1 // SPDX-License-Identifier: GPL-2.0-only
3 * Support code for Analog Devices Sigma-Delta ADCs
5 * Copyright 2012 Analog Devices Inc.
6 * Author: Lars-Peter Clausen <lars@metafoo.de>
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>
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>
25 #include <asm/unaligned.h>
28 #define AD_SD_COMM_CHAN_MASK 0x3
30 #define AD_SD_REG_COMM 0x00
31 #define AD_SD_REG_DATA 0x03
34 * ad_sd_set_comm() - Set communications register
36 * @sigma_delta: The sigma delta device
37 * @comm: New value for the communications register
39 void ad_sd_set_comm(struct ad_sigma_delta *sigma_delta, uint8_t comm)
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;
45 EXPORT_SYMBOL_GPL(ad_sd_set_comm);
48 * ad_sd_write_reg() - Write a register
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
55 * Returns 0 on success, an error code otherwise.
57 int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
58 unsigned int size, unsigned int val)
60 uint8_t *data = sigma_delta->data;
61 struct spi_transfer t = {
64 .cs_change = sigma_delta->keep_cs_asserted,
69 data[0] = (reg << sigma_delta->info->addr_shift) | sigma_delta->comm;
78 put_unaligned_be16(val, &data[1]);
90 spi_message_add_tail(&t, &m);
92 if (sigma_delta->bus_locked)
93 ret = spi_sync_locked(sigma_delta->spi, &m);
95 ret = spi_sync(sigma_delta->spi, &m);
99 EXPORT_SYMBOL_GPL(ad_sd_write_reg);
101 static int ad_sd_read_reg_raw(struct ad_sigma_delta *sigma_delta,
102 unsigned int reg, unsigned int size, uint8_t *val)
104 uint8_t *data = sigma_delta->data;
106 struct spi_transfer t[] = {
113 .cs_change = sigma_delta->bus_locked,
116 struct spi_message m;
118 spi_message_init(&m);
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);
126 spi_message_add_tail(&t[1], &m);
128 if (sigma_delta->bus_locked)
129 ret = spi_sync_locked(sigma_delta->spi, &m);
131 ret = spi_sync(sigma_delta->spi, &m);
137 * ad_sd_read_reg() - Read a register
139 * @sigma_delta: The sigma delta device
140 * @reg: Address of the register
141 * @size: Size of the register (1-4)
144 * Returns 0 on success, an error code otherwise.
146 int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta,
147 unsigned int reg, unsigned int size, unsigned int *val)
151 ret = ad_sd_read_reg_raw(sigma_delta, reg, size, sigma_delta->data);
157 *val = get_unaligned_be32(sigma_delta->data);
160 *val = (sigma_delta->data[0] << 16) |
161 (sigma_delta->data[1] << 8) |
162 sigma_delta->data[2];
165 *val = get_unaligned_be16(sigma_delta->data);
168 *val = sigma_delta->data[0];
178 EXPORT_SYMBOL_GPL(ad_sd_read_reg);
181 * ad_sd_reset() - Reset the serial interface
183 * @sigma_delta: The sigma delta device
184 * @reset_length: Number of SCLKs with DIN = 1
186 * Returns 0 on success, an error code otherwise.
188 int ad_sd_reset(struct ad_sigma_delta *sigma_delta,
189 unsigned int reset_length)
195 size = DIV_ROUND_UP(reset_length, 8);
196 buf = kcalloc(size, sizeof(*buf), GFP_KERNEL);
200 memset(buf, 0xff, size);
201 ret = spi_write(sigma_delta->spi, buf, size);
206 EXPORT_SYMBOL_GPL(ad_sd_reset);
208 int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta,
209 unsigned int mode, unsigned int channel)
212 unsigned long timeout;
214 ret = ad_sigma_delta_set_channel(sigma_delta, channel);
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);
223 ret = ad_sigma_delta_set_mode(sigma_delta, mode);
227 sigma_delta->irq_dis = false;
228 enable_irq(sigma_delta->spi->irq);
229 timeout = wait_for_completion_timeout(&sigma_delta->completion, 2 * HZ);
231 sigma_delta->irq_dis = true;
232 disable_irq_nosync(sigma_delta->spi->irq);
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);
245 EXPORT_SYMBOL_GPL(ad_sd_calibrate);
248 * ad_sd_calibrate_all() - Performs channel calibration
249 * @sigma_delta: The sigma delta device
250 * @cb: Array of channels and calibration type to perform
251 * @n: Number of items in cb
253 * Returns 0 on success, an error code otherwise.
