drivers/hwmon/ina2xx.c

   1 /*
   2  * Driver for Texas Instruments INA219, INA226 power monitor chips
   3  *
   4  * INA219:
   5  * Zero Drift Bi-Directional Current/Power Monitor with I2C Interface
   6  * Datasheet: http://www.ti.com/product/ina219
   7  *
   8  * INA220:
   9  * Bi-Directional Current/Power Monitor with I2C Interface
  10  * Datasheet: http://www.ti.com/product/ina220
  11  *
  12  * INA226:
  13  * Bi-Directional Current/Power Monitor with I2C Interface
  14  * Datasheet: http://www.ti.com/product/ina226
  15  *
  16  * INA230:
  17  * Bi-directional Current/Power Monitor with I2C Interface
  18  * Datasheet: http://www.ti.com/product/ina230
  19  *
  20  * Copyright (C) 2012 Lothar Felten <l-felten@ti.com>
  21  * Thanks to Jan Volkering
  22  *
  23  * This program is free software; you can redistribute it and/or modify
  24  * it under the terms of the GNU General Public License as published by
  25  * the Free Software Foundation; version 2 of the License.
  26  */
  27
  28 #include <linux/kernel.h>
  29 #include <linux/module.h>
  30 #include <linux/init.h>
  31 #include <linux/err.h>
  32 #include <linux/slab.h>
  33 #include <linux/i2c.h>
  34 #include <linux/hwmon.h>
  35 #include <linux/hwmon-sysfs.h>
  36 #include <linux/jiffies.h>
  37 #include <linux/of.h>
  38 #include <linux/delay.h>
  39
  40 #include <linux/platform_data/ina2xx.h>
  41
  42 /* common register definitions */
  43 #define INA2XX_CONFIG                   0x00
  44 #define INA2XX_SHUNT_VOLTAGE            0x01 /* readonly */
  45 #define INA2XX_BUS_VOLTAGE              0x02 /* readonly */
  46 #define INA2XX_POWER                    0x03 /* readonly */
  47 #define INA2XX_CURRENT                  0x04 /* readonly */
  48 #define INA2XX_CALIBRATION              0x05
  49
  50 /* INA226 register definitions */
  51 #define INA226_MASK_ENABLE              0x06
  52 #define INA226_ALERT_LIMIT              0x07
  53 #define INA226_DIE_ID                   0xFF
  54
  55 /* register count */
  56 #define INA219_REGISTERS                6
  57 #define INA226_REGISTERS                8
  58
  59 #define INA2XX_MAX_REGISTERS            8
  60
  61 /* settings - depend on use case */
  62 #define INA219_CONFIG_DEFAULT           0x399F  /* PGA=8 */
  63 #define INA226_CONFIG_DEFAULT           0x4527  /* averages=16 */
  64
  65 /* worst case is 68.10 ms (~14.6Hz, ina219) */
  66 #define INA2XX_CONVERSION_RATE          15
  67 #define INA2XX_MAX_DELAY                69 /* worst case delay in ms */
  68
  69 #define INA2XX_RSHUNT_DEFAULT           10000
  70
  71 /* bit mask for reading the averaging setting in the configuration register */
  72 #define INA226_AVG_RD_MASK              0x0E00
  73
  74 #define INA226_READ_AVG(reg)            (((reg) & INA226_AVG_RD_MASK) >> 9)
  75 #define INA226_SHIFT_AVG(val)           ((val) << 9)
  76
  77 /* common attrs, ina226 attrs and NULL */
  78 #define INA2XX_MAX_ATTRIBUTE_GROUPS     3
  79
  80 /*
  81  * Both bus voltage and shunt voltage conversion times for ina226 are set
  82  * to 0b0100 on POR, which translates to 2200 microseconds in total.
