1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright 2021 Google LLC.
4  *
5  * Common part of most Semtech SAR sensor.
6  */
7 
8 #include <linux/bitops.h>
9 #include <linux/byteorder/generic.h>
10 #include <linux/delay.h>
11 #include <linux/device.h>
12 #include <linux/err.h>
13 #include <linux/export.h>
14 #include <linux/interrupt.h>
15 #include <linux/irqreturn.h>
16 #include <linux/i2c.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/regmap.h>
20 #include <linux/regulator/consumer.h>
21 #include <vdso/bits.h>
22 
23 #include <linux/iio/buffer.h>
24 #include <linux/iio/events.h>
25 #include <linux/iio/iio.h>
26 #include <linux/iio/trigger.h>
27 #include <linux/iio/triggered_buffer.h>
28 #include <linux/iio/trigger_consumer.h>
29 
30 #include "sx_common.h"
31 
32 /* All Semtech SAR sensors have IRQ bit in the same order. */
33 #define   SX_COMMON_CONVDONE_IRQ			BIT(0)
34 #define   SX_COMMON_FAR_IRQ				BIT(2)
35 #define   SX_COMMON_CLOSE_IRQ				BIT(3)
36 
37 const struct iio_event_spec sx_common_events[3] = {
38 	{
39 		.type = IIO_EV_TYPE_THRESH,
40 		.dir = IIO_EV_DIR_RISING,
41 		.mask_shared_by_all = BIT(IIO_EV_INFO_PERIOD),
42 	},
43 	{
44 		.type = IIO_EV_TYPE_THRESH,
45 		.dir = IIO_EV_DIR_FALLING,
46 		.mask_shared_by_all = BIT(IIO_EV_INFO_PERIOD),
47 	},
48 	{
49 		.type = IIO_EV_TYPE_THRESH,
50 		.dir = IIO_EV_DIR_EITHER,
51 		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
52 				 BIT(IIO_EV_INFO_HYSTERESIS) |
53 				 BIT(IIO_EV_INFO_VALUE),
54 	},
55 };
56 EXPORT_SYMBOL_NS_GPL(sx_common_events, SEMTECH_PROX);
57 
58 static irqreturn_t sx_common_irq_handler(int irq, void *private)
59 {
60 	struct iio_dev *indio_dev = private;
61 	struct sx_common_data *data = iio_priv(indio_dev);
62 
63 	if (data->trigger_enabled)
64 		iio_trigger_poll(data->trig);
65 
66 	/*
67 	 * Even if no event is enabled, we need to wake the thread to clear the
68 	 * interrupt state by reading SX_COMMON_REG_IRQ_SRC.
69 	 * It is not possible to do that here because regmap_read takes a mutex.
70 	 */
71 	return IRQ_WAKE_THREAD;
72 }
73 
74 static void sx_common_push_events(struct iio_dev *indio_dev)
75 {
76 	int ret;
77 	unsigned int val, chan;
78 	struct sx_common_data *data = iio_priv(indio_dev);
79 	s64 timestamp = iio_get_time_ns(indio_dev);
80 	unsigned long prox_changed;
81 
82 	/* Read proximity state on all channels */
83 	ret = regmap_read(data->regmap, data->chip_info->reg_stat, &val);
84 	if (ret) {
85 		dev_err(&data->client->dev, "i2c transfer error in irq\n");
86 		return;
87 	}
88 
89 	val >>= data->chip_info->stat_offset;
90 
91 	/*
92 	 * Only iterate over channels with changes on proximity status that have
93 	 * events enabled.
