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.h>
38 #include <linux/delay.h>
39 #include <linux/util_macros.h>
40 #include <linux/regmap.h>
41
42 #include <linux/platform_data/ina2xx.h>
43
44 /* common register definitions */
45 #define INA2XX_CONFIG 0x00
46 #define INA2XX_SHUNT_VOLTAGE 0x01 /* readonly */
47 #define INA2XX_BUS_VOLTAGE 0x02 /* readonly */
48 #define INA2XX_POWER 0x03 /* readonly */
49 #define INA2XX_CURRENT 0x04 /* readonly */
50 #define INA2XX_CALIBRATION 0x05
51
52 /* INA226 register definitions */
53 #define INA226_MASK_ENABLE 0x06
54 #define INA226_ALERT_LIMIT 0x07
55 #define INA226_DIE_ID 0xFF
56
57 /* register count */
58 #define INA219_REGISTERS 6
59 #define INA226_REGISTERS 8
60
61 #define INA2XX_MAX_REGISTERS 8
62
63 /* settings - depend on use case */
64 #define INA219_CONFIG_DEFAULT 0x399F /* PGA=8 */
65 #define INA226_CONFIG_DEFAULT 0x4527 /* averages=16 */
66
67 /* worst case is 68.10 ms (~14.6Hz, ina219) */
68 #define INA2XX_CONVERSION_RATE 15
69 #define INA2XX_MAX_DELAY 69 /* worst case delay in ms */
70
71 #define INA2XX_RSHUNT_DEFAULT 10000
72
73 /* bit mask for reading the averaging setting in the configuration register */
74 #define INA226_AVG_RD_MASK 0x0E00
75
76 #define INA226_READ_AVG(reg) (((reg) & INA226_AVG_RD_MASK) >> 9)
77 #define INA226_SHIFT_AVG(val) ((val) << 9)
78
79 /* common attrs, ina226 attrs and NULL */
80 #define INA2XX_MAX_ATTRIBUTE_GROUPS 3
81
82 /*
83 * Both bus voltage and shunt voltage conversion times for ina226 are set
84 * to 0b0100 on POR, which translates to 2200 microseconds in total.
85 */
86 #define INA226_TOTAL_CONV_TIME_DEFAULT 2200
87
88 static struct regmap_config ina2xx_regmap_config = {
89 .reg_bits = 8,
90 .val_bits = 16,
91 };
92
93 enum ina2xx_ids { ina219, ina226 };
94
95 struct ina2xx_config {
96 u16 config_default;
97 int calibration_value;
98 int registers;
99 int shunt_div;
100 int bus_voltage_shift;
101 int bus_voltage_lsb; /* uV */
102 int power_lsb_factor;
103 };
104
105 struct ina2xx_data {
106 const struct ina2xx_config *config;
107
108 long rshunt;
109 long current_lsb_uA;
110 long power_lsb_uW;
111 struct mutex config_lock;
112 struct regmap *regmap;
113
114 const struct attribute_group *groups[INA2XX_MAX_ATTRIBUTE_GROUPS];
115 };
116
117 static const struct ina2xx_config ina2xx_config[] = {
118 [ina219] = {
119 .config_default = INA219_CONFIG_DEFAULT,
120 .calibration_value = 4096,
121 .registers = INA219_REGISTERS,
122 .shunt_div = 100,
123 .bus_voltage_shift = 3,
124 .bus_voltage_lsb = 4000,
125 .power_lsb_factor = 20,
126 },
127 [ina226] = {
128 .config_default = INA226_CONFIG_DEFAULT,
129 .calibration_value = 2048,
130 .registers = INA226_REGISTERS,
131 .shunt_div = 400,
132 .bus_voltage_shift = 0,
133 .bus_voltage_lsb = 1250,
134 .power_lsb_factor = 25,
135 },
136 };
137
138 /*
139 * Available averaging rates for ina226. The indices correspond with
140 * the bit values expected by the chip (according to the ina226 datasheet,
141 * table 3 AVG bit settings, found at
142 * http://www.ti.com/lit/ds/symlink/ina226.pdf.
