xref: /openbmc/linux/drivers/iio/adc/ina2xx-adc.c (revision c8dbaa22)
1 /*
2  * INA2XX Current and Power Monitors
3  *
4  * Copyright 2015 Baylibre SAS.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  *
10  * Based on linux/drivers/iio/adc/ad7291.c
11  * Copyright 2010-2011 Analog Devices Inc.
12  *
13  * Based on linux/drivers/hwmon/ina2xx.c
14  * Copyright 2012 Lothar Felten <l-felten@ti.com>
15  *
16  * Licensed under the GPL-2 or later.
17  *
18  * IIO driver for INA219-220-226-230-231
19  *
20  * Configurable 7-bit I2C slave address from 0x40 to 0x4F
21  */
22 
23 #include <linux/delay.h>
24 #include <linux/i2c.h>
25 #include <linux/iio/iio.h>
26 #include <linux/iio/buffer.h>
27 #include <linux/iio/kfifo_buf.h>
28 #include <linux/iio/sysfs.h>
29 #include <linux/kthread.h>
30 #include <linux/module.h>
31 #include <linux/of_device.h>
32 #include <linux/regmap.h>
33 #include <linux/util_macros.h>
34 
35 #include <linux/platform_data/ina2xx.h>
36 
37 /* INA2XX registers definition */
38 #define INA2XX_CONFIG                   0x00
39 #define INA2XX_SHUNT_VOLTAGE            0x01	/* readonly */
40 #define INA2XX_BUS_VOLTAGE              0x02	/* readonly */
41 #define INA2XX_POWER                    0x03	/* readonly */
42 #define INA2XX_CURRENT                  0x04	/* readonly */
43 #define INA2XX_CALIBRATION              0x05
44 
45 #define INA226_MASK_ENABLE		0x06
46 #define INA226_CVRF			BIT(3)
47 
48 #define INA2XX_MAX_REGISTERS            8
49 
50 /* settings - depend on use case */
51 #define INA219_CONFIG_DEFAULT           0x399F	/* PGA=8 */
52 #define INA219_DEFAULT_IT		532
53 #define INA226_CONFIG_DEFAULT           0x4327
54 #define INA226_DEFAULT_AVG              4
55 #define INA226_DEFAULT_IT		1110
56 
57 #define INA2XX_RSHUNT_DEFAULT           10000
58 
59 /*
60  * bit masks for reading the settings in the configuration register
61  * FIXME: use regmap_fields.
62  */
63 #define INA2XX_MODE_MASK	GENMASK(3, 0)
64 
65 /* Averaging for VBus/VShunt/Power */
66 #define INA226_AVG_MASK		GENMASK(11, 9)
67 #define INA226_SHIFT_AVG(val)	((val) << 9)
68 
69 /* Integration time for VBus */
70 #define INA219_ITB_MASK		GENMASK(10, 7)
71 #define INA219_SHIFT_ITB(val)	((val) << 7)
72 #define INA226_ITB_MASK		GENMASK(8, 6)
73 #define INA226_SHIFT_ITB(val)	((val) << 6)
74 
75 /* Integration time for VShunt */
76 #define INA219_ITS_MASK		GENMASK(6, 3)
77 #define INA219_SHIFT_ITS(val)	((val) << 3)
78 #define INA226_ITS_MASK		GENMASK(5, 3)
79 #define INA226_SHIFT_ITS(val)	((val) << 3)
80 
81 /* Cosmetic macro giving the sampling period for a full P=UxI cycle */
82 #define SAMPLING_PERIOD(c)	((c->int_time_vbus + c->int_time_vshunt) \
83 				 * c->avg)
84 
85 static bool ina2xx_is_writeable_reg(struct device *dev, unsigned int reg)
86 {
87 	return (reg == INA2XX_CONFIG) || (reg > INA2XX_CURRENT);
88 }
89 
90 static bool ina2xx_is_volatile_reg(struct device *dev, unsigned int reg)
91 {
92 	return (reg != INA2XX_CONFIG);
93 }
94 
95 static inline bool is_signed_reg(unsigned int reg)
96 {
97 	return (reg == INA2XX_SHUNT_VOLTAGE) || (reg == INA2XX_CURRENT);
98 }
99 
100 static const struct regmap_config ina2xx_regmap_config = {
101 	.reg_bits = 8,
102 	.val_bits = 16,
103 	.max_register = INA2XX_MAX_REGISTERS,
104 	.writeable_reg = ina2xx_is_writeable_reg,
105 	.volatile_reg = ina2xx_is_volatile_reg,
106 };
107 
108 enum ina2xx_ids { ina219, ina226 };
