1 // SPDX-License-Identifier: GPL-2.0
2 
3 /*
4  * System Control and Management Interface(SCMI) based IIO sensor driver
5  *
6  * Copyright (C) 2021 Google LLC
7  */
8 
9 #include <linux/delay.h>
10 #include <linux/err.h>
11 #include <linux/iio/buffer.h>
12 #include <linux/iio/iio.h>
13 #include <linux/iio/kfifo_buf.h>
14 #include <linux/iio/sysfs.h>
15 #include <linux/kernel.h>
16 #include <linux/kthread.h>
17 #include <linux/module.h>
18 #include <linux/scmi_protocol.h>
19 #include <linux/time.h>
20 #include <linux/types.h>
21 
22 #define SCMI_IIO_NUM_OF_AXIS 3
23 
24 struct scmi_iio_priv {
25 	const struct scmi_sensor_proto_ops *sensor_ops;
26 	struct scmi_protocol_handle *ph;
27 	const struct scmi_sensor_info *sensor_info;
28 	struct iio_dev *indio_dev;
29 	/* adding one additional channel for timestamp */
30 	s64 iio_buf[SCMI_IIO_NUM_OF_AXIS + 1];
31 	struct notifier_block sensor_update_nb;
32 	u32 *freq_avail;
33 };
34 
35 static int scmi_iio_sensor_update_cb(struct notifier_block *nb,
36 				     unsigned long event, void *data)
37 {
38 	struct scmi_sensor_update_report *sensor_update = data;
39 	struct iio_dev *scmi_iio_dev;
40 	struct scmi_iio_priv *sensor;
41 	s8 tstamp_scale;
42 	u64 time, time_ns;
43 	int i;
44 
45 	if (sensor_update->readings_count == 0)
46 		return NOTIFY_DONE;
47 
48 	sensor = container_of(nb, struct scmi_iio_priv, sensor_update_nb);
49 
50 	for (i = 0; i < sensor_update->readings_count; i++)
51 		sensor->iio_buf[i] = sensor_update->readings[i].value;
52 
53 	if (!sensor->sensor_info->timestamped) {
54 		time_ns = ktime_to_ns(sensor_update->timestamp);
55 	} else {
56 		/*
57 		 *  All the axes are supposed to have the same value for timestamp.
58 		 *  We are just using the values from the Axis 0 here.
59 		 */
60 		time = sensor_update->readings[0].timestamp;
61 
62 		/*
63 		 *  Timestamp returned by SCMI is in seconds and is equal to
64 		 *  time * power-of-10 multiplier(tstamp_scale) seconds.
65 		 *  Converting the timestamp to nanoseconds below.
66 		 */
67 		tstamp_scale = sensor->sensor_info->tstamp_scale +
68 			       const_ilog2(NSEC_PER_SEC) / const_ilog2(10);
69 		if (tstamp_scale < 0) {
70 			do_div(time, int_pow(10, abs(tstamp_scale)));
71 			time_ns = time;
72 		} else {
73 			time_ns = time * int_pow(10, tstamp_scale);
74 		}
75 	}
76 
77 	scmi_iio_dev = sensor->indio_dev;
78 	iio_push_to_buffers_with_timestamp(scmi_iio_dev, sensor->iio_buf,
79 					   time_ns);
80 	return NOTIFY_OK;
81 }
82 
83 static int scmi_iio_buffer_preenable(struct iio_dev *iio_dev)
84 {
85 	struct scmi_iio_priv *sensor = iio_priv(iio_dev);
86 	u32 sensor_config = 0;
87 	int err;
88 
89 	if (sensor->sensor_info->timestamped)
90 		sensor_config |= FIELD_PREP(SCMI_SENS_CFG_TSTAMP_ENABLED_MASK,
91 					    SCMI_SENS_CFG_TSTAMP_ENABLE);
92 
93 	sensor_config |= FIELD_PREP(SCMI_SENS_CFG_SENSOR_ENABLED_MASK,
94 				    SCMI_SENS_CFG_SENSOR_ENABLE);
95 	err = sensor->sensor_ops->config_set(sensor->ph,
