1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * AD7291 8-Channel, I2C, 12-Bit SAR ADC with Temperature Sensor |
4 | * |
5 | * Copyright 2010-2011 Analog Devices Inc. |
6 | */ |
7 | |
8 | #include <linux/device.h> |
9 | #include <linux/err.h> |
10 | #include <linux/i2c.h> |
11 | #include <linux/interrupt.h> |
12 | #include <linux/kernel.h> |
13 | #include <linux/module.h> |
14 | #include <linux/mutex.h> |
15 | #include <linux/regulator/consumer.h> |
16 | #include <linux/slab.h> |
17 | #include <linux/sysfs.h> |
18 | |
19 | #include <linux/iio/iio.h> |
20 | #include <linux/iio/sysfs.h> |
21 | #include <linux/iio/events.h> |
22 | |
23 | /* |
24 | * Simplified handling |
25 | * |
26 | * If no events enabled - single polled channel read |
27 | * If event enabled direct reads disable unless channel |
28 | * is in the read mask. |
29 | * |
30 | * The noise-delayed bit as per datasheet suggestion is always enabled. |
31 | */ |
32 | |
33 | /* |
34 | * AD7291 registers definition |
35 | */ |
36 | #define AD7291_COMMAND 0x00 |
37 | #define AD7291_VOLTAGE 0x01 |
38 | #define AD7291_T_SENSE 0x02 |
39 | #define AD7291_T_AVERAGE 0x03 |
40 | #define AD7291_DATA_HIGH(x) ((x) * 3 + 0x4) |
41 | #define AD7291_DATA_LOW(x) ((x) * 3 + 0x5) |
42 | #define AD7291_HYST(x) ((x) * 3 + 0x6) |
43 | #define AD7291_VOLTAGE_ALERT_STATUS 0x1F |
44 | #define AD7291_T_ALERT_STATUS 0x20 |
45 | |
46 | #define AD7291_BITS 12 |
47 | #define AD7291_VOLTAGE_LIMIT_COUNT 8 |
48 | |
49 | |
50 | /* |
51 | * AD7291 command |
52 | */ |
53 | #define AD7291_AUTOCYCLE BIT(0) |
54 | #define AD7291_RESET BIT(1) |
55 | #define AD7291_ALERT_CLEAR BIT(2) |
56 | #define AD7291_ALERT_POLARITY BIT(3) |
57 | #define AD7291_EXT_REF BIT(4) |
58 | #define AD7291_NOISE_DELAY BIT(5) |
59 | #define AD7291_T_SENSE_MASK BIT(7) |
60 | #define AD7291_VOLTAGE_MASK GENMASK(15, 8) |
61 | #define AD7291_VOLTAGE_OFFSET 8 |
62 | |
63 | /* |
64 | * AD7291 value masks |
65 | */ |
66 | #define AD7291_VALUE_MASK GENMASK(11, 0) |
67 | |
68 | /* |
69 | * AD7291 alert register bits |
70 | */ |
71 | #define AD7291_T_LOW BIT(0) |
72 | #define AD7291_T_HIGH BIT(1) |
73 | #define AD7291_T_AVG_LOW BIT(2) |
74 | #define AD7291_T_AVG_HIGH BIT(3) |
75 | #define AD7291_V_LOW(x) BIT((x) * 2) |
76 | #define AD7291_V_HIGH(x) BIT((x) * 2 + 1) |
77 | |
78 | |
79 | struct ad7291_chip_info { |
80 | struct i2c_client *client; |
81 | struct regulator *reg; |
82 | u16 command; |
83 | u16 c_mask; /* Active voltage channels for events */ |
84 | struct mutex state_lock; |
85 | }; |
86 | |
87 | static int ad7291_i2c_read(struct ad7291_chip_info *chip, u8 reg, u16 *data) |
88 | { |
89 | struct i2c_client *client = chip->client; |
90 | int ret = 0; |
91 | |
92 | ret = i2c_smbus_read_word_swapped(client, command: reg); |
93 | if (ret < 0) { |
94 | dev_err(&client->dev, "I2C read error\n" ); |
