST_MODE       (1 << 4)
  69
  70static inline bool is_power_reg(u8 reg)
  71{
  72        return reg < LTC2945_SENSE_H;
  73}
  74
  75/* Return the value from the given register in uW, mV, or mA */
  76static long long ltc2945_reg_to_val(struct device *dev, u8 reg)
  77{
  78        struct regmap *regmap = dev_get_drvdata(dev);
  79        unsigned int control;
  80        u8 buf[3];
  81        long long val;
  82        int ret;
  83
  84        ret = regmap_bulk_read(regmap, reg, buf,
  85                               is_power_reg(reg) ? 3 : 2);
  86        if (ret < 0)
  87                return ret;
  88
  89        if (is_power_reg(reg)) {
  90                /* power */
  91                val = (buf[0] << 16) + (buf[1] << 8) + buf[2];
  92        } else {
  93                /* current, voltage */
  94                val = (buf[0] << 4) + (buf[1] >> 4);
  95        }
  96
  97        switch (reg) {
  98        case LTC2945_POWER_H:
  99        case LTC2945_MAX_POWER_H:
 100        case LTC2945_MIN_POWER_H:
 101        case LTC2945_MAX_POWER_THRES_H:
 102        case LTC2945_MIN_POWER_THRES_H:
 103                /*
 104                 * Convert to uW by assuming current is measured with
 105                 * an 1mOhm sense resistor, similar to current
 106                 * measurements.
 107                 * Control register bit 0 selects if voltage at SENSE+/VDD
 108                 * or voltage at ADIN is used to measure power.
 109                 */
 110                ret = regmap_read(regmap, LTC2945_CONTROL, &control);
 111                if (ret < 0)
 112                        return ret;
 113                if (control & CONTROL_MULT_SELECT) {
 114                        /* 25 mV * 25 uV = 0.625 uV resolution. */
 115                        val *= 625LL;
 116                } else {
 117                        /* 0.5 mV * 25 uV = 0.0125 uV resolution. */
 118                        val = (val * 25LL) >> 1;
 119                }
 120                break;
 121        case LTC2945_VIN_H:
 122        case LTC2945_MAX_VIN_H:
 123        case LTC2945_MIN_VIN_H:
 124        case LTC2945_MAX_VIN_THRES_H:
 125        case LTC2945_MIN_VIN_THRES_H:
 126                /* 25 mV resolution. Convert to mV. */
 127                val *= 25;
 128                break;
 129        case LTC2945_ADIN_H:
 130        case LTC2945_MAX_ADIN_H:
 131        case LTC2945_MIN_ADIN_THRES_H:
 132        case LTC2945_MAX_ADIN_THRES_H:
 133        case LTC2945_MIN_ADIN_H:
 134                /* 0.5mV resolution. Convert to mV. */
 135                val = val >> 1;
 136                break;
 137        case LTC2945_SENSE_H:
 138        case LTC2945_MAX_SENSE_H:
 139        case LTC2945_MIN_SENSE_H:
 140        case LTC2945_MAX_SENSE_THRES_H:
 141        case LTC2945_MIN_SENSE_THRES_H:
 142                /*
 143                 * 25 uV resolution. Convert to current as measured with
 144                 * an 1 mOhm sense resistor, in mA. If a different sense
 145                 * resistor is installed, calculate the actual current by
 146                 * dividing the reported current by the sense resistor value
 147                 * in mOhm.
 148                 */
 149                val *= 25;
 150                break;
 151        default:
 152                return -EINVAL;
 153        }
 154        return val;
 155}
 156
 157static int ltc2945_val_to_reg(struct device *dev, u8 reg,
 158                              unsigned long val)
 159{
 160        struct regmap *regmap = dev_get_drvdata(dev);
 161        unsigned int control;
 162        int ret;
 163
 164        switch (reg) {
 165        case LTC2945_POWER_H:
 166        case LTC2945_MAX_POWER_H:
 167        case LTC2945_MIN_POWER_H:
 168        case LTC2945_MAX_POWER_THRES_H:
 169        case LTC2945_MIN_POWER_THRES_H:
 170                /*
 171                 * Convert to register value by assuming current is measured
 172                 * with an 1mOhm sense resistor, similar to current
 173                 * measurements.
