xref: /openbmc/linux/drivers/iio/adc/dln2-adc.c (revision cfbb9be8)
1 /*
2  * Driver for the Diolan DLN-2 USB-ADC adapter
3  *
4  * Copyright (c) 2017 Jack Andersen
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License as
8  * published by the Free Software Foundation, version 2.
9  */
10 
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/types.h>
14 #include <linux/platform_device.h>
15 #include <linux/mfd/dln2.h>
16 
17 #include <linux/iio/iio.h>
18 #include <linux/iio/sysfs.h>
19 #include <linux/iio/trigger.h>
20 #include <linux/iio/trigger_consumer.h>
21 #include <linux/iio/triggered_buffer.h>
22 #include <linux/iio/buffer.h>
23 #include <linux/iio/kfifo_buf.h>
24 
25 #define DLN2_ADC_MOD_NAME "dln2-adc"
26 
27 #define DLN2_ADC_ID             0x06
28 
29 #define DLN2_ADC_GET_CHANNEL_COUNT	DLN2_CMD(0x01, DLN2_ADC_ID)
30 #define DLN2_ADC_ENABLE			DLN2_CMD(0x02, DLN2_ADC_ID)
31 #define DLN2_ADC_DISABLE		DLN2_CMD(0x03, DLN2_ADC_ID)
32 #define DLN2_ADC_CHANNEL_ENABLE		DLN2_CMD(0x05, DLN2_ADC_ID)
33 #define DLN2_ADC_CHANNEL_DISABLE	DLN2_CMD(0x06, DLN2_ADC_ID)
34 #define DLN2_ADC_SET_RESOLUTION		DLN2_CMD(0x08, DLN2_ADC_ID)
35 #define DLN2_ADC_CHANNEL_GET_VAL	DLN2_CMD(0x0A, DLN2_ADC_ID)
36 #define DLN2_ADC_CHANNEL_GET_ALL_VAL	DLN2_CMD(0x0B, DLN2_ADC_ID)
37 #define DLN2_ADC_CHANNEL_SET_CFG	DLN2_CMD(0x0C, DLN2_ADC_ID)
38 #define DLN2_ADC_CHANNEL_GET_CFG	DLN2_CMD(0x0D, DLN2_ADC_ID)
39 #define DLN2_ADC_CONDITION_MET_EV	DLN2_CMD(0x10, DLN2_ADC_ID)
40 
41 #define DLN2_ADC_EVENT_NONE		0
42 #define DLN2_ADC_EVENT_BELOW		1
43 #define DLN2_ADC_EVENT_LEVEL_ABOVE	2
44 #define DLN2_ADC_EVENT_OUTSIDE		3
45 #define DLN2_ADC_EVENT_INSIDE		4
46 #define DLN2_ADC_EVENT_ALWAYS		5
47 
48 #define DLN2_ADC_MAX_CHANNELS 8
49 #define DLN2_ADC_DATA_BITS 10
50 
51 /*
52  * Plays similar role to iio_demux_table in subsystem core; except allocated
53  * in a fixed 8-element array.
54  */
55 struct dln2_adc_demux_table {
56 	unsigned int from;
57 	unsigned int to;
58 	unsigned int length;
59 };
60 
61 struct dln2_adc {
62 	struct platform_device *pdev;
63 	struct iio_chan_spec iio_channels[DLN2_ADC_MAX_CHANNELS + 1];
64 	int port, trigger_chan;
65 	struct iio_trigger *trig;
66 	struct mutex mutex;
67 	/* Cached sample period in milliseconds */
68 	unsigned int sample_period;
69 	/* Demux table */
70 	unsigned int demux_count;
71 	struct dln2_adc_demux_table demux[DLN2_ADC_MAX_CHANNELS];
72 	/* Precomputed timestamp padding offset and length */
73 	unsigned int ts_pad_offset, ts_pad_length;
74 };
75 
76 struct dln2_adc_port_chan {
77 	u8 port;
78 	u8 chan;
79 };
80 
81 struct dln2_adc_get_all_vals {
82 	__le16 channel_mask;
83 	__le16 values[DLN2_ADC_MAX_CHANNELS];
84 };
85 
86 static void dln2_adc_add_demux(struct dln2_adc *dln2,
87 	unsigned int in_loc, unsigned int out_loc,
88 	unsigned int length)
89 {
90 	struct dln2_adc_demux_table *p = dln2->demux_count ?