95 | return ret; |
96 | } |
97 | |
98 | *data = ret; |
99 | |
100 | return 0; |
101 | } |
102 | |
103 | static int ad7291_i2c_write(struct ad7291_chip_info *chip, u8 reg, u16 data) |
104 | { |
105 | return i2c_smbus_write_word_swapped(client: chip->client, command: reg, value: data); |
106 | } |
107 | |
108 | static irqreturn_t ad7291_event_handler(int irq, void *private) |
109 | { |
110 | struct iio_dev *indio_dev = private; |
111 | struct ad7291_chip_info *chip = iio_priv(indio_dev: private); |
112 | u16 t_status, v_status; |
113 | u16 command; |
114 | int i; |
115 | s64 timestamp = iio_get_time_ns(indio_dev); |
116 | |
117 | if (ad7291_i2c_read(chip, AD7291_T_ALERT_STATUS, data: &t_status)) |
118 | return IRQ_HANDLED; |
119 | |
120 | if (ad7291_i2c_read(chip, AD7291_VOLTAGE_ALERT_STATUS, data: &v_status)) |
121 | return IRQ_HANDLED; |
122 | |
123 | if (!(t_status || v_status)) |
124 | return IRQ_HANDLED; |
125 | |
126 | command = chip->command | AD7291_ALERT_CLEAR; |
127 | ad7291_i2c_write(chip, AD7291_COMMAND, data: command); |
128 | |
129 | command = chip->command & ~AD7291_ALERT_CLEAR; |
130 | ad7291_i2c_write(chip, AD7291_COMMAND, data: command); |
131 | |
132 | /* For now treat t_sense and t_sense_average the same */ |
133 | if ((t_status & AD7291_T_LOW) || (t_status & AD7291_T_AVG_LOW)) |
134 | iio_push_event(indio_dev, |
135 | IIO_UNMOD_EVENT_CODE(IIO_TEMP, |
136 | 0, |
137 | IIO_EV_TYPE_THRESH, |
138 | IIO_EV_DIR_FALLING), |
139 | timestamp); |
140 | if ((t_status & AD7291_T_HIGH) || (t_status & AD7291_T_AVG_HIGH)) |
141 | iio_push_event(indio_dev, |
142 | IIO_UNMOD_EVENT_CODE(IIO_TEMP, |
143 | 0, |
144 | IIO_EV_TYPE_THRESH, |
145 | IIO_EV_DIR_RISING), |
146 | timestamp); |
147 | |
148 | for (i = 0; i < AD7291_VOLTAGE_LIMIT_COUNT; i++) { |
149 | if (v_status & AD7291_V_LOW(i)) |
150 | iio_push_event(indio_dev, |
151 | IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, |
152 | i, |
153 | IIO_EV_TYPE_THRESH, |
154 | IIO_EV_DIR_FALLING), |
155 | timestamp); |
156 | if (v_status & AD7291_V_HIGH(i)) |
157 | iio_push_event(indio_dev, |
158 | IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, |
159 | i, |
160 | IIO_EV_TYPE_THRESH, |
161 | IIO_EV_DIR_RISING), |
162 | timestamp); |
163 | } |
164 | |
165 | return IRQ_HANDLED; |
166 | } |
167 | |
168 | static unsigned int ad7291_threshold_reg(const struct iio_chan_spec *chan, |
169 | enum iio_event_direction dir, |
170 | enum iio_event_info info) |
171 | { |
172 | unsigned int offset; |
173 | |
174 | switch (chan->type) { |
175 | case IIO_VOLTAGE: |
176 | offset = chan->channel; |
177 | break; |
178 | case IIO_TEMP: |
179 | offset = AD7291_VOLTAGE_OFFSET; |
180 | break; |
181 | default: |
182 | return 0; |
183 | } |
184 | |
185 | switch (info) { |
186 | case IIO_EV_INFO_VALUE: |
187 | if (dir == IIO_EV_DIR_FALLING) |
