ina209.c 18 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633
/*
 * Driver for the Texas Instruments / Burr Brown INA209
 * Bidirectional Current/Power Monitor
 *
 * Copyright (C) 2012 Guenter Roeck <linux@roeck-us.net>
 *
 * Derived from Ira W. Snyder's original driver submission
 *	Copyright (C) 2008 Paul Hays <Paul.Hays@cattail.ca>
 *	Copyright (C) 2008-2009 Ira W. Snyder <iws@ovro.caltech.edu>
 *
 * Aligned with ina2xx driver
 *	Copyright (C) 2012 Lothar Felten <l-felten@ti.com>
 *	Thanks to Jan Volkering
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * Datasheet:
 * http://www.ti.com/lit/gpn/ina209
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/bug.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>

#include <linux/platform_data/ina2xx.h>

/* register definitions */
#define INA209_CONFIGURATION		0x00
#define INA209_STATUS			0x01
#define INA209_STATUS_MASK		0x02
#define INA209_SHUNT_VOLTAGE		0x03
#define INA209_BUS_VOLTAGE		0x04
#define INA209_POWER			0x05
#define INA209_CURRENT			0x06
#define INA209_SHUNT_VOLTAGE_POS_PEAK	0x07
#define INA209_SHUNT_VOLTAGE_NEG_PEAK	0x08
#define INA209_BUS_VOLTAGE_MAX_PEAK	0x09
#define INA209_BUS_VOLTAGE_MIN_PEAK	0x0a
#define INA209_POWER_PEAK		0x0b
#define INA209_SHUNT_VOLTAGE_POS_WARN	0x0c
#define INA209_SHUNT_VOLTAGE_NEG_WARN	0x0d
#define INA209_POWER_WARN		0x0e
#define INA209_BUS_VOLTAGE_OVER_WARN	0x0f
#define INA209_BUS_VOLTAGE_UNDER_WARN	0x10
#define INA209_POWER_OVER_LIMIT		0x11
#define INA209_BUS_VOLTAGE_OVER_LIMIT	0x12
#define INA209_BUS_VOLTAGE_UNDER_LIMIT	0x13
#define INA209_CRITICAL_DAC_POS		0x14
#define INA209_CRITICAL_DAC_NEG		0x15
#define INA209_CALIBRATION		0x16

#define INA209_REGISTERS		0x17

#define INA209_CONFIG_DEFAULT		0x3c47	/* PGA=8, full range */
#define INA209_SHUNT_DEFAULT		10000	/* uOhm */

struct ina209_data {
	struct i2c_client *client;

	struct mutex update_lock;
	bool valid;
	unsigned long last_updated;	/* in jiffies */

	u16 regs[INA209_REGISTERS];	/* All chip registers */

	u16 config_orig;		/* Original configuration */
	u16 calibration_orig;		/* Original calibration */
	u16 update_interval;
};

static struct ina209_data *ina209_update_device(struct device *dev)
{
	struct ina209_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	struct ina209_data *ret = data;
	s32 val;
	int i;

	mutex_lock(&data->update_lock);

	if (!data->valid ||
	    time_after(jiffies, data->last_updated + data->update_interval)) {
		for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
			val = i2c_smbus_read_word_swapped(client, i);
			if (val < 0) {
				ret = ERR_PTR(val);
				goto abort;
			}
			data->regs[i] = val;
		}
		data->last_updated = jiffies;
		data->valid = true;
	}
abort:
	mutex_unlock(&data->update_lock);
	return ret;
}