94 	 */
95 	prox_changed = (data->chan_prox_stat ^ val) & data->chan_event;
96 
97 	for_each_set_bit(chan, &prox_changed, data->chip_info->num_channels) {
98 		int dir;
99 		u64 ev;
100 
101 		dir = (val & BIT(chan)) ? IIO_EV_DIR_FALLING : IIO_EV_DIR_RISING;
102 		ev = IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, chan,
103 					  IIO_EV_TYPE_THRESH, dir);
104 
105 		iio_push_event(indio_dev, ev, timestamp);
106 	}
107 	data->chan_prox_stat = val;
108 }
109 
110 static int sx_common_enable_irq(struct sx_common_data *data, unsigned int irq)
111 {
112 	if (!data->client->irq)
113 		return 0;
114 	return regmap_update_bits(data->regmap, data->chip_info->reg_irq_msk,
115 				  irq << data->chip_info->irq_msk_offset,
116 				  irq << data->chip_info->irq_msk_offset);
117 }
118 
119 static int sx_common_disable_irq(struct sx_common_data *data, unsigned int irq)
120 {
121 	if (!data->client->irq)
122 		return 0;
123 	return regmap_update_bits(data->regmap, data->chip_info->reg_irq_msk,
124 				  irq << data->chip_info->irq_msk_offset, 0);
125 }
126 
127 static int sx_common_update_chan_en(struct sx_common_data *data,
128 				    unsigned long chan_read,
129 				    unsigned long chan_event)
130 {
131 	int ret;
132 	unsigned long channels = chan_read | chan_event;
133 
134 	if ((data->chan_read | data->chan_event) != channels) {
135 		ret = regmap_update_bits(data->regmap,
136 					 data->chip_info->reg_enable_chan,
137 					 data->chip_info->mask_enable_chan,
138 					 channels);
139 		if (ret)
140 			return ret;
141 	}
142 	data->chan_read = chan_read;
143 	data->chan_event = chan_event;
144 	return 0;
145 }
146 
147 static int sx_common_get_read_channel(struct sx_common_data *data, int channel)
148 {
149 	return sx_common_update_chan_en(data, data->chan_read | BIT(channel),
150 				     data->chan_event);
151 }
152 
153 static int sx_common_put_read_channel(struct sx_common_data *data, int channel)
154 {
155 	return sx_common_update_chan_en(data, data->chan_read & ~BIT(channel),
156 				     data->chan_event);
157 }
158 
159 static int sx_common_get_event_channel(struct sx_common_data *data, int channel)
160 {
161 	return sx_common_update_chan_en(data, data->chan_read,
162 				     data->chan_event | BIT(channel));
163 }
164 
165 static int sx_common_put_event_channel(struct sx_common_data *data, int channel)
166 {
167 	return sx_common_update_chan_en(data, data->chan_read,
168 				     data->chan_event & ~BIT(channel));
169 }
170 
171 /**
172  * sx_common_read_proximity() - Read raw proximity value.
173  * @data:	Internal data
174  * @chan:	Channel to read
175  * @val:	pointer to return read value.
176  *
177  * Request a conversion, wait for the sensor to be ready and
178  * return the raw proximity value.
179  */
180 int sx_common_read_proximity(struct sx_common_data *data,
181 			     const struct iio_chan_spec *chan, int *val)
182 {
183 	int ret;
184 	__be16 rawval;
185 
186 	mutex_lock(&data->mutex);
187 
188 	ret = sx_common_get_read_channel(data, chan->channel);
189 	if (ret)
190 		goto out;
191 
192 	ret = sx_common_enable_irq(data, SX_COMMON_CONVDONE_IRQ);
193 	if (ret)
194 		goto out_put_channel;
195 
196 	mutex_unlock(&data->mutex);
197 
198 	if (data->client->irq) {
199 		ret = wait_for_completion_interruptible(&data->completion);
200 		reinit_completion(&data->completion);
201 	} else {
202 		ret = data->chip_info->ops.wait_for_sample(data);
203 	}
204 
205 	mutex_lock(&data->mutex);
206 
207 	if (ret)
208 		goto out_disable_irq;
209 
210 	ret = data->chip_info->ops.read_prox_data(data, chan, &rawval);
211 	if (ret)
212 		goto out_disable_irq;
213 
214 	*val = sign_extend32(be16_to_cpu(rawval), chan->scan_type.realbits - 1);
215 
216 	ret = sx_common_disable_irq(data, SX_COMMON_CONVDONE_IRQ);
217 	if (ret)
218 		goto out_put_channel;
219 
220 	ret = sx_common_put_read_channel(data, chan->channel);
221 	if (ret)
222 		goto out;
223 
224 	mutex_unlock(&data->mutex);
225 
226 	return IIO_VAL_INT;
227 
228 out_disable_irq:
229 	sx_common_disable_irq(data, SX_COMMON_CONVDONE_IRQ);
230 out_put_channel:
231 	sx_common_put_read_channel(data, chan->channel);
232 out:
233 	mutex_unlock(&data->mutex);
234 
235 	return ret;
236 }
237 EXPORT_SYMBOL_NS_GPL(sx_common_read_proximity, SEMTECH_PROX);
238 
239 /**
240  * sx_common_read_event_config() - Configure event setting.
