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
89static struct regmap_config ina2xx_regmap_config = {
90 .reg_bits = 8,
91 .val_bits = 16,
92};
93
94enum ina2xx_ids { ina219, ina226 };
95
96struct 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
106struct 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
118static 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 */
145static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };
146
147static 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 */
162static 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 */
180static 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 */
189static 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
199static 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
257static 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 = (s16)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
293static ssize_t ina2xx_value_show(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, &regval);
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 */
315static 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
332static ssize_t ina2xx_shunt_show(struct device *dev,
333 struct device_attribute *da, 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
340static ssize_t ina2xx_shunt_store(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
358static ssize_t ina226_interval_store(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
382static ssize_t ina226_interval_show(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, &regval);
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 */
397static SENSOR_DEVICE_ATTR_RO(in0_input, ina2xx_value, INA2XX_SHUNT_VOLTAGE);
398
399/* bus voltage */
400static SENSOR_DEVICE_ATTR_RO(in1_input, ina2xx_value, INA2XX_BUS_VOLTAGE);
401
402/* calculated current */
403static SENSOR_DEVICE_ATTR_RO(curr1_input, ina2xx_value, INA2XX_CURRENT);
404
405/* calculated power */
406static SENSOR_DEVICE_ATTR_RO(power1_input, ina2xx_value, INA2XX_POWER);
407
408/* shunt resistance */
409static SENSOR_DEVICE_ATTR_RW(shunt_resistor, ina2xx_shunt, INA2XX_CALIBRATION);
410
411/* update interval (ina226 only) */
412static SENSOR_DEVICE_ATTR_RW(update_interval, ina226_interval, 0);
413
414/* pointers to created device attributes */
415static struct attribute *ina2xx_attrs[] = {
416 &sensor_dev_attr_in0_input.dev_attr.attr,
417 &sensor_dev_attr_in1_input.dev_attr.attr,
418 &sensor_dev_attr_curr1_input.dev_attr.attr,
419 &sensor_dev_attr_power1_input.dev_attr.attr,
420 &sensor_dev_attr_shunt_resistor.dev_attr.attr,
421 NULL,
422};
423
424static const struct attribute_group ina2xx_group = {
425 .attrs = ina2xx_attrs,
426};
427
428static struct attribute *ina226_attrs[] = {
429 &sensor_dev_attr_update_interval.dev_attr.attr,
430 NULL,
431};
432
433static const struct attribute_group ina226_group = {
434 .attrs = ina226_attrs,
435};
436
437static int ina2xx_probe(struct i2c_client *client,
438 const struct i2c_device_id *id)
439{
440 struct device *dev = &client->dev;
441 struct ina2xx_data *data;
442 struct device *hwmon_dev;
443 u32 val;
444 int ret, group = 0;
445 enum ina2xx_ids chip;
446
447 if (client->dev.of_node)
448 chip = (enum ina2xx_ids)of_device_get_match_data(&client->dev);
449 else
450 chip = id->driver_data;
451
452 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
453 if (!data)
454 return -ENOMEM;
455
456 /* set the device type */
457 data->config = &ina2xx_config[chip];
458 mutex_init(&data->config_lock);
459
460 if (of_property_read_u32(dev->of_node, "shunt-resistor", &val) < 0) {
461 struct ina2xx_platform_data *pdata = dev_get_platdata(dev);
462
463 if (pdata)
464 val = pdata->shunt_uohms;
465 else
466 val = INA2XX_RSHUNT_DEFAULT;
467 }
468
469 ina2xx_set_shunt(data, val);
470
471 ina2xx_regmap_config.max_register = data->config->registers;
472
473 data->regmap = devm_regmap_init_i2c(client, &ina2xx_regmap_config);
474 if (IS_ERR(data->regmap)) {
475 dev_err(dev, "failed to allocate register map\n");
476 return PTR_ERR(data->regmap);
477 }
478
479 ret = ina2xx_init(data);
480 if (ret < 0) {
481 dev_err(dev, "error configuring the device: %d\n", ret);
482 return -ENODEV;
483 }
484
485 data->groups[group++] = &ina2xx_group;
486 if (chip == ina226)
487 data->groups[group++] = &ina226_group;
488
489 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
490 data, data->groups);
491 if (IS_ERR(hwmon_dev))
492 return PTR_ERR(hwmon_dev);
493
494 dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
495 client->name, data->rshunt);
496
497 return 0;
498}
499
500static const struct i2c_device_id ina2xx_id[] = {
501 { "ina219", ina219 },
502 { "ina220", ina219 },
503 { "ina226", ina226 },
504 { "ina230", ina226 },
505 { "ina231", ina226 },
506 { }
507};
508MODULE_DEVICE_TABLE(i2c, ina2xx_id);
509
510static const struct of_device_id ina2xx_of_match[] = {
511 {
512 .compatible = "ti,ina219",
513 .data = (void *)ina219
514 },
515 {
516 .compatible = "ti,ina220",
517 .data = (void *)ina219
518 },
519 {
520 .compatible = "ti,ina226",
521 .data = (void *)ina226
522 },
523 {
524 .compatible = "ti,ina230",
525 .data = (void *)ina226
526 },
527 {
528 .compatible = "ti,ina231",
529 .data = (void *)ina226
530 },
531 { },
532};
533MODULE_DEVICE_TABLE(of, ina2xx_of_match);
534
535static struct i2c_driver ina2xx_driver = {
536 .driver = {
537 .name = "ina2xx",
538 .of_match_table = of_match_ptr(ina2xx_of_match),
539 },
540 .probe = ina2xx_probe,
541 .id_table = ina2xx_id,
542};
543
544module_i2c_driver(ina2xx_driver);
545
546MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
547MODULE_DESCRIPTION("ina2xx driver");
548MODULE_LICENSE("GPL");
549