/*
 * Read a value from a device register and convert it to the
 * appropriate sysfs units
 */
static long ina209_from_reg(const u8 reg, const u16 val)
{
	switch (reg) {
	case INA209_SHUNT_VOLTAGE:
	case INA209_SHUNT_VOLTAGE_POS_PEAK:
	case INA209_SHUNT_VOLTAGE_NEG_PEAK:
	case INA209_SHUNT_VOLTAGE_POS_WARN:
	case INA209_SHUNT_VOLTAGE_NEG_WARN:
		/* LSB=10 uV. Convert to mV. */
		return DIV_ROUND_CLOSEST((s16)val, 100);

	case INA209_BUS_VOLTAGE:
	case INA209_BUS_VOLTAGE_MAX_PEAK:
	case INA209_BUS_VOLTAGE_MIN_PEAK:
	case INA209_BUS_VOLTAGE_OVER_WARN:
	case INA209_BUS_VOLTAGE_UNDER_WARN:
	case INA209_BUS_VOLTAGE_OVER_LIMIT:
	case INA209_BUS_VOLTAGE_UNDER_LIMIT:
		/* LSB=4 mV, last 3 bits unused */
		return (val >> 3) * 4;

	case INA209_CRITICAL_DAC_POS:
		/* LSB=1 mV, in the upper 8 bits */
		return val >> 8;

	case INA209_CRITICAL_DAC_NEG:
		/* LSB=1 mV, in the upper 8 bits */
		return -1 * (val >> 8);

	case INA209_POWER:
	case INA209_POWER_PEAK:
	case INA209_POWER_WARN:
	case INA209_POWER_OVER_LIMIT:
		/* LSB=20 mW. Convert to uW */
		return val * 20 * 1000L;

	case INA209_CURRENT:
		/* LSB=1 mA (selected). Is in mA */
		return (s16)val;
	}

	/* programmer goofed */
	WARN_ON_ONCE(1);
	return 0;
}

/*
 * Take a value and convert it to register format, clamping the value
 * to the appropriate range.
 */
static int ina209_to_reg(u8 reg, u16 old, long val)
{
	switch (reg) {
	case INA209_SHUNT_VOLTAGE_POS_WARN:
	case INA209_SHUNT_VOLTAGE_NEG_WARN:
		/* Limit to +- 320 mV, 10 uV LSB */
		return clamp_val(val, -320, 320) * 100;

	case INA209_BUS_VOLTAGE_OVER_WARN:
	case INA209_BUS_VOLTAGE_UNDER_WARN:
	case INA209_BUS_VOLTAGE_OVER_LIMIT:
	case INA209_BUS_VOLTAGE_UNDER_LIMIT:
		/*
		 * Limit to 0-32000 mV, 4 mV LSB
		 *
		 * The last three bits aren't part of the value, but we'll
		 * preserve them in their original state.
		 */
		return (DIV_ROUND_CLOSEST(clamp_val(val, 0, 32000), 4) << 3)
		  | (old & 0x7);

	case INA209_CRITICAL_DAC_NEG:
		/*
		 * Limit to -255-0 mV, 1 mV LSB
		 * Convert the value to a positive value for the register
		 *
		 * The value lives in the top 8 bits only, be careful
		 * and keep original value of other bits.
		 */
		return (clamp_val(-val, 0, 255) << 8) | (old & 0xff);

	case INA209_CRITICAL_DAC_POS:
		/*
		 * Limit to 0-255 mV, 1 mV LSB
		 *
		 * The value lives in the top 8 bits only, be careful
		 * and keep original value of other bits.
		 */
		return (clamp_val(val, 0, 255) << 8) | (old & 0xff);

	case INA209_POWER_WARN:
	case INA209_POWER_OVER_LIMIT:
		/* 20 mW LSB */
		return DIV_ROUND_CLOSEST(val, 20 * 1000);
	}

