xref: /openbmc/linux/drivers/iio/adc/dln2-adc.c (revision 715f23b6)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Driver for the Diolan DLN-2 USB-ADC adapter
4  *
5  * Copyright (c) 2017 Jack Andersen
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/types.h>
11 #include <linux/platform_device.h>
12 #include <linux/mfd/dln2.h>
13 
14 #include <linux/iio/iio.h>
15 #include <linux/iio/sysfs.h>
16 #include <linux/iio/trigger.h>
17 #include <linux/iio/trigger_consumer.h>
18 #include <linux/iio/triggered_buffer.h>
19 #include <linux/iio/buffer.h>
20 #include <linux/iio/kfifo_buf.h>
21 
22 #define DLN2_ADC_MOD_NAME "dln2-adc"
23 
24 #define DLN2_ADC_ID             0x06
25 
26 #define DLN2_ADC_GET_CHANNEL_COUNT	DLN2_CMD(0x01, DLN2_ADC_ID)
27 #define DLN2_ADC_ENABLE			DLN2_CMD(0x02, DLN2_ADC_ID)
28 #define DLN2_ADC_DISABLE		DLN2_CMD(0x03, DLN2_ADC_ID)
29 #define DLN2_ADC_CHANNEL_ENABLE		DLN2_CMD(0x05, DLN2_ADC_ID)
30 #define DLN2_ADC_CHANNEL_DISABLE	DLN2_CMD(0x06, DLN2_ADC_ID)
31 #define DLN2_ADC_SET_RESOLUTION		DLN2_CMD(0x08, DLN2_ADC_ID)
32 #define DLN2_ADC_CHANNEL_GET_VAL	DLN2_CMD(0x0A, DLN2_ADC_ID)
33 #define DLN2_ADC_CHANNEL_GET_ALL_VAL	DLN2_CMD(0x0B, DLN2_ADC_ID)
34 #define DLN2_ADC_CHANNEL_SET_CFG	DLN2_CMD(0x0C, DLN2_ADC_ID)
35 #define DLN2_ADC_CHANNEL_GET_CFG	DLN2_CMD(0x0D, DLN2_ADC_ID)
36 #define DLN2_ADC_CONDITION_MET_EV	DLN2_CMD(0x10, DLN2_ADC_ID)
37 
38 #define DLN2_ADC_EVENT_NONE		0
39 #define DLN2_ADC_EVENT_BELOW		1
40 #define DLN2_ADC_EVENT_LEVEL_ABOVE	2
41 #define DLN2_ADC_EVENT_OUTSIDE		3
42 #define DLN2_ADC_EVENT_INSIDE		4
43 #define DLN2_ADC_EVENT_ALWAYS		5
44 
45 #define DLN2_ADC_MAX_CHANNELS 8
46 #define DLN2_ADC_DATA_BITS 10
47 
48 /*
49  * Plays similar role to iio_demux_table in subsystem core; except allocated
50  * in a fixed 8-element array.
51  */
52 struct dln2_adc_demux_table {
53 	unsigned int from;
54 	unsigned int to;
55 	unsigned int length;
56 };
57 
58 struct dln2_adc {
59 	struct platform_device *pdev;
60 	struct iio_chan_spec iio_channels[DLN2_ADC_MAX_CHANNELS + 1];
61 	int port, trigger_chan;
62 	struct iio_trigger *trig;
63 	struct mutex mutex;
64 	/* Cached sample period in milliseconds */
65 	unsigned int sample_period;
66 	/* Demux table */
67 	unsigned int demux_count;
68 	struct dln2_adc_demux_table demux[DLN2_ADC_MAX_CHANNELS];
69 	/* Precomputed timestamp padding offset and length */
70 	unsigned int ts_pad_offset, ts_pad_length;
71 };
72 
73 struct dln2_adc_port_chan {
74 	u8 port;
75 	u8 chan;
76 };
77 
78 struct dln2_adc_get_all_vals {
79 	__le16 channel_mask;
80 	__le16 values[DLN2_ADC_MAX_CHANNELS];
81 };
82 
83 static void dln2_adc_add_demux(struct dln2_adc *dln2,
84 	unsigned int in_loc, unsigned int out_loc,
85 	unsigned int length)
86 {
87 	struct dln2_adc_demux_table *p = dln2->demux_count ?