109 
110 struct ina2xx_config {
111 	u16 config_default;
112 	int calibration_factor;
113 	int shunt_div;
114 	int bus_voltage_shift;
115 	int bus_voltage_lsb;	/* uV */
116 	int power_lsb;		/* uW */
117 	enum ina2xx_ids chip_id;
118 };
119 
120 struct ina2xx_chip_info {
121 	struct regmap *regmap;
122 	struct task_struct *task;
123 	const struct ina2xx_config *config;
124 	struct mutex state_lock;
125 	unsigned int shunt_resistor;
126 	int avg;
127 	int int_time_vbus; /* Bus voltage integration time uS */
128 	int int_time_vshunt; /* Shunt voltage integration time uS */
129 	bool allow_async_readout;
130 };
131 
132 static const struct ina2xx_config ina2xx_config[] = {
133 	[ina219] = {
134 		.config_default = INA219_CONFIG_DEFAULT,
135 		.calibration_factor = 40960000,
136 		.shunt_div = 100,
137 		.bus_voltage_shift = 3,
138 		.bus_voltage_lsb = 4000,
139 		.power_lsb = 20000,
140 		.chip_id = ina219,
141 	},
142 	[ina226] = {
143 		.config_default = INA226_CONFIG_DEFAULT,
144 		.calibration_factor = 5120000,
145 		.shunt_div = 400,
146 		.bus_voltage_shift = 0,
147 		.bus_voltage_lsb = 1250,
148 		.power_lsb = 25000,
149 		.chip_id = ina226,
150 	},
151 };
152 
153 static int ina2xx_read_raw(struct iio_dev *indio_dev,
154 			   struct iio_chan_spec const *chan,
155 			   int *val, int *val2, long mask)
156 {
157 	int ret;
158 	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
159 	unsigned int regval;
160 
161 	switch (mask) {
162 	case IIO_CHAN_INFO_RAW:
163 		ret = regmap_read(chip->regmap, chan->address, &regval);
164 		if (ret)
165 			return ret;
166 
167 		if (is_signed_reg(chan->address))
168 			*val = (s16) regval;
169 		else
170 			*val  = regval;
171 
172 		return IIO_VAL_INT;
173 
174 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
175 		*val = chip->avg;
176 		return IIO_VAL_INT;
177 
178 	case IIO_CHAN_INFO_INT_TIME:
179 		*val = 0;
180 		if (chan->address == INA2XX_SHUNT_VOLTAGE)
181 			*val2 = chip->int_time_vshunt;
182 		else
183 			*val2 = chip->int_time_vbus;
184 
185 		return IIO_VAL_INT_PLUS_MICRO;
186 
187 	case IIO_CHAN_INFO_SAMP_FREQ:
188 		/*
189 		 * Sample freq is read only, it is a consequence of
190 		 * 1/AVG*(CT_bus+CT_shunt).
191 		 */
192 		*val = DIV_ROUND_CLOSEST(1000000, SAMPLING_PERIOD(chip));
193 
194 		return IIO_VAL_INT;
195 
196 	case IIO_CHAN_INFO_SCALE:
197 		switch (chan->address) {
198 		case INA2XX_SHUNT_VOLTAGE:
199 			/* processed (mV) = raw/shunt_div */
200 			*val2 = chip->config->shunt_div;
201 			*val = 1;
202 			return IIO_VAL_FRACTIONAL;
203 
204 		case INA2XX_BUS_VOLTAGE:
205 			/* processed (mV) = raw*lsb (uV) / (1000 << shift) */
206 			*val = chip->config->bus_voltage_lsb;
207 			*val2 = 1000 << chip->config->bus_voltage_shift;
208 			return IIO_VAL_FRACTIONAL;
209 
210 		case INA2XX_POWER:
211 			/* processed (mW) = raw*lsb (uW) / 1000 */
212 			*val = chip->config->power_lsb;
213 			*val2 = 1000;
214 			return IIO_VAL_FRACTIONAL;
215 
216 		case INA2XX_CURRENT:
217 			/* processed (mA) = raw (mA) */
218 			*val = 1;
219 			return IIO_VAL_INT;
220 		}
221 	}
222 
223 	return -EINVAL;
224 }
225 
226 /*
227  * Available averaging rates for ina226. The indices correspond with
228  * the bit values expected by the chip (according to the ina226 datasheet,
229  * table 3 AVG bit settings, found at
230  * http://www.ti.com/lit/ds/symlink/ina226.pdf.