96 					     sensor->sensor_info->id,
97 					     sensor_config);
98 	if (err)
99 		dev_err(&iio_dev->dev, "Error in enabling sensor %s err %d",
100 			sensor->sensor_info->name, err);
101 
102 	return err;
103 }
104 
105 static int scmi_iio_buffer_postdisable(struct iio_dev *iio_dev)
106 {
107 	struct scmi_iio_priv *sensor = iio_priv(iio_dev);
108 	u32 sensor_config = 0;
109 	int err;
110 
111 	sensor_config |= FIELD_PREP(SCMI_SENS_CFG_SENSOR_ENABLED_MASK,
112 				    SCMI_SENS_CFG_SENSOR_DISABLE);
113 	err = sensor->sensor_ops->config_set(sensor->ph,
114 					     sensor->sensor_info->id,
115 					     sensor_config);
116 	if (err) {
117 		dev_err(&iio_dev->dev,
118 			"Error in disabling sensor %s with err %d",
119 			sensor->sensor_info->name, err);
120 	}
121 
122 	return err;
123 }
124 
125 static const struct iio_buffer_setup_ops scmi_iio_buffer_ops = {
126 	.preenable = scmi_iio_buffer_preenable,
127 	.postdisable = scmi_iio_buffer_postdisable,
128 };
129 
130 static int scmi_iio_set_odr_val(struct iio_dev *iio_dev, int val, int val2)
131 {
132 	struct scmi_iio_priv *sensor = iio_priv(iio_dev);
133 	const unsigned long UHZ_PER_HZ = 1000000UL;
134 	u64 sec, mult, uHz, sf;
135 	u32 sensor_config;
136 	char buf[32];
137 
138 	int err = sensor->sensor_ops->config_get(sensor->ph,
139 						 sensor->sensor_info->id,
140 						 &sensor_config);
141 	if (err) {
142 		dev_err(&iio_dev->dev,
143 			"Error in getting sensor config for sensor %s err %d",
144 			sensor->sensor_info->name, err);
145 		return err;
146 	}
147 
148 	uHz = val * UHZ_PER_HZ + val2;
149 
150 	/*
151 	 * The seconds field in the sensor interval in SCMI is 16 bits long
152 	 * Therefore seconds  = 1/Hz <= 0xFFFF. As floating point calculations are
153 	 * discouraged in the kernel driver code, to calculate the scale factor (sf)
154 	 * (1* 1000000 * sf)/uHz <= 0xFFFF. Therefore, sf <= (uHz * 0xFFFF)/1000000
155 	 * To calculate the multiplier,we convert the sf into char string  and
156 	 * count the number of characters
157 	 */
158 	sf = (u64)uHz * 0xFFFF;
159 	do_div(sf,  UHZ_PER_HZ);
160 	mult = scnprintf(buf, sizeof(buf), "%llu", sf) - 1;
161 
162 	sec = int_pow(10, mult) * UHZ_PER_HZ;
163 	do_div(sec, uHz);
164 	if (sec == 0) {
165 		dev_err(&iio_dev->dev,
166 			"Trying to set invalid sensor update value for sensor %s",
167 			sensor->sensor_info->name);
168 		return -EINVAL;
169 	}
170 
171 	sensor_config &= ~SCMI_SENS_CFG_UPDATE_SECS_MASK;
172 	sensor_config |= FIELD_PREP(SCMI_SENS_CFG_UPDATE_SECS_MASK, sec);
173 	sensor_config &= ~SCMI_SENS_CFG_UPDATE_EXP_MASK;
174 	sensor_config |= FIELD_PREP(SCMI_SENS_CFG_UPDATE_EXP_MASK, -mult);
175 
176 	if (sensor->sensor_info->timestamped) {
177 		sensor_config &= ~SCMI_SENS_CFG_TSTAMP_ENABLED_MASK;
178 		sensor_config |= FIELD_PREP(SCMI_SENS_CFG_TSTAMP_ENABLED_MASK,
179 					    SCMI_SENS_CFG_TSTAMP_ENABLE);
180 	}
181 
182 	sensor_config &= ~SCMI_SENS_CFG_ROUND_MASK;
183 	sensor_config |=
184 		FIELD_PREP(SCMI_SENS_CFG_ROUND_MASK, SCMI_SENS_CFG_ROUND_AUTO);