255 int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
256 const struct ad_sd_calib_data *cb, unsigned int n)
261 for (i = 0; i < n; i++) {
262 ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel);
269 EXPORT_SYMBOL_GPL(ad_sd_calibrate_all);
272 * ad_sigma_delta_single_conversion() - Performs a single data conversion
273 * @indio_dev: The IIO device
274 * @chan: The conversion is done for this channel
275 * @val: Pointer to the location where to store the read value
277 * Returns: 0 on success, an error value otherwise.
279 int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
280 const struct iio_chan_spec *chan, int *val)
282 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
283 unsigned int sample, raw_sample;
284 unsigned int data_reg;
287 if (iio_buffer_enabled(indio_dev))
290 mutex_lock(&indio_dev->mlock);
291 ad_sigma_delta_set_channel(sigma_delta, chan->address);
293 spi_bus_lock(sigma_delta->spi->master);
294 sigma_delta->bus_locked = true;
295 sigma_delta->keep_cs_asserted = true;
296 reinit_completion(&sigma_delta->completion);
298 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE);
300 sigma_delta->irq_dis = false;
301 enable_irq(sigma_delta->spi->irq);
302 ret = wait_for_completion_interruptible_timeout(
303 &sigma_delta->completion, HZ);
310 if (sigma_delta->info->data_reg != 0)
311 data_reg = sigma_delta->info->data_reg;
313 data_reg = AD_SD_REG_DATA;
315 ret = ad_sd_read_reg(sigma_delta, data_reg,
316 DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8),
320 if (!sigma_delta->irq_dis) {
321 disable_irq_nosync(sigma_delta->spi->irq);
322 sigma_delta->irq_dis = true;
325 sigma_delta->keep_cs_asserted = false;
326 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
327 sigma_delta->bus_locked = false;
328 spi_bus_unlock(sigma_delta->spi->master);
329 mutex_unlock(&indio_dev->mlock);
334 sample = raw_sample >> chan->scan_type.shift;
335 sample &= (1 << chan->scan_type.realbits) - 1;
338 ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample);
344 EXPORT_SYMBOL_GPL(ad_sigma_delta_single_conversion);
346 static int ad_sd_buffer_postenable(struct iio_dev *indio_dev)
348 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
349 unsigned int channel;
352 ret = iio_triggered_buffer_postenable(indio_dev);
356 channel = find_first_bit(indio_dev->active_scan_mask,
357 indio_dev->masklength);
358 ret = ad_sigma_delta_set_channel(sigma_delta,
359 indio_dev->channels[channel].address);
363 spi_bus_lock(sigma_delta->spi->master);
364 sigma_delta->bus_locked = true;
365 sigma_delta->keep_cs_asserted = true;
367 ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS);
371 sigma_delta->irq_dis = false;
372 enable_irq(sigma_delta->spi->irq);
377 spi_bus_unlock(sigma_delta->spi->master);
382 static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev)
384 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
386 reinit_completion(&sigma_delta->completion);
387 wait_for_completion_timeout(&sigma_delta->completion, HZ);
389 if (!sigma_delta->irq_dis) {
390 disable_irq_nosync(sigma_delta->spi->irq);
391 sigma_delta->irq_dis = true;
394 sigma_delta->keep_cs_asserted = false;
395 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
397 sigma_delta->bus_locked = false;
398 return spi_bus_unlock(sigma_delta->spi->master);
401 static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
403 struct iio_poll_func *pf = p;
404 struct iio_dev *indio_dev = pf->indio_dev;
405 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
406 unsigned int reg_size;
407 unsigned int data_reg;
411 memset(data, 0x00, 16);
413 reg_size = indio_dev->channels[0].scan_type.realbits +
414 indio_dev->channels[0].scan_type.shift;
415 reg_size = DIV_ROUND_UP(reg_size, 8);
417 if (sigma_delta->info->data_reg != 0)
418 data_reg = sigma_delta->info->data_reg;
420 data_reg = AD_SD_REG_DATA;
426 ret = ad_sd_read_reg_raw(sigma_delta, data_reg, reg_size,
430 /* We store 24 bit samples in a 32 bit word. Keep the upper
431 * byte set to zero. */
432 ret = ad_sd_read_reg_raw(sigma_delta, data_reg, reg_size,
437 iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp);
439 iio_trigger_notify_done(indio_dev->trig);
440 sigma_delta->irq_dis = false;
441 enable_irq(sigma_delta->spi->irq);
446 static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = {
447 .postenable = &ad_sd_buffer_postenable,
448 .predisable = &iio_triggered_buffer_predisable,
449 .postdisable = &ad_sd_buffer_postdisable,
450 .validate_scan_mask = &iio_validate_scan_mask_onehot,
453 static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private)
455 struct ad_sigma_delta *sigma_delta = private;
457 complete(&sigma_delta->completion);
458 disable_irq_nosync(irq);
459 sigma_delta->irq_dis = true;
460 iio_trigger_poll(sigma_delta->trig);
466 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices
467 * @indio_dev: The IIO device
468 * @trig: The new trigger
470 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta
471 * device, -EINVAL otherwise.
