1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Support code for Analog Devices Sigma-Delta ADCs
4 *
5 * Copyright 2012 Analog Devices Inc.
6 * Author: Lars-Peter Clausen <lars@metafoo.de>
7 */
8
9 #include <linux/interrupt.h>
10 #include <linux/device.h>
11 #include <linux/kernel.h>
12 #include <linux/slab.h>
13 #include <linux/spi/spi.h>
14 #include <linux/err.h>
15 #include <linux/module.h>
16
17 #include <linux/iio/iio.h>
18 #include <linux/iio/sysfs.h>
19 #include <linux/iio/buffer.h>
20 #include <linux/iio/trigger.h>
21 #include <linux/iio/trigger_consumer.h>
22 #include <linux/iio/triggered_buffer.h>
23 #include <linux/iio/adc/ad_sigma_delta.h>
24
25 #include <asm/unaligned.h>
26
27
28 #define AD_SD_COMM_CHAN_MASK 0x3
29
30 #define AD_SD_REG_COMM 0x00
31 #define AD_SD_REG_DATA 0x03
32
33 /**
34 * ad_sd_set_comm() - Set communications register
35 *
36 * @sigma_delta: The sigma delta device
37 * @comm: New value for the communications register
38 */
ad_sd_set_comm(struct ad_sigma_delta * sigma_delta,uint8_t comm)39 void ad_sd_set_comm(struct ad_sigma_delta *sigma_delta, uint8_t comm)
40 {
41 /* Some variants use the lower two bits of the communications register
42 * to select the channel */
43 sigma_delta->comm = comm & AD_SD_COMM_CHAN_MASK;
44 }
45 EXPORT_SYMBOL_GPL(ad_sd_set_comm);
46
47 /**
48 * ad_sd_write_reg() - Write a register
49 *
50 * @sigma_delta: The sigma delta device
51 * @reg: Address of the register
52 * @size: Size of the register (0-3)
53 * @val: Value to write to the register
54 *
55 * Returns 0 on success, an error code otherwise.
56 **/
ad_sd_write_reg(struct ad_sigma_delta * sigma_delta,unsigned int reg,unsigned int size,unsigned int val)57 int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
58 unsigned int size, unsigned int val)
59 {
60 uint8_t *data = sigma_delta->data;
61 struct spi_transfer t = {
62 .tx_buf = data,
63 .len = size + 1,
64 .cs_change = sigma_delta->keep_cs_asserted,
65 };
66 struct spi_message m;
67 int ret;
68
69 data[0] = (reg << sigma_delta->info->addr_shift) | sigma_delta->comm;
70
71 switch (size) {
72 case 3:
73 data[1] = val >> 16;
74 data[2] = val >> 8;
75 data[3] = val;
76 break;
77 case 2:
78 put_unaligned_be16(val, &data[1]);
79 break;
80 case 1:
81 data[1] = val;
82 break;
83 case 0:
84 break;
85 default:
86 return -EINVAL;
87 }
88
89 spi_message_init(&m);
90 spi_message_add_tail(&t, &m);
91
92 if (sigma_delta->bus_locked)
93 ret = spi_sync_locked(sigma_delta->spi, &m);
94 else
95 ret = spi_sync(sigma_delta->spi, &m);
96
97 return ret;
98 }
99 EXPORT_SYMBOL_GPL(ad_sd_write_reg);
100
ad_sd_read_reg_raw(struct ad_sigma_delta * sigma_delta,unsigned int reg,unsigned int size,uint8_t * val)101 static int ad_sd_read_reg_raw(struct ad_sigma_delta *sigma_delta,
102 unsigned int reg, unsigned int size, uint8_t *val)
103 {
104 uint8_t *data = sigma_delta->data;
105 int ret;
106 struct spi_transfer t[] = {
107 {
108 .tx_buf = data,
109 .len = 1,
110 }, {
111 .rx_buf = val,
112 .len = size,
113 .cs_change = sigma_delta->bus_locked,
114 },
115 };
116 struct spi_message m;
117
118 spi_message_init(&m);
119
120 if (sigma_delta->info->has_registers) {
121 data[0] = reg << sigma_delta->info->addr_shift;
122 data[0] |= sigma_delta->info->read_mask;
123 data[0] |= sigma_delta->comm;
124 spi_message_add_tail(&t[0], &m);
125 }
126 spi_message_add_tail(&t[1], &m);
127
128 if (sigma_delta->bus_locked)
129 ret = spi_sync_locked(sigma_delta->spi, &m);
130 else
131 ret = spi_sync(sigma_delta->spi, &m);
132
133 return ret;
134 }
135
136 /**
137 * ad_sd_read_reg() - Read a register
138 *
139 * @sigma_delta: The sigma delta device
140 * @reg: Address of the register
141 * @size: Size of the register (1-4)
142 * @val: Read value
143 *
144 * Returns 0 on success, an error code otherwise.