	/* Other registers are read-only, return access error */
	return -EACCES;
}

static int ina209_interval_from_reg(u16 reg)
{
	return 68 >> (15 - ((reg >> 3) & 0x0f));
}

static u16 ina209_reg_from_interval(u16 config, long interval)
{
	int i, adc;

	if (interval <= 0) {
		adc = 8;
	} else {
		adc = 15;
		for (i = 34 + 34 / 2; i; i >>= 1) {
			if (i < interval)
				break;
			adc--;
		}
	}
	return (config & 0xf807) | (adc << 3) | (adc << 7);
}

static ssize_t ina209_set_interval(struct device *dev,
				   struct device_attribute *da,
				   const char *buf, size_t count)
{
	struct ina209_data *data = ina209_update_device(dev);
	long val;
	u16 regval;
	int ret;

	if (IS_ERR(data))
		return PTR_ERR(data);

	ret = kstrtol(buf, 10, &val);
	if (ret < 0)
		return ret;

	mutex_lock(&data->update_lock);
	regval = ina209_reg_from_interval(data->regs[INA209_CONFIGURATION],
					  val);
	i2c_smbus_write_word_swapped(data->client, INA209_CONFIGURATION,
				     regval);
	data->regs[INA209_CONFIGURATION] = regval;
	data->update_interval = ina209_interval_from_reg(regval);
	mutex_unlock(&data->update_lock);
	return count;
}

static ssize_t ina209_show_interval(struct device *dev,
				    struct device_attribute *da, char *buf)
{
	struct ina209_data *data = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "%d\n", data->update_interval);
}

/*
 * History is reset by writing 1 into bit 0 of the respective peak register.
 * Since more than one peak register may be affected by the scope of a
 * reset_history attribute write, use a bit mask in attr->index to identify
 * which registers are affected.
 */
static u16 ina209_reset_history_regs[] = {
	INA209_SHUNT_VOLTAGE_POS_PEAK,
	INA209_SHUNT_VOLTAGE_NEG_PEAK,
	INA209_BUS_VOLTAGE_MAX_PEAK,
	INA209_BUS_VOLTAGE_MIN_PEAK,
	INA209_POWER_PEAK
};

static ssize_t ina209_reset_history(struct device *dev,
				    struct device_attribute *da,
				    const char *buf,
				    size_t count)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ina209_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	u32 mask = attr->index;
	long val;
	int i, ret;

	ret = kstrtol(buf, 10, &val);
	if (ret < 0)
		return ret;

	mutex_lock(&data->update_lock);
	for (i = 0; i < ARRAY_SIZE(ina209_reset_history_regs); i++) {
		if (mask & (1 << i))
			i2c_smbus_write_word_swapped(client,
					ina209_reset_history_regs[i], 1);
	}
	data->valid = false;
	mutex_unlock(&data->update_lock);
	return count;
}

static ssize_t ina209_set_value(struct device *dev,
				struct device_attribute *da,
				const char *buf,
				size_t count)
{
	struct ina209_data *data = ina209_update_device(dev);
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	int reg = attr->index;
	long val;
	int ret;

	if (IS_ERR(data))
		return PTR_ERR(data);

	ret = kstrtol(buf, 10, &val);
	if (ret < 0)
		return ret;

	mutex_lock(&data->update_lock);
	ret = ina209_to_reg(reg, data->regs[reg], val);
	if (ret < 0) {
		count = ret;
		goto abort;
	}
	i2c_smbus_write_word_swapped(data->client, reg, ret);
	data->regs[reg] = ret;
abort:
	mutex_unlock(&data->update_lock);
	return count;
}

static ssize_t ina209_show_value(struct device *dev,
				 struct device_attribute *da,
				 char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ina209_data *data = ina209_update_device(dev);
	long val;

	if (IS_ERR(data))
		return PTR_ERR(data);

	val = ina209_from_reg(attr->index, data->regs[attr->index]);
	return snprintf(buf, PAGE_SIZE, "%ld\n", val);
}

static ssize_t ina209_show_alarm(struct device *dev,
				 struct device_attribute *da,
				 char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ina209_data *data = ina209_update_device(dev);
	const unsigned int mask = attr->index;
	u16 status;

	if (IS_ERR(data))
		return PTR_ERR(data);

	status = data->regs[INA209_STATUS];