91 		&dln2->demux[dln2->demux_count - 1] : NULL;
92 
93 	if (p && p->from + p->length == in_loc &&
94 		p->to + p->length == out_loc) {
95 		p->length += length;
96 	} else if (dln2->demux_count < DLN2_ADC_MAX_CHANNELS) {
97 		p = &dln2->demux[dln2->demux_count++];
98 		p->from = in_loc;
99 		p->to = out_loc;
100 		p->length = length;
101 	}
102 }
103 
104 static void dln2_adc_update_demux(struct dln2_adc *dln2)
105 {
106 	int in_ind = -1, out_ind;
107 	unsigned int in_loc = 0, out_loc = 0;
108 	struct iio_dev *indio_dev = platform_get_drvdata(dln2->pdev);
109 
110 	/* Clear out any old demux */
111 	dln2->demux_count = 0;
112 
113 	/* Optimize all 8-channels case */
114 	if (indio_dev->masklength &&
115 	    (*indio_dev->active_scan_mask & 0xff) == 0xff) {
116 		dln2_adc_add_demux(dln2, 0, 0, 16);
117 		dln2->ts_pad_offset = 0;
118 		dln2->ts_pad_length = 0;
119 		return;
120 	}
121 
122 	/* Build demux table from fixed 8-channels to active_scan_mask */
123 	for_each_set_bit(out_ind,
124 			 indio_dev->active_scan_mask,
125 			 indio_dev->masklength) {
126 		/* Handle timestamp separately */
127 		if (out_ind == DLN2_ADC_MAX_CHANNELS)
128 			break;
129 		for (++in_ind; in_ind != out_ind; ++in_ind)
130 			in_loc += 2;
131 		dln2_adc_add_demux(dln2, in_loc, out_loc, 2);
132 		out_loc += 2;
133 		in_loc += 2;
134 	}
135 
136 	if (indio_dev->scan_timestamp) {
137 		size_t ts_offset = indio_dev->scan_bytes / sizeof(int64_t) - 1;
138 
139 		dln2->ts_pad_offset = out_loc;
140 		dln2->ts_pad_length = ts_offset * sizeof(int64_t) - out_loc;
141 	} else {
142 		dln2->ts_pad_offset = 0;
143 		dln2->ts_pad_length = 0;
144 	}
145 }
146 
147 static int dln2_adc_get_chan_count(struct dln2_adc *dln2)
148 {
149 	int ret;
150 	u8 port = dln2->port;
151 	u8 count;
152 	int olen = sizeof(count);
153 
154 	ret = dln2_transfer(dln2->pdev, DLN2_ADC_GET_CHANNEL_COUNT,
155 			    &port, sizeof(port), &count, &olen);
156 	if (ret < 0) {
157 		dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
158 		return ret;
159 	}
160 	if (olen < sizeof(count))
161 		return -EPROTO;
162 
163 	return count;
164 }
165 
166 static int dln2_adc_set_port_resolution(struct dln2_adc *dln2)
167 {
168 	int ret;
169 	struct dln2_adc_port_chan port_chan = {
170 		.port = dln2->port,
171 		.chan = DLN2_ADC_DATA_BITS,
172 	};
173 
174 	ret = dln2_transfer_tx(dln2->pdev, DLN2_ADC_SET_RESOLUTION,
175 			       &port_chan, sizeof(port_chan));
176 	if (ret < 0)
177 		dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
178 
179 	return ret;
180 }
181 
182 static int dln2_adc_set_chan_enabled(struct dln2_adc *dln2,
183 				     int channel, bool enable)
184 {
185 	int ret;
186 	struct dln2_adc_port_chan port_chan = {
