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