 174                 * Control register bit 0 selects if voltage at SENSE+/VDD
 175                 * or voltage at ADIN is used to measure power, which in turn
 176                 * determines register calculations.
 177                 */
 178                ret = regmap_read(regmap, LTC2945_CONTROL, &control);
 179                if (ret < 0)
 180                        return ret;
 181                if (control & CONTROL_MULT_SELECT) {
 182                        /* 25 mV * 25 uV = 0.625 uV resolution. */
 183                        val = DIV_ROUND_CLOSEST(val, 625);
 184                } else {
 185                        /*
 186                         * 0.5 mV * 25 uV = 0.0125 uV resolution.
 187                         * Divide first to avoid overflow;
 188                         * accept loss of accuracy.
 189                         */
 190                        val = DIV_ROUND_CLOSEST(val, 25) * 2;
 191                }
 192                break;
 193        case LTC2945_VIN_H:
 194        case LTC2945_MAX_VIN_H:
 195        case LTC2945_MIN_VIN_H:
 196        case LTC2945_MAX_VIN_THRES_H:
 197        case LTC2945_MIN_VIN_THRES_H:
 198                /* 25 mV resolution. */
 199                val /= 25;
 200                break;
 201        case LTC2945_ADIN_H:
 202        case LTC2945_MAX_ADIN_H:
 203        case LTC2945_MIN_ADIN_THRES_H:
 204        case LTC2945_MAX_ADIN_THRES_H:
 205        case LTC2945_MIN_ADIN_H:
 206                /* 0.5mV resolution. */
 207                val *= 2;
 208                break;
 209        case LTC2945_SENSE_H:
 210        case LTC2945_MAX_SENSE_H:
 211        case LTC2945_MIN_SENSE_H:
 212        case LTC2945_MAX_SENSE_THRES_H:
 213        case LTC2945_MIN_SENSE_THRES_H:
 214                /*
 215                 * 25 uV resolution. Convert to current as measured with
 216                 * an 1 mOhm sense resistor, in mA. If a different sense
 217                 * resistor is installed, calculate the actual current by
 218                 * dividing the reported current by the sense resistor value
 219                 * in mOhm.
 220                 */
 221                val = DIV_ROUND_CLOSEST(val, 25);
 222                break;
 223        default:
 224                return -EINVAL;
 225        }
 226        return val;
 227}
 228
 229static ssize_t ltc2945_show_value(struct device *dev,
 230                                  struct device_attribute *da, char *buf)
 231{
 232        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 233        long long value;
 234
 235        value = ltc2945_reg_to_val(dev, attr->index);
 236        if (value < 0)
 237                return value;
 238        return snprintf(buf, PAGE_SIZE, "%lld\n", value);
 239}
 240
 241static ssize_t ltc2945_set_value(struct device *dev,
 242                                     struct device_attribute *da,
 243                                     const char *buf, size_t count)
 244{
 245        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 246        struct regmap *regmap = dev_get_drvdata(dev);
 247        u8 reg = attr->index;
 248        unsigned long val;
 249        u8 regbuf[3];
 250        int num_regs;
 251        int regval;
 252        int ret;
 253
 254        ret = kstrtoul(buf, 10, &val);
 255        if (ret)
 256                return ret;
 257
 258        /* convert to register value, then clamp and write result */
 259        regval = ltc2945_val_to_reg(dev, reg, val);
 260        if (is_power_reg(reg)) {
 261                regval = clamp_val(regval, 0, 0xffffff);
 262                regbuf[0] = regval >> 16;
 263                regbuf[1] = (regval >> 8) & 0xff;
 264                regbuf[2] = regval;
 265                num_regs = 3;