88 		&dln2->demux[dln2->demux_count - 1] : NULL;
89 
90 	if (p && p->from + p->length == in_loc &&
91 		p->to + p->length == out_loc) {
92 		p->length += length;
93 	} else if (dln2->demux_count < DLN2_ADC_MAX_CHANNELS) {
94 		p = &dln2->demux[dln2->demux_count++];
95 		p->from = in_loc;
96 		p->to = out_loc;
97 		p->length = length;
98 	}
99 }
100 
101 static void dln2_adc_update_demux(struct dln2_adc *dln2)
102 {
103 	int in_ind = -1, out_ind;
104 	unsigned int in_loc = 0, out_loc = 0;
105 	struct iio_dev *indio_dev = platform_get_drvdata(dln2->pdev);
106 
107 	/* Clear out any old demux */
108 	dln2->demux_count = 0;
109 
110 	/* Optimize all 8-channels case */
111 	if (indio_dev->masklength &&
112 	    (*indio_dev->active_scan_mask & 0xff) == 0xff) {
113 		dln2_adc_add_demux(dln2, 0, 0, 16);
114 		dln2->ts_pad_offset = 0;
115 		dln2->ts_pad_length = 0;
116 		return;
117 	}
118 
119 	/* Build demux table from fixed 8-channels to active_scan_mask */
120 	for_each_set_bit(out_ind,
121 			 indio_dev->active_scan_mask,
122 			 indio_dev->masklength) {
123 		/* Handle timestamp separately */
124 		if (out_ind == DLN2_ADC_MAX_CHANNELS)
125 			break;
126 		for (++in_ind; in_ind != out_ind; ++in_ind)
127 			in_loc += 2;
128 		dln2_adc_add_demux(dln2, in_loc, out_loc, 2);
129 		out_loc += 2;
130 		in_loc += 2;
131 	}
132 
133 	if (indio_dev->scan_timestamp) {
134 		size_t ts_offset = indio_dev->scan_bytes / sizeof(int64_t) - 1;
135 
136 		dln2->ts_pad_offset = out_loc;
137 		dln2->ts_pad_length = ts_offset * sizeof(int64_t) - out_loc;
138 	} else {
139 		dln2->ts_pad_offset = 0;
140 		dln2->ts_pad_length = 0;
141 	}
142 }
143 
144 static int dln2_adc_get_chan_count(struct dln2_adc *dln2)
145 {
146 	int ret;
147 	u8 port = dln2->port;
148 	u8 count;
149 	int olen = sizeof(count);
150 
151 	ret = dln2_transfer(dln2->pdev, DLN2_ADC_GET_CHANNEL_COUNT,
152 			    &port, sizeof(port), &count, &olen);
153 	if (ret < 0) {
154 		dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
155 		return ret;
156 	}
157 	if (olen < sizeof(count))
158 		return -EPROTO;
159 
160 	return count;
161 }
162 
163 static int dln2_adc_set_port_resolution(struct dln2_adc *dln2)
164 {
165 	int ret;
166 	struct dln2_adc_port_chan port_chan = {
167 		.port = dln2->port,
168 		.chan = DLN2_ADC_DATA_BITS,
169 	};
170 
171 	ret = dln2_transfer_tx(dln2->pdev, DLN2_ADC_SET_RESOLUTION,
172 			       &port_chan, sizeof(port_chan));
173 	if (ret < 0)
174 		dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
175 
176 	return ret;
177 }
178 
179 static int dln2_adc_set_chan_enabled(struct dln2_adc *dln2,
180 				     int channel, bool enable)
181 {
182 	int ret;
183 	struct dln2_adc_port_chan port_chan = {
