summaryrefslogtreecommitdiff
path: root/drivers/hwmon/ina2xx.c
blob: 611ec4edd97993871437b90272fb0f19aeaa03c3 (plain)
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
/*
 * Driver for Texas Instruments INA219, INA226 power monitor chips
 *
 * INA219:
 * Zero Drift Bi-Directional Current/Power Monitor with I2C Interface
 * Datasheet: http://www.ti.com/product/ina219
 *
 * INA220:
 * Bi-Directional Current/Power Monitor with I2C Interface
 * Datasheet: http://www.ti.com/product/ina220
 *
 * INA226:
 * Bi-Directional Current/Power Monitor with I2C Interface
 * Datasheet: http://www.ti.com/product/ina226
 *
 * INA230:
 * Bi-directional Current/Power Monitor with I2C Interface
 * Datasheet: http://www.ti.com/product/ina230
 *
 * 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.
 */

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

#include <linux/platform_data/ina2xx.h>

/* common register definitions */
#define INA2XX_CONFIG			0x00
#define INA2XX_SHUNT_VOLTAGE		0x01 /* readonly */
#define INA2XX_BUS_VOLTAGE		0x02 /* readonly */
#define INA2XX_POWER			0x03 /* readonly */
#define INA2XX_CURRENT			0x04 /* readonly */
#define INA2XX_CALIBRATION		0x05

/* INA226 register definitions */
#define INA226_MASK_ENABLE		0x06
#define INA226_ALERT_LIMIT		0x07
#define INA226_DIE_ID			0xFF

/* register count */
#define INA219_REGISTERS		6
#define INA226_REGISTERS		8

#define INA2XX_MAX_REGISTERS		8

/* settings - depend on use case */
#define INA219_CONFIG_DEFAULT		0x399F	/* PGA=8 */
#define INA226_CONFIG_DEFAULT		0x4527	/* averages=16 */

/* worst case is 68.10 ms (~14.6Hz, ina219) */
#define INA2XX_CONVERSION_RATE		15
#define INA2XX_MAX_DELAY		69 /* worst case delay in ms */

#define INA2XX_RSHUNT_DEFAULT		10000

/* bit mask for reading the averaging setting in the configuration register */
#define INA226_AVG_RD_MASK		0x0E00

#define INA226_READ_AVG(reg)		(((reg) & INA226_AVG_RD_MASK) >> 9)
#define INA226_SHIFT_AVG(val)		((val) << 9)

/* common attrs, ina226 attrs and NULL */
#define INA2XX_MAX_ATTRIBUTE_GROUPS	3

/*
 * Both bus voltage and shunt voltage conversion times for ina226 are set
 * to 0b0100 on POR, which translates to 2200 microseconds in total.
 */
#define INA226_TOTAL_CONV_TIME_DEFAULT	2200

enum ina2xx_ids { ina219, ina226 };

struct ina2xx_config {
	u16 config_default;
	int calibration_factor;
	int registers;
	int shunt_div;
	int bus_voltage_shift;
	int bus_voltage_lsb;	/* uV */
	int power_lsb;		/* uW */
};

struct ina2xx_data {
	struct i2c_client *client;
	const struct ina2xx_config *config;

	long rshunt;
	u16 curr_config;

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

	int kind;
	const struct attribute_group *groups[INA2XX_MAX_ATTRIBUTE_GROUPS];
	u16 regs[INA2XX_MAX_REGISTERS];
};

static const struct ina2xx_config ina2xx_config[] = {
	[ina219] = {
		.config_default = INA219_CONFIG_DEFAULT,
		.calibration_factor = 40960000,
		.registers = INA219_REGISTERS,
		.shunt_div = 100,
		.bus_voltage_shift = 3,
		.bus_voltage_lsb = 4000,
		.power_lsb = 20000,
	},
	[ina226] = {
		.config_default = INA226_CONFIG_DEFAULT,
		.calibration_factor = 5120000,
		.registers = INA226_REGISTERS,
		.shunt_div = 400,
		.bus_voltage_shift = 0,
		.bus_voltage_lsb = 1250,
		.power_lsb = 25000,
	},
};

/*
 * Available averaging rates for ina226. The indices correspond with
 * the bit values expected by the chip (according to the ina226 datasheet,
 * table 3 AVG bit settings, found at
 * http://www.ti.com/lit/ds/symlink/ina226.pdf.
 */
static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };

static int ina226_avg_bits(int avg)
{
	int i;

	/* Get the closest average from the tab. */
	for (i = 0; i < ARRAY_SIZE(ina226_avg_tab) - 1; i++) {
		if (avg <= (ina226_avg_tab[i] + ina226_avg_tab[i + 1]) / 2)
			break;
	}

	return i; /* Return 0b0111 for values greater than 1024. */
}

static int ina226_reg_to_interval(u16 config)
{
	int avg = ina226_avg_tab[INA226_READ_AVG(config)];