231  */
232 static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };
233 
234 static int ina226_set_average(struct ina2xx_chip_info *chip, unsigned int val,
235 			      unsigned int *config)
236 {
237 	int bits;
238 
239 	if (val > 1024 || val < 1)
240 		return -EINVAL;
241 
242 	bits = find_closest(val, ina226_avg_tab,
243 			    ARRAY_SIZE(ina226_avg_tab));
244 
245 	chip->avg = ina226_avg_tab[bits];
246 
247 	*config &= ~INA226_AVG_MASK;
248 	*config |= INA226_SHIFT_AVG(bits) & INA226_AVG_MASK;
249 
250 	return 0;
251 }
252 
253 /* Conversion times in uS */
254 static const int ina226_conv_time_tab[] = { 140, 204, 332, 588, 1100,
255 					    2116, 4156, 8244 };
256 
257 static int ina226_set_int_time_vbus(struct ina2xx_chip_info *chip,
258 				    unsigned int val_us, unsigned int *config)
259 {
260 	int bits;
261 
262 	if (val_us > 8244 || val_us < 140)
263 		return -EINVAL;
264 
265 	bits = find_closest(val_us, ina226_conv_time_tab,
266 			    ARRAY_SIZE(ina226_conv_time_tab));
267 
268 	chip->int_time_vbus = ina226_conv_time_tab[bits];
269 
270 	*config &= ~INA226_ITB_MASK;
271 	*config |= INA226_SHIFT_ITB(bits) & INA226_ITB_MASK;
272 
273 	return 0;
274 }
275 
276 static int ina226_set_int_time_vshunt(struct ina2xx_chip_info *chip,
277 				      unsigned int val_us, unsigned int *config)
278 {
279 	int bits;
280 
281 	if (val_us > 8244 || val_us < 140)
282 		return -EINVAL;
283 
284 	bits = find_closest(val_us, ina226_conv_time_tab,
285 			    ARRAY_SIZE(ina226_conv_time_tab));
286 
287 	chip->int_time_vshunt = ina226_conv_time_tab[bits];
288 
289 	*config &= ~INA226_ITS_MASK;
290 	*config |= INA226_SHIFT_ITS(bits) & INA226_ITS_MASK;
291 
292 	return 0;
293 }
294 
295 /* Conversion times in uS. */
296 static const int ina219_conv_time_tab_subsample[] = { 84, 148, 276, 532 };
297 static const int ina219_conv_time_tab_average[] = { 532, 1060, 2130, 4260,
298 						    8510, 17020, 34050, 68100};
299 
300 static int ina219_lookup_int_time(unsigned int *val_us, int *bits)
301 {
302 	if (*val_us > 68100 || *val_us < 84)
303 		return -EINVAL;
304 
305 	if (*val_us <= 532) {
306 		*bits = find_closest(*val_us, ina219_conv_time_tab_subsample,
307 				    ARRAY_SIZE(ina219_conv_time_tab_subsample));
308 		*val_us = ina219_conv_time_tab_subsample[*bits];
309 	} else {
310 		*bits = find_closest(*val_us, ina219_conv_time_tab_average,
311 				    ARRAY_SIZE(ina219_conv_time_tab_average));
312 		*val_us = ina219_conv_time_tab_average[*bits];
313 		*bits |= 0x8;
314 	}
315 
316 	return 0;
317 }
318 
319 static int ina219_set_int_time_vbus(struct ina2xx_chip_info *chip,
320 				    unsigned int val_us, unsigned int *config)
321 {
322 	int bits, ret;
323 	unsigned int val_us_best = val_us;
324 
325 	ret = ina219_lookup_int_time(&val_us_best, &bits);
326 	if (ret)
327 		return ret;
328 
329 	chip->int_time_vbus = val_us_best;
330 
331 	*config &= ~INA219_ITB_MASK;
332 	*config |= INA219_SHIFT_ITB(bits) & INA219_ITB_MASK;
333 