143 */
144 static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };
145
ina226_reg_to_interval(u16 config)146 static int ina226_reg_to_interval(u16 config)
147 {
148 int avg = ina226_avg_tab[INA226_READ_AVG(config)];
149
150 /*
151 * Multiply the total conversion time by the number of averages.
152 * Return the result in milliseconds.
153 */
154 return DIV_ROUND_CLOSEST(avg * INA226_TOTAL_CONV_TIME_DEFAULT, 1000);
155 }
156
157 /*
158 * Return the new, shifted AVG field value of CONFIG register,
159 * to use with regmap_update_bits
160 */
ina226_interval_to_reg(int interval)161 static u16 ina226_interval_to_reg(int interval)
162 {
163 int avg, avg_bits;
164
165 avg = DIV_ROUND_CLOSEST(interval * 1000,
166 INA226_TOTAL_CONV_TIME_DEFAULT);
167 avg_bits = find_closest(avg, ina226_avg_tab,
168 ARRAY_SIZE(ina226_avg_tab));
169
170 return INA226_SHIFT_AVG(avg_bits);
171 }
172
173 /*
174 * Calibration register is set to the best value, which eliminates
175 * truncation errors on calculating current register in hardware.
176 * According to datasheet (eq. 3) the best values are 2048 for
177 * ina226 and 4096 for ina219. They are hardcoded as calibration_value.
178 */
ina2xx_calibrate(struct ina2xx_data * data)179 static int ina2xx_calibrate(struct ina2xx_data *data)
180 {
181 return regmap_write(data->regmap, INA2XX_CALIBRATION,
182 data->config->calibration_value);
183 }
184
185 /*
186 * Initialize the configuration and calibration registers.
187 */
ina2xx_init(struct ina2xx_data * data)188 static int ina2xx_init(struct ina2xx_data *data)
189 {
190 int ret = regmap_write(data->regmap, INA2XX_CONFIG,
191 data->config->config_default);
192 if (ret < 0)
193 return ret;
194
195 return ina2xx_calibrate(data);
196 }
197
ina2xx_read_reg(struct device * dev,int reg,unsigned int * regval)198 static int ina2xx_read_reg(struct device *dev, int reg, unsigned int *regval)
199 {
200 struct ina2xx_data *data = dev_get_drvdata(dev);
201 int ret, retry;
202
203 dev_dbg(dev, "Starting register %d read\n", reg);
204
205 for (retry = 5; retry; retry--) {
206
207 ret = regmap_read(data->regmap, reg, regval);
208 if (ret < 0)
209 return ret;
210
211 dev_dbg(dev, "read %d, val = 0x%04x\n", reg, *regval);
212
213 /*
214 * If the current value in the calibration register is 0, the
215 * power and current registers will also remain at 0. In case
216 * the chip has been reset let's check the calibration
217 * register and reinitialize if needed.
218 * We do that extra read of the calibration register if there
219 * is some hint of a chip reset.
220 */
221 if (*regval == 0) {
222 unsigned int cal;
223
224 ret = regmap_read(data->regmap, INA2XX_CALIBRATION,
225 &cal);
226 if (ret < 0)
227 return ret;
228
229 if (cal == 0) {
230 dev_warn(dev, "chip not calibrated, reinitializing\n");
231
232 ret = ina2xx_init(data);
233 if (ret < 0)
234 return ret;
235 /*
236 * Let's make sure the power and current
237 * registers have been updated before trying
238 * again.
239 */
240 msleep(INA2XX_MAX_DELAY);
241 continue;
242 }
243 }
244 return 0;
245 }
246
247 /*
248 * If we're here then although all write operations succeeded, the
249 * chip still returns 0 in the calibration register. Nothing more we
250 * can do here.