	/*
	 * Multiply the total conversion time by the number of averages.
	 * Return the result in milliseconds.
	 */
	return DIV_ROUND_CLOSEST(avg * INA226_TOTAL_CONV_TIME_DEFAULT, 1000);
}

static u16 ina226_interval_to_reg(int interval, u16 config)
{
	int avg, avg_bits;

	avg = DIV_ROUND_CLOSEST(interval * 1000,
				INA226_TOTAL_CONV_TIME_DEFAULT);
	avg_bits = ina226_avg_bits(avg);

	return (config & ~INA226_AVG_RD_MASK) | INA226_SHIFT_AVG(avg_bits);
}

static void ina226_set_update_interval(struct ina2xx_data *data)
{
	int ms;

	ms = ina226_reg_to_interval(data->curr_config);
	data->update_interval = msecs_to_jiffies(ms);
}

static int ina2xx_calibrate(struct ina2xx_data *data)
{
	u16 val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
				    data->rshunt);

	return i2c_smbus_write_word_swapped(data->client,
					    INA2XX_CALIBRATION, val);
}

/*
 * Initialize the configuration and calibration registers.
 */
static int ina2xx_init(struct ina2xx_data *data)
{
	struct i2c_client *client = data->client;
	int ret;

	/* device configuration */
	ret = i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
					   data->curr_config);
	if (ret < 0)
		return ret;

	/*
	 * Set current LSB to 1mA, shunt is in uOhms
	 * (equation 13 in datasheet).
	 */
	return ina2xx_calibrate(data);
}

static int ina2xx_do_update(struct device *dev)
{
	struct ina2xx_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	int i, rv, retry;

	dev_dbg(&client->dev, "Starting ina2xx update\n");

	for (retry = 5; retry; retry--) {
		/* Read all registers */
		for (i = 0; i < data->config->registers; i++) {
			rv = i2c_smbus_read_word_swapped(client, i);
			if (rv < 0)
				return rv;
			data->regs[i] = rv;
		}

		/*
		 * If the current value in the calibration register is 0, the
		 * power and current registers will also remain at 0. In case
		 * the chip has been reset let's check the calibration
		 * register and reinitialize if needed.
		 */
		if (data->regs[INA2XX_CALIBRATION] == 0) {
			dev_warn(dev, "chip not calibrated, reinitializing\n");

			rv = ina2xx_init(data);
			if (rv < 0)
				return rv;

			/*
			 * Let's make sure the power and current registers
			 * have been updated before trying again.
			 */
			msleep(INA2XX_MAX_DELAY);
			continue;
		}

		data->last_updated = jiffies;
		data->valid = 1;

		return 0;
	}

	/*
	 * If we're here then although all write operations succeeded, the
	 * chip still returns 0 in the calibration register. Nothing more we
	 * can do here.
	 */
	dev_err(dev, "unable to reinitialize the chip\n");
	return -ENODEV;
}

static struct ina2xx_data *ina2xx_update_device(struct device *dev)
{
	struct ina2xx_data *data = dev_get_drvdata(dev);
	struct ina2xx_data *ret = data;
	unsigned long after;
	int rv;

	mutex_lock(&data->update_lock);

	after = data->last_updated + data->update_interval;
	if (time_after(jiffies, after) || !data->valid) {
		rv = ina2xx_do_update(dev);
		if (rv < 0)
			ret = ERR_PTR(rv);
	}

	mutex_unlock(&data->update_lock);
	return ret;
}

static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
{
	int val;

	switch (reg) {
	case INA2XX_SHUNT_VOLTAGE:
		/* signed register */
		val = DIV_ROUND_CLOSEST((s16)data->regs[reg],
					data->config->shunt_div);
		break;
	case INA2XX_BUS_VOLTAGE:
		val = (data->regs[reg] >> data->config->bus_voltage_shift)
		  * data->config->bus_voltage_lsb;
		val = DIV_ROUND_CLOSEST(val, 1000);
		break;
	case INA2XX_POWER:
		val = data->regs[reg] * data->config->power_lsb;
		break;
	case INA2XX_CURRENT:
		/* signed register, LSB=1mA (selected), in mA */
		val = (s16)data->regs[reg];
		break;
	case INA2XX_CALIBRATION:
		val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
					data->regs[reg]);
		break;
	default:
		/* programmer goofed */
		WARN_ON_ONCE(1);
		val = 0;
		break;
	}

	return val;
}

static ssize_t ina2xx_show_value(struct device *dev,
				 struct device_attribute *da, char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ina2xx_data *data = ina2xx_update_device(dev);

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

	return snprintf(buf, PAGE_SIZE, "%d\n",
			ina2xx_get_value(data, attr->index));
}

static ssize_t ina2xx_set_shunt(struct device *dev,
				struct device_attribute *da,
				const char *buf, size_t count)
{
	struct ina2xx_data *data = ina2xx_update_device(dev);
	unsigned long val;
	int status;