	/*
	 * All alarms are in the INA209_STATUS register. To avoid a long
	 * switch statement, the mask is passed in attr->index
	 */
	return snprintf(buf, PAGE_SIZE, "%u\n", !!(status & mask));
}

/* Shunt voltage, history, limits, alarms */
static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina209_show_value, NULL,
			  INA209_SHUNT_VOLTAGE);
static SENSOR_DEVICE_ATTR(in0_input_highest, S_IRUGO, ina209_show_value, NULL,
			  INA209_SHUNT_VOLTAGE_POS_PEAK);
static SENSOR_DEVICE_ATTR(in0_input_lowest, S_IRUGO, ina209_show_value, NULL,
			  INA209_SHUNT_VOLTAGE_NEG_PEAK);
static SENSOR_DEVICE_ATTR(in0_reset_history, S_IWUSR, NULL,
			  ina209_reset_history, (1 << 0) | (1 << 1));
static SENSOR_DEVICE_ATTR(in0_max, S_IRUGO | S_IWUSR, ina209_show_value,
			  ina209_set_value, INA209_SHUNT_VOLTAGE_POS_WARN);
static SENSOR_DEVICE_ATTR(in0_min, S_IRUGO | S_IWUSR, ina209_show_value,
			  ina209_set_value, INA209_SHUNT_VOLTAGE_NEG_WARN);
static SENSOR_DEVICE_ATTR(in0_crit_max, S_IRUGO | S_IWUSR, ina209_show_value,
			  ina209_set_value, INA209_CRITICAL_DAC_POS);
static SENSOR_DEVICE_ATTR(in0_crit_min, S_IRUGO | S_IWUSR, ina209_show_value,
			  ina209_set_value, INA209_CRITICAL_DAC_NEG);

static SENSOR_DEVICE_ATTR(in0_min_alarm,  S_IRUGO, ina209_show_alarm, NULL,
			  1 << 11);
static SENSOR_DEVICE_ATTR(in0_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
			  1 << 12);
static SENSOR_DEVICE_ATTR(in0_crit_min_alarm, S_IRUGO, ina209_show_alarm, NULL,
			  1 << 6);
static SENSOR_DEVICE_ATTR(in0_crit_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
			  1 << 7);

/* Bus voltage, history, limits, alarms */
static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina209_show_value, NULL,
			  INA209_BUS_VOLTAGE);
static SENSOR_DEVICE_ATTR(in1_input_highest, S_IRUGO, ina209_show_value, NULL,
			  INA209_BUS_VOLTAGE_MAX_PEAK);
static SENSOR_DEVICE_ATTR(in1_input_lowest, S_IRUGO, ina209_show_value, NULL,
			  INA209_BUS_VOLTAGE_MIN_PEAK);
static SENSOR_DEVICE_ATTR(in1_reset_history, S_IWUSR, NULL,
			  ina209_reset_history, (1 << 2) | (1 << 3));
static SENSOR_DEVICE_ATTR(in1_max, S_IRUGO | S_IWUSR, ina209_show_value,
			  ina209_set_value, INA209_BUS_VOLTAGE_OVER_WARN);
static SENSOR_DEVICE_ATTR(in1_min, S_IRUGO | S_IWUSR, ina209_show_value,
			  ina209_set_value, INA209_BUS_VOLTAGE_UNDER_WARN);
static SENSOR_DEVICE_ATTR(in1_crit_max, S_IRUGO | S_IWUSR, ina209_show_value,
			  ina209_set_value, INA209_BUS_VOLTAGE_OVER_LIMIT);
static SENSOR_DEVICE_ATTR(in1_crit_min, S_IRUGO | S_IWUSR, ina209_show_value,
			  ina209_set_value, INA209_BUS_VOLTAGE_UNDER_LIMIT);

static SENSOR_DEVICE_ATTR(in1_min_alarm, S_IRUGO, ina209_show_alarm, NULL,
			  1 << 14);
static SENSOR_DEVICE_ATTR(in1_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
			  1 << 15);
static SENSOR_DEVICE_ATTR(in1_crit_min_alarm, S_IRUGO, ina209_show_alarm, NULL,
			  1 << 9);
static SENSOR_DEVICE_ATTR(in1_crit_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
			  1 << 10);