334 	return 0;
335 }
336 
337 static int ina219_set_int_time_vshunt(struct ina2xx_chip_info *chip,
338 				      unsigned int val_us, unsigned int *config)
339 {
340 	int bits, ret;
341 	unsigned int val_us_best = val_us;
342 
343 	ret = ina219_lookup_int_time(&val_us_best, &bits);
344 	if (ret)
345 		return ret;
346 
347 	chip->int_time_vshunt = val_us_best;
348 
349 	*config &= ~INA219_ITS_MASK;
350 	*config |= INA219_SHIFT_ITS(bits) & INA219_ITS_MASK;
351 
352 	return 0;
353 }
354 
355 static int ina2xx_write_raw(struct iio_dev *indio_dev,
356 			    struct iio_chan_spec const *chan,
357 			    int val, int val2, long mask)
358 {
359 	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
360 	unsigned int config, tmp;
361 	int ret;
362 
363 	if (iio_buffer_enabled(indio_dev))
364 		return -EBUSY;
365 
366 	mutex_lock(&chip->state_lock);
367 
368 	ret = regmap_read(chip->regmap, INA2XX_CONFIG, &config);
369 	if (ret)
370 		goto err;
371 
372 	tmp = config;
373 
374 	switch (mask) {
375 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
376 		ret = ina226_set_average(chip, val, &tmp);
377 		break;
378 
379 	case IIO_CHAN_INFO_INT_TIME:
380 		if (chip->config->chip_id == ina226) {
381 			if (chan->address == INA2XX_SHUNT_VOLTAGE)
382 				ret = ina226_set_int_time_vshunt(chip, val2,
383 								 &tmp);
384 			else
385 				ret = ina226_set_int_time_vbus(chip, val2,
386 							       &tmp);
387 		} else {
388 			if (chan->address == INA2XX_SHUNT_VOLTAGE)
389 				ret = ina219_set_int_time_vshunt(chip, val2,
390 								 &tmp);
391 			else
392 				ret = ina219_set_int_time_vbus(chip, val2,
393 							       &tmp);
394 		}
395 		break;
396 
397 	default:
398 		ret = -EINVAL;
399 	}
400 
401 	if (!ret && (tmp != config))
402 		ret = regmap_write(chip->regmap, INA2XX_CONFIG, tmp);
403 err:
404 	mutex_unlock(&chip->state_lock);
405 
406 	return ret;
407 }
408 
409 static ssize_t ina2xx_allow_async_readout_show(struct device *dev,
410 					   struct device_attribute *attr,
411 					   char *buf)
412 {
413 	struct ina2xx_chip_info *chip = iio_priv(dev_to_iio_dev(dev));
414 
415 	return sprintf(buf, "%d\n", chip->allow_async_readout);
416 }
417 
418 static ssize_t ina2xx_allow_async_readout_store(struct device *dev,
419 				struct device_attribute *attr,
420 				const char *buf, size_t len)
421 {
422 	struct ina2xx_chip_info *chip = iio_priv(dev_to_iio_dev(dev));
423 	bool val;
424 	int ret;
425 
426 	ret = strtobool((const char *) buf, &val);
427 	if (ret)
428 		return ret;
429 
430 	chip->allow_async_readout = val;
431 
432 	return len;
433 }
434 
435 /*
436  * Set current LSB to 1mA, shunt is in uOhms
437  * (equation 13 in datasheet). We hardcode a Current_LSB
438  * of 1.0 x10-6. The only remaining parameter is RShunt.
439  * There is no need to expose the CALIBRATION register
440  * to the user for now. But we need to reset this register
441  * if the user updates RShunt after driver init, e.g upon
442  * reading an EEPROM/Probe-type value.