145 **/
ad_sd_read_reg(struct ad_sigma_delta * sigma_delta,unsigned int reg,unsigned int size,unsigned int * val)146 int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta,
147 unsigned int reg, unsigned int size, unsigned int *val)
148 {
149 int ret;
150
151 ret = ad_sd_read_reg_raw(sigma_delta, reg, size, sigma_delta->data);
152 if (ret < 0)
153 goto out;
154
155 switch (size) {
156 case 4:
157 *val = get_unaligned_be32(sigma_delta->data);
158 break;
159 case 3:
160 *val = (sigma_delta->data[0] << 16) |
161 (sigma_delta->data[1] << 8) |
162 sigma_delta->data[2];
163 break;
164 case 2:
165 *val = get_unaligned_be16(sigma_delta->data);
166 break;
167 case 1:
168 *val = sigma_delta->data[0];
169 break;
170 default:
171 ret = -EINVAL;
172 break;
173 }
174
175 out:
176 return ret;
177 }
178 EXPORT_SYMBOL_GPL(ad_sd_read_reg);
179
180 /**
181 * ad_sd_reset() - Reset the serial interface
182 *
183 * @sigma_delta: The sigma delta device
184 * @reset_length: Number of SCLKs with DIN = 1
185 *
186 * Returns 0 on success, an error code otherwise.
187 **/
ad_sd_reset(struct ad_sigma_delta * sigma_delta,unsigned int reset_length)188 int ad_sd_reset(struct ad_sigma_delta *sigma_delta,
189 unsigned int reset_length)
190 {
191 uint8_t *buf;
192 unsigned int size;
193 int ret;
194
195 size = DIV_ROUND_UP(reset_length, 8);
196 buf = kcalloc(size, sizeof(*buf), GFP_KERNEL);
197 if (!buf)
198 return -ENOMEM;
199
200 memset(buf, 0xff, size);
201 ret = spi_write(sigma_delta->spi, buf, size);
202 kfree(buf);
203
204 return ret;
205 }
206 EXPORT_SYMBOL_GPL(ad_sd_reset);
207
ad_sd_calibrate(struct ad_sigma_delta * sigma_delta,unsigned int mode,unsigned int channel)208 static int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta,
209 unsigned int mode, unsigned int channel)
210 {
211 int ret;
212 unsigned long timeout;
213
214 ret = ad_sigma_delta_set_channel(sigma_delta, channel);
215 if (ret)
216 return ret;
217
218 spi_bus_lock(sigma_delta->spi->master);
219 sigma_delta->bus_locked = true;
220 sigma_delta->keep_cs_asserted = true;
221 reinit_completion(&sigma_delta->completion);
222
223 ret = ad_sigma_delta_set_mode(sigma_delta, mode);
224 if (ret < 0)
225 goto out;
226
227 sigma_delta->irq_dis = false;
228 enable_irq(sigma_delta->spi->irq);
229 timeout = wait_for_completion_timeout(&sigma_delta->completion, 2 * HZ);
230 if (timeout == 0) {
231 sigma_delta->irq_dis = true;
232 disable_irq_nosync(sigma_delta->spi->irq);
233 ret = -EIO;
234 } else {
235 ret = 0;
236 }
237 out:
238 sigma_delta->keep_cs_asserted = false;
239 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
240 sigma_delta->bus_locked = false;
241 spi_bus_unlock(sigma_delta->spi->master);
242
243 return ret;
244 }
245
246 /**
247 * ad_sd_calibrate_all() - Performs channel calibration
248 * @sigma_delta: The sigma delta device
249 * @cb: Array of channels and calibration type to perform
250 * @n: Number of items in cb
251 *
252 * Returns 0 on success, an error code otherwise.