187 		.port = dln2->port,
188 		.chan = channel,
189 	};
190 	u16 cmd = enable ? DLN2_ADC_CHANNEL_ENABLE : DLN2_ADC_CHANNEL_DISABLE;
191 
192 	ret = dln2_transfer_tx(dln2->pdev, cmd, &port_chan, sizeof(port_chan));
193 	if (ret < 0)
194 		dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
195 
196 	return ret;
197 }
198 
199 static int dln2_adc_set_port_enabled(struct dln2_adc *dln2, bool enable,
200 				     u16 *conflict_out)
201 {
202 	int ret;
203 	u8 port = dln2->port;
204 	__le16 conflict;
205 	int olen = sizeof(conflict);
206 	u16 cmd = enable ? DLN2_ADC_ENABLE : DLN2_ADC_DISABLE;
207 
208 	if (conflict_out)
209 		*conflict_out = 0;
210 
211 	ret = dln2_transfer(dln2->pdev, cmd, &port, sizeof(port),
212 			    &conflict, &olen);
213 	if (ret < 0) {
214 		dev_dbg(&dln2->pdev->dev, "Problem in %s(%d)\n",
215 			__func__, (int)enable);
216 		if (conflict_out && enable && olen >= sizeof(conflict))
217 			*conflict_out = le16_to_cpu(conflict);
218 		return ret;
219 	}
220 	if (enable && olen < sizeof(conflict))
221 		return -EPROTO;
222 
223 	return ret;
224 }
225 
226 static int dln2_adc_set_chan_period(struct dln2_adc *dln2,
227 	unsigned int channel, unsigned int period)
228 {
229 	int ret;
230 	struct {
231 		struct dln2_adc_port_chan port_chan;
232 		__u8 type;
233 		__le16 period;
234 		__le16 low;
235 		__le16 high;
236 	} __packed set_cfg = {
237 		.port_chan.port = dln2->port,
238 		.port_chan.chan = channel,
239 		.type = period ? DLN2_ADC_EVENT_ALWAYS : DLN2_ADC_EVENT_NONE,
240 		.period = cpu_to_le16(period)
241 	};
242 
243 	ret = dln2_transfer_tx(dln2->pdev, DLN2_ADC_CHANNEL_SET_CFG,
244 			       &set_cfg, sizeof(set_cfg));
245 	if (ret < 0)
246 		dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
247 
248 	return ret;
249 }
250 
251 static int dln2_adc_read(struct dln2_adc *dln2, unsigned int channel)
252 {
253 	int ret, i;
254 	struct iio_dev *indio_dev = platform_get_drvdata(dln2->pdev);
255 	u16 conflict;
256 	__le16 value;
257 	int olen = sizeof(value);
258 	struct dln2_adc_port_chan port_chan = {
259 		.port = dln2->port,
260 		.chan = channel,
261 	};
262 
263 	ret = iio_device_claim_direct_mode(indio_dev);
264 	if (ret < 0)
265 		return ret;
266 
267 	ret = dln2_adc_set_chan_enabled(dln2, channel, true);
268 	if (ret < 0)
269 		goto release_direct;
270 
271 	ret = dln2_adc_set_port_enabled(dln2, true, &conflict);
272 	if (ret < 0) {
273 		if (conflict) {
274 			dev_err(&dln2->pdev->dev,
275 				"ADC pins conflict with mask %04X\n",
276 				(int)conflict);
277 			ret = -EBUSY;
278 		}
279 		goto disable_chan;
280 	}
281 
282 	/*
283 	 * Call GET_VAL twice due to initial zero-return immediately after
284 	 * enabling channel.