185 
186 	err = sensor->sensor_ops->config_set(sensor->ph,
187 					     sensor->sensor_info->id,
188 					     sensor_config);
189 	if (err)
190 		dev_err(&iio_dev->dev,
191 			"Error in setting sensor update interval for sensor %s value %u err %d",
192 			sensor->sensor_info->name, sensor_config, err);
193 
194 	return err;
195 }
196 
197 static int scmi_iio_write_raw(struct iio_dev *iio_dev,
198 			      struct iio_chan_spec const *chan, int val,
199 			      int val2, long mask)
200 {
201 	int err;
202 
203 	switch (mask) {
204 	case IIO_CHAN_INFO_SAMP_FREQ:
205 		mutex_lock(&iio_dev->mlock);
206 		err = scmi_iio_set_odr_val(iio_dev, val, val2);
207 		mutex_unlock(&iio_dev->mlock);
208 		return err;
209 	default:
210 		return -EINVAL;
211 	}
212 }
213 
214 static int scmi_iio_read_avail(struct iio_dev *iio_dev,
215 			       struct iio_chan_spec const *chan,
216 			       const int **vals, int *type, int *length,
217 			       long mask)
218 {
219 	struct scmi_iio_priv *sensor = iio_priv(iio_dev);
220 
221 	switch (mask) {
222 	case IIO_CHAN_INFO_SAMP_FREQ:
223 		*vals = sensor->freq_avail;
224 		*type = IIO_VAL_INT_PLUS_MICRO;
225 		*length = sensor->sensor_info->intervals.count * 2;
226 		if (sensor->sensor_info->intervals.segmented)
227 			return IIO_AVAIL_RANGE;
228 		else
229 			return IIO_AVAIL_LIST;
230 	default:
231 		return -EINVAL;
232 	}
233 }
234 
235 static void convert_ns_to_freq(u64 interval_ns, u64 *hz, u64 *uhz)
236 {
237 	u64 rem, freq;
238 
239 	freq = NSEC_PER_SEC;
240 	rem = do_div(freq, interval_ns);
241 	*hz = freq;
242 	*uhz = rem * 1000000UL;
243 	do_div(*uhz, interval_ns);
244 }
245 
246 static int scmi_iio_get_odr_val(struct iio_dev *iio_dev, int *val, int *val2)
247 {
248 	u64 sensor_update_interval, sensor_interval_mult, hz, uhz;
249 	struct scmi_iio_priv *sensor = iio_priv(iio_dev);
250 	u32 sensor_config;
251 	int mult;
252 
253 	int err = sensor->sensor_ops->config_get(sensor->ph,
254 						 sensor->sensor_info->id,
255 						 &sensor_config);
256 	if (err) {
257 		dev_err(&iio_dev->dev,
258 			"Error in getting sensor config for sensor %s err %d",
259 			sensor->sensor_info->name, err);
260 		return err;
261 	}
262 
263 	sensor_update_interval =
264 		SCMI_SENS_CFG_GET_UPDATE_SECS(sensor_config) * NSEC_PER_SEC;
265 
266 	mult = SCMI_SENS_CFG_GET_UPDATE_EXP(sensor_config);
267 	if (mult < 0) {
268 		sensor_interval_mult = int_pow(10, abs(mult));
269 		do_div(sensor_update_interval, sensor_interval_mult);
270 	} else {
271 		sensor_interval_mult = int_pow(10, mult);
272 		sensor_update_interval =
273 			sensor_update_interval * sensor_interval_mult;
274 	}
275 
276 	convert_ns_to_freq(sensor_update_interval, &hz, &uhz);
277 	*val = hz;
278 	*val2 = uhz;
279 	return 0;
280 }
281 
282 static int scmi_iio_read_raw(struct iio_dev *iio_dev,
283 			     struct iio_chan_spec const *ch, int *val,
284 			     int *val2, long mask)
285 {
286 	struct scmi_iio_priv *sensor = iio_priv(iio_dev);
