xref: /linux/drivers/hwmon/ina2xx.c (revision c0e297dc61f8d4453e07afbea1fa8d0e67cd4a34) 
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 #include <linux/util_macros.h>
40 
41 #include <linux/platform_data/ina2xx.h>
42 
43 /* common register definitions */
44 #define INA2XX_CONFIG			0x00
45 #define INA2XX_SHUNT_VOLTAGE		0x01 /* readonly */
46 #define INA2XX_BUS_VOLTAGE		0x02 /* readonly */
47 #define INA2XX_POWER			0x03 /* readonly */
48 #define INA2XX_CURRENT			0x04 /* readonly */
49 #define INA2XX_CALIBRATION		0x05
50 
51 /* INA226 register definitions */
52 #define INA226_MASK_ENABLE		0x06
53 #define INA226_ALERT_LIMIT		0x07
54 #define INA226_DIE_ID			0xFF
55 
56 /* register count */
57 #define INA219_REGISTERS		6
58 #define INA226_REGISTERS		8
59 
60 #define INA2XX_MAX_REGISTERS		8
61 
62 /* settings - depend on use case */
63 #define INA219_CONFIG_DEFAULT		0x399F	/* PGA=8 */
64 #define INA226_CONFIG_DEFAULT		0x4527	/* averages=16 */
65 
66 /* worst case is 68.10 ms (~14.6Hz, ina219) */
67 #define INA2XX_CONVERSION_RATE		15
68 #define INA2XX_MAX_DELAY		69 /* worst case delay in ms */
69 
70 #define INA2XX_RSHUNT_DEFAULT		10000
71 
72 /* bit mask for reading the averaging setting in the configuration register */
73 #define INA226_AVG_RD_MASK		0x0E00
74 
75 #define INA226_READ_AVG(reg)		(((reg) & INA226_AVG_RD_MASK) >> 9)
76 #define INA226_SHIFT_AVG(val)		((val) << 9)
77 
78 /* common attrs, ina226 attrs and NULL */
79 #define INA2XX_MAX_ATTRIBUTE_GROUPS	3
80 
81 /*
82  * Both bus voltage and shunt voltage conversion times for ina226 are set
83  * to 0b0100 on POR, which translates to 2200 microseconds in total.
84  */
85 #define INA226_TOTAL_CONV_TIME_DEFAULT	2200
86 
87 enum ina2xx_ids { ina219, ina226 };
88 
89 struct ina2xx_config {
90 	u16 config_default;
91 	int calibration_factor;
92 	int registers;
93 	int shunt_div;
94 	int bus_voltage_shift;
95 	int bus_voltage_lsb;	/* uV */
96 	int power_lsb;		/* uW */
97 };
98 
99 struct ina2xx_data {
100 	struct i2c_client *client;
101 	const struct ina2xx_config *config;
102 
103 	long rshunt;
104 	u16 curr_config;
105 
106 	struct mutex update_lock;
107 	bool valid;
108 	unsigned long last_updated;
109 	int update_interval; /* in jiffies */
110 
111 	int kind;
112 	const struct attribute_group *groups[INA2XX_MAX_ATTRIBUTE_GROUPS];
113 	u16 regs[INA2XX_MAX_REGISTERS];
114 };
115 
116 static const struct ina2xx_config ina2xx_config[] = {
117 	[ina219] = {
118 		.config_default = INA219_CONFIG_DEFAULT,
119 		.calibration_factor = 40960000,
120 		.registers = INA219_REGISTERS,
121 		.shunt_div = 100,
122 		.bus_voltage_shift = 3,
123 		.bus_voltage_lsb = 4000,
124 		.power_lsb = 20000,
125 	},
126 	[ina226] = {
127 		.config_default = INA226_CONFIG_DEFAULT,
128 		.calibration_factor = 5120000,
129 		.registers = INA226_REGISTERS,
130 		.shunt_div = 400,
131 		.bus_voltage_shift = 0,
132 		.bus_voltage_lsb = 1250,
133 		.power_lsb = 25000,
134 	},
135 };
136 
137 /*
138  * Available averaging rates for ina226. The indices correspond with
139  * the bit values expected by the chip (according to the ina226 datasheet,
140  * table 3 AVG bit settings, found at
141  * http://www.ti.com/lit/ds/symlink/ina226.pdf.