241  * @indio_dev:	iio device object
242  * @chan:	Channel to read
243  * @type:	Type of event (unused)
244  * @dir:	Direction of event (unused)
245  *
246  * return if the given channel is used for event gathering.
247  */
248 int sx_common_read_event_config(struct iio_dev *indio_dev,
249 				const struct iio_chan_spec *chan,
250 				enum iio_event_type type,
251 				enum iio_event_direction dir)
252 {
253 	struct sx_common_data *data = iio_priv(indio_dev);
254 
255 	return !!(data->chan_event & BIT(chan->channel));
256 }
257 EXPORT_SYMBOL_NS_GPL(sx_common_read_event_config, SEMTECH_PROX);
258 
259 /**
260  * sx_common_write_event_config() - Configure event setting.
261  * @indio_dev:	iio device object
262  * @chan:	Channel to enable
263  * @type:	Type of event (unused)
264  * @dir:	Direction of event (unused)
265  * @state:	State of the event.
266  *
267  * Enable/Disable event on a given channel.
268  */
269 int sx_common_write_event_config(struct iio_dev *indio_dev,
270 				 const struct iio_chan_spec *chan,
271 				 enum iio_event_type type,
272 				 enum iio_event_direction dir, int state)
273 {
274 	struct sx_common_data *data = iio_priv(indio_dev);
275 	unsigned int eventirq = SX_COMMON_FAR_IRQ | SX_COMMON_CLOSE_IRQ;
276 	int ret;
277 
278 	/* If the state hasn't changed, there's nothing to do. */
279 	if (!!(data->chan_event & BIT(chan->channel)) == state)
280 		return 0;
281 
282 	mutex_lock(&data->mutex);
283 	if (state) {
284 		ret = sx_common_get_event_channel(data, chan->channel);
285 		if (ret)
286 			goto out_unlock;
287 		if (!(data->chan_event & ~BIT(chan->channel))) {
288 			ret = sx_common_enable_irq(data, eventirq);
289 			if (ret)
290 				sx_common_put_event_channel(data, chan->channel);
291 		}
292 	} else {
293 		ret = sx_common_put_event_channel(data, chan->channel);
294 		if (ret)
295 			goto out_unlock;
296 		if (!data->chan_event) {
297 			ret = sx_common_disable_irq(data, eventirq);
298 			if (ret)
299 				sx_common_get_event_channel(data, chan->channel);
300 		}
301 	}
302 
303 out_unlock:
304 	mutex_unlock(&data->mutex);
305 	return ret;
306 }
307 EXPORT_SYMBOL_NS_GPL(sx_common_write_event_config, SEMTECH_PROX);
308 
309 static int sx_common_set_trigger_state(struct iio_trigger *trig, bool state)
310 {
311 	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
312 	struct sx_common_data *data = iio_priv(indio_dev);
313 	int ret = 0;
314 
315 	mutex_lock(&data->mutex);
316 
317 	if (state)
318 		ret = sx_common_enable_irq(data, SX_COMMON_CONVDONE_IRQ);
319 	else if (!data->chan_read)
320 		ret = sx_common_disable_irq(data, SX_COMMON_CONVDONE_IRQ);
321 	if (ret)
322 		goto out;
323 
324 	data->trigger_enabled = state;
325 
326 out:
327 	mutex_unlock(&data->mutex);
328 
329 	return ret;
330 }
331 
332 static const struct iio_trigger_ops sx_common_trigger_ops = {
333 	.set_trigger_state = sx_common_set_trigger_state,
334 };
335 
336 static irqreturn_t sx_common_irq_thread_handler(int irq, void *private)
337 {
338 	struct iio_dev *indio_dev = private;
339 	struct sx_common_data *data = iio_priv(indio_dev);
340 	int ret;
341 	unsigned int val;
342 
343 	mutex_lock(&data->mutex);
344 
345 	ret = regmap_read(data->regmap, SX_COMMON_REG_IRQ_SRC, &val);
346 	if (ret) {
347 		dev_err(&data->client->dev, "i2c transfer error in irq\n");
348 		goto out;
349 	}
350 
351 	if (val & ((SX_COMMON_FAR_IRQ | SX_COMMON_CLOSE_IRQ) << data->chip_info->irq_msk_offset))
352 		sx_common_push_events(indio_dev);
