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"); 559