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

	status = kstrtoul(buf, 10, &val);
	if (status < 0)
		return status;

	if (val == 0 ||
	    /* Values greater than the calibration factor make no sense. */
	    val > data->config->calibration_factor)
		return -EINVAL;

	mutex_lock(&data->update_lock);
	data->rshunt = val;
	status = ina2xx_calibrate(data);
	mutex_unlock(&data->update_lock);
	if (status < 0)
		return status;

	return count;
}

static ssize_t ina226_set_interval(struct device *dev,
				   struct device_attribute *da,
				   const char *buf, size_t count)
{
	struct ina2xx_data *data = dev_get_drvdata(dev);
	unsigned long val;
	int status;

	status = kstrtoul(buf, 10, &val);
	if (status < 0)
		return status;

	if (val > INT_MAX || val == 0)
		return -EINVAL;

	mutex_lock(&data->update_lock);
	data->curr_config = ina226_interval_to_reg(val,
						   data->regs[INA2XX_CONFIG]);
	status = i2c_smbus_write_word_swapped(data->client,
					      INA2XX_CONFIG,
					      data->curr_config);

	ina226_set_update_interval(data);
	/* Make sure the next access re-reads all registers. */
	data->valid = 0;
	mutex_unlock(&data->update_lock);
	if (status < 0)
		return status;

	return count;
}

static ssize_t ina226_show_interval(struct device *dev,
				    struct device_attribute *da, char *buf)
{
	struct ina2xx_data *data = ina2xx_update_device(dev);

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

	/*
	 * We don't use data->update_interval here as we want to display
	 * the actual interval used by the chip and jiffies_to_msecs()
	 * doesn't seem to be accurate enough.
	 */
	return snprintf(buf, PAGE_SIZE, "%d\n",
			ina226_reg_to_interval(data->regs[INA2XX_CONFIG]));
}

/* shunt voltage */
static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
			  INA2XX_SHUNT_VOLTAGE);

/* bus voltage */
static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
			  INA2XX_BUS_VOLTAGE);

/* calculated current */
static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
			  INA2XX_CURRENT);

/* calculated power */
static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
			  INA2XX_POWER);

/* shunt resistance */
static SENSOR_DEVICE_ATTR(shunt_resistor, S_IRUGO | S_IWUSR,
			  ina2xx_show_value, ina2xx_set_shunt,
			  INA2XX_CALIBRATION);

/* update interval (ina226 only) */
static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
			  ina226_show_interval, ina226_set_interval, 0);

/* pointers to created device attributes */
static struct attribute *ina2xx_attrs[] = {
	&sensor_dev_attr_in0_input.dev_attr.attr,
	&sensor_dev_attr_in1_input.dev_attr.attr,
	&sensor_dev_attr_curr1_input.dev_attr.attr,
	&sensor_dev_attr_power1_input.dev_attr.attr,
	&sensor_dev_attr_shunt_resistor.dev_attr.attr,
	NULL,
};

static const struct attribute_group ina2xx_group = {
	.attrs = ina2xx_attrs,
};

static struct attribute *ina226_attrs[] = {
	&sensor_dev_attr_update_interval.dev_attr.attr,
	NULL,
};

static const struct attribute_group ina226_group = {
	.attrs = ina226_attrs,
};

static int ina2xx_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct i2c_adapter *adapter = client->adapter;
	struct ina2xx_platform_data *pdata;
	struct device *dev = &client->dev;
	struct ina2xx_data *data;
	struct device *hwmon_dev;
	u32 val;
	int ret, group = 0;

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

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

	if (dev_get_platdata(dev)) {
		pdata = dev_get_platdata(dev);
		data->rshunt = pdata->shunt_uohms;
	} else if (!of_property_read_u32(dev->of_node,
					 "shunt-resistor", &val)) {
		data->rshunt = val;
	} else {
		data->rshunt = INA2XX_RSHUNT_DEFAULT;
	}

	/* set the device type */
	data->kind = id->driver_data;
	data->config = &ina2xx_config[data->kind];
	data->curr_config = data->config->config_default;
	data->client = client;

	/*
	 * Ina226 has a variable update_interval. For ina219 we
	 * use a constant value.
	 */
	if (data->kind == ina226)
		ina226_set_update_interval(data);
	else
		data->update_interval = HZ / INA2XX_CONVERSION_RATE;

	if (data->rshunt <= 0 ||
	    data->rshunt > data->config->calibration_factor)
		return -ENODEV;

	ret = ina2xx_init(data);
	if (ret < 0) {
		dev_err(dev, "error configuring the device: %d\n", ret);
		return -ENODEV;
	}

	mutex_init(&data->update_lock);

	data->groups[group++] = &ina2xx_group;
	if (data->kind == ina226)
		data->groups[group++] = &ina226_group;

	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
							   data, data->groups);
	if (IS_ERR(hwmon_dev))
		return PTR_ERR(hwmon_dev);

	dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
		 id->name, data->rshunt);

	return 0;
}

static const struct i2c_device_id ina2xx_id[] = {
	{ "ina219", ina219 },
	{ "ina220", ina219 },
	{ "ina226", ina226 },
	{ "ina230", ina226 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ina2xx_id);

static struct i2c_driver ina2xx_driver = {
	.driver = {
		.name	= "ina2xx",
	},
	.probe		= ina2xx_probe,
	.id_table	= ina2xx_id,
};

module_i2c_driver(ina2xx_driver);

MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
MODULE_DESCRIPTION("ina2xx driver");
MODULE_LICENSE("GPL");