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_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 = 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, ®val); 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_store_shunt(struct device *dev, 333 struct device_attribute *da, 334 const char *buf, size_t count) 335 { 336 unsigned long val; 337 int status; 338 struct ina2xx_data *data = dev_get_drvdata(dev); 339 340 status = kstrtoul(buf, 10, &val); 341 if (status < 0) 342 return status; 343 344 status = ina2xx_set_shunt(data, val); 345 if (status < 0) 346 return status; 347 return count; 348 } 349 350 static ssize_t ina226_set_interval(struct device *dev, 351 struct device_attribute *da, 352 const char *buf, size_t count) 353 { 354 struct ina2xx_data *data = dev_get_drvdata(dev); 355 unsigned long val; 356 int status; 357 358 status = kstrtoul(buf, 10, &val); 359 if (status < 0) 360 return status; 361 362 if (val > INT_MAX || val == 0) 363 return -EINVAL; 364 365 status = regmap_update_bits(data->regmap, INA2XX_CONFIG, 366 INA226_AVG_RD_MASK, 367 ina226_interval_to_reg(val)); 368 if (status < 0) 369 return status; 370 371 return count; 372 } 373 374 static ssize_t ina226_show_interval(struct device *dev, 375 struct device_attribute *da, char *buf) 376 { 377 struct ina2xx_data *data = dev_get_drvdata(dev); 378 int status; 379 unsigned int regval; 380 381 status = regmap_read(data->regmap, INA2XX_CONFIG, ®val); 382 if (status) 383 return status; 384 385 return snprintf(buf, PAGE_SIZE, "%d\n", ina226_reg_to_interval(regval)); 386 } 387 388 /* shunt voltage */ 389 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL, 390 INA2XX_SHUNT_VOLTAGE); 391 392 /* bus voltage */ 393 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL, 394 INA2XX_BUS_VOLTAGE); 395 396 /* calculated current */ 397 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL, 398 INA2XX_CURRENT); 399 400 /* calculated power */ 401 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL, 402 INA2XX_POWER); 403 404 /* shunt resistance */ 405 static SENSOR_DEVICE_ATTR(shunt_resistor, S_IRUGO | S_IWUSR, 406 ina2xx_show_value, ina2xx_store_shunt, 407 INA2XX_CALIBRATION); 408 409 /* update interval (ina226 only) */ 410 static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR, 411 ina226_show_interval, ina226_set_interval, 0); 412 413 /* pointers to created device attributes */ 414 static struct attribute *ina2xx_attrs[] = { 415 &sensor_dev_attr_in0_input.dev_attr.attr, 416 &sensor_dev_attr_in1_input.dev_attr.attr, 417 &sensor_dev_attr_curr1_input.dev_attr.attr, 418 &sensor_dev_attr_power1_input.dev_attr.attr, 419 &sensor_dev_attr_shunt_resistor.dev_attr.attr, 420 NULL, 421 }; 422 423 static const struct attribute_group ina2xx_group = { 424 .attrs = ina2xx_attrs, 425 }; 426 427 static struct attribute *ina226_attrs[] = { 428 &sensor_dev_attr_update_interval.dev_attr.attr, 429 NULL, 430 }; 431 432 static const struct attribute_group ina226_group = { 433 .attrs = ina226_attrs, 434 }; 435 436 static int ina2xx_probe(struct i2c_client *client, 437 const struct i2c_device_id *id) 438 { 439 struct device *dev = &client->dev; 440 struct ina2xx_data *data; 441 struct device *hwmon_dev; 442 u32 val; 443 int ret, group = 0; 444 enum ina2xx_ids chip; 445 446 if (client->dev.of_node) 447 chip = (enum ina2xx_ids)of_device_get_match_data(&client->dev); 448 else 449 chip = id->driver_data; 450 451 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 452 if (!data) 453 return -ENOMEM; 454 455 /* set the device type */ 456 data->config = &ina2xx_config[chip]; 457 mutex_init(&data->config_lock); 458 459 if (of_property_read_u32(dev->of_node, "shunt-resistor", &val) < 0) { 460 struct ina2xx_platform_data *pdata = dev_get_platdata(dev); 461 462 if (pdata) 463 val = pdata->shunt_uohms; 464 else 465 val = INA2XX_RSHUNT_DEFAULT; 466 } 467 468 ina2xx_set_shunt(data, val); 469 470 ina2xx_regmap_config.max_register = data->config->registers; 471 472 data->regmap = devm_regmap_init_i2c(client, &ina2xx_regmap_config); 473 if (IS_ERR(data->regmap)) { 474 dev_err(dev, "failed to allocate register map\n"); 475 return PTR_ERR(data->regmap); 476 } 477 478 ret = ina2xx_init(data); 479 if (ret < 0) { 480 dev_err(dev, "error configuring the device: %d\n", ret); 481 return -ENODEV; 482 } 483 484 data->groups[group++] = &ina2xx_group; 485 if (id->driver_data == ina226) 486 data->groups[group++] = &ina226_group; 487 488 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, 489 data, data->groups); 490 if (IS_ERR(hwmon_dev)) 491 return PTR_ERR(hwmon_dev); 492 493 dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n", 494 id->name, data->rshunt); 495 496 return 0; 497 } 498 499 static const struct i2c_device_id ina2xx_id[] = { 500 { "ina219", ina219 }, 501 { "ina220", ina219 }, 502 { "ina226", ina226 }, 503 { "ina230", ina226 }, 504 { "ina231", ina226 }, 505 { } 506 }; 507 MODULE_DEVICE_TABLE(i2c, ina2xx_id); 508 509 static const struct of_device_id ina2xx_of_match[] = { 510 { 511 .compatible = "ti,ina219", 512 .data = (void *)ina219 513 }, 514 { 515 .compatible = "ti,ina220", 516 .data = (void *)ina219 517 }, 518 { 519 .compatible = "ti,ina226", 520 .data = (void *)ina226 521 }, 522 { 523 .compatible = "ti,ina230", 524 .data = (void *)ina226 525 }, 526 { 527 .compatible = "ti,ina231", 528 .data = (void *)ina226 529 }, 530 { }, 531 }; 532 MODULE_DEVICE_TABLE(of, ina2xx_of_match); 533 534 static struct i2c_driver ina2xx_driver = { 535 .driver = { 536 .name = "ina2xx", 537 .of_match_table = of_match_ptr(ina2xx_of_match), 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"); 548