473 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig)
475 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
477 if (sigma_delta->trig != trig)
482 EXPORT_SYMBOL_GPL(ad_sd_validate_trigger);
484 static const struct iio_trigger_ops ad_sd_trigger_ops = {
487 static int ad_sd_probe_trigger(struct iio_dev *indio_dev)
489 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
492 sigma_delta->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name,
494 if (sigma_delta->trig == NULL) {
498 sigma_delta->trig->ops = &ad_sd_trigger_ops;
499 init_completion(&sigma_delta->completion);
501 ret = request_irq(sigma_delta->spi->irq,
502 ad_sd_data_rdy_trig_poll,
503 sigma_delta->info->irq_flags,
507 goto error_free_trig;
509 if (!sigma_delta->irq_dis) {
510 sigma_delta->irq_dis = true;
511 disable_irq_nosync(sigma_delta->spi->irq);
513 sigma_delta->trig->dev.parent = &sigma_delta->spi->dev;
514 iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta);
516 ret = iio_trigger_register(sigma_delta->trig);
520 /* select default trigger */
521 indio_dev->trig = iio_trigger_get(sigma_delta->trig);
526 free_irq(sigma_delta->spi->irq, sigma_delta);
528 iio_trigger_free(sigma_delta->trig);
533 static void ad_sd_remove_trigger(struct iio_dev *indio_dev)
535 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
537 iio_trigger_unregister(sigma_delta->trig);
538 free_irq(sigma_delta->spi->irq, sigma_delta);
539 iio_trigger_free(sigma_delta->trig);
543 * ad_sd_setup_buffer_and_trigger() -
544 * @indio_dev: The IIO device
546 int ad_sd_setup_buffer_and_trigger(struct iio_dev *indio_dev)
550 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
551 &ad_sd_trigger_handler, &ad_sd_buffer_setup_ops);
555 ret = ad_sd_probe_trigger(indio_dev);
557 iio_triggered_buffer_cleanup(indio_dev);
563 EXPORT_SYMBOL_GPL(ad_sd_setup_buffer_and_trigger);
566 * ad_sd_cleanup_buffer_and_trigger() -
567 * @indio_dev: The IIO device
569 void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev)
571 ad_sd_remove_trigger(indio_dev);
572 iio_triggered_buffer_cleanup(indio_dev);
574 EXPORT_SYMBOL_GPL(ad_sd_cleanup_buffer_and_trigger);
577 * ad_sd_init() - Initializes a ad_sigma_delta struct
578 * @sigma_delta: The ad_sigma_delta device
579 * @indio_dev: The IIO device which the Sigma Delta device is used for
580 * @spi: The SPI device for the ad_sigma_delta device
581 * @info: Device specific callbacks and options
583 * This function needs to be called before any other operations are performed on
584 * the ad_sigma_delta struct.
586 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
587 struct spi_device *spi, const struct ad_sigma_delta_info *info)
589 sigma_delta->spi = spi;
590 sigma_delta->info = info;
591 iio_device_set_drvdata(indio_dev, sigma_delta);
595 EXPORT_SYMBOL_GPL(ad_sd_init);
597 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
598 MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs");
599 MODULE_LICENSE("GPL v2");