142  */
143 static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };
144 
145 static int ina226_reg_to_interval(u16 config)
146 {
147 	int avg = ina226_avg_tab[INA226_READ_AVG(config)];
148 
149 	/*
150 	 * Multiply the total conversion time by the number of averages.
151 	 * Return the result in milliseconds.
152 	 */
153 	return DIV_ROUND_CLOSEST(avg * INA226_TOTAL_CONV_TIME_DEFAULT, 1000);
154 }
155 
156 static u16 ina226_interval_to_reg(int interval, u16 config)
157 {
158 	int avg, avg_bits;
159 
160 	avg = DIV_ROUND_CLOSEST(interval * 1000,
161 				INA226_TOTAL_CONV_TIME_DEFAULT);
162 	avg_bits = find_closest(avg, ina226_avg_tab,
163 				ARRAY_SIZE(ina226_avg_tab));
164 
165 	return (config & ~INA226_AVG_RD_MASK) | INA226_SHIFT_AVG(avg_bits);
166 }
167 
168 static void ina226_set_update_interval(struct ina2xx_data *data)
169 {
170 	int ms;
171 
172 	ms = ina226_reg_to_interval(data->curr_config);
173 	data->update_interval = msecs_to_jiffies(ms);
174 }
175 
176 static int ina2xx_calibrate(struct ina2xx_data *data)
177 {
178 	u16 val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
179 				    data->rshunt);
180 
181 	return i2c_smbus_write_word_swapped(data->client,
182 					    INA2XX_CALIBRATION, val);
183 }
184 
185 /*
186  * Initialize the configuration and calibration registers.
187  */
188 static int ina2xx_init(struct ina2xx_data *data)
189 {
190 	struct i2c_client *client = data->client;
191 	int ret;
192 
193 	/* device configuration */
194 	ret = i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
195 					   data->curr_config);
196 	if (ret < 0)
197 		return ret;
198 
199 	/*
200 	 * Set current LSB to 1mA, shunt is in uOhms
201 	 * (equation 13 in datasheet).
202 	 */
203 	return ina2xx_calibrate(data);
204 }
205 
206 static int ina2xx_do_update(struct device *dev)
207 {
208 	struct ina2xx_data *data = dev_get_drvdata(dev);
209 	struct i2c_client *client = data->client;
210 	int i, rv, retry;
211 
212 	dev_dbg(&client->dev, "Starting ina2xx update\n");
213 
214 	for (retry = 5; retry; retry--) {
215 		/* Read all registers */
216 		for (i = 0; i < data->config->registers; i++) {
217 			rv = i2c_smbus_read_word_swapped(client, i);
218 			if (rv < 0)
219 				return rv;
220 			data->regs[i] = rv;
221 		}
222 
223 		/*
224 		 * If the current value in the calibration register is 0, the
225 		 * power and current registers will also remain at 0. In case
226 		 * the chip has been reset let's check the calibration
227 		 * register and reinitialize if needed.
228 		 */
229 		if (data->regs[INA2XX_CALIBRATION] == 0) {
230 			dev_warn(dev, "chip not calibrated, reinitializing\n");
231 
232 			rv = ina2xx_init(data);
233 			if (rv < 0)
234 				return rv;
235 
236 			/*
237 			 * Let's make sure the power and current registers
238 			 * have been updated before trying again.
239 			 */
240 			msleep(INA2XX_MAX_DELAY);
241 			continue;
242 		}
243 
244 		data->last_updated = jiffies;
245 		data->valid = 1;
246 
247 		return 0;
248 	}
249 
250 	/*
251 	 * If we're here then although all write operations succeeded, the
252 	 * chip still returns 0 in the calibration register. Nothing more we
253 	 * can do here.