 266        } else {
 267                regval = clamp_val(regval, 0, 0xfff) << 4;
 268                regbuf[0] = regval >> 8;
 269                regbuf[1] = regval & 0xff;
 270                num_regs = 2;
 271        }
 272        ret = regmap_bulk_write(regmap, reg, regbuf, num_regs);
 273        return ret < 0 ? ret : count;
 274}
 275
 276static ssize_t ltc2945_reset_history(struct device *dev,
 277                                     struct device_attribute *da,
 278                                     const char *buf, size_t count)
 279{
 280        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 281        struct regmap *regmap = dev_get_drvdata(dev);
 282        u8 reg = attr->index;
 283        int num_regs = is_power_reg(reg) ? 3 : 2;
 284        u8 buf_min[3] = { 0xff, 0xff, 0xff };
 285        u8 buf_max[3] = { 0, 0, 0 };
 286        unsigned long val;
 287        int ret;
 288
 289        ret = kstrtoul(buf, 10, &val);
 290        if (ret)
 291                return ret;
 292        if (val != 1)
 293                return -EINVAL;
 294
 295        ret = regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE,
 296                                 CONTROL_TEST_MODE);
 297
 298        /* Reset minimum */
 299        ret = regmap_bulk_write(regmap, reg, buf_min, num_regs);
 300        if (ret)
 301                return ret;
 302
 303        switch (reg) {
 304        case LTC2945_MIN_POWER_H:
 305                reg = LTC2945_MAX_POWER_H;
 306                break;
 307        case LTC2945_MIN_SENSE_H:
 308                reg = LTC2945_MAX_SENSE_H;
 309                break;
 310        case LTC2945_MIN_VIN_H:
 311                reg = LTC2945_MAX_VIN_H;
 312                break;
 313        case LTC2945_MIN_ADIN_H:
 314                reg = LTC2945_MAX_ADIN_H;
 315                break;
 316        default:
 317                WARN_ONCE(1, "Bad register: 0x%x\n", reg);
 318                return -EINVAL;
 319        }
 320        /* Reset maximum */
 321        ret = regmap_bulk_write(regmap, reg, buf_max, num_regs);
 322
 323        /* Try resetting test mode even if there was an error */
 324        regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE, 0);
 325
 326        return ret ? : count;
 327}
 328
 329static ssize_t ltc2945_show_bool(struct device *dev,
 330                                 struct device_attribute *da, char *buf)
 331{
 332        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 333        struct regmap *regmap = dev_get_drvdata(dev);
 334        unsigned int fault;
 335        int ret;
 336
 337        ret = regmap_read(regmap, LTC2945_FAULT, &fault);
 338        if (ret < 0)
 339                return ret;
 340
 341        fault &= attr->index;
 342        if (fault)              /* Clear reported faults in chip register */
 343                regmap_update_bits(regmap, LTC2945_FAULT, attr->index, 0);
 344
 345        return snprintf(buf, PAGE_SIZE, "%d\n", !!fault);
 346}
 347
 348/* Input voltages */
 349
 350static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc2945_show_value, NULL,
 351                          LTC2945_VIN_H);
 352static SENSOR_DEVICE_ATTR(in1_min, S_IRUGO | S_IWUSR, ltc2945_show_value,
 353                          ltc2945_set_value, LTC2945_MIN_VIN_THRES_H);
 354static SENSOR_DEVICE_ATTR(in1_max, S_IRUGO | S_IWUSR, ltc2945_show_value,
 355                          ltc2945_set_value, LTC2945_MAX_VIN_THRES_H);
 356static SENSOR_DEVICE_ATTR(in1_lowest, S_IRUGO, ltc2945_show_value, NULL,
 357                          LTC2945_MIN_VIN_H);
 358static SENSOR_DEVICE_ATTR(in1_highest, S_IRUGO, ltc2945_show_value, NULL,
 359                          LTC2945_MAX_VIN_H);
 360static SENSOR_DEVICE_ATTR(in1_reset_history, S_IWUSR, NULL,
