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 <lothar.felten@gmail.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_device.h>
  38 #include <linux/of.h>
  39 #include <linux/delay.h>
  40 #include <linux/util_macros.h>
  41 #include <linux/regmap.h>
  42
  43 #include <linux/platform_data/ina2xx.h>
  44
  45 /* common register definitions */
  46 #define INA2XX_CONFIG                   0x00
  47 #define INA2XX_SHUNT_VOLTAGE            0x01 /* readonly */
  48 #define INA2XX_BUS_VOLTAGE              0x02 /* readonly */
  49 #define INA2XX_POWER                    0x03 /* readonly */
  50 #define INA2XX_CURRENT                  0x04 /* readonly */
  51 #define INA2XX_CALIBRATION              0x05
  52
  53 /* INA226 register definitions */
  54 #define INA226_MASK_ENABLE              0x06
  55 #define INA226_ALERT_LIMIT              0x07
  56 #define INA226_DIE_ID                   0xFF
  57
  58 /* register count */
  59 #define INA219_REGISTERS                6
  60 #define INA226_REGISTERS                8
  61
  62 #define INA2XX_MAX_REGISTERS            8
  63
  64 /* settings - depend on use case */
  65 #define INA219_CONFIG_DEFAULT           0x399F  /* PGA=8 */
  66 #define INA226_CONFIG_DEFAULT           0x4527  /* averages=16 */
  67
  68 /* worst case is 68.10 ms (~14.6Hz, ina219) */
  69 #define INA2XX_CONVERSION_RATE          15
  70 #define INA2XX_MAX_DELAY                69 /* worst case delay in ms */
  71
  72 #define INA2XX_RSHUNT_DEFAULT           10000
  73
  74 /* bit mask for reading the averaging setting in the configuration register */
  75 #define INA226_AVG_RD_MASK              0x0E00
  76
  77 #define INA226_READ_AVG(reg)            (((reg) & INA226_AVG_RD_MASK) >> 9)
  78 #define INA226_SHIFT_AVG(val)           ((val) << 9)
  79
  80 /* common attrs, ina226 attrs and NULL */
  81 #define INA2XX_MAX_ATTRIBUTE_GROUPS     3
  82
  83 /*
  84  * Both bus voltage and shunt voltage conversion times for ina226 are set
  85  * to 0b0100 on POR, which translates to 2200 microseconds in total.
  86  */
  87 #define INA226_TOTAL_CONV_TIME_DEFAULT  2200
  88
  89 static struct regmap_config ina2xx_regmap_config = {
  90         .reg_bits = 8,
  91         .val_bits = 16,
  92 };
  93
  94 enum ina2xx_ids { ina219, ina226 };
  95
  96 struct ina2xx_config {
  97         u16 config_default;
  98         int calibration_value;
  99         int registers;
 100         int shunt_div;
 101         int bus_voltage_shift;
 102         int bus_voltage_lsb;    /* uV */
 103         int power_lsb_factor;
 104 };
 105
 106 struct ina2xx_data {
 107         const struct ina2xx_config *config;
 108
 109         long rshunt;
 110         long current_lsb_uA;
 111         long power_lsb_uW;
 112         struct mutex config_lock;
 113         struct regmap *regmap;
 114
 115         const struct attribute_group *groups[INA2XX_MAX_ATTRIBUTE_GROUPS];
 116 };
 117
 118 static const struct ina2xx_config ina2xx_config[] = {
 119         [ina219] = {
 120                 .config_default = INA219_CONFIG_DEFAULT,
 121                 .calibration_value = 4096,
 122                 .registers = INA219_REGISTERS,
 123                 .shunt_div = 100,
 124                 .bus_voltage_shift = 3,
 125                 .bus_voltage_lsb = 4000,
 126                 .power_lsb_factor = 20,
 127         },
 128         [ina226] = {
 129                 .config_default = INA226_CONFIG_DEFAULT,
 130                 .calibration_value = 2048,
 131                 .registers = INA226_REGISTERS,
 132                 .shunt_div = 400,
 133                 .bus_voltage_shift = 0,
 134                 .bus_voltage_lsb = 1250,
 135                 .power_lsb_factor = 25,
 136         },
 137 };
 138
 139 /*
 140  * Available averaging rates for ina226. The indices correspond with
 141  * the bit values expected by the chip (according to the ina226 datasheet,
 142  * table 3 AVG bit settings, found at
 143  * http://www.ti.com/lit/ds/symlink/ina226.pdf.
 144  */
 145 static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };
 146
 147 static int ina226_reg_to_interval(u16 config)
 148 {
 149         int avg = ina226_avg_tab[INA226_READ_AVG(config)];
 150
 151         /*
 152          * Multiply the total conversion time by the number of averages.