285 	 */
286 	for (i = 0; i < 2; ++i) {
287 		ret = dln2_transfer(dln2->pdev, DLN2_ADC_CHANNEL_GET_VAL,
288 				    &port_chan, sizeof(port_chan),
289 				    &value, &olen);
290 		if (ret < 0) {
291 			dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
292 			goto disable_port;
293 		}
294 		if (olen < sizeof(value)) {
295 			ret = -EPROTO;
296 			goto disable_port;
297 		}
298 	}
299 
300 	ret = le16_to_cpu(value);
301 
302 disable_port:
303 	dln2_adc_set_port_enabled(dln2, false, NULL);
304 disable_chan:
305 	dln2_adc_set_chan_enabled(dln2, channel, false);
306 release_direct:
307 	iio_device_release_direct_mode(indio_dev);
308 
309 	return ret;
310 }
311 
312 static int dln2_adc_read_all(struct dln2_adc *dln2,
313 			     struct dln2_adc_get_all_vals *get_all_vals)
314 {
315 	int ret;
316 	__u8 port = dln2->port;
317 	int olen = sizeof(*get_all_vals);
318 
319 	ret = dln2_transfer(dln2->pdev, DLN2_ADC_CHANNEL_GET_ALL_VAL,
320 			    &port, sizeof(port), get_all_vals, &olen);
321 	if (ret < 0) {
322 		dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
323 		return ret;
324 	}
325 	if (olen < sizeof(*get_all_vals))
326 		return -EPROTO;
327 
328 	return ret;
329 }
330 
331 static int dln2_adc_read_raw(struct iio_dev *indio_dev,
332 			     struct iio_chan_spec const *chan,
333 			     int *val,
334 			     int *val2,
335 			     long mask)
336 {
337 	int ret;
338 	unsigned int microhertz;
339 	struct dln2_adc *dln2 = iio_priv(indio_dev);
340 
341 	switch (mask) {
342 	case IIO_CHAN_INFO_RAW:
343 		mutex_lock(&dln2->mutex);
344 		ret = dln2_adc_read(dln2, chan->channel);
345 		mutex_unlock(&dln2->mutex);
346 
347 		if (ret < 0)
348 			return ret;
349 
350 		*val = ret;
351 		return IIO_VAL_INT;
352 
353 	case IIO_CHAN_INFO_SCALE:
354 		/*
355 		 * Voltage reference is fixed at 3.3v
356 		 *  3.3 / (1 << 10) * 1000000000
357 		 */
358 		*val = 0;
359 		*val2 = 3222656;
360 		return IIO_VAL_INT_PLUS_NANO;
361 
362 	case IIO_CHAN_INFO_SAMP_FREQ:
363 		if (dln2->sample_period) {
364 			microhertz = 1000000000 / dln2->sample_period;
365 			*val = microhertz / 1000000;
366 			*val2 = microhertz % 1000000;
367 		} else {
368 			*val = 0;
369 			*val2 = 0;
370 		}
371 
372 		return IIO_VAL_INT_PLUS_MICRO;
373 
374 	default:
375 		return -EINVAL;
376 	}
377 }
378 
379 static int dln2_adc_write_raw(struct iio_dev *indio_dev,
380 			      struct iio_chan_spec const *chan,
381 			      int val,
382 			      int val2,
383 			      long mask)
384 {
385 	int ret;
386 	unsigned int microhertz;
387 	struct dln2_adc *dln2 = iio_priv(indio_dev);
388 
389 	switch (mask) {
390 	case IIO_CHAN_INFO_SAMP_FREQ:
391 		microhertz = 1000000 * val + val2;
392 
393 		mutex_lock(&dln2->mutex);
394 
395 		dln2->sample_period =
396 			microhertz ? 1000000000 / microhertz : UINT_MAX;
397 		if (dln2->sample_period > 65535) {
398 			dln2->sample_period = 65535;
399 			dev_warn(&dln2->pdev->dev,
400 				 "clamping period to 65535ms\n");
401 		}
402 
403 		/*
404 		 * The first requested channel is arbitrated as a shared
405 		 * trigger source, so only one event is registered with the
406 		 * DLN. The event handler will then read all enabled channel
407 		 * values using DLN2_ADC_CHANNEL_GET_ALL_VAL to maintain
408 		 * synchronization between ADC readings.
