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 static 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);
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
252 * Returns 0 on success, an error code otherwise.
254 int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
255 const struct ad_sd_calib_data *cb, unsigned int n)
260 for (i = 0; i < n; i++) {
261 ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel);
268 EXPORT_SYMBOL_GPL(ad_sd_calibrate_all);
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
276 * Returns: 0 on success, an error value otherwise.
278 int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
279 const struct iio_chan_spec *chan, int *val)
281 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
282 unsigned int sample, raw_sample;
283 unsigned int data_reg;
286 if (iio_buffer_enabled(indio_dev))
289 mutex_lock(&indio_dev->mlock);
290 ad_sigma_delta_set_channel(sigma_delta, chan->address);
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);
297 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE);
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);
309 if (sigma_delta->info->data_reg != 0)
310 data_reg = sigma_delta->info->data_reg;
312 data_reg = AD_SD_REG_DATA;
314 ret = ad_sd_read_reg(sigma_delta, data_reg,
315 DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8),
319 if (!sigma_delta->irq_dis) {
320 disable_irq_nosync(sigma_delta->spi->irq);
321 sigma_delta->irq_dis = true;
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);
333 sample = raw_sample >> chan->scan_type.shift;
334 sample &= (1 << chan->scan_type.realbits) - 1;
337 ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample);
343 EXPORT_SYMBOL_GPL(ad_sigma_delta_single_conversion);
345 static int ad_sd_buffer_postenable(struct iio_dev *indio_dev)
347 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
348 unsigned int channel;
351 ret = iio_triggered_buffer_postenable(indio_dev);
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);
362 spi_bus_lock(sigma_delta->spi->master);
363 sigma_delta->bus_locked = true;
364 sigma_delta->keep_cs_asserted = true;
366 ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS);
370 sigma_delta->irq_dis = false;
371 enable_irq(sigma_delta->spi->irq);
376 spi_bus_unlock(sigma_delta->spi->master);
381 static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev)
383 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
385 reinit_completion(&sigma_delta->completion);
386 wait_for_completion_timeout(&sigma_delta->completion, HZ);
388 if (!sigma_delta->irq_dis) {
389 disable_irq_nosync(sigma_delta->spi->irq);
390 sigma_delta->irq_dis = true;
393 sigma_delta->keep_cs_asserted = false;
394 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
396 sigma_delta->bus_locked = false;
397 return spi_bus_unlock(sigma_delta->spi->master);
400 static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
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;
410 memset(data, 0x00, 16);
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);
416 if (sigma_delta->info->data_reg != 0)
417 data_reg = sigma_delta->info->data_reg;
419 data_reg = AD_SD_REG_DATA;
425 ret = ad_sd_read_reg_raw(sigma_delta, data_reg, reg_size,
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,
436 iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp);
438 iio_trigger_notify_done(indio_dev->trig);
439 sigma_delta->irq_dis = false;
440 enable_irq(sigma_delta->spi->irq);
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,
452 static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private)
454 struct ad_sigma_delta *sigma_delta = private;
456 complete(&sigma_delta->completion);
457 disable_irq_nosync(irq);
458 sigma_delta->irq_dis = true;
459 iio_trigger_poll(sigma_delta->trig);
465 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices
466 * @indio_dev: The IIO device
467 * @trig: The new trigger
469 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta
470 * device, -EINVAL otherwise.
472 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig)
474 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
476 if (sigma_delta->trig != trig)
481 EXPORT_SYMBOL_GPL(ad_sd_validate_trigger);
483 static const struct iio_trigger_ops ad_sd_trigger_ops = {
486 static int ad_sd_probe_trigger(struct iio_dev *indio_dev)
488 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
491 sigma_delta->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name,
493 if (sigma_delta->trig == NULL) {
497 sigma_delta->trig->ops = &ad_sd_trigger_ops;
498 init_completion(&sigma_delta->completion);
500 ret = request_irq(sigma_delta->spi->irq,
501 ad_sd_data_rdy_trig_poll,
506 goto error_free_trig;
508 if (!sigma_delta->irq_dis) {
509 sigma_delta->irq_dis = true;
510 disable_irq_nosync(sigma_delta->spi->irq);
512 sigma_delta->trig->dev.parent = &sigma_delta->spi->dev;
513 iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta);
515 ret = iio_trigger_register(sigma_delta->trig);
519 /* select default trigger */
520 indio_dev->trig = iio_trigger_get(sigma_delta->trig);
525 free_irq(sigma_delta->spi->irq, sigma_delta);
527 iio_trigger_free(sigma_delta->trig);
532 static void ad_sd_remove_trigger(struct iio_dev *indio_dev)
534 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
536 iio_trigger_unregister(sigma_delta->trig);
537 free_irq(sigma_delta->spi->irq, sigma_delta);
538 iio_trigger_free(sigma_delta->trig);
542 * ad_sd_setup_buffer_and_trigger() -
543 * @indio_dev: The IIO device
545 int ad_sd_setup_buffer_and_trigger(struct iio_dev *indio_dev)
549 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
550 &ad_sd_trigger_handler, &ad_sd_buffer_setup_ops);
554 ret = ad_sd_probe_trigger(indio_dev);
556 iio_triggered_buffer_cleanup(indio_dev);
562 EXPORT_SYMBOL_GPL(ad_sd_setup_buffer_and_trigger);
565 * ad_sd_cleanup_buffer_and_trigger() -
566 * @indio_dev: The IIO device
568 void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev)
570 ad_sd_remove_trigger(indio_dev);
571 iio_triggered_buffer_cleanup(indio_dev);
573 EXPORT_SYMBOL_GPL(ad_sd_cleanup_buffer_and_trigger);
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
582 * This function needs to be called before any other operations are performed on
583 * the ad_sigma_delta struct.
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)
588 sigma_delta->spi = spi;
589 sigma_delta->info = info;
590 iio_device_set_drvdata(indio_dev, sigma_delta);
594 EXPORT_SYMBOL_GPL(ad_sd_init);
596 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
597 MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs");
598 MODULE_LICENSE("GPL v2");