184 		.port = dln2->port,
185 		.chan = channel,
186 	};
187 	u16 cmd = enable ? DLN2_ADC_CHANNEL_ENABLE : DLN2_ADC_CHANNEL_DISABLE;
188 
189 	ret = dln2_transfer_tx(dln2->pdev, cmd, &port_chan, sizeof(port_chan));
190 	if (ret < 0)
191 		dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
192 
193 	return ret;
194 }
195 
196 static int dln2_adc_set_port_enabled(struct dln2_adc *dln2, bool enable,
197 				     u16 *conflict_out)
198 {
199 	int ret;
200 	u8 port = dln2->port;
201 	__le16 conflict;
202 	int olen = sizeof(conflict);
203 	u16 cmd = enable ? DLN2_ADC_ENABLE : DLN2_ADC_DISABLE;
204 
205 	if (conflict_out)
206 		*conflict_out = 0;
207 
208 	ret = dln2_transfer(dln2->pdev, cmd, &port, sizeof(port),
209 			    &conflict, &olen);
210 	if (ret < 0) {
211 		dev_dbg(&dln2->pdev->dev, "Problem in %s(%d)\n",
212 			__func__, (int)enable);
213 		if (conflict_out && enable && olen >= sizeof(conflict))
214 			*conflict_out = le16_to_cpu(conflict);
215 		return ret;
216 	}
217 	if (enable && olen < sizeof(conflict))
218 		return -EPROTO;
219 
220 	return ret;
221 }
222 
223 static int dln2_adc_set_chan_period(struct dln2_adc *dln2,
224 	unsigned int channel, unsigned int period)
225 {
226 	int ret;
227 	struct {
228 		struct dln2_adc_port_chan port_chan;
229 		__u8 type;
230 		__le16 period;
231 		__le16 low;
232 		__le16 high;
233 	} __packed set_cfg = {
234 		.port_chan.port = dln2->port,
235 		.port_chan.chan = channel,
236 		.type = period ? DLN2_ADC_EVENT_ALWAYS : DLN2_ADC_EVENT_NONE,
237 		.period = cpu_to_le16(period)
238 	};
239 
240 	ret = dln2_transfer_tx(dln2->pdev, DLN2_ADC_CHANNEL_SET_CFG,
241 			       &set_cfg, sizeof(set_cfg));
242 	if (ret < 0)
243 		dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
244 
245 	return ret;
246 }
247 
248 static int dln2_adc_read(struct dln2_adc *dln2, unsigned int channel)
249 {
250 	int ret, i;
251 	struct iio_dev *indio_dev = platform_get_drvdata(dln2->pdev);
252 	u16 conflict;
253 	__le16 value;
254 	int olen = sizeof(value);
255 	struct dln2_adc_port_chan port_chan = {
256 		.port = dln2->port,
257 		.chan = channel,
258 	};
259 
260 	ret = iio_device_claim_direct_mode(indio_dev);
261 	if (ret < 0)
262 		return ret;
263 
264 	ret = dln2_adc_set_chan_enabled(dln2, channel, true);
265 	if (ret < 0)
266 		goto release_direct;
267 
268 	ret = dln2_adc_set_port_enabled(dln2, true, &conflict);
269 	if (ret < 0) {
270 		if (conflict) {
271 			dev_err(&dln2->pdev->dev,
272 				"ADC pins conflict with mask %04X\n",
273 				(int)conflict);
274 			ret = -EBUSY;
275 		}
276 		goto disable_chan;
277 	}
278 
279 	/*
280 	 * Call GET_VAL twice due to initial zero-return immediately after
281 	 * enabling channel.