188 | return AD7291_DATA_HIGH(offset); |
189 | else |
190 | return AD7291_DATA_LOW(offset); |
191 | case IIO_EV_INFO_HYSTERESIS: |
192 | return AD7291_HYST(offset); |
193 | default: |
194 | break; |
195 | } |
196 | return 0; |
197 | } |
198 | |
199 | static int ad7291_read_event_value(struct iio_dev *indio_dev, |
200 | const struct iio_chan_spec *chan, |
201 | enum iio_event_type type, |
202 | enum iio_event_direction dir, |
203 | enum iio_event_info info, |
204 | int *val, int *val2) |
205 | { |
206 | struct ad7291_chip_info *chip = iio_priv(indio_dev); |
207 | int ret; |
208 | u16 uval; |
209 | |
210 | ret = ad7291_i2c_read(chip, reg: ad7291_threshold_reg(chan, dir, info), |
211 | data: &uval); |
212 | if (ret < 0) |
213 | return ret; |
214 | |
215 | if (info == IIO_EV_INFO_HYSTERESIS || chan->type == IIO_VOLTAGE) |
216 | *val = uval & AD7291_VALUE_MASK; |
217 | |
218 | else |
219 | *val = sign_extend32(value: uval, index: 11); |
220 | |
221 | return IIO_VAL_INT; |
222 | } |
223 | |
224 | static int ad7291_write_event_value(struct iio_dev *indio_dev, |
225 | const struct iio_chan_spec *chan, |
226 | enum iio_event_type type, |
227 | enum iio_event_direction dir, |
228 | enum iio_event_info info, |
229 | int val, int val2) |
230 | { |
231 | struct ad7291_chip_info *chip = iio_priv(indio_dev); |
232 | |
233 | if (info == IIO_EV_INFO_HYSTERESIS || chan->type == IIO_VOLTAGE) { |
234 | if (val > AD7291_VALUE_MASK || val < 0) |
235 | return -EINVAL; |
236 | } else { |
237 | if (val > 2047 || val < -2048) |
238 | return -EINVAL; |
239 | } |
240 | |
241 | return ad7291_i2c_write(chip, reg: ad7291_threshold_reg(chan, dir, info), |
242 | data: val); |
243 | } |
244 | |
245 | static int ad7291_read_event_config(struct iio_dev *indio_dev, |
246 | const struct iio_chan_spec *chan, |
247 | enum iio_event_type type, |
248 | enum iio_event_direction dir) |
249 | { |
250 | struct ad7291_chip_info *chip = iio_priv(indio_dev); |
251 | /* |
252 | * To be enabled the channel must simply be on. If any are enabled |
253 | * we are in continuous sampling mode |
254 | */ |
255 | |
256 | switch (chan->type) { |
257 | case IIO_VOLTAGE: |
258 | return !!(chip->c_mask & BIT(15 - chan->channel)); |
259 | case IIO_TEMP: |
260 | /* always on */ |
261 | return 1; |
262 | default: |
263 | return -EINVAL; |
264 | } |
265 | |
266 | } |
267 | |
268 | static int ad7291_write_event_config(struct iio_dev *indio_dev, |
269 | const struct iio_chan_spec *chan, |
270 | enum iio_event_type type, |
271 | enum iio_event_direction dir, |
272 | int state) |
273 | { |
274 | int ret = 0; |
275 | struct ad7291_chip_info *chip = iio_priv(indio_dev); |
276 | unsigned int mask; |
277 | u16 regval; |
278 | |
279 | mutex_lock(&chip->state_lock); |
280 | regval = chip->command; |
281 | /* |
282 | * To be enabled the channel must simply be on. If any are enabled |