409 		 */
410 		if (dln2->trigger_chan != -1)
411 			ret = dln2_adc_set_chan_period(dln2,
412 				dln2->trigger_chan, dln2->sample_period);
413 		else
414 			ret = 0;
415 
416 		mutex_unlock(&dln2->mutex);
417 
418 		return ret;
419 
420 	default:
421 		return -EINVAL;
422 	}
423 }
424 
425 static int dln2_update_scan_mode(struct iio_dev *indio_dev,
426 				 const unsigned long *scan_mask)
427 {
428 	struct dln2_adc *dln2 = iio_priv(indio_dev);
429 	int chan_count = indio_dev->num_channels - 1;
430 	int ret, i, j;
431 
432 	mutex_lock(&dln2->mutex);
433 
434 	for (i = 0; i < chan_count; ++i) {
435 		ret = dln2_adc_set_chan_enabled(dln2, i,
436 						test_bit(i, scan_mask));
437 		if (ret < 0) {
438 			for (j = 0; j < i; ++j)
439 				dln2_adc_set_chan_enabled(dln2, j, false);
440 			mutex_unlock(&dln2->mutex);
441 			dev_err(&dln2->pdev->dev,
442 				"Unable to enable ADC channel %d\n", i);
443 			return -EBUSY;
444 		}
445 	}
446 
447 	dln2_adc_update_demux(dln2);
448 
449 	mutex_unlock(&dln2->mutex);
450 
451 	return 0;
452 }
453 
454 #define DLN2_ADC_CHAN(lval, idx) {					\
455 	lval.type = IIO_VOLTAGE;					\
456 	lval.channel = idx;						\
457 	lval.indexed = 1;						\
458 	lval.info_mask_separate = BIT(IIO_CHAN_INFO_RAW);		\
459 	lval.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE) |	\
460 				       BIT(IIO_CHAN_INFO_SAMP_FREQ);	\
461 	lval.scan_index = idx;						\
462 	lval.scan_type.sign = 'u';					\
463 	lval.scan_type.realbits = DLN2_ADC_DATA_BITS;			\
464 	lval.scan_type.storagebits = 16;				\
465 	lval.scan_type.endianness = IIO_LE;				\
466 }
467 
468 /* Assignment version of IIO_CHAN_SOFT_TIMESTAMP */
469 #define IIO_CHAN_SOFT_TIMESTAMP_ASSIGN(lval, _si) {	\
470 	lval.type = IIO_TIMESTAMP;			\
471 	lval.channel = -1;				\
472 	lval.scan_index = _si;				\
473 	lval.scan_type.sign = 's';			\
474 	lval.scan_type.realbits = 64;			\
475 	lval.scan_type.storagebits = 64;		\
476 }
477 
478 static const struct iio_info dln2_adc_info = {
479 	.read_raw = dln2_adc_read_raw,
480 	.write_raw = dln2_adc_write_raw,
481 	.update_scan_mode = dln2_update_scan_mode,
482 };
483 
484 static irqreturn_t dln2_adc_trigger_h(int irq, void *p)
485 {
486 	struct iio_poll_func *pf = p;
487 	struct iio_dev *indio_dev = pf->indio_dev;
488 	struct {
489 		__le16 values[DLN2_ADC_MAX_CHANNELS];
490 		int64_t timestamp_space;
491 	} data;
492 	struct dln2_adc_get_all_vals dev_data;
493 	struct dln2_adc *dln2 = iio_priv(indio_dev);
494 	const struct dln2_adc_demux_table *t;
495 	int ret, i;
496 
497 	mutex_lock(&dln2->mutex);
498 	ret = dln2_adc_read_all(dln2, &dev_data);
499 	mutex_unlock(&dln2->mutex);
500 	if (ret < 0)
501 		goto done;
502 
503 	/* Demux operation */
504 	for (i = 0; i < dln2->demux_count; ++i) {
505 		t = &dln2->demux[i];
506 		memcpy((void *)data.values + t->to,
507 		       (void *)dev_data.values + t->from, t->length);
508 	}
509 
510 	/* Zero padding space between values and timestamp */
511 	if (dln2->ts_pad_length)
512 		memset((void *)data.values + dln2->ts_pad_offset,