287 	s8 scale;
288 	int ret;
289 
290 	switch (mask) {
291 	case IIO_CHAN_INFO_SCALE:
292 		scale = sensor->sensor_info->axis[ch->scan_index].scale;
293 		if (scale < 0) {
294 			*val = 1;
295 			*val2 = int_pow(10, abs(scale));
296 			return IIO_VAL_FRACTIONAL;
297 		}
298 		*val = int_pow(10, scale);
299 		return IIO_VAL_INT;
300 	case IIO_CHAN_INFO_SAMP_FREQ:
301 		ret = scmi_iio_get_odr_val(iio_dev, val, val2);
302 		return ret ? ret : IIO_VAL_INT_PLUS_MICRO;
303 	default:
304 		return -EINVAL;
305 	}
306 }
307 
308 static const struct iio_info scmi_iio_info = {
309 	.read_raw = scmi_iio_read_raw,
310 	.read_avail = scmi_iio_read_avail,
311 	.write_raw = scmi_iio_write_raw,
312 };
313 
314 static ssize_t scmi_iio_get_raw_available(struct iio_dev *iio_dev,
315 					  uintptr_t private,
316 					  const struct iio_chan_spec *chan,
317 					  char *buf)
318 {
319 	struct scmi_iio_priv *sensor = iio_priv(iio_dev);
320 	u64 resolution, rem;
321 	s64 min_range, max_range;
322 	s8 exponent, scale;
323 	int len = 0;
324 
325 	/*
326 	 * All the axes are supposed to have the same value for range and resolution.
327 	 * We are just using the values from the Axis 0 here.
328 	 */
329 	if (sensor->sensor_info->axis[0].extended_attrs) {
330 		min_range = sensor->sensor_info->axis[0].attrs.min_range;
331 		max_range = sensor->sensor_info->axis[0].attrs.max_range;
332 		resolution = sensor->sensor_info->axis[0].resolution;
333 		exponent = sensor->sensor_info->axis[0].exponent;
334 		scale = sensor->sensor_info->axis[0].scale;
335 
336 		/*
337 		 * To provide the raw value for the resolution to the userspace,
338 		 * need to divide the resolution exponent by the sensor scale
339 		 */
340 		exponent = exponent - scale;
341 		if (exponent < 0) {
342 			rem = do_div(resolution,
343 				     int_pow(10, abs(exponent))
344 				     );
345 			len = scnprintf(buf, PAGE_SIZE,
346 					"[%lld %llu.%llu %lld]\n", min_range,
347 					resolution, rem, max_range);
348 		} else {
349 			resolution = resolution * int_pow(10, exponent);
350 			len = scnprintf(buf, PAGE_SIZE, "[%lld %llu %lld]\n",
351 					min_range, resolution, max_range);
352 		}
353 	}
354 	return len;
355 }
356 
357 static const struct iio_chan_spec_ext_info scmi_iio_ext_info[] = {
358 	{
359 		.name = "raw_available",
360 		.read = scmi_iio_get_raw_available,
361 		.shared = IIO_SHARED_BY_TYPE,
362 	},
363 	{},
364 };
365 
366 static void scmi_iio_set_timestamp_channel(struct iio_chan_spec *iio_chan,
367 					   int scan_index)
368 {
369 	iio_chan->type = IIO_TIMESTAMP;
370 	iio_chan->channel = -1;
371 	iio_chan->scan_index = scan_index;
372 	iio_chan->scan_type.sign = 'u';
373 	iio_chan->scan_type.realbits = 64;
374 	iio_chan->scan_type.storagebits = 64;
375 }
376 
377 static void scmi_iio_set_data_channel(struct iio_chan_spec *iio_chan,
378 				      enum iio_chan_type type,
379 				      enum iio_modifier mod, int scan_index)
380 {
381 	iio_chan->type = type;
382 	iio_chan->modified = 1;