/* Power */
static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina209_show_value, NULL,
			  INA209_POWER);
static SENSOR_DEVICE_ATTR(power1_input_highest, S_IRUGO, ina209_show_value,
			  NULL, INA209_POWER_PEAK);
static SENSOR_DEVICE_ATTR(power1_reset_history, S_IWUSR, NULL,
			  ina209_reset_history, 1 << 4);
static SENSOR_DEVICE_ATTR(power1_max, S_IRUGO | S_IWUSR, ina209_show_value,
			  ina209_set_value, INA209_POWER_WARN);
static SENSOR_DEVICE_ATTR(power1_crit, S_IRUGO | S_IWUSR, ina209_show_value,
			  ina209_set_value, INA209_POWER_OVER_LIMIT);

static SENSOR_DEVICE_ATTR(power1_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
			  1 << 13);
static SENSOR_DEVICE_ATTR(power1_crit_alarm, S_IRUGO, ina209_show_alarm, NULL,
			  1 << 8);

/* Current */
static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina209_show_value, NULL,
			  INA209_CURRENT);

static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
			  ina209_show_interval, ina209_set_interval, 0);

/*
 * Finally, construct an array of pointers to members of the above objects,
 * as required for sysfs_create_group()
 */
static struct attribute *ina209_attrs[] = {
	&sensor_dev_attr_in0_input.dev_attr.attr,
	&sensor_dev_attr_in0_input_highest.dev_attr.attr,
	&sensor_dev_attr_in0_input_lowest.dev_attr.attr,
	&sensor_dev_attr_in0_reset_history.dev_attr.attr,
	&sensor_dev_attr_in0_max.dev_attr.attr,
	&sensor_dev_attr_in0_min.dev_attr.attr,
	&sensor_dev_attr_in0_crit_max.dev_attr.attr,
	&sensor_dev_attr_in0_crit_min.dev_attr.attr,
	&sensor_dev_attr_in0_max_alarm.dev_attr.attr,
	&sensor_dev_attr_in0_min_alarm.dev_attr.attr,
	&sensor_dev_attr_in0_crit_max_alarm.dev_attr.attr,
	&sensor_dev_attr_in0_crit_min_alarm.dev_attr.attr,

	&sensor_dev_attr_in1_input.dev_attr.attr,
	&sensor_dev_attr_in1_input_highest.dev_attr.attr,
	&sensor_dev_attr_in1_input_lowest.dev_attr.attr,
	&sensor_dev_attr_in1_reset_history.dev_attr.attr,
	&sensor_dev_attr_in1_max.dev_attr.attr,
	&sensor_dev_attr_in1_min.dev_attr.attr,
	&sensor_dev_attr_in1_crit_max.dev_attr.attr,
	&sensor_dev_attr_in1_crit_min.dev_attr.attr,
	&sensor_dev_attr_in1_max_alarm.dev_attr.attr,
	&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
	&sensor_dev_attr_in1_crit_max_alarm.dev_attr.attr,
	&sensor_dev_attr_in1_crit_min_alarm.dev_attr.attr,

	&sensor_dev_attr_power1_input.dev_attr.attr,
	&sensor_dev_attr_power1_input_highest.dev_attr.attr,
	&sensor_dev_attr_power1_reset_history.dev_attr.attr,
	&sensor_dev_attr_power1_max.dev_attr.attr,
	&sensor_dev_attr_power1_crit.dev_attr.attr,
	&sensor_dev_attr_power1_max_alarm.dev_attr.attr,
	&sensor_dev_attr_power1_crit_alarm.dev_attr.attr,