513 		       0, dln2->ts_pad_length);
514 
515 	iio_push_to_buffers_with_timestamp(indio_dev, &data,
516 					   iio_get_time_ns(indio_dev));
517 
518 done:
519 	iio_trigger_notify_done(indio_dev->trig);
520 	return IRQ_HANDLED;
521 }
522 
523 static int dln2_adc_triggered_buffer_postenable(struct iio_dev *indio_dev)
524 {
525 	int ret;
526 	struct dln2_adc *dln2 = iio_priv(indio_dev);
527 	u16 conflict;
528 	unsigned int trigger_chan;
529 
530 	mutex_lock(&dln2->mutex);
531 
532 	/* Enable ADC */
533 	ret = dln2_adc_set_port_enabled(dln2, true, &conflict);
534 	if (ret < 0) {
535 		mutex_unlock(&dln2->mutex);
536 		dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
537 		if (conflict) {
538 			dev_err(&dln2->pdev->dev,
539 				"ADC pins conflict with mask %04X\n",
540 				(int)conflict);
541 			ret = -EBUSY;
542 		}
543 		return ret;
544 	}
545 
546 	/* Assign trigger channel based on first enabled channel */
547 	trigger_chan = find_first_bit(indio_dev->active_scan_mask,
548 				      indio_dev->masklength);
549 	if (trigger_chan < DLN2_ADC_MAX_CHANNELS) {
550 		dln2->trigger_chan = trigger_chan;
551 		ret = dln2_adc_set_chan_period(dln2, dln2->trigger_chan,
552 					       dln2->sample_period);
553 		mutex_unlock(&dln2->mutex);
554 		if (ret < 0) {
555 			dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
556 			return ret;
557 		}
558 	} else {
559 		dln2->trigger_chan = -1;
560 		mutex_unlock(&dln2->mutex);
561 	}
562 
563 	return iio_triggered_buffer_postenable(indio_dev);
564 }
565 
566 static int dln2_adc_triggered_buffer_predisable(struct iio_dev *indio_dev)
567 {
568 	int ret;
569 	struct dln2_adc *dln2 = iio_priv(indio_dev);
570 
571 	mutex_lock(&dln2->mutex);
572 
573 	/* Disable trigger channel */
574 	if (dln2->trigger_chan != -1) {
575 		dln2_adc_set_chan_period(dln2, dln2->trigger_chan, 0);
576 		dln2->trigger_chan = -1;
577 	}
578 
579 	/* Disable ADC */
580 	ret = dln2_adc_set_port_enabled(dln2, false, NULL);
581 
582 	mutex_unlock(&dln2->mutex);
583 	if (ret < 0) {
584 		dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
585 		return ret;
586 	}
587 
588 	return iio_triggered_buffer_predisable(indio_dev);
589 }
590 
591 static const struct iio_buffer_setup_ops dln2_adc_buffer_setup_ops = {
592 	.postenable = dln2_adc_triggered_buffer_postenable,
593 	.predisable = dln2_adc_triggered_buffer_predisable,
594 };
595 
596 static void dln2_adc_event(struct platform_device *pdev, u16 echo,
597 			   const void *data, int len)
598 {
599 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
600 	struct dln2_adc *dln2 = iio_priv(indio_dev);
601 
602 	/* Called via URB completion handler */
603 	iio_trigger_poll(dln2->trig);
604 }
605 
606 static int dln2_adc_probe(struct platform_device *pdev)
607 {
608 	struct device *dev = &pdev->dev;
609 	struct dln2_adc *dln2;
610 	struct dln2_platform_data *pdata = dev_get_platdata(&pdev->dev);
611 	struct iio_dev *indio_dev;
612 	int i, ret, chans;
613 
614 	indio_dev = devm_iio_device_alloc(dev, sizeof(*dln2));
615 	if (!indio_dev) {