253 **/
ad_sd_calibrate_all(struct ad_sigma_delta * sigma_delta,const struct ad_sd_calib_data * cb,unsigned int n)254 int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
255 const struct ad_sd_calib_data *cb, unsigned int n)
256 {
257 unsigned int i;
258 int ret;
259
260 for (i = 0; i < n; i++) {
261 ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel);
262 if (ret)
263 return ret;
264 }
265
266 return 0;
267 }
268 EXPORT_SYMBOL_GPL(ad_sd_calibrate_all);
269
270 /**
271 * ad_sigma_delta_single_conversion() - Performs a single data conversion
272 * @indio_dev: The IIO device
273 * @chan: The conversion is done for this channel
274 * @val: Pointer to the location where to store the read value
275 *
276 * Returns: 0 on success, an error value otherwise.
277 */
ad_sigma_delta_single_conversion(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,int * val)278 int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
279 const struct iio_chan_spec *chan, int *val)
280 {
281 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
282 unsigned int sample, raw_sample;
283 unsigned int data_reg;
284 int ret = 0;
285
286 if (iio_buffer_enabled(indio_dev))
287 return -EBUSY;
288
289 mutex_lock(&indio_dev->mlock);
290 ad_sigma_delta_set_channel(sigma_delta, chan->address);
291
292 spi_bus_lock(sigma_delta->spi->master);
293 sigma_delta->bus_locked = true;
294 sigma_delta->keep_cs_asserted = true;
295 reinit_completion(&sigma_delta->completion);
296
297 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE);
298
299 sigma_delta->irq_dis = false;
300 enable_irq(sigma_delta->spi->irq);
301 ret = wait_for_completion_interruptible_timeout(
302 &sigma_delta->completion, HZ);
303
304 if (ret == 0)
305 ret = -EIO;
306 if (ret < 0)
307 goto out;
308
309 if (sigma_delta->info->data_reg != 0)
310 data_reg = sigma_delta->info->data_reg;
311 else
312 data_reg = AD_SD_REG_DATA;
313
314 ret = ad_sd_read_reg(sigma_delta, data_reg,
315 DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8),
316 &raw_sample);
317
318 out:
319 if (!sigma_delta->irq_dis) {
320 disable_irq_nosync(sigma_delta->spi->irq);
321 sigma_delta->irq_dis = true;
322 }
323
324 sigma_delta->keep_cs_asserted = false;
325 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
326 sigma_delta->bus_locked = false;
327 spi_bus_unlock(sigma_delta->spi->master);
328 mutex_unlock(&indio_dev->mlock);
329
330 if (ret)
331 return ret;
332
333 sample = raw_sample >> chan->scan_type.shift;
334 sample &= (1 << chan->scan_type.realbits) - 1;
335 *val = sample;
336
337 ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample);
338 if (ret)
339 return ret;
340
341 return IIO_VAL_INT;
342 }
343 EXPORT_SYMBOL_GPL(ad_sigma_delta_single_conversion);
344
ad_sd_buffer_postenable(struct iio_dev * indio_dev)345 static int ad_sd_buffer_postenable(struct iio_dev *indio_dev)
346 {
347 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
348 unsigned int channel;
349 int ret;
350
351 ret = iio_triggered_buffer_postenable(indio_dev);
352 if (ret < 0)
353 return ret;
354
355 channel = find_first_bit(indio_dev->active_scan_mask,
356 indio_dev->masklength);
357 ret = ad_sigma_delta_set_channel(sigma_delta,