282 	 */
283 	for (i = 0; i < 2; ++i) {
284 		ret = dln2_transfer(dln2->pdev, DLN2_ADC_CHANNEL_GET_VAL,
285 				    &port_chan, sizeof(port_chan),
286 				    &value, &olen);
287 		if (ret < 0) {
288 			dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
289 			goto disable_port;
290 		}
291 		if (olen < sizeof(value)) {
292 			ret = -EPROTO;
293 			goto disable_port;
294 		}
295 	}
296 
297 	ret = le16_to_cpu(value);
298 
299 disable_port:
300 	dln2_adc_set_port_enabled(dln2, false, NULL);
301 disable_chan:
302 	dln2_adc_set_chan_enabled(dln2, channel, false);
303 release_direct:
304 	iio_device_release_direct_mode(indio_dev);
305 
306 	return ret;
307 }
308 
309 static int dln2_adc_read_all(struct dln2_adc *dln2,
310 			     struct dln2_adc_get_all_vals *get_all_vals)
311 {
312 	int ret;
313 	__u8 port = dln2->port;
314 	int olen = sizeof(*get_all_vals);
315 
316 	ret = dln2_transfer(dln2->pdev, DLN2_ADC_CHANNEL_GET_ALL_VAL,
317 			    &port, sizeof(port), get_all_vals, &olen);
318 	if (ret < 0) {
319 		dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
320 		return ret;
321 	}
322 	if (olen < sizeof(*get_all_vals))
323 		return -EPROTO;
324 
325 	return ret;
326 }
327 
328 static int dln2_adc_read_raw(struct iio_dev *indio_dev,
329 			     struct iio_chan_spec const *chan,
330 			     int *val,
331 			     int *val2,
332 			     long mask)
333 {
334 	int ret;
335 	unsigned int microhertz;
336 	struct dln2_adc *dln2 = iio_priv(indio_dev);
337 
338 	switch (mask) {
339 	case IIO_CHAN_INFO_RAW:
340 		mutex_lock(&dln2->mutex);
341 		ret = dln2_adc_read(dln2, chan->channel);
342 		mutex_unlock(&dln2->mutex);
343 
344 		if (ret < 0)
345 			return ret;
346 
347 		*val = ret;
348 		return IIO_VAL_INT;
349 
350 	case IIO_CHAN_INFO_SCALE:
351 		/*
352 		 * Voltage reference is fixed at 3.3v
353 		 *  3.3 / (1 << 10) * 1000000000
354 		 */
355 		*val = 0;
356 		*val2 = 3222656;
357 		return IIO_VAL_INT_PLUS_NANO;
358 
359 	case IIO_CHAN_INFO_SAMP_FREQ:
360 		if (dln2->sample_period) {
361 			microhertz = 1000000000 / dln2->sample_period;
362 			*val = microhertz / 1000000;
363 			*val2 = microhertz % 1000000;
364 		} else {
365 			*val = 0;
366 			*val2 = 0;
367 		}
368 
369 		return IIO_VAL_INT_PLUS_MICRO;
370 
371 	default:
372 		return -EINVAL;
373 	}
374 }
375 
376 static int dln2_adc_write_raw(struct iio_dev *indio_dev,
377 			      struct iio_chan_spec const *chan,
378 			      int val,
379 			      int val2,
380 			      long mask)
381 {
382 	int ret;
383 	unsigned int microhertz;
384 	struct dln2_adc *dln2 = iio_priv(indio_dev);
385 
386 	switch (mask) {
387 	case IIO_CHAN_INFO_SAMP_FREQ:
388 		microhertz = 1000000 * val + val2;
389 
390 		mutex_lock(&dln2->mutex);
391 
392 		dln2->sample_period =
393 			microhertz ? 1000000000 / microhertz : UINT_MAX;
394 		if (dln2->sample_period > 65535) {
395 			dln2->sample_period = 65535;
396 			dev_warn(&dln2->pdev->dev,
397 				 "clamping period to 65535ms\n");
398 		}
399 
400 		/*
401 		 * The first requested channel is arbitrated as a shared
402 		 * trigger source, so only one event is registered with the
403 		 * DLN. The event handler will then read all enabled channel
404 		 * values using DLN2_ADC_CHANNEL_GET_ALL_VAL to maintain
405 		 * synchronization between ADC readings.