254 	 */
255 	dev_err(dev, "unable to reinitialize the chip\n");
256 	return -ENODEV;
257 }
258 
259 static struct ina2xx_data *ina2xx_update_device(struct device *dev)
260 {
261 	struct ina2xx_data *data = dev_get_drvdata(dev);
262 	struct ina2xx_data *ret = data;
263 	unsigned long after;
264 	int rv;
265 
266 	mutex_lock(&data->update_lock);
267 
268 	after = data->last_updated + data->update_interval;
269 	if (time_after(jiffies, after) || !data->valid) {
270 		rv = ina2xx_do_update(dev);
271 		if (rv < 0)
272 			ret = ERR_PTR(rv);
273 	}
274 
275 	mutex_unlock(&data->update_lock);
276 	return ret;
277 }
278 
279 static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
280 {
281 	int val;
282 
283 	switch (reg) {
284 	case INA2XX_SHUNT_VOLTAGE:
285 		/* signed register */
286 		val = DIV_ROUND_CLOSEST((s16)data->regs[reg],
287 					data->config->shunt_div);
288 		break;
289 	case INA2XX_BUS_VOLTAGE:
290 		val = (data->regs[reg] >> data->config->bus_voltage_shift)
291 		  * data->config->bus_voltage_lsb;
292 		val = DIV_ROUND_CLOSEST(val, 1000);
293 		break;
294 	case INA2XX_POWER:
295 		val = data->regs[reg] * data->config->power_lsb;
296 		break;
297 	case INA2XX_CURRENT:
298 		/* signed register, LSB=1mA (selected), in mA */
299 		val = (s16)data->regs[reg];
300 		break;
301 	case INA2XX_CALIBRATION:
302 		val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
303 					data->regs[reg]);
304 		break;
305 	default:
306 		/* programmer goofed */
307 		WARN_ON_ONCE(1);
308 		val = 0;
309 		break;
310 	}
311 
312 	return val;
313 }
314 
315 static ssize_t ina2xx_show_value(struct device *dev,
316 				 struct device_attribute *da, char *buf)
317 {
318 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
319 	struct ina2xx_data *data = ina2xx_update_device(dev);
320 
321 	if (IS_ERR(data))
322 		return PTR_ERR(data);
323 
324 	return snprintf(buf, PAGE_SIZE, "%d\n",
325 			ina2xx_get_value(data, attr->index));
326 }
327 
328 static ssize_t ina2xx_set_shunt(struct device *dev,
329 				struct device_attribute *da,
330 				const char *buf, size_t count)
331 {
332 	struct ina2xx_data *data = ina2xx_update_device(dev);
333 	unsigned long val;
334 	int status;
335 
336 	if (IS_ERR(data))
337 		return PTR_ERR(data);
338 
339 	status = kstrtoul(buf, 10, &val);
340 	if (status < 0)
341 		return status;
342 
343 	if (val == 0 ||
344 	    /* Values greater than the calibration factor make no sense. */
345 	    val > data->config->calibration_factor)
346 		return -EINVAL;
347 
348 	mutex_lock(&data->update_lock);
349 	data->rshunt = val;
350 	status = ina2xx_calibrate(data);
351 	mutex_unlock(&data->update_lock);
352 	if (status < 0)
353 		return status;
354 
355 	return count;
356 }
357 
358 static ssize_t ina226_set_interval(struct device *dev,
359 				   struct device_attribute *da,
360 				   const char *buf, size_t count)
361 {
362 	struct ina2xx_data *data = dev_get_drvdata(dev);
363 	unsigned long val;
364 	int status;
365 
366 	status = kstrtoul(buf, 10, &val);
367 	if (status < 0)
368 		return status;
369 
370 	if (val > INT_MAX || val == 0)
371 		return -EINVAL;
372 
373 	mutex_lock(&data->update_lock);
374 	data->curr_config = ina226_interval_to_reg(val,
375 						   data->regs[INA2XX_CONFIG]);
376 	status = i2c_smbus_write_word_swapped(data->client,
377 					      INA2XX_CONFIG,
378 					      data->curr_config);
379 
380 	ina226_set_update_interval(data);
381 	/* Make sure the next access re-reads all registers. */
382 	data->valid = 0;
383 	mutex_unlock(&data->update_lock);
384 	if (status < 0)
385 		return status;
386 
387 	return count;
388 }
389 
390 static ssize_t ina226_show_interval(struct device *dev,
391 				    struct device_attribute *da, char *buf)
392 {
393 	struct ina2xx_data *data = ina2xx_update_device(dev);
394 
395 	if (IS_ERR(data))
396 		return PTR_ERR(data);
397 
398 	/*
399 	 * We don't use data->update_interval here as we want to display
400 	 * the actual interval used by the chip and jiffies_to_msecs()
401 	 * doesn't seem to be accurate enough.