  83  */
  84 #define INA226_TOTAL_CONV_TIME_DEFAULT  2200
  85
  86 enum ina2xx_ids { ina219, ina226 };
  87
  88 struct ina2xx_config {
  89         u16 config_default;
  90         int calibration_factor;
  91         int registers;
  92         int shunt_div;
  93         int bus_voltage_shift;
  94         int bus_voltage_lsb;    /* uV */
  95         int power_lsb;          /* uW */
  96 };
  97
  98 struct ina2xx_data {
  99         struct i2c_client *client;
 100         const struct ina2xx_config *config;
 101
 102         long rshunt;
 103         u16 curr_config;
 104
 105         struct mutex update_lock;
 106         bool valid;
 107         unsigned long last_updated;
 108         int update_interval; /* in jiffies */
 109
 110         int kind;
 111         const struct attribute_group *groups[INA2XX_MAX_ATTRIBUTE_GROUPS];
 112         u16 regs[INA2XX_MAX_REGISTERS];
 113 };
 114
 115 static const struct ina2xx_config ina2xx_config[] = {
 116         [ina219] = {
 117                 .config_default = INA219_CONFIG_DEFAULT,
 118                 .calibration_factor = 40960000,
 119                 .registers = INA219_REGISTERS,
 120                 .shunt_div = 100,
 121                 .bus_voltage_shift = 3,
 122                 .bus_voltage_lsb = 4000,
 123                 .power_lsb = 20000,
 124         },
 125         [ina226] = {
 126                 .config_default = INA226_CONFIG_DEFAULT,
 127                 .calibration_factor = 5120000,
 128                 .registers = INA226_REGISTERS,
 129                 .shunt_div = 400,
 130                 .bus_voltage_shift = 0,
 131                 .bus_voltage_lsb = 1250,
 132                 .power_lsb = 25000,
 133         },
 134 };
 135
 136 /*
 137  * Available averaging rates for ina226. The indices correspond with
 138  * the bit values expected by the chip (according to the ina226 datasheet,
 139  * table 3 AVG bit settings, found at
 140  * http://www.ti.com/lit/ds/symlink/ina226.pdf.
 141  */
 142 static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };
 143
 144 static int ina226_avg_bits(int avg)
 145 {
 146         int i;
 147
 148         /* Get the closest average from the tab. */
 149         for (i = 0; i < ARRAY_SIZE(ina226_avg_tab) - 1; i++) {
 150                 if (avg <= (ina226_avg_tab[i] + ina226_avg_tab[i + 1]) / 2)
 151                         break;
 152         }
 153
 154         return i; /* Return 0b0111 for values greater than 1024. */
 155 }
 156
 157 static int ina226_reg_to_interval(u16 config)
 158 {
 159         int avg = ina226_avg_tab[INA226_READ_AVG(config)];
 160
 161         /*
 162          * Multiply the total conversion time by the number of averages.
 163          * Return the result in milliseconds.
 164          */
 165         return DIV_ROUND_CLOSEST(avg * INA226_TOTAL_CONV_TIME_DEFAULT, 1000);
 166 }
 167
 168 static u16 ina226_interval_to_reg(int interval, u16 config)
 169 {
 170         int avg, avg_bits;
 171
 172         avg = DIV_ROUND_CLOSEST(interval * 1000,
 173                                 INA226_TOTAL_CONV_TIME_DEFAULT);
 174         avg_bits = ina226_avg_bits(avg);
 175
 176         return (config & ~INA226_AVG_RD_MASK) | INA226_SHIFT_AVG(avg_bits);
 177 }
 178
 179 static void ina226_set_update_interval(struct ina2xx_data *data)
 180 {
 181         int ms;
 182
 183         ms = ina226_reg_to_interval(data->curr_config);
 184         data->update_interval = msecs_to_jiffies(ms);
 185 }
 186
 187 static int ina2xx_calibrate(struct ina2xx_data *data)
 188 {
 189         u16 val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
 190                                     data->rshunt);
 191
 192         return i2c_smbus_write_word_swapped(data->client,
 193                                             INA2XX_CALIBRATION, val);
 194 }
 195
 196 /*
 197  * Initialize the configuration and calibration registers.
