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9#include <linux/delay.h>
10#include <linux/i2c.h>
11#include <linux/interrupt.h>
12#include <linux/module.h>
13#include <linux/wait.h>
14#include <linux/log2.h>
15#include <linux/of.h>
16
17#include <linux/iio/iio.h>
18#include <linux/iio/sysfs.h>
19
20#define NAU7802_REG_PUCTRL 0x00
21#define NAU7802_PUCTRL_RR(x) (x << 0)
22#define NAU7802_PUCTRL_RR_BIT NAU7802_PUCTRL_RR(1)
23#define NAU7802_PUCTRL_PUD(x) (x << 1)
24#define NAU7802_PUCTRL_PUD_BIT NAU7802_PUCTRL_PUD(1)
25#define NAU7802_PUCTRL_PUA(x) (x << 2)
26#define NAU7802_PUCTRL_PUA_BIT NAU7802_PUCTRL_PUA(1)
27#define NAU7802_PUCTRL_PUR(x) (x << 3)
28#define NAU7802_PUCTRL_PUR_BIT NAU7802_PUCTRL_PUR(1)
29#define NAU7802_PUCTRL_CS(x) (x << 4)
30#define NAU7802_PUCTRL_CS_BIT NAU7802_PUCTRL_CS(1)
31#define NAU7802_PUCTRL_CR(x) (x << 5)
32#define NAU7802_PUCTRL_CR_BIT NAU7802_PUCTRL_CR(1)
33#define NAU7802_PUCTRL_AVDDS(x) (x << 7)
34#define NAU7802_PUCTRL_AVDDS_BIT NAU7802_PUCTRL_AVDDS(1)
35#define NAU7802_REG_CTRL1 0x01
36#define NAU7802_CTRL1_VLDO(x) (x << 3)
37#define NAU7802_CTRL1_GAINS(x) (x)
38#define NAU7802_CTRL1_GAINS_BITS 0x07
39#define NAU7802_REG_CTRL2 0x02
40#define NAU7802_CTRL2_CHS(x) (x << 7)
41#define NAU7802_CTRL2_CRS(x) (x << 4)
42#define NAU7802_SAMP_FREQ_320 0x07
43#define NAU7802_CTRL2_CHS_BIT NAU7802_CTRL2_CHS(1)
44#define NAU7802_REG_ADC_B2 0x12
45#define NAU7802_REG_ADC_B1 0x13
46#define NAU7802_REG_ADC_B0 0x14
47#define NAU7802_REG_ADC_CTRL 0x15
48
49#define NAU7802_MIN_CONVERSIONS 6
50
51struct nau7802_state {
52 struct i2c_client *client;
53 s32 last_value;
54 struct mutex lock;
55 struct mutex data_lock;
56 u32 vref_mv;
57 u32 conversion_count;
58 u32 min_conversions;
59 u8 sample_rate;
60 u32 scale_avail[8];
61 struct completion value_ok;
62};
63
64#define NAU7802_CHANNEL(chan) { \
65 .type = IIO_VOLTAGE, \
66 .indexed = 1, \
67 .channel = (chan), \
68 .scan_index = (chan), \
69 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
70 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
71 BIT(IIO_CHAN_INFO_SAMP_FREQ) \
72}
73
74static const struct iio_chan_spec nau7802_chan_array[] = {
75 NAU7802_CHANNEL(0),
76 NAU7802_CHANNEL(1),
77};
78
79static const u16 nau7802_sample_freq_avail[] = {10, 20, 40, 80,
80 10, 10, 10, 320};
81
82static ssize_t nau7802_show_scales(struct device *dev,
83 struct device_attribute *attr, char *buf)
84{
85 struct nau7802_state *st = iio_priv(dev_to_iio_dev(dev));
86 int i, len = 0;
87
88 for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++)
89 len += scnprintf(buf + len, PAGE_SIZE - len, "0.%09d ",
90 st->scale_avail[i]);
91
92 buf[len-1] = '\n';
93
94 return len;
95}
96
97static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("10 40 80 320");
98
99static IIO_DEVICE_ATTR(in_voltage_scale_available, S_IRUGO, nau7802_show_scales,
100 NULL, 0);
101