406 		 */
407 		if (dln2->trigger_chan != -1)
408 			ret = dln2_adc_set_chan_period(dln2,
409 				dln2->trigger_chan, dln2->sample_period);
410 		else
411 			ret = 0;
412 
413 		mutex_unlock(&dln2->mutex);
414 
415 		return ret;
416 
417 	default:
418 		return -EINVAL;
419 	}
420 }
421 
422 static int dln2_update_scan_mode(struct iio_dev *indio_dev,
423 				 const unsigned long *scan_mask)
424 {
425 	struct dln2_adc *dln2 = iio_priv(indio_dev);
426 	int chan_count = indio_dev->num_channels - 1;
427 	int ret, i, j;
428 
429 	mutex_lock(&dln2->mutex);
430 
431 	for (i = 0; i < chan_count; ++i) {
432 		ret = dln2_adc_set_chan_enabled(dln2, i,
433 						test_bit(i, scan_mask));
434 		if (ret < 0) {
435 			for (j = 0; j < i; ++j)
436 				dln2_adc_set_chan_enabled(dln2, j, false);
437 			mutex_unlock(&dln2->mutex);
438 			dev_err(&dln2->pdev->dev,
439 				"Unable to enable ADC channel %d\n", i);
440 			return -EBUSY;
441 		}
442 	}
443 
444 	dln2_adc_update_demux(dln2);
445 
446 	mutex_unlock(&dln2->mutex);
447 
448 	return 0;
449 }
450 
451 #define DLN2_ADC_CHAN(lval, idx) {					\
452 	lval.type = IIO_VOLTAGE;					\
453 	lval.channel = idx;						\
454 	lval.indexed = 1;						\
455 	lval.info_mask_separate = BIT(IIO_CHAN_INFO_RAW);		\
456 	lval.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE) |	\
457 				       BIT(IIO_CHAN_INFO_SAMP_FREQ);	\
458 	lval.scan_index = idx;						\
459 	lval.scan_type.sign = 'u';					\
460 	lval.scan_type.realbits = DLN2_ADC_DATA_BITS;			\
461 	lval.scan_type.storagebits = 16;				\
462 	lval.scan_type.endianness = IIO_LE;				\
463 }
464 
465 /* Assignment version of IIO_CHAN_SOFT_TIMESTAMP */
466 #define IIO_CHAN_SOFT_TIMESTAMP_ASSIGN(lval, _si) {	\
467 	lval.type = IIO_TIMESTAMP;			\
468 	lval.channel = -1;				\
469 	lval.scan_index = _si;				\
470 	lval.scan_type.sign = 's';			\
471 	lval.scan_type.realbits = 64;			\
472 	lval.scan_type.storagebits = 64;		\
473 }
474 
475 static const struct iio_info dln2_adc_info = {
476 	.read_raw = dln2_adc_read_raw,
477 	.write_raw = dln2_adc_write_raw,
478 	.update_scan_mode = dln2_update_scan_mode,
479 };
480 
481 static irqreturn_t dln2_adc_trigger_h(int irq, void *p)
482 {
483 	struct iio_poll_func *pf = p;
484 	struct iio_dev *indio_dev = pf->indio_dev;
485 	struct {
486 		__le16 values[DLN2_ADC_MAX_CHANNELS];
487 		int64_t timestamp_space;
488 	} data;
489 	struct dln2_adc_get_all_vals dev_data;
490 	struct dln2_adc *dln2 = iio_priv(indio_dev);
491 	const struct dln2_adc_demux_table *t;
492 	int ret, i;
493 
494 	mutex_lock(&dln2->mutex);
495 	ret = dln2_adc_read_all(dln2, &dev_data);
496 	mutex_unlock(&dln2->mutex);
497 	if (ret < 0)
498 		goto done;
499 
500 	/* Demux operation */
501 	for (i = 0; i < dln2->demux_count; ++i) {
502 		t = &dln2->demux[i];
503 		memcpy((void *)data.values + t->to,
504 		       (void *)dev_data.values + t->from, t->length);
505 	}
506 
507 	/* Zero padding space between values and timestamp */
508 	if (dln2->ts_pad_length)
509 		memset((void *)data.values + dln2->ts_pad_offset,
510 		       0, dln2->ts_pad_length);
511 