 198  */
 199 static int ina2xx_init(struct ina2xx_data *data)
 200 {
 201         struct i2c_client *client = data->client;
 202         int ret;
 203
 204         /* device configuration */
 205         ret = i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
 206                                            data->curr_config);
 207         if (ret < 0)
 208                 return ret;
 209
 210         /*
 211          * Set current LSB to 1mA, shunt is in uOhms
 212          * (equation 13 in datasheet).
 213          */
 214         return ina2xx_calibrate(data);
 215 }
 216
 217 static int ina2xx_do_update(struct device *dev)
 218 {
 219         struct ina2xx_data *data = dev_get_drvdata(dev);
 220         struct i2c_client *client = data->client;
 221         int i, rv, retry;
 222
 223         dev_dbg(&client->dev, "Starting ina2xx update\n");
 224
 225         for (retry = 5; retry; retry--) {
 226                 /* Read all registers */
 227                 for (i = 0; i < data->config->registers; i++) {
 228                         rv = i2c_smbus_read_word_swapped(client, i);
 229                         if (rv < 0)
 230                                 return rv;
 231                         data->regs[i] = rv;
 232                 }
 233
 234                 /*
 235                  * If the current value in the calibration register is 0, the
 236                  * power and current registers will also remain at 0. In case
 237                  * the chip has been reset let's check the calibration
 238                  * register and reinitialize if needed.
 239                  */
 240                 if (data->regs[INA2XX_CALIBRATION] == 0) {
 241                         dev_warn(dev, "chip not calibrated, reinitializing\n");
 242
 243                         rv = ina2xx_init(data);
 244                         if (rv < 0)
 245                                 return rv;
 246
 247                         /*
 248                          * Let's make sure the power and current registers
 249                          * have been updated before trying again.
 250                          */
 251                         msleep(INA2XX_MAX_DELAY);
 252                         continue;
 253                 }
 254
 255                 data->last_updated = jiffies;
 256                 data->valid = 1;
 257
 258                 return 0;
 259         }
 260
 261         /*
 262          * If we're here then although all write operations succeeded, the
 263          * chip still returns 0 in the calibration register. Nothing more we
 264          * can do here.
 265          */
 266         dev_err(dev, "unable to reinitialize the chip\n");
 267         return -ENODEV;
 268 }
 269
 270 static struct ina2xx_data *ina2xx_update_device(struct device *dev)
 271 {
 272         struct ina2xx_data *data = dev_get_drvdata(dev);
 273         struct ina2xx_data *ret = data;
 274         unsigned long after;
 275         int rv;
 276
 277         mutex_lock(&data->update_lock);
 278
 279         after = data->last_updated + data->update_interval;
 280         if (time_after(jiffies, after) || !data->valid) {
 281                 rv = ina2xx_do_update(dev);
 282                 if (rv < 0)
 283                         ret = ERR_PTR(rv);
 284         }
 285
 286         mutex_unlock(&data->update_lock);
 287         return ret;
 288 }
 289
 290 static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
 291 {
 292         int val;
 293
 294         switch (reg) {
 295         case INA2XX_SHUNT_VOLTAGE:
 296                 /* signed register */
 297                 val = DIV_ROUND_CLOSEST((s16)data->regs[reg],
 298                                         data->config->shunt_div);
 299                 break;
 300         case INA2XX_BUS_VOLTAGE:
 301                 val = (data->regs[reg] >> data->config->bus_voltage_shift)
 302                   * data->config->bus_voltage_lsb;
 303                 val = DIV_ROUND_CLOSEST(val, 1000);