283 | * use continuous sampling mode. |
284 | * Possible to disable temp as well but that makes single read tricky. |
285 | */ |
286 | |
287 | mask = BIT(15 - chan->channel); |
288 | |
289 | switch (chan->type) { |
290 | case IIO_VOLTAGE: |
291 | if ((!state) && (chip->c_mask & mask)) |
292 | chip->c_mask &= ~mask; |
293 | else if (state && (!(chip->c_mask & mask))) |
294 | chip->c_mask |= mask; |
295 | else |
296 | break; |
297 | |
298 | regval &= ~AD7291_AUTOCYCLE; |
299 | regval |= chip->c_mask; |
300 | if (chip->c_mask) /* Enable autocycle? */ |
301 | regval |= AD7291_AUTOCYCLE; |
302 | |
303 | ret = ad7291_i2c_write(chip, AD7291_COMMAND, data: regval); |
304 | if (ret < 0) |
305 | goto error_ret; |
306 | |
307 | chip->command = regval; |
308 | break; |
309 | default: |
310 | ret = -EINVAL; |
311 | } |
312 | |
313 | error_ret: |
314 | mutex_unlock(lock: &chip->state_lock); |
315 | return ret; |
316 | } |
317 | |
318 | static int ad7291_read_raw(struct iio_dev *indio_dev, |
319 | struct iio_chan_spec const *chan, |
320 | int *val, |
321 | int *val2, |
322 | long mask) |
323 | { |
324 | int ret; |
325 | struct ad7291_chip_info *chip = iio_priv(indio_dev); |
326 | u16 regval; |
327 | |
328 | switch (mask) { |
329 | case IIO_CHAN_INFO_RAW: |
330 | switch (chan->type) { |
331 | case IIO_VOLTAGE: |
332 | mutex_lock(&chip->state_lock); |
333 | /* If in autocycle mode drop through */ |
334 | if (chip->command & AD7291_AUTOCYCLE) { |
335 | mutex_unlock(lock: &chip->state_lock); |
336 | return -EBUSY; |
337 | } |
338 | /* Enable this channel alone */ |
339 | regval = chip->command & (~AD7291_VOLTAGE_MASK); |
340 | regval |= BIT(15 - chan->channel); |
341 | ret = ad7291_i2c_write(chip, AD7291_COMMAND, data: regval); |
342 | if (ret < 0) { |
343 | mutex_unlock(lock: &chip->state_lock); |
344 | return ret; |
345 | } |
346 | /* Read voltage */ |
347 | ret = i2c_smbus_read_word_swapped(client: chip->client, |
348 | AD7291_VOLTAGE); |
349 | if (ret < 0) { |
350 | mutex_unlock(lock: &chip->state_lock); |
351 | return ret; |
352 | } |
353 | *val = ret & AD7291_VALUE_MASK; |
354 | mutex_unlock(lock: &chip->state_lock); |
355 | return IIO_VAL_INT; |
356 | case IIO_TEMP: |
357 | /* Assumes tsense bit of command register always set */ |
358 | ret = i2c_smbus_read_word_swapped(client: chip->client, |
359 | AD7291_T_SENSE); |
360 | if (ret < 0) |
361 | return ret; |
362 | *val = sign_extend32(value: ret, index: 11); |
363 | return IIO_VAL_INT; |
364 | default: |
365 | return -EINVAL; |
366 | } |
367 | case IIO_CHAN_INFO_AVERAGE_RAW: |
368 | ret = i2c_smbus_read_word_swapped(client: chip->client, |
369 | AD7291_T_AVERAGE); |
370 | if (ret < 0) |
371 | return ret; |
372 | *val = sign_extend32(value: ret, index: 11); |
373 | return IIO_VAL_INT; |
374 | case IIO_CHAN_INFO_SCALE: |
375 | switch (chan->type) { |
