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 <lothar.felten@gmail.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
ina226_reg_to_interval(u16 config)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 */
ina226_interval_to_reg(int interval)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 */
ina2xx_calibrate(struct ina2xx_data * data)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 */
ina2xx_init(struct ina2xx_data * data)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
ina2xx_read_reg(struct device * dev,int reg,unsigned int * regval)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
ina2xx_get_value(struct ina2xx_data * data,u8 reg,unsigned int regval)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
ina2xx_show_value(struct device * dev,struct device_attribute * da,char * buf)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 */
ina2xx_set_shunt(struct ina2xx_data * data,long val)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
ina2xx_show_shunt(struct device * dev,struct device_attribute * da,char * buf)332 static ssize_t ina2xx_show_shunt(struct device *dev,
333 struct device_attribute *da,
334 char *buf)
335 {
336 struct ina2xx_data *data = dev_get_drvdata(dev);
337
338 return snprintf(buf, PAGE_SIZE, "%li\n", data->rshunt);
339 }
340
ina2xx_store_shunt(struct device * dev,struct device_attribute * da,const char * buf,size_t count)341 static ssize_t ina2xx_store_shunt(struct device *dev,
342 struct device_attribute *da,
343 const char *buf, size_t count)
344 {
345 unsigned long val;
346 int status;
347 struct ina2xx_data *data = dev_get_drvdata(dev);
348
349 status = kstrtoul(buf, 10, &val);
350 if (status < 0)
351 return status;
352
353 status = ina2xx_set_shunt(data, val);
354 if (status < 0)
355 return status;
356 return count;
357 }
358
ina226_set_interval(struct device * dev,struct device_attribute * da,const char * buf,size_t count)359 static ssize_t ina226_set_interval(struct device *dev,
360 struct device_attribute *da,
361 const char *buf, size_t count)
362 {
363 struct ina2xx_data *data = dev_get_drvdata(dev);
364 unsigned long val;
365 int status;
366
367 status = kstrtoul(buf, 10, &val);
368 if (status < 0)
369 return status;
370
371 if (val > INT_MAX || val == 0)
372 return -EINVAL;
373
374 status = regmap_update_bits(data->regmap, INA2XX_CONFIG,
375 INA226_AVG_RD_MASK,
376 ina226_interval_to_reg(val));
377 if (status < 0)
378 return status;
379
380 return count;
381 }
382
ina226_show_interval(struct device * dev,struct device_attribute * da,char * buf)383 static ssize_t ina226_show_interval(struct device *dev,
384 struct device_attribute *da, char *buf)
385 {
386 struct ina2xx_data *data = dev_get_drvdata(dev);
387 int status;
388 unsigned int regval;
389
390 status = regmap_read(data->regmap, INA2XX_CONFIG, ®val);
391 if (status)
392 return status;
393
394 return snprintf(buf, PAGE_SIZE, "%d\n", ina226_reg_to_interval(regval));
395 }
396
397 /* shunt voltage */
398 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
399 INA2XX_SHUNT_VOLTAGE);
400
401 /* bus voltage */
402 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
403 INA2XX_BUS_VOLTAGE);
404
405 /* calculated current */
406 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
407 INA2XX_CURRENT);
408
409 /* calculated power */
410 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
411 INA2XX_POWER);
412
413 /* shunt resistance */
414 static SENSOR_DEVICE_ATTR(shunt_resistor, S_IRUGO | S_IWUSR,
415 ina2xx_show_shunt, ina2xx_store_shunt,
416 INA2XX_CALIBRATION);
417
418 /* update interval (ina226 only) */
