2 * Support code for Analog Devices Sigma-Delta ADCs
4 * Copyright 2012 Analog Devices Inc.
5 * Author: Lars-Peter Clausen <lars@metafoo.de>
7 * Licensed under the GPL-2.
10 #include <linux/interrupt.h>
11 #include <linux/device.h>
12 #include <linux/kernel.h>
13 #include <linux/slab.h>
14 #include <linux/spi/spi.h>
15 #include <linux/err.h>
16 #include <linux/module.h>
18 #include <linux/iio/iio.h>
19 #include <linux/iio/sysfs.h>
20 #include <linux/iio/buffer.h>
21 #include <linux/iio/trigger.h>
22 #include <linux/iio/trigger_consumer.h>
23 #include <linux/iio/triggered_buffer.h>
24 #include <linux/iio/adc/ad_sigma_delta.h>
26 #include <asm/unaligned.h>
29 #define AD_SD_COMM_CHAN_MASK 0x3
31 #define AD_SD_REG_COMM 0x00
32 #define AD_SD_REG_DATA 0x03
35 * ad_sd_set_comm() - Set communications register
37 * @sigma_delta: The sigma delta device
38 * @comm: New value for the communications register
40 void ad_sd_set_comm(struct ad_sigma_delta *sigma_delta, uint8_t comm)
42 /* Some variants use the lower two bits of the communications register
43 * to select the channel */
44 sigma_delta->comm = comm & AD_SD_COMM_CHAN_MASK;
46 EXPORT_SYMBOL_GPL(ad_sd_set_comm);
49 * ad_sd_write_reg() - Write a register
51 * @sigma_delta: The sigma delta device
52 * @reg: Address of the register
53 * @size: Size of the register (0-3)
54 * @val: Value to write to the register
56 * Returns 0 on success, an error code otherwise.
58 int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
59 unsigned int size, unsigned int val)
61 uint8_t *data = sigma_delta->data;
62 struct spi_transfer t = {
65 .cs_change = sigma_delta->keep_cs_asserted,
70 data[0] = (reg << sigma_delta->info->addr_shift) | sigma_delta->comm;
79 put_unaligned_be16(val, &data[1]);
91 spi_message_add_tail(&t, &m);
93 if (sigma_delta->bus_locked)
94 ret = spi_sync_locked(sigma_delta->spi, &m);
96 ret = spi_sync(sigma_delta->spi, &m);
100 EXPORT_SYMBOL_GPL(ad_sd_write_reg);
102 static int ad_sd_read_reg_raw(struct ad_sigma_delta *sigma_delta,
103 unsigned int reg, unsigned int size, uint8_t *val)
105 uint8_t *data = sigma_delta->data;
107 struct spi_transfer t[] = {
114 .cs_change = sigma_delta->bus_locked,
117 struct spi_message m;
119 spi_message_init(&m);
121 if (sigma_delta->info->has_registers) {
122 data[0] = reg << sigma_delta->info->addr_shift;
123 data[0] |= sigma_delta->info->read_mask;
124 data[0] |= sigma_delta->comm;
125 spi_message_add_tail(&t[0], &m);
127 spi_message_add_tail(&t[1], &m);
129 if (sigma_delta->bus_locked)
130 ret = spi_sync_locked(sigma_delta->spi, &m);
132 ret = spi_sync(sigma_delta->spi, &m);
138 * ad_sd_read_reg() - Read a register
140 * @sigma_delta: The sigma delta device
141 * @reg: Address of the register
142 * @size: Size of the register (1-4)
145 * Returns 0 on success, an error code otherwise.
147 int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta,
148 unsigned int reg, unsigned int size, unsigned int *val)
152 ret = ad_sd_read_reg_raw(sigma_delta, reg, size, sigma_delta->data);
158 *val = get_unaligned_be32(sigma_delta->data);
161 *val = (sigma_delta->data[0] << 16) |
162 (sigma_delta->data[1] << 8) |
163 sigma_delta->data[2];
166 *val = get_unaligned_be16(sigma_delta->data);
169 *val = sigma_delta->data[0];
179 EXPORT_SYMBOL_GPL(ad_sd_read_reg);
182 * ad_sd_reset() - Reset the serial interface
184 * @sigma_delta: The sigma delta device
185 * @reset_length: Number of SCLKs with DIN = 1
187 * Returns 0 on success, an error code otherwise.