358 indio_dev->channels[channel].address);
359 if (ret)
360 return ret;
361
362 spi_bus_lock(sigma_delta->spi->master);
363 sigma_delta->bus_locked = true;
364 sigma_delta->keep_cs_asserted = true;
365
366 ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS);
367 if (ret)
368 goto err_unlock;
369
370 sigma_delta->irq_dis = false;
371 enable_irq(sigma_delta->spi->irq);
372
373 return 0;
374
375 err_unlock:
376 spi_bus_unlock(sigma_delta->spi->master);
377
378 return ret;
379 }
380
ad_sd_buffer_postdisable(struct iio_dev * indio_dev)381 static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev)
382 {
383 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
384
385 reinit_completion(&sigma_delta->completion);
386 wait_for_completion_timeout(&sigma_delta->completion, HZ);
387
388 if (!sigma_delta->irq_dis) {
389 disable_irq_nosync(sigma_delta->spi->irq);
390 sigma_delta->irq_dis = true;
391 }
392
393 sigma_delta->keep_cs_asserted = false;
394 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
395
396 sigma_delta->bus_locked = false;
397 return spi_bus_unlock(sigma_delta->spi->master);
398 }
399
ad_sd_trigger_handler(int irq,void * p)400 static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
401 {
402 struct iio_poll_func *pf = p;
403 struct iio_dev *indio_dev = pf->indio_dev;
404 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
405 unsigned int reg_size;
406 unsigned int data_reg;
407 uint8_t data[16];
408 int ret;
409
410 memset(data, 0x00, 16);
411
412 reg_size = indio_dev->channels[0].scan_type.realbits +
413 indio_dev->channels[0].scan_type.shift;
414 reg_size = DIV_ROUND_UP(reg_size, 8);
415
416 if (sigma_delta->info->data_reg != 0)
417 data_reg = sigma_delta->info->data_reg;
418 else
419 data_reg = AD_SD_REG_DATA;
420
421 switch (reg_size) {
422 case 4:
423 case 2:
424 case 1:
425 ret = ad_sd_read_reg_raw(sigma_delta, data_reg, reg_size,
426 &data[0]);
427 break;
428 case 3:
429 /* We store 24 bit samples in a 32 bit word. Keep the upper
430 * byte set to zero. */
431 ret = ad_sd_read_reg_raw(sigma_delta, data_reg, reg_size,
432 &data[1]);
433 break;
434 }
435
436 iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp);
437
438 iio_trigger_notify_done(indio_dev->trig);
439 sigma_delta->irq_dis = false;
440 enable_irq(sigma_delta->spi->irq);
441
442 return IRQ_HANDLED;
443 }
444
445 static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = {
446 .postenable = &ad_sd_buffer_postenable,
447 .predisable = &iio_triggered_buffer_predisable,
448 .postdisable = &ad_sd_buffer_postdisable,
449 .validate_scan_mask = &iio_validate_scan_mask_onehot,
450 };
451
ad_sd_data_rdy_trig_poll(int irq,void * private)452 static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private)
453 {
454 struct ad_sigma_delta *sigma_delta = private;
455
456 complete(&sigma_delta->completion);
457 disable_irq_nosync(irq);
458 sigma_delta->irq_dis = true;
459 iio_trigger_poll(sigma_delta->trig);
460
461 return IRQ_HANDLED;
462 }
463
464 /**
465 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices
466 * @indio_dev: The IIO device
467 * @trig: The new trigger
468 *
469 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta
470 * device, -EINVAL otherwise.