376 | case IIO_VOLTAGE: |
377 | if (chip->reg) { |
378 | int vref; |
379 | |
380 | vref = regulator_get_voltage(regulator: chip->reg); |
381 | if (vref < 0) |
382 | return vref; |
383 | *val = vref / 1000; |
384 | } else { |
385 | *val = 2500; |
386 | } |
387 | *val2 = AD7291_BITS; |
388 | return IIO_VAL_FRACTIONAL_LOG2; |
389 | case IIO_TEMP: |
390 | /* |
391 | * One LSB of the ADC corresponds to 0.25 deg C. |
392 | * The temperature reading is in 12-bit twos |
393 | * complement format |
394 | */ |
395 | *val = 250; |
396 | return IIO_VAL_INT; |
397 | default: |
398 | return -EINVAL; |
399 | } |
400 | default: |
401 | return -EINVAL; |
402 | } |
403 | } |
404 | |
405 | static const struct iio_event_spec ad7291_events[] = { |
406 | { |
407 | .type = IIO_EV_TYPE_THRESH, |
408 | .dir = IIO_EV_DIR_RISING, |
409 | .mask_separate = BIT(IIO_EV_INFO_VALUE) | |
410 | BIT(IIO_EV_INFO_ENABLE), |
411 | }, { |
412 | .type = IIO_EV_TYPE_THRESH, |
413 | .dir = IIO_EV_DIR_FALLING, |
414 | .mask_separate = BIT(IIO_EV_INFO_VALUE) | |
415 | BIT(IIO_EV_INFO_ENABLE), |
416 | }, { |
417 | .type = IIO_EV_TYPE_THRESH, |
418 | .dir = IIO_EV_DIR_EITHER, |
419 | .mask_separate = BIT(IIO_EV_INFO_HYSTERESIS), |
420 | }, |
421 | }; |
422 | |
423 | #define AD7291_VOLTAGE_CHAN(_chan) \ |
424 | { \ |
425 | .type = IIO_VOLTAGE, \ |
426 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ |
427 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ |
428 | .indexed = 1, \ |
429 | .channel = _chan, \ |
430 | .event_spec = ad7291_events, \ |
431 | .num_event_specs = ARRAY_SIZE(ad7291_events), \ |
432 | } |
433 | |
434 | static const struct iio_chan_spec ad7291_channels[] = { |
435 | AD7291_VOLTAGE_CHAN(0), |
436 | AD7291_VOLTAGE_CHAN(1), |
437 | AD7291_VOLTAGE_CHAN(2), |
438 | AD7291_VOLTAGE_CHAN(3), |
439 | AD7291_VOLTAGE_CHAN(4), |
440 | AD7291_VOLTAGE_CHAN(5), |
441 | AD7291_VOLTAGE_CHAN(6), |
442 | AD7291_VOLTAGE_CHAN(7), |
443 | { |
444 | .type = IIO_TEMP, |
445 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | |
446 | BIT(IIO_CHAN_INFO_AVERAGE_RAW) | |
447 | BIT(IIO_CHAN_INFO_SCALE), |
448 | .indexed = 1, |
449 | .channel = 0, |
450 | .event_spec = ad7291_events, |
451 | .num_event_specs = ARRAY_SIZE(ad7291_events), |
452 | } |
453 | }; |
454 | |
455 | static const struct iio_info ad7291_info = { |
456 | .read_raw = &ad7291_read_raw, |
457 | .read_event_config = &ad7291_read_event_config, |
458 | .write_event_config = &ad7291_write_event_config, |
459 | .read_event_value = &ad7291_read_event_value, |
460 | .write_event_value = &ad7291_write_event_value, |
461 | }; |
462 | |
463 | static void ad7291_reg_disable(void *reg) |
464 | { |
465 | regulator_disable(regulator: reg); |
466 | } |
467 | |
468 | static int ad7291_probe(struct i2c_client *client) |
469 | { |
470 | const struct i2c_device_id *id = i2c_client_get_device_id(client); |