383 	iio_chan->channel2 = mod;
384 	iio_chan->info_mask_separate = BIT(IIO_CHAN_INFO_SCALE);
385 	iio_chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ);
386 	iio_chan->info_mask_shared_by_type_available =
387 		BIT(IIO_CHAN_INFO_SAMP_FREQ);
388 	iio_chan->scan_index = scan_index;
389 	iio_chan->scan_type.sign = 's';
390 	iio_chan->scan_type.realbits = 64;
391 	iio_chan->scan_type.storagebits = 64;
392 	iio_chan->scan_type.endianness = IIO_LE;
393 	iio_chan->ext_info = scmi_iio_ext_info;
394 }
395 
396 static int scmi_iio_get_chan_modifier(const char *name,
397 				      enum iio_modifier *modifier)
398 {
399 	char *pch, mod;
400 
401 	if (!name)
402 		return -EINVAL;
403 
404 	pch = strrchr(name, '_');
405 	if (!pch)
406 		return -EINVAL;
407 
408 	mod = *(pch + 1);
409 	switch (mod) {
410 	case 'X':
411 		*modifier = IIO_MOD_X;
412 		return 0;
413 	case 'Y':
414 		*modifier = IIO_MOD_Y;
415 		return 0;
416 	case 'Z':
417 		*modifier = IIO_MOD_Z;
418 		return 0;
419 	default:
420 		return -EINVAL;
421 	}
422 }
423 
424 static int scmi_iio_get_chan_type(u8 scmi_type, enum iio_chan_type *iio_type)
425 {
426 	switch (scmi_type) {
427 	case METERS_SEC_SQUARED:
428 		*iio_type = IIO_ACCEL;
429 		return 0;
430 	case RADIANS_SEC:
431 		*iio_type = IIO_ANGL_VEL;
432 		return 0;
433 	default:
434 		return -EINVAL;
435 	}
436 }
437 
438 static u64 scmi_iio_convert_interval_to_ns(u32 val)
439 {
440 	u64 sensor_update_interval =
441 		SCMI_SENS_INTVL_GET_SECS(val) * NSEC_PER_SEC;
442 	u64 sensor_interval_mult;
443 	int mult;
444 
445 	mult = SCMI_SENS_INTVL_GET_EXP(val);
446 	if (mult < 0) {
447 		sensor_interval_mult = int_pow(10, abs(mult));
448 		do_div(sensor_update_interval, sensor_interval_mult);
449 	} else {
450 		sensor_interval_mult = int_pow(10, mult);
451 		sensor_update_interval =
452 			sensor_update_interval * sensor_interval_mult;
453 	}
454 	return sensor_update_interval;
455 }
456 
457 static int scmi_iio_set_sampling_freq_avail(struct iio_dev *iio_dev)
458 {
459 	u64 cur_interval_ns, low_interval_ns, high_interval_ns, step_size_ns,
460 		hz, uhz;
461 	unsigned int cur_interval, low_interval, high_interval, step_size;
462 	struct scmi_iio_priv *sensor = iio_priv(iio_dev);
463 	int i;
464 
465 	sensor->freq_avail =
466 		devm_kzalloc(&iio_dev->dev,
467 			     sizeof(*sensor->freq_avail) *
468 				     (sensor->sensor_info->intervals.count * 2),
469 			     GFP_KERNEL);
470 	if (!sensor->freq_avail)
471 		return -ENOMEM;
472 
473 	if (sensor->sensor_info->intervals.segmented) {
474 		low_interval = sensor->sensor_info->intervals
475 				       .desc[SCMI_SENS_INTVL_SEGMENT_LOW];
476 		low_interval_ns = scmi_iio_convert_interval_to_ns(low_interval);
477 		convert_ns_to_freq(low_interval_ns, &hz, &uhz);
478 		sensor->freq_avail[0] = hz;
479 		sensor->freq_avail[1] = uhz;
480 
481 		step_size = sensor->sensor_info->intervals
482 				    .desc[SCMI_SENS_INTVL_SEGMENT_STEP];
483 		step_size_ns = scmi_iio_convert_interval_to_ns(step_size);