102static struct attribute *nau7802_attributes[] = {
103 &iio_const_attr_sampling_frequency_available.dev_attr.attr,
104 &iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
105 NULL
106};
107
108static const struct attribute_group nau7802_attribute_group = {
109 .attrs = nau7802_attributes,
110};
111
112static int nau7802_set_gain(struct nau7802_state *st, int gain)
113{
114 int ret;
115
116 mutex_lock(&st->lock);
117 st->conversion_count = 0;
118
119 ret = i2c_smbus_read_byte_data(st->client, NAU7802_REG_CTRL1);
120 if (ret < 0)
121 goto nau7802_sysfs_set_gain_out;
122 ret = i2c_smbus_write_byte_data(st->client, NAU7802_REG_CTRL1,
123 (ret & (~NAU7802_CTRL1_GAINS_BITS)) |
124 gain);
125
126nau7802_sysfs_set_gain_out:
127 mutex_unlock(&st->lock);
128
129 return ret;
130}
131
132static int nau7802_read_conversion(struct nau7802_state *st)
133{
134 int data;
135
136 mutex_lock(&st->data_lock);
137 data = i2c_smbus_read_byte_data(st->client, NAU7802_REG_ADC_B2);
138 if (data < 0)
139 goto nau7802_read_conversion_out;
140 st->last_value = data << 16;
141
142 data = i2c_smbus_read_byte_data(st->client, NAU7802_REG_ADC_B1);
143 if (data < 0)
144 goto nau7802_read_conversion_out;
145 st->last_value |= data << 8;
146
147 data = i2c_smbus_read_byte_data(st->client, NAU7802_REG_ADC_B0);
148 if (data < 0)
149 goto nau7802_read_conversion_out;
150 st->last_value |= data;
151
152 st->last_value = sign_extend32(st->last_value, 23);
153
154nau7802_read_conversion_out:
155 mutex_unlock(&st->data_lock);
156
157 return data;
158}
159
160
161
162
163static int nau7802_sync(struct nau7802_state *st)
164{
165 int ret;
166
167 ret = i2c_smbus_read_byte_data(st->client, NAU7802_REG_PUCTRL);
168 if (ret < 0)
169 return ret;
170 ret = i2c_smbus_write_byte_data(st->client, NAU7802_REG_PUCTRL,
171 ret | NAU7802_PUCTRL_CS_BIT);
172
173 return ret;
174}
175
176static irqreturn_t nau7802_eoc_trigger(int irq, void *private)
177{
178 struct iio_dev *indio_dev = private;
179 struct nau7802_state *st = iio_priv(indio_dev);
180 int status;
181
182 status = i2c_smbus_read_byte_data(st->client, NAU7802_REG_PUCTRL);
183 if (status < 0)
184 return IRQ_HANDLED;
185
186 if (!(status & NAU7802_PUCTRL_CR_BIT))
187 return IRQ_NONE;
188
189 if (nau7802_read_conversion(st) < 0)
190 return IRQ_HANDLED;
191
192
193
194
195
196
197 if (st->conversion_count < NAU7802_MIN_CONVERSIONS)
198 st->conversion_count++;
199 if (st->conversion_count >= NAU7802_MIN_CONVERSIONS)
200 complete(&st->value_ok);
201
202 return IRQ_HANDLED;
203}
204
205static int nau7802_read_irq(struct iio_dev *indio_dev,
206 struct iio_chan_spec const *chan,
207 int *val)
208{
209 struct nau7802_state *st = iio_priv(indio_dev);
210 int ret;
211
212 reinit_completion(&st->value_ok);
213 enable_irq(st->client->irq);
214
215 nau7802_sync(st);
216
217
218 ret = nau7802_read_conversion(st);
219 if (ret < 0)
220 goto read_chan_info_failure;