 304                 break;
 305         case INA2XX_POWER:
 306                 val = data->regs[reg] * data->config->power_lsb;
 307                 break;
 308         case INA2XX_CURRENT:
 309                 /* signed register, LSB=1mA (selected), in mA */
 310                 val = (s16)data->regs[reg];
 311                 break;
 312         case INA2XX_CALIBRATION:
 313                 val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
 314                                         data->regs[reg]);
 315                 break;
 316         default:
 317                 /* programmer goofed */
 318                 WARN_ON_ONCE(1);
 319                 val = 0;
 320                 break;
 321         }
 322
 323         return val;
 324 }
 325
 326 static ssize_t ina2xx_show_value(struct device *dev,
 327                                  struct device_attribute *da, char *buf)
 328 {
 329         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 330         struct ina2xx_data *data = ina2xx_update_device(dev);
 331
 332         if (IS_ERR(data))
 333                 return PTR_ERR(data);
 334
 335         return snprintf(buf, PAGE_SIZE, "%d\n",
 336                         ina2xx_get_value(data, attr->index));
 337 }
 338
 339 static ssize_t ina2xx_set_shunt(struct device *dev,
 340                                 struct device_attribute *da,
 341                                 const char *buf, size_t count)
 342 {
 343         struct ina2xx_data *data = ina2xx_update_device(dev);
 344         unsigned long val;
 345         int status;
 346
 347         if (IS_ERR(data))
 348                 return PTR_ERR(data);
 349
 350         status = kstrtoul(buf, 10, &val);
 351         if (status < 0)
 352                 return status;
 353
 354         if (val == 0 ||
 355             /* Values greater than the calibration factor make no sense. */
 356             val > data->config->calibration_factor)
 357                 return -EINVAL;
 358
 359         mutex_lock(&data->update_lock);
 360         data->rshunt = val;
 361         status = ina2xx_calibrate(data);
 362         mutex_unlock(&data->update_lock);
 363         if (status < 0)
 364                 return status;
 365
 366         return count;
 367 }
 368
 369 static ssize_t ina226_set_interval(struct device *dev,
 370                                    struct device_attribute *da,
 371                                    const char *buf, size_t count)
 372 {
 373         struct ina2xx_data *data = dev_get_drvdata(dev);
 374         unsigned long val;
 375         int status;
 376
 377         status = kstrtoul(buf, 10, &val);
 378         if (status < 0)
 379                 return status;
 380
 381         if (val > INT_MAX || val == 0)
 382                 return -EINVAL;
 383
 384         mutex_lock(&data->update_lock);
 385         data->curr_config = ina226_interval_to_reg(val,
 386                                                    data->regs[INA2XX_CONFIG]);
 387         status = i2c_smbus_write_word_swapped(data->client,
 388                                               INA2XX_CONFIG,
 389                                               data->curr_config);
 390
 391         ina226_set_update_interval(data);
 392         /* Make sure the next access re-reads all registers. */
 393         data->valid = 0;
 394         mutex_unlock(&data->update_lock);
 395         if (status < 0)
 396                 return status;
 397
 398         return count;
 399 }
 400
 401 static ssize_t ina226_show_interval(struct device *dev,
 402                                     struct device_attribute *da, char *buf)
 403 {
 404         struct ina2xx_data *data = ina2xx_update_device(dev);
 405
 406         if (IS_ERR(data))
 407                 return PTR_ERR(data);
 408
 409         /*
 410          * We don't use data->update_interval here as we want to display
 411          * the actual interval used by the chip and jiffies_to_msecs()
 412          * doesn't seem to be accurate enough.