443  */
444 static int ina2xx_set_calibration(struct ina2xx_chip_info *chip)
445 {
446 	u16 regval = DIV_ROUND_CLOSEST(chip->config->calibration_factor,
447 				   chip->shunt_resistor);
448 
449 	return regmap_write(chip->regmap, INA2XX_CALIBRATION, regval);
450 }
451 
452 static int set_shunt_resistor(struct ina2xx_chip_info *chip, unsigned int val)
453 {
454 	if (val <= 0 || val > chip->config->calibration_factor)
455 		return -EINVAL;
456 
457 	chip->shunt_resistor = val;
458 
459 	return 0;
460 }
461 
462 static ssize_t ina2xx_shunt_resistor_show(struct device *dev,
463 					  struct device_attribute *attr,
464 					  char *buf)
465 {
466 	struct ina2xx_chip_info *chip = iio_priv(dev_to_iio_dev(dev));
467 
468 	return sprintf(buf, "%d\n", chip->shunt_resistor);
469 }
470 
471 static ssize_t ina2xx_shunt_resistor_store(struct device *dev,
472 					   struct device_attribute *attr,
473 					   const char *buf, size_t len)
474 {
475 	struct ina2xx_chip_info *chip = iio_priv(dev_to_iio_dev(dev));
476 	unsigned long val;
477 	int ret;
478 
479 	ret = kstrtoul((const char *) buf, 10, &val);
480 	if (ret)
481 		return ret;
482 
483 	ret = set_shunt_resistor(chip, val);
484 	if (ret)
485 		return ret;
486 
487 	/* Update the Calibration register */
488 	ret = ina2xx_set_calibration(chip);
489 	if (ret)
490 		return ret;
491 
492 	return len;
493 }
494 
495 #define INA219_CHAN(_type, _index, _address) { \
496 	.type = (_type), \
497 	.address = (_address), \
498 	.indexed = 1, \
499 	.channel = (_index), \
500 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
501 			      BIT(IIO_CHAN_INFO_SCALE), \
502 	.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
503 	.scan_index = (_index), \
504 	.scan_type = { \
505 		.sign = 'u', \
506 		.realbits = 16, \
507 		.storagebits = 16, \
508 		.endianness = IIO_CPU, \
509 	} \
510 }
511 
512 #define INA226_CHAN(_type, _index, _address) { \
513 	.type = (_type), \
514 	.address = (_address), \
515 	.indexed = 1, \
516 	.channel = (_index), \
517 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
518 			      BIT(IIO_CHAN_INFO_SCALE), \
519 	.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
520 				   BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
521 	.scan_index = (_index), \
522 	.scan_type = { \
523 		.sign = 'u', \
524 		.realbits = 16, \
525 		.storagebits = 16, \
526 		.endianness = IIO_CPU, \
527 	} \
528 }
529 
530 /*
531  * Sampling Freq is a consequence of the integration times of
532  * the Voltage channels.
533  */
534 #define INA219_CHAN_VOLTAGE(_index, _address) { \
535 	.type = IIO_VOLTAGE, \
536 	.address = (_address), \
537 	.indexed = 1, \
538 	.channel = (_index), \
539 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
540 			      BIT(IIO_CHAN_INFO_SCALE) | \
541 			      BIT(IIO_CHAN_INFO_INT_TIME), \
542 	.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
543 	.scan_index = (_index), \
544 	.scan_type = { \
545 		.sign = 'u', \
546 		.realbits = 16, \
547 		.storagebits = 16, \
548 		.endianness = IIO_LE, \
549 	} \
550 }
551 
552 #define INA226_CHAN_VOLTAGE(_index, _address) { \
553 	.type = IIO_VOLTAGE, \
554 	.address = (_address), \
555 	.indexed = 1, \
556 	.channel = (_index), \
557 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
558 			      BIT(IIO_CHAN_INFO_SCALE) | \
559 			      BIT(IIO_CHAN_INFO_INT_TIME), \
560 	.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
561 				   BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
562 	.scan_index = (_index), \
563 	.scan_type = { \
564 		.sign = 'u', \
565 		.realbits = 16, \
566 		.storagebits = 16, \
567 		.endianness = IIO_LE, \
568 	} \
569 }
570 
571 
572 static const struct iio_chan_spec ina226_channels[] = {
573 	INA226_CHAN_VOLTAGE(0, INA2XX_SHUNT_VOLTAGE),
574 	INA226_CHAN_VOLTAGE(1, INA2XX_BUS_VOLTAGE),
575 	INA226_CHAN(IIO_POWER, 2, INA2XX_POWER),
576 	INA226_CHAN(IIO_CURRENT, 3, INA2XX_CURRENT),
577 	IIO_CHAN_SOFT_TIMESTAMP(4),
578 };
579 
580 static const struct iio_chan_spec ina219_channels[] = {
581 	INA219_CHAN_VOLTAGE(0, INA2XX_SHUNT_VOLTAGE),
582 	INA219_CHAN_VOLTAGE(1, INA2XX_BUS_VOLTAGE),
583 	INA219_CHAN(IIO_POWER, 2, INA2XX_POWER),
584 	INA219_CHAN(IIO_CURRENT, 3, INA2XX_CURRENT),
585 	IIO_CHAN_SOFT_TIMESTAMP(4),
586 };
587 
588 static int ina2xx_work_buffer(struct iio_dev *indio_dev)
589 {
590 	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
591 	unsigned short data[8];
592 	int bit, ret, i = 0;
593 	s64 time_a, time_b;
594 	unsigned int alert;
595 
596 	time_a = iio_get_time_ns(indio_dev);
597 
598 	/*
599 	 * Because the timer thread and the chip conversion clock
600 	 * are asynchronous, the period difference will eventually
601 	 * result in reading V[k-1] again, or skip V[k] at time Tk.