	&sensor_dev_attr_curr1_input.dev_attr.attr,

	&sensor_dev_attr_update_interval.dev_attr.attr,

	NULL,
};
ATTRIBUTE_GROUPS(ina209);

static void ina209_restore_conf(struct i2c_client *client,
				struct ina209_data *data)
{
	/* Restore initial configuration */
	i2c_smbus_write_word_swapped(client, INA209_CONFIGURATION,
				     data->config_orig);
	i2c_smbus_write_word_swapped(client, INA209_CALIBRATION,
				     data->calibration_orig);
}

static int ina209_init_client(struct i2c_client *client,
			      struct ina209_data *data)
{
	struct ina2xx_platform_data *pdata = dev_get_platdata(&client->dev);
	u32 shunt;
	int reg;

	reg = i2c_smbus_read_word_swapped(client, INA209_CALIBRATION);
	if (reg < 0)
		return reg;
	data->calibration_orig = reg;

	reg = i2c_smbus_read_word_swapped(client, INA209_CONFIGURATION);
	if (reg < 0)
		return reg;
	data->config_orig = reg;

	if (pdata) {
		if (pdata->shunt_uohms <= 0)
			return -EINVAL;
		shunt = pdata->shunt_uohms;
	} else if (!of_property_read_u32(client->dev.of_node, "shunt-resistor",
					 &shunt)) {
		if (shunt == 0)
			return -EINVAL;
	} else {
		shunt = data->calibration_orig ?
		  40960000 / data->calibration_orig : INA209_SHUNT_DEFAULT;
	}

	i2c_smbus_write_word_swapped(client, INA209_CONFIGURATION,
				     INA209_CONFIG_DEFAULT);
	data->update_interval = ina209_interval_from_reg(INA209_CONFIG_DEFAULT);

	/*
	 * Calibrate current LSB to 1mA. Shunt is in uOhms.
	 * See equation 13 in datasheet.
	 */
	i2c_smbus_write_word_swapped(client, INA209_CALIBRATION,
				     clamp_val(40960000 / shunt, 1, 65535));

	/* Clear status register */
	i2c_smbus_read_word_swapped(client, INA209_STATUS);

	return 0;
}

static int ina209_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct i2c_adapter *adapter = client->adapter;
	struct ina209_data *data;
	struct device *hwmon_dev;
	int ret;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
		return -ENODEV;

	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	i2c_set_clientdata(client, data);
	data->client = client;
	mutex_init(&data->update_lock);

	ret = ina209_init_client(client, data);
	if (ret)
		return ret;

	hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
							   client->name,
							   data, ina209_groups);
	if (IS_ERR(hwmon_dev)) {
		ret = PTR_ERR(hwmon_dev);
		goto out_restore_conf;
	}

	return 0;

out_restore_conf:
	ina209_restore_conf(client, data);
	return ret;
}

static int ina209_remove(struct i2c_client *client)
{
	struct ina209_data *data = i2c_get_clientdata(client);

	ina209_restore_conf(client, data);

	return 0;
}

static const struct i2c_device_id ina209_id[] = {
	{ "ina209", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ina209_id);

static const struct of_device_id ina209_of_match[] = {
	{ .compatible = "ti,ina209" },
	{ },
};
MODULE_DEVICE_TABLE(of, ina209_of_match);

/* This is the driver that will be inserted */
static struct i2c_driver ina209_driver = {
	.class		= I2C_CLASS_HWMON,
	.driver = {
		.name	= "ina209",
		.of_match_table = of_match_ptr(ina209_of_match),
	},
	.probe		= ina209_probe,
	.remove		= ina209_remove,
	.id_table	= ina209_id,
};

module_i2c_driver(ina209_driver);

MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>, Paul Hays <Paul.Hays@cattail.ca>, Guenter Roeck <linux@roeck-us.net>");
MODULE_DESCRIPTION("INA209 driver");
MODULE_LICENSE("GPL");