512 	iio_push_to_buffers_with_timestamp(indio_dev, &data,
513 					   iio_get_time_ns(indio_dev));
514 
515 done:
516 	iio_trigger_notify_done(indio_dev->trig);
517 	return IRQ_HANDLED;
518 }
519 
520 static int dln2_adc_triggered_buffer_postenable(struct iio_dev *indio_dev)
521 {
522 	int ret;
523 	struct dln2_adc *dln2 = iio_priv(indio_dev);
524 	u16 conflict;
525 	unsigned int trigger_chan;
526 
527 	ret = iio_triggered_buffer_postenable(indio_dev);
528 	if (ret)
529 		return ret;
530 
531 	mutex_lock(&dln2->mutex);
532 
533 	/* Enable ADC */
534 	ret = dln2_adc_set_port_enabled(dln2, true, &conflict);
535 	if (ret < 0) {
536 		mutex_unlock(&dln2->mutex);
537 		dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
538 		if (conflict) {
539 			dev_err(&dln2->pdev->dev,
540 				"ADC pins conflict with mask %04X\n",
541 				(int)conflict);
542 			ret = -EBUSY;
543 		}
544 		iio_triggered_buffer_predisable(indio_dev);
545 		return ret;
546 	}
547 
548 	/* Assign trigger channel based on first enabled channel */
549 	trigger_chan = find_first_bit(indio_dev->active_scan_mask,
550 				      indio_dev->masklength);
551 	if (trigger_chan < DLN2_ADC_MAX_CHANNELS) {
552 		dln2->trigger_chan = trigger_chan;
553 		ret = dln2_adc_set_chan_period(dln2, dln2->trigger_chan,
554 					       dln2->sample_period);
555 		mutex_unlock(&dln2->mutex);
556 		if (ret < 0) {
557 			dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
558 			iio_triggered_buffer_predisable(indio_dev);
559 			return ret;
560 		}
561 	} else {
562 		dln2->trigger_chan = -1;
563 		mutex_unlock(&dln2->mutex);
564 	}
565 
566 	return 0;
567 }
568 
569 static int dln2_adc_triggered_buffer_predisable(struct iio_dev *indio_dev)
570 {
571 	int ret, ret2;
572 	struct dln2_adc *dln2 = iio_priv(indio_dev);
573 
574 	mutex_lock(&dln2->mutex);
575 
576 	/* Disable trigger channel */
577 	if (dln2->trigger_chan != -1) {
578 		dln2_adc_set_chan_period(dln2, dln2->trigger_chan, 0);
579 		dln2->trigger_chan = -1;
580 	}
581 
582 	/* Disable ADC */
583 	ret = dln2_adc_set_port_enabled(dln2, false, NULL);
584 
585 	mutex_unlock(&dln2->mutex);
586 	if (ret < 0)
587 		dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
588 
589 	ret2 = iio_triggered_buffer_predisable(indio_dev);
590 	if (ret == 0)
591 		ret = ret2;
592 
593 	return ret;
594 }
595 
596 static const struct iio_buffer_setup_ops dln2_adc_buffer_setup_ops = {
597 	.postenable = dln2_adc_triggered_buffer_postenable,
598 	.predisable = dln2_adc_triggered_buffer_predisable,
599 };
600 
601 static void dln2_adc_event(struct platform_device *pdev, u16 echo,
602 			   const void *data, int len)
603 {
604 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
605 	struct dln2_adc *dln2 = iio_priv(indio_dev);
606 
607 	/* Called via URB completion handler */
608 	iio_trigger_poll(dln2->trig);
609 }
610 
611 static int dln2_adc_probe(struct platform_device *pdev)
612 {
613 	struct device *dev = &pdev->dev;
614 	struct dln2_adc *dln2;
615 	struct dln2_platform_data *pdata = dev_get_platdata(&pdev->dev);
616 	struct iio_dev *indio_dev;
617 	int i, ret, chans;
618 