602 	 * In order to resync the timer with the conversion process
603 	 * we check the ConVersionReadyFlag.
604 	 * On hardware that supports using the ALERT pin to toggle a
605 	 * GPIO a triggered buffer could be used instead.
606 	 * For now, we pay for that extra read of the ALERT register
607 	 */
608 	if (!chip->allow_async_readout)
609 		do {
610 			ret = regmap_read(chip->regmap, INA226_MASK_ENABLE,
611 					  &alert);
612 			if (ret < 0)
613 				return ret;
614 
615 			alert &= INA226_CVRF;
616 		} while (!alert);
617 
618 	/*
619 	 * Single register reads: bulk_read will not work with ina226
620 	 * as there is no auto-increment of the address register for
621 	 * data length longer than 16bits.
622 	 */
623 	for_each_set_bit(bit, indio_dev->active_scan_mask,
624 			 indio_dev->masklength) {
625 		unsigned int val;
626 
627 		ret = regmap_read(chip->regmap,
628 				  INA2XX_SHUNT_VOLTAGE + bit, &val);
629 		if (ret < 0)
630 			return ret;
631 
632 		data[i++] = val;
633 	}
634 
635 	time_b = iio_get_time_ns(indio_dev);
636 
637 	iio_push_to_buffers_with_timestamp(indio_dev,
638 					   (unsigned int *)data, time_a);
639 
640 	return (unsigned long)(time_b - time_a) / 1000;
641 };
642 
643 static int ina2xx_capture_thread(void *data)
644 {
645 	struct iio_dev *indio_dev = data;
646 	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
647 	unsigned int sampling_us = SAMPLING_PERIOD(chip);
648 	int buffer_us;
649 
650 	/*
651 	 * Poll a bit faster than the chip internal Fs, in case
652 	 * we wish to sync with the conversion ready flag.
653 	 */
654 	if (!chip->allow_async_readout)
655 		sampling_us -= 200;
656 
657 	do {
658 		buffer_us = ina2xx_work_buffer(indio_dev);
659 		if (buffer_us < 0)
660 			return buffer_us;
661 
662 		if (sampling_us > buffer_us)
663 			udelay(sampling_us - buffer_us);
664 
665 	} while (!kthread_should_stop());
666 
667 	return 0;
668 }
669 
670 static int ina2xx_buffer_enable(struct iio_dev *indio_dev)
671 {
672 	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
673 	unsigned int sampling_us = SAMPLING_PERIOD(chip);
674 
675 	dev_dbg(&indio_dev->dev, "Enabling buffer w/ scan_mask %02x, freq = %d, avg =%u\n",
676 		(unsigned int)(*indio_dev->active_scan_mask),
677 		1000000 / sampling_us, chip->avg);
678 
679 	dev_dbg(&indio_dev->dev, "Expected work period: %u us\n", sampling_us);
680 	dev_dbg(&indio_dev->dev, "Async readout mode: %d\n",
681 		chip->allow_async_readout);
682 
683 	chip->task = kthread_run(ina2xx_capture_thread, (void *)indio_dev,
684 				 "%s:%d-%uus", indio_dev->name, indio_dev->id,
685 				 sampling_us);
686 
687 	return PTR_ERR_OR_ZERO(chip->task);
688 }
689 
690 static int ina2xx_buffer_disable(struct iio_dev *indio_dev)
691 {
692 	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
693 
694 	if (chip->task) {
695 		kthread_stop(chip->task);
696 		chip->task = NULL;
697 	}
698 
699 	return 0;
700 }
701 
702 static const struct iio_buffer_setup_ops ina2xx_setup_ops = {
703 	.postenable = &ina2xx_buffer_enable,
704 	.predisable = &ina2xx_buffer_disable,
705 };
706 
707 static int ina2xx_debug_reg(struct iio_dev *indio_dev,
708 			    unsigned reg, unsigned writeval, unsigned *readval)
709 {
710 	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
711 
712 	if (!readval)
713 		return regmap_write(chip->regmap, reg, writeval);
714 