251 */
252 dev_err(dev, "unable to reinitialize the chip\n");
253 return -ENODEV;
254 }
255
ina2xx_get_value(struct ina2xx_data * data,u8 reg,unsigned int regval)256 static int ina2xx_get_value(struct ina2xx_data *data, u8 reg,
257 unsigned int regval)
258 {
259 int val;
260
261 switch (reg) {
262 case INA2XX_SHUNT_VOLTAGE:
263 /* signed register */
264 val = DIV_ROUND_CLOSEST((s16)regval, data->config->shunt_div);
265 break;
266 case INA2XX_BUS_VOLTAGE:
267 val = (regval >> data->config->bus_voltage_shift)
268 * data->config->bus_voltage_lsb;
269 val = DIV_ROUND_CLOSEST(val, 1000);
270 break;
271 case INA2XX_POWER:
272 val = regval * data->power_lsb_uW;
273 break;
274 case INA2XX_CURRENT:
275 /* signed register, result in mA */
276 val = (s16)regval * data->current_lsb_uA;
277 val = DIV_ROUND_CLOSEST(val, 1000);
278 break;
279 case INA2XX_CALIBRATION:
280 val = regval;
281 break;
282 default:
283 /* programmer goofed */
284 WARN_ON_ONCE(1);
285 val = 0;
286 break;
287 }
288
289 return val;
290 }
291
ina2xx_show_value(struct device * dev,struct device_attribute * da,char * buf)292 static ssize_t ina2xx_show_value(struct device *dev,
293 struct device_attribute *da, char *buf)
294 {
295 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
296 struct ina2xx_data *data = dev_get_drvdata(dev);
297 unsigned int regval;
298
299 int err = ina2xx_read_reg(dev, attr->index, ®val);
300
301 if (err < 0)
302 return err;
303
304 return snprintf(buf, PAGE_SIZE, "%d\n",
305 ina2xx_get_value(data, attr->index, regval));
306 }
307
308 /*
309 * In order to keep calibration register value fixed, the product
310 * of current_lsb and shunt_resistor should also be fixed and equal
311 * to shunt_voltage_lsb = 1 / shunt_div multiplied by 10^9 in order
312 * to keep the scale.
313 */
ina2xx_set_shunt(struct ina2xx_data * data,long val)314 static int ina2xx_set_shunt(struct ina2xx_data *data, long val)
315 {
316 unsigned int dividend = DIV_ROUND_CLOSEST(1000000000,
317 data->config->shunt_div);
318 if (val <= 0 || val > dividend)
319 return -EINVAL;
320
321 mutex_lock(&data->config_lock);
322 data->rshunt = val;
323 data->current_lsb_uA = DIV_ROUND_CLOSEST(dividend, val);
324 data->power_lsb_uW = data->config->power_lsb_factor *
325 data->current_lsb_uA;
326 mutex_unlock(&data->config_lock);
327
328 return 0;
329 }
330
ina2xx_show_shunt(struct device * dev,struct device_attribute * da,char * buf)331 static ssize_t ina2xx_show_shunt(struct device *dev,
332 struct device_attribute *da,
333 char *buf)
334 {
335 struct ina2xx_data *data = dev_get_drvdata(dev);
336
337 return snprintf(buf, PAGE_SIZE, "%li\n", data->rshunt);
338 }
339
ina2xx_store_shunt(struct device * dev,struct device_attribute * da,const char * buf,size_t count)340 static ssize_t ina2xx_store_shunt(struct device *dev,
341 struct device_attribute *da,
342 const char *buf, size_t count)
343 {
344 unsigned long val;
345 int status;
346 struct ina2xx_data *data = dev_get_drvdata(dev);
347
348 status = kstrtoul(buf, 10, &val);
349 if (status < 0)
350 return status;
351
352 status = ina2xx_set_shunt(data, val);
353 if (status < 0)
354 return status;
355 return count;
356 }
357
ina226_set_interval(struct device * dev,struct device_attribute * da,const char * buf,size_t count)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 status = regmap_update_bits(data->regmap, INA2XX_CONFIG,
374 INA226_AVG_RD_MASK,
375 ina226_interval_to_reg(val));
376 if (status < 0)
377 return status;
378
379 return count;
380 }
381
ina226_show_interval(struct device * dev,struct device_attribute * da,char * buf)382 static ssize_t ina226_show_interval(struct device *dev,
383 struct device_attribute *da, char *buf)
384 {
385 struct ina2xx_data *data = dev_get_drvdata(dev);
386 int status;
387 unsigned int regval;
388