619 	indio_dev = devm_iio_device_alloc(dev, sizeof(*dln2));
620 	if (!indio_dev) {
621 		dev_err(dev, "failed allocating iio device\n");
622 		return -ENOMEM;
623 	}
624 
625 	dln2 = iio_priv(indio_dev);
626 	dln2->pdev = pdev;
627 	dln2->port = pdata->port;
628 	dln2->trigger_chan = -1;
629 	mutex_init(&dln2->mutex);
630 
631 	platform_set_drvdata(pdev, indio_dev);
632 
633 	ret = dln2_adc_set_port_resolution(dln2);
634 	if (ret < 0) {
635 		dev_err(dev, "failed to set ADC resolution to 10 bits\n");
636 		return ret;
637 	}
638 
639 	chans = dln2_adc_get_chan_count(dln2);
640 	if (chans < 0) {
641 		dev_err(dev, "failed to get channel count: %d\n", chans);
642 		return chans;
643 	}
644 	if (chans > DLN2_ADC_MAX_CHANNELS) {
645 		chans = DLN2_ADC_MAX_CHANNELS;
646 		dev_warn(dev, "clamping channels to %d\n",
647 			 DLN2_ADC_MAX_CHANNELS);
648 	}
649 
650 	for (i = 0; i < chans; ++i)
651 		DLN2_ADC_CHAN(dln2->iio_channels[i], i)
652 	IIO_CHAN_SOFT_TIMESTAMP_ASSIGN(dln2->iio_channels[i], i);
653 
654 	indio_dev->name = DLN2_ADC_MOD_NAME;
655 	indio_dev->dev.parent = dev;
656 	indio_dev->info = &dln2_adc_info;
657 	indio_dev->modes = INDIO_DIRECT_MODE;
658 	indio_dev->channels = dln2->iio_channels;
659 	indio_dev->num_channels = chans + 1;
660 	indio_dev->setup_ops = &dln2_adc_buffer_setup_ops;
661 
662 	dln2->trig = devm_iio_trigger_alloc(dev, "%s-dev%d",
663 					    indio_dev->name, indio_dev->id);
664 	if (!dln2->trig) {
665 		dev_err(dev, "failed to allocate trigger\n");
666 		return -ENOMEM;
667 	}
668 	iio_trigger_set_drvdata(dln2->trig, dln2);
669 	devm_iio_trigger_register(dev, dln2->trig);
670 	iio_trigger_set_immutable(indio_dev, dln2->trig);
671 
672 	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
673 					      dln2_adc_trigger_h,
674 					      &dln2_adc_buffer_setup_ops);
675 	if (ret) {
676 		dev_err(dev, "failed to allocate triggered buffer: %d\n", ret);
677 		return ret;
678 	}
679 
680 	ret = dln2_register_event_cb(pdev, DLN2_ADC_CONDITION_MET_EV,
681 				     dln2_adc_event);
682 	if (ret) {
683 		dev_err(dev, "failed to setup DLN2 periodic event: %d\n", ret);
684 		return ret;
685 	}
686 
687 	ret = iio_device_register(indio_dev);
688 	if (ret) {
689 		dev_err(dev, "failed to register iio device: %d\n", ret);
690 		goto unregister_event;
691 	}
692 
693 	return ret;
694 
695 unregister_event:
696 	dln2_unregister_event_cb(pdev, DLN2_ADC_CONDITION_MET_EV);
697 
698 	return ret;
699 }
700 
701 static int dln2_adc_remove(struct platform_device *pdev)
702 {
703 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
704 
705 	iio_device_unregister(indio_dev);
706 	dln2_unregister_event_cb(pdev, DLN2_ADC_CONDITION_MET_EV);
707 	return 0;
708 }
709 
710 static struct platform_driver dln2_adc_driver = {
711 	.driver.name	= DLN2_ADC_MOD_NAME,
712 	.probe		= dln2_adc_probe,
713 	.remove		= dln2_adc_remove,
714 };
715 
716 module_platform_driver(dln2_adc_driver);
717 
718 MODULE_AUTHOR("Jack Andersen <jackoalan@gmail.com");
719 MODULE_DESCRIPTION("Driver for the Diolan DLN2 ADC interface");
720 MODULE_LICENSE("GPL v2");
721 MODULE_ALIAS("platform:dln2-adc");
722