 153          * Return the result in milliseconds.
 154          */
 155         return DIV_ROUND_CLOSEST(avg * INA226_TOTAL_CONV_TIME_DEFAULT, 1000);
 156 }
 157
 158 /*
 159  * Return the new, shifted AVG field value of CONFIG register,
 160  * to use with regmap_update_bits
 161  */
 162 static u16 ina226_interval_to_reg(int interval)
 163 {
 164         int avg, avg_bits;
 165
 166         avg = DIV_ROUND_CLOSEST(interval * 1000,
 167                                 INA226_TOTAL_CONV_TIME_DEFAULT);
 168         avg_bits = find_closest(avg, ina226_avg_tab,
 169                                 ARRAY_SIZE(ina226_avg_tab));
 170
 171         return INA226_SHIFT_AVG(avg_bits);
 172 }
 173
 174 /*
 175  * Calibration register is set to the best value, which eliminates
 176  * truncation errors on calculating current register in hardware.
 177  * According to datasheet (eq. 3) the best values are 2048 for
 178  * ina226 and 4096 for ina219. They are hardcoded as calibration_value.
 179  */
 180 static int ina2xx_calibrate(struct ina2xx_data *data)
 181 {
 182         return regmap_write(data->regmap, INA2XX_CALIBRATION,
 183                             data->config->calibration_value);
 184 }
 185
 186 /*
 187  * Initialize the configuration and calibration registers.
 188  */
 189 static int ina2xx_init(struct ina2xx_data *data)
 190 {
 191         int ret = regmap_write(data->regmap, INA2XX_CONFIG,
 192                                data->config->config_default);
 193         if (ret < 0)
 194                 return ret;
 195
 196         return ina2xx_calibrate(data);
 197 }
 198
 199 static int ina2xx_read_reg(struct device *dev, int reg, unsigned int *regval)
 200 {
 201         struct ina2xx_data *data = dev_get_drvdata(dev);
 202         int ret, retry;
 203
 204         dev_dbg(dev, "Starting register %d read\n", reg);
 205
 206         for (retry = 5; retry; retry--) {
 207
 208                 ret = regmap_read(data->regmap, reg, regval);
 209                 if (ret < 0)
 210                         return ret;
 211
 212                 dev_dbg(dev, "read %d, val = 0x%04x\n", reg, *regval);
 213
 214                 /*
 215                  * If the current value in the calibration register is 0, the
 216                  * power and current registers will also remain at 0. In case
 217                  * the chip has been reset let's check the calibration
 218                  * register and reinitialize if needed.
 219                  * We do that extra read of the calibration register if there
 220                  * is some hint of a chip reset.
 221                  */
 222                 if (*regval == 0) {
 223                         unsigned int cal;
 224
 225                         ret = regmap_read(data->regmap, INA2XX_CALIBRATION,
 226                                           &cal);
 227                         if (ret < 0)
 228                                 return ret;
 229
 230                         if (cal == 0) {
 231                                 dev_warn(dev, "chip not calibrated, reinitializing\n");
 232
 233                                 ret = ina2xx_init(data);
 234                                 if (ret < 0)
 235                                         return ret;
 236                                 /*
 237                                  * Let's make sure the power and current
 238                                  * registers have been updated before trying
 239                                  * again.
 240                                  */
 241                                 msleep(INA2XX_MAX_DELAY);
 242                                 continue;
 243                         }
 244                 }
 245                 return 0;
 246         }
 247
 248         /*
 249          * If we're here then although all write operations succeeded, the
 250          * chip still returns 0 in the calibration register. Nothing more we
 251          * can do here.