402 	 */
403 	return snprintf(buf, PAGE_SIZE, "%d\n",
404 			ina226_reg_to_interval(data->regs[INA2XX_CONFIG]));
405 }
406 
407 /* shunt voltage */
408 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
409 			  INA2XX_SHUNT_VOLTAGE);
410 
411 /* bus voltage */
412 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
413 			  INA2XX_BUS_VOLTAGE);
414 
415 /* calculated current */
416 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
417 			  INA2XX_CURRENT);
418 
419 /* calculated power */
420 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
421 			  INA2XX_POWER);
422 
423 /* shunt resistance */
424 static SENSOR_DEVICE_ATTR(shunt_resistor, S_IRUGO | S_IWUSR,
425 			  ina2xx_show_value, ina2xx_set_shunt,
426 			  INA2XX_CALIBRATION);
427 
428 /* update interval (ina226 only) */
429 static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
430 			  ina226_show_interval, ina226_set_interval, 0);
431 
432 /* pointers to created device attributes */
433 static struct attribute *ina2xx_attrs[] = {
434 	&sensor_dev_attr_in0_input.dev_attr.attr,
435 	&sensor_dev_attr_in1_input.dev_attr.attr,
436 	&sensor_dev_attr_curr1_input.dev_attr.attr,
437 	&sensor_dev_attr_power1_input.dev_attr.attr,
438 	&sensor_dev_attr_shunt_resistor.dev_attr.attr,
439 	NULL,
440 };
441 
442 static const struct attribute_group ina2xx_group = {
443 	.attrs = ina2xx_attrs,
444 };
445 
446 static struct attribute *ina226_attrs[] = {
447 	&sensor_dev_attr_update_interval.dev_attr.attr,
448 	NULL,
449 };
450 
451 static const struct attribute_group ina226_group = {
452 	.attrs = ina226_attrs,
453 };
454 
455 static int ina2xx_probe(struct i2c_client *client,
456 			const struct i2c_device_id *id)
457 {
458 	struct i2c_adapter *adapter = client->adapter;
459 	struct ina2xx_platform_data *pdata;
460 	struct device *dev = &client->dev;
461 	struct ina2xx_data *data;
462 	struct device *hwmon_dev;
463 	u32 val;
464 	int ret, group = 0;
465 
466 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
467 		return -ENODEV;
468 
469 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
470 	if (!data)
471 		return -ENOMEM;
472 
473 	if (dev_get_platdata(dev)) {
474 		pdata = dev_get_platdata(dev);
475 		data->rshunt = pdata->shunt_uohms;
476 	} else if (!of_property_read_u32(dev->of_node,
477 					 "shunt-resistor", &val)) {
478 		data->rshunt = val;
479 	} else {
480 		data->rshunt = INA2XX_RSHUNT_DEFAULT;
481 	}
482 
483 	/* set the device type */
484 	data->kind = id->driver_data;
485 	data->config = &ina2xx_config[data->kind];
486 	data->curr_config = data->config->config_default;
487 	data->client = client;
488 
489 	/*
490 	 * Ina226 has a variable update_interval. For ina219 we
491 	 * use a constant value.
492 	 */
493 	if (data->kind == ina226)
494 		ina226_set_update_interval(data);
495 	else
496 		data->update_interval = HZ / INA2XX_CONVERSION_RATE;
497 
498 	if (data->rshunt <= 0 ||
499 	    data->rshunt > data->config->calibration_factor)
500 		return -ENODEV;
501 
502 	ret = ina2xx_init(data);
503 	if (ret < 0) {
504 		dev_err(dev, "error configuring the device: %d\n", ret);
505 		return -ENODEV;
506 	}
507 
508 	mutex_init(&data->update_lock);
509 
510 	data->groups[group++] = &ina2xx_group;
511 	if (data->kind == ina226)
512 		data->groups[group++] = &ina226_group;
513 
514 	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
515 							   data, data->groups);
516 	if (IS_ERR(hwmon_dev))
517 		return PTR_ERR(hwmon_dev);
518 
519 	dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
520 		 id->name, data->rshunt);
521 
522 	return 0;
523 }
524 
525 static const struct i2c_device_id ina2xx_id[] = {
526 	{ "ina219", ina219 },
527 	{ "ina220", ina219 },
528 	{ "ina226", ina226 },
529 	{ "ina230", ina226 },
530 	{ "ina231", ina226 },
531 	{ }
532 };
533 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
534 
535 static struct i2c_driver ina2xx_driver = {
536 	.driver = {
537 		.name	= "ina2xx",
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