221
222
223 ret = wait_for_completion_interruptible_timeout(&st->value_ok,
224 msecs_to_jiffies(1000));
225 if (ret == 0)
226 ret = -ETIMEDOUT;
227
228 if (ret < 0)
229 goto read_chan_info_failure;
230
231 disable_irq(st->client->irq);
232
233 *val = st->last_value;
234
235 return IIO_VAL_INT;
236
237read_chan_info_failure:
238 disable_irq(st->client->irq);
239
240 return ret;
241}
242
243static int nau7802_read_poll(struct iio_dev *indio_dev,
244 struct iio_chan_spec const *chan,
245 int *val)
246{
247 struct nau7802_state *st = iio_priv(indio_dev);
248 int ret;
249
250 nau7802_sync(st);
251
252
253 ret = nau7802_read_conversion(st);
254 if (ret < 0)
255 return ret;
256
257
258
259
260
261
262 do {
263 ret = i2c_smbus_read_byte_data(st->client, NAU7802_REG_PUCTRL);
264 if (ret < 0)
265 return ret;
266
267 while (!(ret & NAU7802_PUCTRL_CR_BIT)) {
268 if (st->sample_rate != NAU7802_SAMP_FREQ_320)
269 msleep(20);
270 else
271 mdelay(4);
272 ret = i2c_smbus_read_byte_data(st->client,
273 NAU7802_REG_PUCTRL);
274 if (ret < 0)
275 return ret;
276 }
277
278 ret = nau7802_read_conversion(st);
279 if (ret < 0)
280 return ret;
281 if (st->conversion_count < NAU7802_MIN_CONVERSIONS)
282 st->conversion_count++;
283 } while (st->conversion_count < NAU7802_MIN_CONVERSIONS);
284
285 *val = st->last_value;
286
287 return IIO_VAL_INT;
288}
289
290static int nau7802_read_raw(struct iio_dev *indio_dev,
291 struct iio_chan_spec const *chan,
292 int *val, int *val2, long mask)
293{
294 struct nau7802_state *st = iio_priv(indio_dev);
295 int ret;
296
297 switch (mask) {
298 case IIO_CHAN_INFO_RAW:
299 mutex_lock(&st->lock);
300
301
302
303
304
305 ret = i2c_smbus_read_byte_data(st->client, NAU7802_REG_CTRL2);
306 if (ret < 0) {
307 mutex_unlock(&st->lock);
308 return ret;
309 }
310
311 if (((ret & NAU7802_CTRL2_CHS_BIT) && !chan->channel) ||
312 (!(ret & NAU7802_CTRL2_CHS_BIT) &&
313 chan->channel)) {
314 st->conversion_count = 0;
315 ret = i2c_smbus_write_byte_data(st->client,
316 NAU7802_REG_CTRL2,
317 NAU7802_CTRL2_CHS(chan->channel) |
318 NAU7802_CTRL2_CRS(st->sample_rate));
319
320 if (ret < 0) {
321 mutex_unlock(&st->lock);
322 return ret;
323 }
324 }
325
326 if (st->client->irq)
327 ret = nau7802_read_irq(indio_dev, chan, val);
328 else
329 ret = nau7802_read_poll(indio_dev, chan, val);
330
331 mutex_unlock(&st->lock);
332 return ret;
333
334 case IIO_CHAN_INFO_SCALE:
335 ret = i2c_smbus_read_byte_data(st->client, NAU7802_REG_CTRL1);
336 if (ret < 0)
337 return ret;
338
339
340
341
342
343 *val = st->vref_mv;
344 *val2 = 23 + (ret & NAU7802_CTRL1_GAINS_BITS);
345
346 return IIO_VAL_FRACTIONAL_LOG2;
347
348 case IIO_CHAN_INFO_SAMP_FREQ:
349 *val = nau7802_sample_freq_avail[st->sample_rate];
350 *val2 = 0;
351 return IIO_VAL_INT;
352
353 default:
354 break;
355 }
356
357 return -EINVAL;
358}
359
360static int nau7802_write_raw(struct iio_dev *indio_dev,