 252          */
 253         dev_err(dev, "unable to reinitialize the chip\n");
 254         return -ENODEV;
 255 }
 256
 257 static int ina2xx_get_value(struct ina2xx_data *data, u8 reg,
 258                             unsigned int regval)
 259 {
 260         int val;
 261
 262         switch (reg) {
 263         case INA2XX_SHUNT_VOLTAGE:
 264                 /* signed register */
 265                 val = DIV_ROUND_CLOSEST((s16)regval, data->config->shunt_div);
 266                 break;
 267         case INA2XX_BUS_VOLTAGE:
 268                 val = (regval >> data->config->bus_voltage_shift)
 269                   * data->config->bus_voltage_lsb;
 270                 val = DIV_ROUND_CLOSEST(val, 1000);
 271                 break;
 272         case INA2XX_POWER:
 273                 val = regval * data->power_lsb_uW;
 274                 break;
 275         case INA2XX_CURRENT:
 276                 /* signed register, result in mA */
 277                 val = (s16)regval * data->current_lsb_uA;
 278                 val = DIV_ROUND_CLOSEST(val, 1000);
 279                 break;
 280         case INA2XX_CALIBRATION:
 281                 val = regval;
 282                 break;
 283         default:
 284                 /* programmer goofed */
 285                 WARN_ON_ONCE(1);
 286                 val = 0;
 287                 break;
 288         }
 289
 290         return val;
 291 }
 292
 293 static ssize_t ina2xx_show_value(struct device *dev,
 294                                  struct device_attribute *da, char *buf)
 295 {
 296         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 297         struct ina2xx_data *data = dev_get_drvdata(dev);
 298         unsigned int regval;
 299
 300         int err = ina2xx_read_reg(dev, attr->index, &regval);
 301
 302         if (err < 0)
 303                 return err;
 304
 305         return snprintf(buf, PAGE_SIZE, "%d\n",
 306                         ina2xx_get_value(data, attr->index, regval));
 307 }
 308
 309 /*
 310  * In order to keep calibration register value fixed, the product
 311  * of current_lsb and shunt_resistor should also be fixed and equal
 312  * to shunt_voltage_lsb = 1 / shunt_div multiplied by 10^9 in order
 313  * to keep the scale.
 314  */
 315 static int ina2xx_set_shunt(struct ina2xx_data *data, long val)
 316 {
 317         unsigned int dividend = DIV_ROUND_CLOSEST(1000000000,
 318                                                   data->config->shunt_div);
 319         if (val <= 0 || val > dividend)
 320                 return -EINVAL;
 321
 322         mutex_lock(&data->config_lock);
 323         data->rshunt = val;
 324         data->current_lsb_uA = DIV_ROUND_CLOSEST(dividend, val);
 325         data->power_lsb_uW = data->config->power_lsb_factor *
 326                              data->current_lsb_uA;
 327         mutex_unlock(&data->config_lock);
 328
 329         return 0;
 330 }
 331
 332 static ssize_t ina2xx_show_shunt(struct device *dev,
 333                               struct device_attribute *da,
 334                               char *buf)
 335 {
 336         struct ina2xx_data *data = dev_get_drvdata(dev);
 337
 338         return snprintf(buf, PAGE_SIZE, "%li\n", data->rshunt);
 339 }
 340
 341 static ssize_t ina2xx_store_shunt(struct device *dev,
 342                                   struct device_attribute *da,
 343                                   const char *buf, size_t count)
 344 {
 345         unsigned long val;
 346         int status;
 347         struct ina2xx_data *data = dev_get_drvdata(dev);
 348
 349         status = kstrtoul(buf, 10, &val);
 350         if (status < 0)
 351                 return status;
 352
 353         status = ina2xx_set_shunt(data, val);
 354         if (status < 0)
 355                 return status;
 356         return count;
 357 }
 358
 359 static ssize_t ina226_set_interval(struct device *dev,
 360                                    struct device_attribute *da,
 361                                    const char *buf, size_t count)
 362 {
 363         struct ina2xx_data *data = dev_get_drvdata(dev);
 364         unsigned long val;
 365         int status;
 366
 367         status = kstrtoul(buf, 10, &val);
 368         if (status < 0)
 369                 return status;
 370
 371         if (val > INT_MAX || val == 0)
 372                 return -EINVAL;
 373
 374         status = regmap_update_bits(data->regmap, INA2XX_CONFIG,
 375                                     INA226_AVG_RD_MASK,
 376                                     ina226_interval_to_reg(val));
 377         if (status < 0)
 378                 return status;
 379
 380         return count;
 381 }
 382
 383 static ssize_t ina226_show_interval(struct device *dev,
 384                                     struct device_attribute *da, char *buf)
 385 {
 386         struct ina2xx_data *data = dev_get_drvdata(dev);
 387         int status;
 388         unsigned int regval;
 389
 390         status = regmap_read(data->regmap, INA2XX_CONFIG, &regval);
 391         if (status)
 392                 return status;
 393
 394         return snprintf(buf, PAGE_SIZE, "%d\n", ina226_reg_to_interval(regval));
 395 }
 396
 397 /* shunt voltage */
 398 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
 399                           INA2XX_SHUNT_VOLTAGE);
 400
 401 /* bus voltage */