 413          */
 414         return snprintf(buf, PAGE_SIZE, "%d\n",
 415                         ina226_reg_to_interval(data->regs[INA2XX_CONFIG]));
 416 }
 417
 418 /* shunt voltage */
 419 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
 420                           INA2XX_SHUNT_VOLTAGE);
 421
 422 /* bus voltage */
 423 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
 424                           INA2XX_BUS_VOLTAGE);
 425
 426 /* calculated current */
 427 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
 428                           INA2XX_CURRENT);
 429
 430 /* calculated power */
 431 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
 432                           INA2XX_POWER);
 433
 434 /* shunt resistance */
 435 static SENSOR_DEVICE_ATTR(shunt_resistor, S_IRUGO | S_IWUSR,
 436                           ina2xx_show_value, ina2xx_set_shunt,
 437                           INA2XX_CALIBRATION);
 438
 439 /* update interval (ina226 only) */
 440 static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
 441                           ina226_show_interval, ina226_set_interval, 0);
 442
 443 /* pointers to created device attributes */
 444 static struct attribute *ina2xx_attrs[] = {
 445         &sensor_dev_attr_in0_input.dev_attr.attr,
 446         &sensor_dev_attr_in1_input.dev_attr.attr,
 447         &sensor_dev_attr_curr1_input.dev_attr.attr,
 448         &sensor_dev_attr_power1_input.dev_attr.attr,
 449         &sensor_dev_attr_shunt_resistor.dev_attr.attr,
 450         NULL,
 451 };
 452
 453 static const struct attribute_group ina2xx_group = {
 454         .attrs = ina2xx_attrs,
 455 };
 456
 457 static struct attribute *ina226_attrs[] = {
 458         &sensor_dev_attr_update_interval.dev_attr.attr,
 459         NULL,
 460 };
 461
 462 static const struct attribute_group ina226_group = {
 463         .attrs = ina226_attrs,
 464 };
 465
 466 static int ina2xx_probe(struct i2c_client *client,
 467                         const struct i2c_device_id *id)
 468 {
 469         struct i2c_adapter *adapter = client->adapter;
 470         struct ina2xx_platform_data *pdata;
 471         struct device *dev = &client->dev;
 472         struct ina2xx_data *data;
 473         struct device *hwmon_dev;
 474         u32 val;
 475         int ret, group = 0;
 476
 477         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 478                 return -ENODEV;
 479
 480         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 481         if (!data)
 482                 return -ENOMEM;
 483
 484         if (dev_get_platdata(dev)) {
 485                 pdata = dev_get_platdata(dev);
 486                 data->rshunt = pdata->shunt_uohms;
 487         } else if (!of_property_read_u32(dev->of_node,
 488                                          "shunt-resistor", &val)) {
 489                 data->rshunt = val;
 490         } else {
 491                 data->rshunt = INA2XX_RSHUNT_DEFAULT;
 492         }
 493
 494         /* set the device type */
 495         data->kind = id->driver_data;
 496         data->config = &ina2xx_config[data->kind];
 497         data->curr_config = data->config->config_default;
 498         data->client = client;
 499
 500         /*
 501          * Ina226 has a variable update_interval. For ina219 we
 502          * use a constant value.
 503          */
 504         if (data->kind == ina226)
 505                 ina226_set_update_interval(data);
 506         else
 507                 data->update_interval = HZ / INA2XX_CONVERSION_RATE;
 508
 509         if (data->rshunt <= 0 ||
 510             data->rshunt > data->config->calibration_factor)
 511                 return -ENODEV;
 512
 513         ret = ina2xx_init(data);
 514         if (ret < 0) {
 515                 dev_err(dev, "error configuring the device: %d\n", ret);
 516                 return -ENODEV;
 517         }
 518
 519         mutex_init(&data->update_lock);
 520
 521         data->groups[group++] = &ina2xx_group;
 522         if (data->kind == ina226)
 523                 data->groups[group++] = &ina226_group;
 524
 525         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 526                                                            data, data->groups);
 527         if (IS_ERR(hwmon_dev))
 528                 return PTR_ERR(hwmon_dev);
 529
 530         dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
 531                  id->name, data->rshunt);
 532
 533         return 0;
 534 }
 535
 536 static const struct i2c_device_id ina2xx_id[] = {
 537         { "ina219", ina219 },
 538         { "ina220", ina219 },
 539         { "ina226", ina226 },
 540         { "ina230", ina226 },
 541         { "ina231", ina226 },
 542         { }
 543 };
 544 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
 545
 546 static struct i2c_driver ina2xx_driver = {
 547         .driver = {
 548                 .name   = "ina2xx",
 549         },
 550         .probe          = ina2xx_probe,
 551         .id_table       = ina2xx_id,
 552 };
 553
 554 module_i2c_driver(ina2xx_driver);
 555
 556 MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
 557 MODULE_DESCRIPTION("ina2xx driver");
 558 MODULE_LICENSE("GPL");