361 struct iio_chan_spec const *chan,
362 int val, int val2, long mask)
363{
364 struct nau7802_state *st = iio_priv(indio_dev);
365 int i, ret;
366
367 switch (mask) {
368 case IIO_CHAN_INFO_SCALE:
369 for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++)
370 if (val2 == st->scale_avail[i])
371 return nau7802_set_gain(st, i);
372
373 break;
374
375 case IIO_CHAN_INFO_SAMP_FREQ:
376 for (i = 0; i < ARRAY_SIZE(nau7802_sample_freq_avail); i++)
377 if (val == nau7802_sample_freq_avail[i]) {
378 mutex_lock(&st->lock);
379 st->sample_rate = i;
380 st->conversion_count = 0;
381 ret = i2c_smbus_write_byte_data(st->client,
382 NAU7802_REG_CTRL2,
383 NAU7802_CTRL2_CRS(st->sample_rate));
384 mutex_unlock(&st->lock);
385 return ret;
386 }
387
388 break;
389
390 default:
391 break;
392 }
393
394 return -EINVAL;
395}
396
397static int nau7802_write_raw_get_fmt(struct iio_dev *indio_dev,
398 struct iio_chan_spec const *chan,
399 long mask)
400{
401 return IIO_VAL_INT_PLUS_NANO;
402}
403
404static const struct iio_info nau7802_info = {
405 .driver_module = THIS_MODULE,
406 .read_raw = &nau7802_read_raw,
407 .write_raw = &nau7802_write_raw,
408 .write_raw_get_fmt = nau7802_write_raw_get_fmt,
409 .attrs = &nau7802_attribute_group,
410};
411
412static int nau7802_probe(struct i2c_client *client,
413 const struct i2c_device_id *id)
414{
415 struct iio_dev *indio_dev;
416 struct nau7802_state *st;
417 struct device_node *np = client->dev.of_node;
418 int i, ret;
419 u8 data;
420 u32 tmp = 0;
421
422 if (!client->dev.of_node) {
423 dev_err(&client->dev, "No device tree node available.\n");
424 return -EINVAL;
425 }
426
427 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
428 if (indio_dev == NULL)
429 return -ENOMEM;
430
431 st = iio_priv(indio_dev);
432
433 i2c_set_clientdata(client, indio_dev);
434
435 indio_dev->dev.parent = &client->dev;
436 indio_dev->dev.of_node = client->dev.of_node;
437 indio_dev->name = dev_name(&client->dev);
438 indio_dev->modes = INDIO_DIRECT_MODE;
439 indio_dev->info = &nau7802_info;
440
441 st->client = client;
442
443
444 ret = i2c_smbus_write_byte_data(st->client, NAU7802_REG_PUCTRL,
445 NAU7802_PUCTRL_RR_BIT);
446 if (ret < 0)
447 return ret;
448
449
450 ret = i2c_smbus_write_byte_data(st->client, NAU7802_REG_PUCTRL,
451 NAU7802_PUCTRL_PUD_BIT);
452 if (ret < 0)
453 return ret;
454
455
456
457
458
459 udelay(210);
460 ret = i2c_smbus_read_byte_data(st->client, NAU7802_REG_PUCTRL);
461 if (ret < 0)
462 return ret;
463 if (!(ret & NAU7802_PUCTRL_PUR_BIT))
464 return ret;
465
466 of_property_read_u32(np, "nuvoton,vldo", &tmp);
467 st->vref_mv = tmp;
468
469 data = NAU7802_PUCTRL_PUD_BIT | NAU7802_PUCTRL_PUA_BIT |
470 NAU7802_PUCTRL_CS_BIT;
471 if (tmp >= 2400)
472 data |= NAU7802_PUCTRL_AVDDS_BIT;
473
474 ret = i2c_smbus_write_byte_data(st->client, NAU7802_REG_PUCTRL, data);
475 if (ret < 0)