715 	return regmap_read(chip->regmap, reg, readval);
716 }
717 
718 /* Possible integration times for vshunt and vbus */
719 static IIO_CONST_ATTR_NAMED(ina219_integration_time_available,
720 			    integration_time_available,
721 			    "0.000084 0.000148 0.000276 0.000532 0.001060 0.002130 0.004260 0.008510 0.017020 0.034050 0.068100");
722 
723 static IIO_CONST_ATTR_NAMED(ina226_integration_time_available,
724 			    integration_time_available,
725 			    "0.000140 0.000204 0.000332 0.000588 0.001100 0.002116 0.004156 0.008244");
726 
727 
728 static IIO_DEVICE_ATTR(in_allow_async_readout, S_IRUGO | S_IWUSR,
729 		       ina2xx_allow_async_readout_show,
730 		       ina2xx_allow_async_readout_store, 0);
731 
732 static IIO_DEVICE_ATTR(in_shunt_resistor, S_IRUGO | S_IWUSR,
733 		       ina2xx_shunt_resistor_show,
734 		       ina2xx_shunt_resistor_store, 0);
735 
736 static struct attribute *ina219_attributes[] = {
737 	&iio_dev_attr_in_allow_async_readout.dev_attr.attr,
738 	&iio_const_attr_ina219_integration_time_available.dev_attr.attr,
739 	&iio_dev_attr_in_shunt_resistor.dev_attr.attr,
740 	NULL,
741 };
742 
743 static struct attribute *ina226_attributes[] = {
744 	&iio_dev_attr_in_allow_async_readout.dev_attr.attr,
745 	&iio_const_attr_ina226_integration_time_available.dev_attr.attr,
746 	&iio_dev_attr_in_shunt_resistor.dev_attr.attr,
747 	NULL,
748 };
749 
750 static const struct attribute_group ina219_attribute_group = {
751 	.attrs = ina219_attributes,
752 };
753 
754 static const struct attribute_group ina226_attribute_group = {
755 	.attrs = ina226_attributes,
756 };
757 
758 static const struct iio_info ina219_info = {
759 	.driver_module = THIS_MODULE,
760 	.attrs = &ina219_attribute_group,
761 	.read_raw = ina2xx_read_raw,
762 	.write_raw = ina2xx_write_raw,
763 	.debugfs_reg_access = ina2xx_debug_reg,
764 };
765 
766 static const struct iio_info ina226_info = {
767 	.driver_module = THIS_MODULE,
768 	.attrs = &ina226_attribute_group,
769 	.read_raw = ina2xx_read_raw,
770 	.write_raw = ina2xx_write_raw,
771 	.debugfs_reg_access = ina2xx_debug_reg,
772 };
773 
774 /* Initialize the configuration and calibration registers. */
775 static int ina2xx_init(struct ina2xx_chip_info *chip, unsigned int config)
776 {
777 	int ret = regmap_write(chip->regmap, INA2XX_CONFIG, config);
778 	if (ret)
779 		return ret;
780 
781 	return ina2xx_set_calibration(chip);
782 }
783 
784 static int ina2xx_probe(struct i2c_client *client,
785 			const struct i2c_device_id *id)
786 {
787 	struct ina2xx_chip_info *chip;
788 	struct iio_dev *indio_dev;
789 	struct iio_buffer *buffer;
790 	unsigned int val;
791 	enum ina2xx_ids type;
792 	int ret;
793 
794 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
795 	if (!indio_dev)
796 		return -ENOMEM;
797 
798 	chip = iio_priv(indio_dev);
799 
800 	/* This is only used for device removal purposes. */
801 	i2c_set_clientdata(client, indio_dev);
802 
803 	chip->regmap = devm_regmap_init_i2c(client, &ina2xx_regmap_config);
804 	if (IS_ERR(chip->regmap)) {
805 		dev_err(&client->dev, "failed to allocate register map\n");
806 		return PTR_ERR(chip->regmap);
807 	}
808 
809 	if (client->dev.of_node)
810 		type = (enum ina2xx_ids)of_device_get_match_data(&client->dev);
811 	else
812 		type = id->driver_data;
813 	chip->config = &ina2xx_config[type];
814 
815 	mutex_init(&chip->state_lock);
816 