 402 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
 403                           INA2XX_BUS_VOLTAGE);
 404
 405 /* calculated current */
 406 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
 407                           INA2XX_CURRENT);
 408
 409 /* calculated power */
 410 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
 411                           INA2XX_POWER);
 412
 413 /* shunt resistance */
 414 static SENSOR_DEVICE_ATTR(shunt_resistor, S_IRUGO | S_IWUSR,
 415                           ina2xx_show_shunt, ina2xx_store_shunt,
 416                           INA2XX_CALIBRATION);
 417
 418 /* update interval (ina226 only) */
 419 static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
 420                           ina226_show_interval, ina226_set_interval, 0);
 421
 422 /* pointers to created device attributes */
 423 static struct attribute *ina2xx_attrs[] = {
 424         &sensor_dev_attr_in0_input.dev_attr.attr,
 425         &sensor_dev_attr_in1_input.dev_attr.attr,
 426         &sensor_dev_attr_curr1_input.dev_attr.attr,
 427         &sensor_dev_attr_power1_input.dev_attr.attr,
 428         &sensor_dev_attr_shunt_resistor.dev_attr.attr,
 429         NULL,
 430 };
 431
 432 static const struct attribute_group ina2xx_group = {
 433         .attrs = ina2xx_attrs,
 434 };
 435
 436 static struct attribute *ina226_attrs[] = {
 437         &sensor_dev_attr_update_interval.dev_attr.attr,
 438         NULL,
 439 };
 440
 441 static const struct attribute_group ina226_group = {
 442         .attrs = ina226_attrs,
 443 };
 444
 445 static int ina2xx_probe(struct i2c_client *client,
 446                         const struct i2c_device_id *id)
 447 {
 448         struct device *dev = &client->dev;
 449         struct ina2xx_data *data;
 450         struct device *hwmon_dev;
 451         u32 val;
 452         int ret, group = 0;
 453         enum ina2xx_ids chip;
 454
 455         if (client->dev.of_node)
 456                 chip = (enum ina2xx_ids)of_device_get_match_data(&client->dev);
 457         else
 458                 chip = id->driver_data;
 459
 460         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 461         if (!data)
 462                 return -ENOMEM;
 463
 464         /* set the device type */
 465         data->config = &ina2xx_config[chip];
 466         mutex_init(&data->config_lock);
 467
 468         if (of_property_read_u32(dev->of_node, "shunt-resistor", &val) < 0) {
 469                 struct ina2xx_platform_data *pdata = dev_get_platdata(dev);
 470
 471                 if (pdata)
 472                         val = pdata->shunt_uohms;
 473                 else
 474                         val = INA2XX_RSHUNT_DEFAULT;
 475         }
 476
 477         ina2xx_set_shunt(data, val);
 478
 479         ina2xx_regmap_config.max_register = data->config->registers;
 480
 481         data->regmap = devm_regmap_init_i2c(client, &ina2xx_regmap_config);
 482         if (IS_ERR(data->regmap)) {
 483                 dev_err(dev, "failed to allocate register map\n");
 484                 return PTR_ERR(data->regmap);
 485         }
 486
 487         ret = ina2xx_init(data);
 488         if (ret < 0) {
 489                 dev_err(dev, "error configuring the device: %d\n", ret);
 490                 return -ENODEV;
 491         }
 492
 493         data->groups[group++] = &ina2xx_group;
 494         if (chip == ina226)
 495                 data->groups[group++] = &ina226_group;
 496
 497         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 498                                                            data, data->groups);
 499         if (IS_ERR(hwmon_dev))
 500                 return PTR_ERR(hwmon_dev);
 501
 502         dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
 503                  client->name, data->rshunt);
 504
 505         return 0;
 506 }
 507
 508 static const struct i2c_device_id ina2xx_id[] = {
 509         { "ina219", ina219 },
 510         { "ina220", ina219 },
 511         { "ina226", ina226 },
 512         { "ina230", ina226 },
 513         { "ina231", ina226 },
 514         { }
 515 };
 516 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
 517
 518 static const struct of_device_id ina2xx_of_match[] = {
 519         {
 520                 .compatible = "ti,ina219",
 521                 .data = (void *)ina219
 522         },
 523         {
 524                 .compatible = "ti,ina220",
 525                 .data = (void *)ina219
 526         },
 527         {
 528                 .compatible = "ti,ina226",
 529                 .data = (void *)ina226
 530         },
 531         {
 532                 .compatible = "ti,ina230",
 533                 .data = (void *)ina226
 534         },
 535         {
 536                 .compatible = "ti,ina231",
 537                 .data = (void *)ina226
 538         },
 539         { },
 540 };
 541 MODULE_DEVICE_TABLE(of, ina2xx_of_match);
 542
 543 static struct i2c_driver ina2xx_driver = {
 544         .driver = {
 545                 .name   = "ina2xx",
 546                 .of_match_table = of_match_ptr(ina2xx_of_match),
 547         },
 548         .probe          = ina2xx_probe,
 549         .id_table       = ina2xx_id,
 550 };
 551
 552 module_i2c_driver(ina2xx_driver);
 553
 554 MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
 555 MODULE_DESCRIPTION("ina2xx driver");
 556 MODULE_LICENSE("GPL");