471 | struct ad7291_chip_info *chip; |
472 | struct iio_dev *indio_dev; |
473 | int ret; |
474 | |
475 | indio_dev = devm_iio_device_alloc(parent: &client->dev, sizeof_priv: sizeof(*chip)); |
476 | if (!indio_dev) |
477 | return -ENOMEM; |
478 | chip = iio_priv(indio_dev); |
479 | |
480 | mutex_init(&chip->state_lock); |
481 | |
482 | chip->client = client; |
483 | |
484 | chip->command = AD7291_NOISE_DELAY | |
485 | AD7291_T_SENSE_MASK | /* Tsense always enabled */ |
486 | AD7291_ALERT_POLARITY; /* set irq polarity low level */ |
487 | |
488 | chip->reg = devm_regulator_get_optional(dev: &client->dev, id: "vref" ); |
489 | if (IS_ERR(ptr: chip->reg)) { |
490 | if (PTR_ERR(ptr: chip->reg) != -ENODEV) |
491 | return PTR_ERR(ptr: chip->reg); |
492 | |
493 | chip->reg = NULL; |
494 | } |
495 | |
496 | if (chip->reg) { |
497 | ret = regulator_enable(regulator: chip->reg); |
498 | if (ret) |
499 | return ret; |
500 | |
501 | ret = devm_add_action_or_reset(&client->dev, ad7291_reg_disable, |
502 | chip->reg); |
503 | if (ret) |
504 | return ret; |
505 | |
506 | chip->command |= AD7291_EXT_REF; |
507 | } |
508 | |
509 | indio_dev->name = id->name; |
510 | indio_dev->channels = ad7291_channels; |
511 | indio_dev->num_channels = ARRAY_SIZE(ad7291_channels); |
512 | |
513 | indio_dev->info = &ad7291_info; |
514 | indio_dev->modes = INDIO_DIRECT_MODE; |
515 | |
516 | ret = ad7291_i2c_write(chip, AD7291_COMMAND, AD7291_RESET); |
517 | if (ret) |
518 | return -EIO; |
519 | |
520 | ret = ad7291_i2c_write(chip, AD7291_COMMAND, data: chip->command); |
521 | if (ret) |
522 | return -EIO; |
523 | |
524 | if (client->irq > 0) { |
525 | ret = devm_request_threaded_irq(dev: &client->dev, irq: client->irq, |
526 | NULL, |
527 | thread_fn: &ad7291_event_handler, |
528 | IRQF_TRIGGER_LOW | IRQF_ONESHOT, |
529 | devname: id->name, |
530 | dev_id: indio_dev); |
531 | if (ret) |
532 | return ret; |
533 | } |
534 | |
535 | return devm_iio_device_register(&client->dev, indio_dev); |
536 | } |
537 | |
538 | static const struct i2c_device_id ad7291_id[] = { |
539 | { "ad7291" , 0 }, |
540 | {} |
541 | }; |
542 | |
543 | MODULE_DEVICE_TABLE(i2c, ad7291_id); |
544 | |
545 | static const struct of_device_id ad7291_of_match[] = { |
546 | { .compatible = "adi,ad7291" }, |
547 | {} |
548 | }; |
549 | MODULE_DEVICE_TABLE(of, ad7291_of_match); |
550 | |
551 | static struct i2c_driver ad7291_driver = { |
552 | .driver = { |
553 | .name = KBUILD_MODNAME, |
554 | .of_match_table = ad7291_of_match, |
555 | }, |
556 | .probe = ad7291_probe, |
557 | .id_table = ad7291_id, |
558 | }; |
559 | module_i2c_driver(ad7291_driver); |
560 | |
561 | MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>" ); |
562 | MODULE_DESCRIPTION("Analog Devices AD7291 ADC driver" ); |
563 | MODULE_LICENSE("GPL v2" ); |
564 | |