353 
354 	if (val & (SX_COMMON_CONVDONE_IRQ << data->chip_info->irq_msk_offset))
355 		complete(&data->completion);
356 
357 out:
358 	mutex_unlock(&data->mutex);
359 
360 	return IRQ_HANDLED;
361 }
362 
363 static irqreturn_t sx_common_trigger_handler(int irq, void *private)
364 {
365 	struct iio_poll_func *pf = private;
366 	struct iio_dev *indio_dev = pf->indio_dev;
367 	struct sx_common_data *data = iio_priv(indio_dev);
368 	__be16 val;
369 	int bit, ret, i = 0;
370 
371 	mutex_lock(&data->mutex);
372 
373 	for_each_set_bit(bit, indio_dev->active_scan_mask,
374 			 indio_dev->masklength) {
375 		ret = data->chip_info->ops.read_prox_data(data,
376 						     &indio_dev->channels[bit],
377 						     &val);
378 		if (ret)
379 			goto out;
380 
381 		data->buffer.channels[i++] = val;
382 	}
383 
384 	iio_push_to_buffers_with_timestamp(indio_dev, &data->buffer,
385 					   pf->timestamp);
386 
387 out:
388 	mutex_unlock(&data->mutex);
389 
390 	iio_trigger_notify_done(indio_dev->trig);
391 
392 	return IRQ_HANDLED;
393 }
394 
395 static int sx_common_buffer_preenable(struct iio_dev *indio_dev)
396 {
397 	struct sx_common_data *data = iio_priv(indio_dev);
398 	unsigned long channels = 0;
399 	int bit, ret;
400 
401 	mutex_lock(&data->mutex);
402 	for_each_set_bit(bit, indio_dev->active_scan_mask,
403 			 indio_dev->masklength)
404 		__set_bit(indio_dev->channels[bit].channel, &channels);
405 
406 	ret = sx_common_update_chan_en(data, channels, data->chan_event);
407 	mutex_unlock(&data->mutex);
408 	return ret;
409 }
410 
411 static int sx_common_buffer_postdisable(struct iio_dev *indio_dev)
412 {
413 	struct sx_common_data *data = iio_priv(indio_dev);
414 	int ret;
415 
416 	mutex_lock(&data->mutex);
417 	ret = sx_common_update_chan_en(data, 0, data->chan_event);
418 	mutex_unlock(&data->mutex);
419 	return ret;
420 }
421 
422 static const struct iio_buffer_setup_ops sx_common_buffer_setup_ops = {
423 	.preenable = sx_common_buffer_preenable,
424 	.postdisable = sx_common_buffer_postdisable,
425 };
426 
427 static void sx_common_regulator_disable(void *_data)
428 {
429 	struct sx_common_data *data = _data;
430 
431 	regulator_bulk_disable(ARRAY_SIZE(data->supplies), data->supplies);
432 }
433 
434 #define SX_COMMON_SOFT_RESET				0xde
435 
436 static int sx_common_init_device(struct device *dev, struct iio_dev *indio_dev)
437 {
438 	struct sx_common_data *data = iio_priv(indio_dev);
439 	struct sx_common_reg_default tmp;
440 	const struct sx_common_reg_default *initval;
441 	int ret;
442 	unsigned int i, val;
443 
444 	ret = regmap_write(data->regmap, data->chip_info->reg_reset,
445 			   SX_COMMON_SOFT_RESET);
446 	if (ret)
447 		return ret;
448 
449 	usleep_range(1000, 2000); /* power-up time is ~1ms. */
450 
451 	/* Clear reset interrupt state by reading SX_COMMON_REG_IRQ_SRC. */
452 	ret = regmap_read(data->regmap, SX_COMMON_REG_IRQ_SRC, &val);
453 	if (ret)
454 		return ret;
455 
456 	/* Program defaults from constant or BIOS. */
457 	for (i = 0; i < data->chip_info->num_default_regs; i++) {
458 		initval = data->chip_info->ops.get_default_reg(dev, i, &tmp);
459 		ret = regmap_write(data->regmap, initval->reg, initval->def);
460 		if (ret)
461 			return ret;
462 	}
463 
464 	return data->chip_info->ops.init_compensation(indio_dev);
465 }
466 
467 /**
468  * sx_common_probe() - Common setup for Semtech SAR sensor
469  * @client:		I2C client object
470  * @chip_info:		Semtech sensor chip information.