484 		convert_ns_to_freq(step_size_ns, &hz, &uhz);
485 		sensor->freq_avail[2] = hz;
486 		sensor->freq_avail[3] = uhz;
487 
488 		high_interval = sensor->sensor_info->intervals
489 					.desc[SCMI_SENS_INTVL_SEGMENT_HIGH];
490 		high_interval_ns =
491 			scmi_iio_convert_interval_to_ns(high_interval);
492 		convert_ns_to_freq(high_interval_ns, &hz, &uhz);
493 		sensor->freq_avail[4] = hz;
494 		sensor->freq_avail[5] = uhz;
495 	} else {
496 		for (i = 0; i < sensor->sensor_info->intervals.count; i++) {
497 			cur_interval = sensor->sensor_info->intervals.desc[i];
498 			cur_interval_ns =
499 				scmi_iio_convert_interval_to_ns(cur_interval);
500 			convert_ns_to_freq(cur_interval_ns, &hz, &uhz);
501 			sensor->freq_avail[i * 2] = hz;
502 			sensor->freq_avail[i * 2 + 1] = uhz;
503 		}
504 	}
505 	return 0;
506 }
507 
508 static struct iio_dev *
509 scmi_alloc_iiodev(struct scmi_device *sdev,
510 		  const struct scmi_sensor_proto_ops *ops,
511 		  struct scmi_protocol_handle *ph,
512 		  const struct scmi_sensor_info *sensor_info)
513 {
514 	struct iio_chan_spec *iio_channels;
515 	struct scmi_iio_priv *sensor;
516 	enum iio_modifier modifier;
517 	enum iio_chan_type type;
518 	struct iio_dev *iiodev;
519 	struct device *dev = &sdev->dev;
520 	const struct scmi_handle *handle = sdev->handle;
521 	int i, ret;
522 
523 	iiodev = devm_iio_device_alloc(dev, sizeof(*sensor));
524 	if (!iiodev)
525 		return ERR_PTR(-ENOMEM);
526 
527 	iiodev->modes = INDIO_DIRECT_MODE;
528 	iiodev->dev.parent = dev;
529 	sensor = iio_priv(iiodev);
530 	sensor->sensor_ops = ops;
531 	sensor->ph = ph;
532 	sensor->sensor_info = sensor_info;
533 	sensor->sensor_update_nb.notifier_call = scmi_iio_sensor_update_cb;
534 	sensor->indio_dev = iiodev;
535 
536 	/* adding one additional channel for timestamp */
537 	iiodev->num_channels = sensor_info->num_axis + 1;
538 	iiodev->name = sensor_info->name;
539 	iiodev->info = &scmi_iio_info;
540 
541 	iio_channels =
542 		devm_kzalloc(dev,
543 			     sizeof(*iio_channels) * (iiodev->num_channels),
544 			     GFP_KERNEL);
545 	if (!iio_channels)
546 		return ERR_PTR(-ENOMEM);
547 
548 	ret = scmi_iio_set_sampling_freq_avail(iiodev);
549 	if (ret < 0)
550 		return ERR_PTR(ret);
551 
552 	for (i = 0; i < sensor_info->num_axis; i++) {
553 		ret = scmi_iio_get_chan_type(sensor_info->axis[i].type, &type);
554 		if (ret < 0)
555 			return ERR_PTR(ret);
556 
557 		ret = scmi_iio_get_chan_modifier(sensor_info->axis[i].name,
558 						 &modifier);
559 		if (ret < 0)
560 			return ERR_PTR(ret);
561 
562 		scmi_iio_set_data_channel(&iio_channels[i], type, modifier,
563 					  sensor_info->axis[i].id);
564 	}
565 
566 	ret = handle->notify_ops->devm_event_notifier_register(sdev,
567 				SCMI_PROTOCOL_SENSOR, SCMI_EVENT_SENSOR_UPDATE,
568 				&sensor->sensor_info->id,
569 				&sensor->sensor_update_nb);
570 	if (ret) {
571 		dev_err(&iiodev->dev,
572 			"Error in registering sensor update notifier for sensor %s err %d",