419 static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
420 ina226_show_interval, ina226_set_interval, 0);
421
422 /* pointers to created device attributes */
423 static struct attribute *ina2xx_attrs[] = {
424 &sensor_dev_attr_in0_input.dev_attr.attr,
425 &sensor_dev_attr_in1_input.dev_attr.attr,
426 &sensor_dev_attr_curr1_input.dev_attr.attr,
427 &sensor_dev_attr_power1_input.dev_attr.attr,
428 &sensor_dev_attr_shunt_resistor.dev_attr.attr,
429 NULL,
430 };
431
432 static const struct attribute_group ina2xx_group = {
433 .attrs = ina2xx_attrs,
434 };
435
436 static struct attribute *ina226_attrs[] = {
437 &sensor_dev_attr_update_interval.dev_attr.attr,
438 NULL,
439 };
440
441 static const struct attribute_group ina226_group = {
442 .attrs = ina226_attrs,
443 };
444
ina2xx_probe(struct i2c_client * client,const struct i2c_device_id * id)445 static int ina2xx_probe(struct i2c_client *client,
446 const struct i2c_device_id *id)
447 {
448 struct device *dev = &client->dev;
449 struct ina2xx_data *data;
450 struct device *hwmon_dev;
451 u32 val;
452 int ret, group = 0;
453 enum ina2xx_ids chip;
454
455 if (client->dev.of_node)
456 chip = (enum ina2xx_ids)of_device_get_match_data(&client->dev);
457 else
458 chip = id->driver_data;
459
460 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
461 if (!data)
462 return -ENOMEM;
463
464 /* set the device type */
465 data->config = &ina2xx_config[chip];
466 mutex_init(&data->config_lock);
467
468 if (of_property_read_u32(dev->of_node, "shunt-resistor", &val) < 0) {
469 struct ina2xx_platform_data *pdata = dev_get_platdata(dev);
470
471 if (pdata)
472 val = pdata->shunt_uohms;
473 else
474 val = INA2XX_RSHUNT_DEFAULT;
475 }
476
477 ina2xx_set_shunt(data, val);
478
479 ina2xx_regmap_config.max_register = data->config->registers;
480
481 data->regmap = devm_regmap_init_i2c(client, &ina2xx_regmap_config);
482 if (IS_ERR(data->regmap)) {
483 dev_err(dev, "failed to allocate register map\n");
484 return PTR_ERR(data->regmap);
485 }
486
487 ret = ina2xx_init(data);
488 if (ret < 0) {
489 dev_err(dev, "error configuring the device: %d\n", ret);
490 return -ENODEV;
491 }
492
493 data->groups[group++] = &ina2xx_group;
494 if (id->driver_data == ina226)
495 data->groups[group++] = &ina226_group;
496
497 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
498 data, data->groups);
499 if (IS_ERR(hwmon_dev))
500 return PTR_ERR(hwmon_dev);
501
502 dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
503 id->name, data->rshunt);
504
505 return 0;
506 }
507
508 static const struct i2c_device_id ina2xx_id[] = {
509 { "ina219", ina219 },
510 { "ina220", ina219 },
511 { "ina226", ina226 },
512 { "ina230", ina226 },
513 { "ina231", ina226 },
514 { }
515 };
516 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
517
518 static const struct of_device_id ina2xx_of_match[] = {
519 {
520 .compatible = "ti,ina219",
521 .data = (void *)ina219
522 },
523 {
524 .compatible = "ti,ina220",
525 .data = (void *)ina219
526 },
527 {
528 .compatible = "ti,ina226",
529 .data = (void *)ina226
530 },
531 {
532 .compatible = "ti,ina230",
533 .data = (void *)ina226
534 },
535 {
536 .compatible = "ti,ina231",
537 .data = (void *)ina226
538 },
539 { },
540 };
541 MODULE_DEVICE_TABLE(of, ina2xx_of_match);
542
543 static struct i2c_driver ina2xx_driver = {
544 .driver = {
545 .name = "ina2xx",
546 .of_match_table = of_match_ptr(ina2xx_of_match),
547 },
548 .probe = ina2xx_probe,
549 .id_table = ina2xx_id,
550 };
551
552 module_i2c_driver(ina2xx_driver);
553
554 MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
555 MODULE_DESCRIPTION("ina2xx driver");
556 MODULE_LICENSE("GPL");
557