471  * @regmap_config:	Sensor registers map configuration.
472  */
473 int sx_common_probe(struct i2c_client *client,
474 		    const struct sx_common_chip_info *chip_info,
475 		    const struct regmap_config *regmap_config)
476 {
477 	struct device *dev = &client->dev;
478 	struct iio_dev *indio_dev;
479 	struct sx_common_data *data;
480 	int ret;
481 
482 	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
483 	if (!indio_dev)
484 		return -ENOMEM;
485 
486 	data = iio_priv(indio_dev);
487 
488 	data->chip_info = chip_info;
489 	data->client = client;
490 	data->supplies[0].supply = "vdd";
491 	data->supplies[1].supply = "svdd";
492 	mutex_init(&data->mutex);
493 	init_completion(&data->completion);
494 
495 	data->regmap = devm_regmap_init_i2c(client, regmap_config);
496 	if (IS_ERR(data->regmap))
497 		return dev_err_probe(dev, PTR_ERR(data->regmap),
498 				     "Could init register map\n");
499 
500 	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(data->supplies),
501 				      data->supplies);
502 	if (ret)
503 		return dev_err_probe(dev, ret, "Unable to get regulators\n");
504 
505 	ret = regulator_bulk_enable(ARRAY_SIZE(data->supplies), data->supplies);
506 	if (ret)
507 		return dev_err_probe(dev, ret, "Unable to enable regulators\n");
508 
509 	/* Must wait for Tpor time after initial power up */
510 	usleep_range(1000, 1100);
511 
512 	ret = devm_add_action_or_reset(dev, sx_common_regulator_disable, data);
513 	if (ret)
514 		return dev_err_probe(dev, ret,
515 				     "Unable to register regulators deleter\n");
516 
517 	ret = data->chip_info->ops.check_whoami(dev, indio_dev);
518 	if (ret)
519 		return dev_err_probe(dev, ret, "error reading WHOAMI\n");
520 
521 	indio_dev->modes = INDIO_DIRECT_MODE;
522 
523 	indio_dev->channels =  data->chip_info->iio_channels;
524 	indio_dev->num_channels = data->chip_info->num_iio_channels;
525 	indio_dev->info = &data->chip_info->iio_info;
526 
527 	i2c_set_clientdata(client, indio_dev);
528 
529 	ret = sx_common_init_device(dev, indio_dev);
530 	if (ret)
531 		return dev_err_probe(dev, ret, "Unable to initialize sensor\n");
532 
533 	if (client->irq) {
534 		ret = devm_request_threaded_irq(dev, client->irq,
535 						sx_common_irq_handler,
536 						sx_common_irq_thread_handler,
537 						IRQF_ONESHOT,
538 						"sx_event", indio_dev);
539 		if (ret)
540 			return dev_err_probe(dev, ret, "No IRQ\n");
541 
542 		data->trig = devm_iio_trigger_alloc(dev, "%s-dev%d",
543 						    indio_dev->name,
544 						    iio_device_id(indio_dev));
545 		if (!data->trig)
546 			return -ENOMEM;
547 
548 		data->trig->ops = &sx_common_trigger_ops;
549 		iio_trigger_set_drvdata(data->trig, indio_dev);
550 
551 		ret = devm_iio_trigger_register(dev, data->trig);
552 		if (ret)
553 			return ret;
554 	}
555 
556 	ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
557 					      iio_pollfunc_store_time,
558 					      sx_common_trigger_handler,
559 					      &sx_common_buffer_setup_ops);
560 	if (ret)
561 		return ret;
562 
563 	return devm_iio_device_register(dev, indio_dev);
564 }
565 EXPORT_SYMBOL_NS_GPL(sx_common_probe, SEMTECH_PROX);
566 
567 MODULE_AUTHOR("Gwendal Grignou <gwendal@chromium.org>");
568 MODULE_DESCRIPTION("Common functions and structures for Semtech sensor");
569 MODULE_LICENSE("GPL v2");
570