471 */
ad_sd_validate_trigger(struct iio_dev * indio_dev,struct iio_trigger * trig)472 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig)
473 {
474 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
475
476 if (sigma_delta->trig != trig)
477 return -EINVAL;
478
479 return 0;
480 }
481 EXPORT_SYMBOL_GPL(ad_sd_validate_trigger);
482
483 static const struct iio_trigger_ops ad_sd_trigger_ops = {
484 };
485
ad_sd_probe_trigger(struct iio_dev * indio_dev)486 static int ad_sd_probe_trigger(struct iio_dev *indio_dev)
487 {
488 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
489 int ret;
490
491 sigma_delta->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name,
492 indio_dev->id);
493 if (sigma_delta->trig == NULL) {
494 ret = -ENOMEM;
495 goto error_ret;
496 }
497 sigma_delta->trig->ops = &ad_sd_trigger_ops;
498 init_completion(&sigma_delta->completion);
499
500 ret = request_irq(sigma_delta->spi->irq,
501 ad_sd_data_rdy_trig_poll,
502 IRQF_TRIGGER_LOW,
503 indio_dev->name,
504 sigma_delta);
505 if (ret)
506 goto error_free_trig;
507
508 if (!sigma_delta->irq_dis) {
509 sigma_delta->irq_dis = true;
510 disable_irq_nosync(sigma_delta->spi->irq);
511 }
512 sigma_delta->trig->dev.parent = &sigma_delta->spi->dev;
513 iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta);
514
515 ret = iio_trigger_register(sigma_delta->trig);
516 if (ret)
517 goto error_free_irq;
518
519 /* select default trigger */
520 indio_dev->trig = iio_trigger_get(sigma_delta->trig);
521
522 return 0;
523
524 error_free_irq:
525 free_irq(sigma_delta->spi->irq, sigma_delta);
526 error_free_trig:
527 iio_trigger_free(sigma_delta->trig);
528 error_ret:
529 return ret;
530 }
531
ad_sd_remove_trigger(struct iio_dev * indio_dev)532 static void ad_sd_remove_trigger(struct iio_dev *indio_dev)
533 {
534 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
535
536 iio_trigger_unregister(sigma_delta->trig);
537 free_irq(sigma_delta->spi->irq, sigma_delta);
538 iio_trigger_free(sigma_delta->trig);
539 }
540
541 /**
542 * ad_sd_setup_buffer_and_trigger() -
543 * @indio_dev: The IIO device
544 */
ad_sd_setup_buffer_and_trigger(struct iio_dev * indio_dev)545 int ad_sd_setup_buffer_and_trigger(struct iio_dev *indio_dev)
546 {
547 int ret;
548
549 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
550 &ad_sd_trigger_handler, &ad_sd_buffer_setup_ops);
551 if (ret)
552 return ret;
553
554 ret = ad_sd_probe_trigger(indio_dev);
555 if (ret) {
556 iio_triggered_buffer_cleanup(indio_dev);
557 return ret;
558 }
559
560 return 0;
561 }
562 EXPORT_SYMBOL_GPL(ad_sd_setup_buffer_and_trigger);
563
564 /**
565 * ad_sd_cleanup_buffer_and_trigger() -
566 * @indio_dev: The IIO device
567 */
ad_sd_cleanup_buffer_and_trigger(struct iio_dev * indio_dev)568 void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev)
569 {
570 ad_sd_remove_trigger(indio_dev);
571 iio_triggered_buffer_cleanup(indio_dev);
572 }
573 EXPORT_SYMBOL_GPL(ad_sd_cleanup_buffer_and_trigger);
574
575 /**
576 * ad_sd_init() - Initializes a ad_sigma_delta struct
577 * @sigma_delta: The ad_sigma_delta device
578 * @indio_dev: The IIO device which the Sigma Delta device is used for
579 * @spi: The SPI device for the ad_sigma_delta device
580 * @info: Device specific callbacks and options
581 *
582 * This function needs to be called before any other operations are performed on
583 * the ad_sigma_delta struct.
584 */
ad_sd_init(struct ad_sigma_delta * sigma_delta,struct iio_dev * indio_dev,struct spi_device * spi,const struct ad_sigma_delta_info * info)585 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
586 struct spi_device *spi, const struct ad_sigma_delta_info *info)
587 {
588 sigma_delta->spi = spi;
589 sigma_delta->info = info;
590 iio_device_set_drvdata(indio_dev, sigma_delta);
591
592 return 0;
593 }
594 EXPORT_SYMBOL_GPL(ad_sd_init);
595
596 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
597 MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs");
598 MODULE_LICENSE("GPL v2");
599