573 			sensor->sensor_info->name, ret);
574 		return ERR_PTR(ret);
575 	}
576 
577 	scmi_iio_set_timestamp_channel(&iio_channels[i], i);
578 	iiodev->channels = iio_channels;
579 	return iiodev;
580 }
581 
582 static int scmi_iio_dev_probe(struct scmi_device *sdev)
583 {
584 	const struct scmi_sensor_info *sensor_info;
585 	struct scmi_handle *handle = sdev->handle;
586 	const struct scmi_sensor_proto_ops *sensor_ops;
587 	struct scmi_protocol_handle *ph;
588 	struct device *dev = &sdev->dev;
589 	struct iio_dev *scmi_iio_dev;
590 	u16 nr_sensors;
591 	int err = -ENODEV, i;
592 
593 	if (!handle)
594 		return -ENODEV;
595 
596 	sensor_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_SENSOR, &ph);
597 	if (IS_ERR(sensor_ops)) {
598 		dev_err(dev, "SCMI device has no sensor interface\n");
599 		return PTR_ERR(sensor_ops);
600 	}
601 
602 	nr_sensors = sensor_ops->count_get(ph);
603 	if (!nr_sensors) {
604 		dev_dbg(dev, "0 sensors found via SCMI bus\n");
605 		return -ENODEV;
606 	}
607 
608 	for (i = 0; i < nr_sensors; i++) {
609 		sensor_info = sensor_ops->info_get(ph, i);
610 		if (!sensor_info) {
611 			dev_err(dev, "SCMI sensor %d has missing info\n", i);
612 			return -EINVAL;
613 		}
614 
615 		/* This driver only supports 3-axis accel and gyro, skipping other sensors */
616 		if (sensor_info->num_axis != SCMI_IIO_NUM_OF_AXIS)
617 			continue;
618 
619 		/* This driver only supports 3-axis accel and gyro, skipping other sensors */
620 		if (sensor_info->axis[0].type != METERS_SEC_SQUARED &&
621 		    sensor_info->axis[0].type != RADIANS_SEC)
622 			continue;
623 
624 		scmi_iio_dev = scmi_alloc_iiodev(sdev, sensor_ops, ph,
625 						 sensor_info);
626 		if (IS_ERR(scmi_iio_dev)) {
627 			dev_err(dev,
628 				"failed to allocate IIO device for sensor %s: %ld\n",
629 				sensor_info->name, PTR_ERR(scmi_iio_dev));
630 			return PTR_ERR(scmi_iio_dev);
631 		}
632 
633 		err = devm_iio_kfifo_buffer_setup(&scmi_iio_dev->dev,
634 						  scmi_iio_dev,
635 						  INDIO_BUFFER_SOFTWARE,
636 						  &scmi_iio_buffer_ops);
637 		if (err < 0) {
638 			dev_err(dev,
639 				"IIO buffer setup error at sensor %s: %d\n",
640 				sensor_info->name, err);
641 			return err;
642 		}
643 
644 		err = devm_iio_device_register(dev, scmi_iio_dev);
645 		if (err) {
646 			dev_err(dev,
647 				"IIO device registration failed at sensor %s: %d\n",
648 				sensor_info->name, err);
649 			return err;
650 		}
651 	}
652 	return err;
653 }
654 
655 static const struct scmi_device_id scmi_id_table[] = {
656 	{ SCMI_PROTOCOL_SENSOR, "iiodev" },
657 	{},
658 };
659 
660 MODULE_DEVICE_TABLE(scmi, scmi_id_table);
661 
662 static struct scmi_driver scmi_iiodev_driver = {
663 	.name = "scmi-sensor-iiodev",
664 	.probe = scmi_iio_dev_probe,
665 	.id_table = scmi_id_table,
666 };
667 
668 module_scmi_driver(scmi_iiodev_driver);
669 
670 MODULE_AUTHOR("Jyoti Bhayana <jbhayana@google.com>");
671 MODULE_DESCRIPTION("SCMI IIO Driver");
672 MODULE_LICENSE("GPL v2");
673