817 	if (of_property_read_u32(client->dev.of_node,
818 				 "shunt-resistor", &val) < 0) {
819 		struct ina2xx_platform_data *pdata =
820 		    dev_get_platdata(&client->dev);
821 
822 		if (pdata)
823 			val = pdata->shunt_uohms;
824 		else
825 			val = INA2XX_RSHUNT_DEFAULT;
826 	}
827 
828 	ret = set_shunt_resistor(chip, val);
829 	if (ret)
830 		return ret;
831 
832 	/* Patch the current config register with default. */
833 	val = chip->config->config_default;
834 
835 	if (id->driver_data == ina226) {
836 		ina226_set_average(chip, INA226_DEFAULT_AVG, &val);
837 		ina226_set_int_time_vbus(chip, INA226_DEFAULT_IT, &val);
838 		ina226_set_int_time_vshunt(chip, INA226_DEFAULT_IT, &val);
839 	} else {
840 		chip->avg = 1;
841 		ina219_set_int_time_vbus(chip, INA219_DEFAULT_IT, &val);
842 		ina219_set_int_time_vshunt(chip, INA219_DEFAULT_IT, &val);
843 	}
844 
845 	ret = ina2xx_init(chip, val);
846 	if (ret) {
847 		dev_err(&client->dev, "error configuring the device\n");
848 		return ret;
849 	}
850 
851 	indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
852 	indio_dev->dev.parent = &client->dev;
853 	indio_dev->dev.of_node = client->dev.of_node;
854 	if (id->driver_data == ina226) {
855 		indio_dev->channels = ina226_channels;
856 		indio_dev->num_channels = ARRAY_SIZE(ina226_channels);
857 		indio_dev->info = &ina226_info;
858 	} else {
859 		indio_dev->channels = ina219_channels;
860 		indio_dev->num_channels = ARRAY_SIZE(ina219_channels);
861 		indio_dev->info = &ina219_info;
862 	}
863 	indio_dev->name = id->name;
864 	indio_dev->setup_ops = &ina2xx_setup_ops;
865 
866 	buffer = devm_iio_kfifo_allocate(&indio_dev->dev);
867 	if (!buffer)
868 		return -ENOMEM;
869 
870 	iio_device_attach_buffer(indio_dev, buffer);
871 
872 	return iio_device_register(indio_dev);
873 }
874 
875 static int ina2xx_remove(struct i2c_client *client)
876 {
877 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
878 	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
879 
880 	iio_device_unregister(indio_dev);
881 
882 	/* Powerdown */
883 	return regmap_update_bits(chip->regmap, INA2XX_CONFIG,
884 				  INA2XX_MODE_MASK, 0);
885 }
886 
887 static const struct i2c_device_id ina2xx_id[] = {
888 	{"ina219", ina219},
889 	{"ina220", ina219},
890 	{"ina226", ina226},
891 	{"ina230", ina226},
892 	{"ina231", ina226},
893 	{}
894 };
895 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
896 
897 static const struct of_device_id ina2xx_of_match[] = {
898 	{
899 		.compatible = "ti,ina219",
900 		.data = (void *)ina219
901 	},
902 	{
903 		.compatible = "ti,ina220",
904 		.data = (void *)ina219
905 	},
906 	{
907 		.compatible = "ti,ina226",
908 		.data = (void *)ina226
909 	},
910 	{
911 		.compatible = "ti,ina230",
912 		.data = (void *)ina226
913 	},
914 	{
915 		.compatible = "ti,ina231",
916 		.data = (void *)ina226
917 	},
918 	{},
919 };
920 MODULE_DEVICE_TABLE(of, ina2xx_of_match);
921 
922 static struct i2c_driver ina2xx_driver = {
923 	.driver = {
924 		   .name = KBUILD_MODNAME,
925 		   .of_match_table = ina2xx_of_match,
926 	},
927 	.probe = ina2xx_probe,
928 	.remove = ina2xx_remove,
929 	.id_table = ina2xx_id,
930 };
931 module_i2c_driver(ina2xx_driver);
932 
933 MODULE_AUTHOR("Marc Titinger <marc.titinger@baylibre.com>");
934 MODULE_DESCRIPTION("Texas Instruments INA2XX ADC driver");
935 MODULE_LICENSE("GPL v2");
936