 361                          ltc2945_reset_history, LTC2945_MIN_VIN_H);
 362
 363static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc2945_show_value, NULL,
 364                          LTC2945_ADIN_H);
 365static SENSOR_DEVICE_ATTR(in2_min, S_IRUGO | S_IWUSR, ltc2945_show_value,
 366                          ltc2945_set_value, LTC2945_MIN_ADIN_THRES_H);
 367static SENSOR_DEVICE_ATTR(in2_max, S_IRUGO | S_IWUSR, ltc2945_show_value,
 368                          ltc2945_set_value, LTC2945_MAX_ADIN_THRES_H);
 369static SENSOR_DEVICE_ATTR(in2_lowest, S_IRUGO, ltc2945_show_value, NULL,
 370                          LTC2945_MIN_ADIN_H);
 371static SENSOR_DEVICE_ATTR(in2_highest, S_IRUGO, ltc2945_show_value, NULL,
 372                          LTC2945_MAX_ADIN_H);
 373static SENSOR_DEVICE_ATTR(in2_reset_history, S_IWUSR, NULL,
 374                          ltc2945_reset_history, LTC2945_MIN_ADIN_H);
 375
 376/* Voltage alarms */
 377
 378static SENSOR_DEVICE_ATTR(in1_min_alarm, S_IRUGO, ltc2945_show_bool, NULL,
 379                          FAULT_VIN_UV);
 380static SENSOR_DEVICE_ATTR(in1_max_alarm, S_IRUGO, ltc2945_show_bool, NULL,
 381                          FAULT_VIN_OV);
 382static SENSOR_DEVICE_ATTR(in2_min_alarm, S_IRUGO, ltc2945_show_bool, NULL,
 383                          FAULT_ADIN_UV);
 384static SENSOR_DEVICE_ATTR(in2_max_alarm, S_IRUGO, ltc2945_show_bool, NULL,
 385                          FAULT_ADIN_OV);
 386
 387/* Currents (via sense resistor) */
 388
 389static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc2945_show_value, NULL,
 390                          LTC2945_SENSE_H);
 391static SENSOR_DEVICE_ATTR(curr1_min, S_IRUGO | S_IWUSR, ltc2945_show_value,
 392                          ltc2945_set_value, LTC2945_MIN_SENSE_THRES_H);
 393static SENSOR_DEVICE_ATTR(curr1_max, S_IRUGO | S_IWUSR, ltc2945_show_value,
 394                          ltc2945_set_value, LTC2945_MAX_SENSE_THRES_H);
 395static SENSOR_DEVICE_ATTR(curr1_lowest, S_IRUGO, ltc2945_show_value, NULL,
 396                          LTC2945_MIN_SENSE_H);
 397static SENSOR_DEVICE_ATTR(curr1_highest, S_IRUGO, ltc2945_show_value, NULL,
 398                          LTC2945_MAX_SENSE_H);
 399static SENSOR_DEVICE_ATTR(curr1_reset_history, S_IWUSR, NULL,
 400                          ltc2945_reset_history, LTC2945_MIN_SENSE_H);
 401
 402/* Current alarms */
 403
 404static SENSOR_DEVICE_ATTR(curr1_min_alarm, S_IRUGO, ltc2945_show_bool, NULL,
 405                          FAULT_SENSE_UV);
 406static SENSOR_DEVICE_ATTR(curr1_max_alarm, S_IRUGO, ltc2945_show_bool, NULL,
 407                          FAULT_SENSE_OV);
 408
 409/* Power */
 410
 411static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ltc2945_show_value, NULL,
 412                          LTC2945_POWER_H);
 413static SENSOR_DEVICE_ATTR(power1_min, S_IRUGO | S_IWUSR, ltc2945_show_value,
 414                          ltc2945_set_value, LTC2945_MIN_POWER_THRES_H);
 415static SENSOR_DEVICE_ATTR(power1_max, S_IRUGO | S_IWUSR, ltc2945_show_value,
 416                          ltc2945_set_value, LTC2945_MAX_POWER_THRES_H);
 417static SENSOR_DEVICE_ATTR(power1_input_lowest, S_IRUGO, ltc2945_show_value,
 418                          NULL, LTC2945_MIN_POWER_H);
 419static SENSOR_DEVICE_ATTR(power1_input_highest, S_IRUGO, ltc2945_show_value,
 420                          NULL, LTC2945_MAX_POWER_H);
 421static SENSOR_DEVICE_ATTR(power1_reset_history, S_IWUSR, NULL,
 422                          ltc2945_reset_history, LTC2945_MIN_POWER_H);
 423
 424/* Power alarms */
 425
 426static SENSOR_DEVICE_ATTR(power1_min_alarm, S_IRUGO, ltc2945_show_bool, NULL,
 427                          FAULT_POWER_UV);
 428static SENSOR_DEVICE_ATTR(power1_max_alarm, S_IRUGO, ltc2945_show_bool, NULL,