189 int ad_sd_reset(struct ad_sigma_delta *sigma_delta,
190 unsigned int reset_length)
196 size = DIV_ROUND_UP(reset_length, 8);
197 buf = kcalloc(size, sizeof(*buf), GFP_KERNEL);
201 memset(buf, 0xff, size);
202 ret = spi_write(sigma_delta->spi, buf, size);
207 EXPORT_SYMBOL_GPL(ad_sd_reset);
209 static int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta,
210 unsigned int mode, unsigned int channel)
213 unsigned long timeout;
215 ret = ad_sigma_delta_set_channel(sigma_delta, channel);
219 spi_bus_lock(sigma_delta->spi->master);
220 sigma_delta->bus_locked = true;
221 sigma_delta->keep_cs_asserted = true;
222 reinit_completion(&sigma_delta->completion);
224 ret = ad_sigma_delta_set_mode(sigma_delta, mode);
228 sigma_delta->irq_dis = false;
229 enable_irq(sigma_delta->spi->irq);
230 timeout = wait_for_completion_timeout(&sigma_delta->completion, 2 * HZ);
232 sigma_delta->irq_dis = true;
233 disable_irq_nosync(sigma_delta->spi->irq);
239 sigma_delta->keep_cs_asserted = false;
240 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
241 sigma_delta->bus_locked = false;
242 spi_bus_unlock(sigma_delta->spi->master);
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);
383 static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev)
385 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
387 reinit_completion(&sigma_delta->completion);
388 wait_for_completion_timeout(&sigma_delta->completion, HZ);
390 if (!sigma_delta->irq_dis) {
391 disable_irq_nosync(sigma_delta->spi->irq);
392 sigma_delta->irq_dis = true;
395 sigma_delta->keep_cs_asserted = false;
396 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
398 sigma_delta->bus_locked = false;
399 return spi_bus_unlock(sigma_delta->spi->master);
402 static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
404 struct iio_poll_func *pf = p;
405 struct iio_dev *indio_dev = pf->indio_dev;
406 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
407 unsigned int reg_size;
408 unsigned int data_reg;
412 memset(data, 0x00, 16);
414 reg_size = indio_dev->channels[0].scan_type.realbits +
415 indio_dev->channels[0].scan_type.shift;
416 reg_size = DIV_ROUND_UP(reg_size, 8);
418 if (sigma_delta->info->data_reg != 0)
419 data_reg = sigma_delta->info->data_reg;
421 data_reg = AD_SD_REG_DATA;
427 ret = ad_sd_read_reg_raw(sigma_delta, data_reg, reg_size,
431 /* We store 24 bit samples in a 32 bit word. Keep the upper
432 * byte set to zero. */
433 ret = ad_sd_read_reg_raw(sigma_delta, data_reg, reg_size,
438 iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp);
440 iio_trigger_notify_done(indio_dev->trig);
441 sigma_delta->irq_dis = false;
442 enable_irq(sigma_delta->spi->irq);
447 static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = {
448 .postenable = &ad_sd_buffer_postenable,
449 .predisable = &iio_triggered_buffer_predisable,
450 .postdisable = &ad_sd_buffer_postdisable,
451 .validate_scan_mask = &iio_validate_scan_mask_onehot,
454 static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private)
456 struct ad_sigma_delta *sigma_delta = private;
458 complete(&sigma_delta->completion);
459 disable_irq_nosync(irq);
460 sigma_delta->irq_dis = true;
461 iio_trigger_poll(sigma_delta->trig);
467 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices
468 * @indio_dev: The IIO device
469 * @trig: The new trigger
471 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta
472 * device, -EINVAL otherwise.
474 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig)
476 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
478 if (sigma_delta->trig != trig)
483 EXPORT_SYMBOL_GPL(ad_sd_validate_trigger);
485 static const struct iio_trigger_ops ad_sd_trigger_ops = {
488 static int ad_sd_probe_trigger(struct iio_dev *indio_dev)
490 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
493 sigma_delta->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name,
495 if (sigma_delta->trig == NULL) {
499 sigma_delta->trig->ops = &ad_sd_trigger_ops;
500 init_completion(&sigma_delta->completion);
502 ret = request_irq(sigma_delta->spi->irq,
503 ad_sd_data_rdy_trig_poll,
508 goto error_free_trig;
510 if (!sigma_delta->irq_dis) {
511 sigma_delta->irq_dis = true;
512 disable_irq_nosync(sigma_delta->spi->irq);
514 sigma_delta->trig->dev.parent = &sigma_delta->spi->dev;
515 iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta);
517 ret = iio_trigger_register(sigma_delta->trig);
521 /* select default trigger */
522 indio_dev->trig = iio_trigger_get(sigma_delta->trig);
527 free_irq(sigma_delta->spi->irq, sigma_delta);
529 iio_trigger_free(sigma_delta->trig);
534 static void ad_sd_remove_trigger(struct iio_dev *indio_dev)
536 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
538 iio_trigger_unregister(sigma_delta->trig);
539 free_irq(sigma_delta->spi->irq, sigma_delta);
540 iio_trigger_free(sigma_delta->trig);
544 * ad_sd_setup_buffer_and_trigger() -
545 * @indio_dev: The IIO device
547 int ad_sd_setup_buffer_and_trigger(struct iio_dev *indio_dev)
551 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
552 &ad_sd_trigger_handler, &ad_sd_buffer_setup_ops);
556 ret = ad_sd_probe_trigger(indio_dev);
558 iio_triggered_buffer_cleanup(indio_dev);
564 EXPORT_SYMBOL_GPL(ad_sd_setup_buffer_and_trigger);
567 * ad_sd_cleanup_buffer_and_trigger() -
568 * @indio_dev: The IIO device
570 void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev)
572 ad_sd_remove_trigger(indio_dev);
573 iio_triggered_buffer_cleanup(indio_dev);
575 EXPORT_SYMBOL_GPL(ad_sd_cleanup_buffer_and_trigger);
578 * ad_sd_init() - Initializes a ad_sigma_delta struct
579 * @sigma_delta: The ad_sigma_delta device
580 * @indio_dev: The IIO device which the Sigma Delta device is used for
581 * @spi: The SPI device for the ad_sigma_delta device
582 * @info: Device specific callbacks and options
584 * This function needs to be called before any other operations are performed on
585 * the ad_sigma_delta struct.
587 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
588 struct spi_device *spi, const struct ad_sigma_delta_info *info)
590 sigma_delta->spi = spi;
591 sigma_delta->info = info;
592 iio_device_set_drvdata(indio_dev, sigma_delta);
596 EXPORT_SYMBOL_GPL(ad_sd_init);
598 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
599 MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs");
600 MODULE_LICENSE("GPL v2");