476 return ret;
477 ret = i2c_smbus_write_byte_data(st->client, NAU7802_REG_ADC_CTRL, 0x30);
478 if (ret < 0)
479 return ret;
480
481 if (tmp >= 2400) {
482 data = NAU7802_CTRL1_VLDO((4500 - tmp) / 300);
483 ret = i2c_smbus_write_byte_data(st->client, NAU7802_REG_CTRL1,
484 data);
485 if (ret < 0)
486 return ret;
487 }
488
489
490 for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++)
491 st->scale_avail[i] = (((u64)st->vref_mv) * 1000000000ULL)
492 >> (23 + i);
493
494 init_completion(&st->value_ok);
495
496
497
498
499
500
501 if (client->irq) {
502 ret = request_threaded_irq(client->irq,
503 NULL,
504 nau7802_eoc_trigger,
505 IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
506 client->dev.driver->name,
507 indio_dev);
508 if (ret) {
509
510
511
512
513
514
515
516
517 dev_info(&client->dev,
518 "Failed to allocate IRQ, using polling mode\n");
519 client->irq = 0;
520 } else
521 disable_irq(client->irq);
522 }
523
524 if (!client->irq) {
525
526
527
528
529 st->sample_rate = NAU7802_SAMP_FREQ_320;
530 ret = i2c_smbus_write_byte_data(st->client, NAU7802_REG_CTRL2,
531 NAU7802_CTRL2_CRS(st->sample_rate));
532 if (ret)
533 goto error_free_irq;
534 }
535
536
537 indio_dev->num_channels = ARRAY_SIZE(nau7802_chan_array);
538 indio_dev->channels = nau7802_chan_array;
539
540 mutex_init(&st->lock);
541 mutex_init(&st->data_lock);
542
543 ret = iio_device_register(indio_dev);
544 if (ret < 0) {
545 dev_err(&client->dev, "Couldn't register the device.\n");
546 goto error_device_register;
547 }
548
549 return 0;
550
551error_device_register:
552 mutex_destroy(&st->lock);
553 mutex_destroy(&st->data_lock);
554error_free_irq:
555 if (client->irq)
556 free_irq(client->irq, indio_dev);
557
558 return ret;
559}
560
561static int nau7802_remove(struct i2c_client *client)
562{
563 struct iio_dev *indio_dev = i2c_get_clientdata(client);
564 struct nau7802_state *st = iio_priv(indio_dev);
565
566 iio_device_unregister(indio_dev);
567 mutex_destroy(&st->lock);
568 mutex_destroy(&st->data_lock);
569 if (client->irq)
570 free_irq(client->irq, indio_dev);
571
572 return 0;
573}
574
575static const struct i2c_device_id nau7802_i2c_id[] = {
576 { "nau7802", 0 },
577 { }
578};
579MODULE_DEVICE_TABLE(i2c, nau7802_i2c_id);
580
581static const struct of_device_id nau7802_dt_ids[] = {
582 { .compatible = "nuvoton,nau7802" },
583 {},
584};
585MODULE_DEVICE_TABLE(of, nau7802_dt_ids);
586
587static struct i2c_driver nau7802_driver = {
588 .probe = nau7802_probe,
589 .remove = nau7802_remove,
590 .id_table = nau7802_i2c_id,
591 .driver = {
592 .name = "nau7802",
593 .of_match_table = nau7802_dt_ids,
594 },
595};
596
597module_i2c_driver(nau7802_driver);
598
599MODULE_LICENSE("GPL");
600MODULE_DESCRIPTION("Nuvoton NAU7802 ADC Driver");
601MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
602MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
603