616 		dev_err(dev, "failed allocating iio device\n");
617 		return -ENOMEM;
618 	}
619 
620 	dln2 = iio_priv(indio_dev);
621 	dln2->pdev = pdev;
622 	dln2->port = pdata->port;
623 	dln2->trigger_chan = -1;
624 	mutex_init(&dln2->mutex);
625 
626 	platform_set_drvdata(pdev, indio_dev);
627 
628 	ret = dln2_adc_set_port_resolution(dln2);
629 	if (ret < 0) {
630 		dev_err(dev, "failed to set ADC resolution to 10 bits\n");
631 		return ret;
632 	}
633 
634 	chans = dln2_adc_get_chan_count(dln2);
635 	if (chans < 0) {
636 		dev_err(dev, "failed to get channel count: %d\n", chans);
637 		return chans;
638 	}
639 	if (chans > DLN2_ADC_MAX_CHANNELS) {
640 		chans = DLN2_ADC_MAX_CHANNELS;
641 		dev_warn(dev, "clamping channels to %d\n",
642 			 DLN2_ADC_MAX_CHANNELS);
643 	}
644 
645 	for (i = 0; i < chans; ++i)
646 		DLN2_ADC_CHAN(dln2->iio_channels[i], i)
647 	IIO_CHAN_SOFT_TIMESTAMP_ASSIGN(dln2->iio_channels[i], i);
648 
649 	indio_dev->name = DLN2_ADC_MOD_NAME;
650 	indio_dev->dev.parent = dev;
651 	indio_dev->info = &dln2_adc_info;
652 	indio_dev->modes = INDIO_DIRECT_MODE;
653 	indio_dev->channels = dln2->iio_channels;
654 	indio_dev->num_channels = chans + 1;
655 	indio_dev->setup_ops = &dln2_adc_buffer_setup_ops;
656 
657 	dln2->trig = devm_iio_trigger_alloc(dev, "%s-dev%d",
658 					    indio_dev->name, indio_dev->id);
659 	if (!dln2->trig) {
660 		dev_err(dev, "failed to allocate trigger\n");
661 		return -ENOMEM;
662 	}
663 	iio_trigger_set_drvdata(dln2->trig, dln2);
664 	devm_iio_trigger_register(dev, dln2->trig);
665 	iio_trigger_set_immutable(indio_dev, dln2->trig);
666 
667 	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
668 					      dln2_adc_trigger_h,
669 					      &dln2_adc_buffer_setup_ops);
670 	if (ret) {
671 		dev_err(dev, "failed to allocate triggered buffer: %d\n", ret);
672 		return ret;
673 	}
674 
675 	ret = dln2_register_event_cb(pdev, DLN2_ADC_CONDITION_MET_EV,
676 				     dln2_adc_event);
677 	if (ret) {
678 		dev_err(dev, "failed to setup DLN2 periodic event: %d\n", ret);
679 		return ret;
680 	}
681 
682 	ret = iio_device_register(indio_dev);
683 	if (ret) {
684 		dev_err(dev, "failed to register iio device: %d\n", ret);
685 		goto unregister_event;
686 	}
687 
688 	return ret;
689 
690 unregister_event:
691 	dln2_unregister_event_cb(pdev, DLN2_ADC_CONDITION_MET_EV);
692 
693 	return ret;
694 }
695 
696 static int dln2_adc_remove(struct platform_device *pdev)
697 {
698 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
699 
700 	iio_device_unregister(indio_dev);
701 	dln2_unregister_event_cb(pdev, DLN2_ADC_CONDITION_MET_EV);
702 	return 0;
703 }
704 
705 static struct platform_driver dln2_adc_driver = {
706 	.driver.name	= DLN2_ADC_MOD_NAME,
707 	.probe		= dln2_adc_probe,
708 	.remove		= dln2_adc_remove,
709 };
710 
711 module_platform_driver(dln2_adc_driver);
712 
713 MODULE_AUTHOR("Jack Andersen <jackoalan@gmail.com");
714 MODULE_DESCRIPTION("Driver for the Diolan DLN2 ADC interface");
715 MODULE_LICENSE("GPL v2");
716 MODULE_ALIAS("platform:dln2-adc");
717