 429                          FAULT_POWER_OV);
 430
 431static struct attribute *ltc2945_attrs[] = {
 432        &sensor_dev_attr_in1_input.dev_attr.attr,
 433        &sensor_dev_attr_in1_min.dev_attr.attr,
 434        &sensor_dev_attr_in1_max.dev_attr.attr,
 435        &sensor_dev_attr_in1_lowest.dev_attr.attr,
 436        &sensor_dev_attr_in1_highest.dev_attr.attr,
 437        &sensor_dev_attr_in1_reset_history.dev_attr.attr,
 438        &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
 439        &sensor_dev_attr_in1_max_alarm.dev_attr.attr,
 440
 441        &sensor_dev_attr_in2_input.dev_attr.attr,
 442        &sensor_dev_attr_in2_min.dev_attr.attr,
 443        &sensor_dev_attr_in2_max.dev_attr.attr,
 444        &sensor_dev_attr_in2_lowest.dev_attr.attr,
 445        &sensor_dev_attr_in2_highest.dev_attr.attr,
 446        &sensor_dev_attr_in2_reset_history.dev_attr.attr,
 447        &sensor_dev_attr_in2_min_alarm.dev_attr.attr,
 448        &sensor_dev_attr_in2_max_alarm.dev_attr.attr,
 449
 450        &sensor_dev_attr_curr1_input.dev_attr.attr,
 451        &sensor_dev_attr_curr1_min.dev_attr.attr,
 452        &sensor_dev_attr_curr1_max.dev_attr.attr,
 453        &sensor_dev_attr_curr1_lowest.dev_attr.attr,
 454        &sensor_dev_attr_curr1_highest.dev_attr.attr,
 455        &sensor_dev_attr_curr1_reset_history.dev_attr.attr,
 456        &sensor_dev_attr_curr1_min_alarm.dev_attr.attr,
 457        &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
 458
 459        &sensor_dev_attr_power1_input.dev_attr.attr,
 460        &sensor_dev_attr_power1_min.dev_attr.attr,
 461        &sensor_dev_attr_power1_max.dev_attr.attr,
 462        &sensor_dev_attr_power1_input_lowest.dev_attr.attr,
 463        &sensor_dev_attr_power1_input_highest.dev_attr.attr,
 464        &sensor_dev_attr_power1_reset_history.dev_attr.attr,
 465        &sensor_dev_attr_power1_min_alarm.dev_attr.attr,
 466        &sensor_dev_attr_power1_max_alarm.dev_attr.attr,
 467
 468        NULL,
 469};
 470ATTRIBUTE_GROUPS(ltc2945);
 471
 472static const struct regmap_config ltc2945_regmap_config = {
 473        .reg_bits = 8,
 474        .val_bits = 8,
 475        .max_register = LTC2945_MIN_ADIN_THRES_L,
 476};
 477
 478static int ltc2945_probe(struct i2c_client *client,
 479                         const struct i2c_device_id *id)
 480{
 481        struct device *dev = &client->dev;
 482        struct device *hwmon_dev;
 483        struct regmap *regmap;
 484
 485        regmap = devm_regmap_init_i2c(client, &ltc2945_regmap_config);
 486        if (IS_ERR(regmap)) {
 487                dev_err(dev, "failed to allocate register map\n");
 488                return PTR_ERR(regmap);
 489        }
 490
 491        /* Clear faults */
 492        regmap_write(regmap, LTC2945_FAULT, 0x00);
 493
 494        hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 495                                                           regmap,
 496                                                           ltc2945_groups);
 497        return PTR_ERR_OR_ZERO(hwmon_dev);
 498}
 499
 500static const struct i2c_device_id ltc2945_id[] = {
 501        {"ltc2945", 0},
 502        { }
 503};
 504
 505MODULE_DEVICE_TABLE(i2c, ltc2945_id);
 506
 507static struct i2c_driver ltc2945_driver = {
 508        .driver = {
 509                   .name = "ltc2945",
 510                   },
 511        .probe = ltc2945_probe,
 512        .id_table = ltc2945_id,
 513};
 514
 515module_i2c_driver(ltc2945_driver);
 516
 517MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
 518MODULE_DESCRIPTION("LTC2945 driver");
 519MODULE_LICENSE("GPL");
 520
Hosted by Missing Link Electronics. The original LXR software by the LXR community, this experimental version by lxr@linux.no.