389 status = regmap_read(data->regmap, INA2XX_CONFIG, ®val);
390 if (status)
391 return status;
392
393 return snprintf(buf, PAGE_SIZE, "%d\n", ina226_reg_to_interval(regval));
394 }
395
396 /* shunt voltage */
397 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
398 INA2XX_SHUNT_VOLTAGE);
399
400 /* bus voltage */
401 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
402 INA2XX_BUS_VOLTAGE);
403
404 /* calculated current */
405 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
406 INA2XX_CURRENT);
407
408 /* calculated power */
409 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
410 INA2XX_POWER);
411
412 /* shunt resistance */
413 static SENSOR_DEVICE_ATTR(shunt_resistor, S_IRUGO | S_IWUSR,
414 ina2xx_show_shunt, ina2xx_store_shunt,
415 INA2XX_CALIBRATION);
416
417 /* update interval (ina226 only) */
418 static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
419 ina226_show_interval, ina226_set_interval, 0);
420
421 /* pointers to created device attributes */
422 static struct attribute *ina2xx_attrs[] = {
423 &sensor_dev_attr_in0_input.dev_attr.attr,
424 &sensor_dev_attr_in1_input.dev_attr.attr,
425 &sensor_dev_attr_curr1_input.dev_attr.attr,
426 &sensor_dev_attr_power1_input.dev_attr.attr,
427 &sensor_dev_attr_shunt_resistor.dev_attr.attr,
428 NULL,
429 };
430
431 static const struct attribute_group ina2xx_group = {
432 .attrs = ina2xx_attrs,
433 };
434
435 static struct attribute *ina226_attrs[] = {
436 &sensor_dev_attr_update_interval.dev_attr.attr,
437 NULL,
438 };
439
440 static const struct attribute_group ina226_group = {
441 .attrs = ina226_attrs,
442 };
443
ina2xx_probe(struct i2c_client * client,const struct i2c_device_id * id)444 static int ina2xx_probe(struct i2c_client *client,
445 const struct i2c_device_id *id)
446 {
447 struct device *dev = &client->dev;
448 struct ina2xx_data *data;
449 struct device *hwmon_dev;
450 u32 val;
451 int ret, group = 0;
452
453 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
454 if (!data)
455 return -ENOMEM;
456
457 /* set the device type */
458 data->config = &ina2xx_config[id->driver_data];
459 mutex_init(&data->config_lock);
460
461 if (of_property_read_u32(dev->of_node, "shunt-resistor", &val) < 0) {
462 struct ina2xx_platform_data *pdata = dev_get_platdata(dev);
463
464 if (pdata)
465 val = pdata->shunt_uohms;
466 else
467 val = INA2XX_RSHUNT_DEFAULT;
468 }
469
470 ina2xx_set_shunt(data, val);
471
472 ina2xx_regmap_config.max_register = data->config->registers;
473
474 data->regmap = devm_regmap_init_i2c(client, &ina2xx_regmap_config);
475 if (IS_ERR(data->regmap)) {
476 dev_err(dev, "failed to allocate register map\n");
477 return PTR_ERR(data->regmap);
478 }
479
480 ret = ina2xx_init(data);
481 if (ret < 0) {
482 dev_err(dev, "error configuring the device: %d\n", ret);
483 return -ENODEV;
484 }
485
486 data->groups[group++] = &ina2xx_group;
487 if (id->driver_data == ina226)
488 data->groups[group++] = &ina226_group;
489
490 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
491 data, data->groups);
492 if (IS_ERR(hwmon_dev))
493 return PTR_ERR(hwmon_dev);
494
495 dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
496 id->name, data->rshunt);
497
498 return 0;
499 }
500
501 static const struct i2c_device_id ina2xx_id[] = {
502 { "ina219", ina219 },
503 { "ina220", ina219 },
504 { "ina226", ina226 },
505 { "ina230", ina226 },
506 { "ina231", ina226 },
507 { }
508 };
509 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
510
511 static struct i2c_driver ina2xx_driver = {
512 .driver = {
513 .name = "ina2xx",
514 },
515 .probe = ina2xx_probe,
516 .id_table = ina2xx_id,
517 };
518
519 module_i2c_driver(ina2xx_driver);
520
521 MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
522 MODULE_DESCRIPTION("ina2xx driver");
523 MODULE_LICENSE("GPL");
524