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;
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 ret = ad_sd_read_reg(sigma_delta, AD_SD_REG_DATA,
310 DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8),
314 if (!sigma_delta->irq_dis) {
315 disable_irq_nosync(sigma_delta->spi->irq);
316 sigma_delta->irq_dis = true;
319 sigma_delta->keep_cs_asserted = false;
320 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
321 sigma_delta->bus_locked = false;
322 spi_bus_unlock(sigma_delta->spi->master);
323 mutex_unlock(&indio_dev->mlock);
328 sample = raw_sample >> chan->scan_type.shift;
329 sample &= (1 << chan->scan_type.realbits) - 1;
332 ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample);
338 EXPORT_SYMBOL_GPL(ad_sigma_delta_single_conversion);
340 static int ad_sd_buffer_postenable(struct iio_dev *indio_dev)
342 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
343 unsigned int channel;
346 ret = iio_triggered_buffer_postenable(indio_dev);
350 channel = find_first_bit(indio_dev->active_scan_mask,
351 indio_dev->masklength);
352 ret = ad_sigma_delta_set_channel(sigma_delta,
353 indio_dev->channels[channel].address);
357 spi_bus_lock(sigma_delta->spi->master);
358 sigma_delta->bus_locked = true;
359 sigma_delta->keep_cs_asserted = true;
361 ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS);
365 sigma_delta->irq_dis = false;
366 enable_irq(sigma_delta->spi->irq);
371 spi_bus_unlock(sigma_delta->spi->master);
377 static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev)
379 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
381 reinit_completion(&sigma_delta->completion);
382 wait_for_completion_timeout(&sigma_delta->completion, HZ);
384 if (!sigma_delta->irq_dis) {
385 disable_irq_nosync(sigma_delta->spi->irq);
386 sigma_delta->irq_dis = true;
389 sigma_delta->keep_cs_asserted = false;
390 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
392 sigma_delta->bus_locked = false;
393 return spi_bus_unlock(sigma_delta->spi->master);
396 static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
398 struct iio_poll_func *pf = p;
399 struct iio_dev *indio_dev = pf->indio_dev;
400 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
401 unsigned int reg_size;
405 memset(data, 0x00, 16);
407 reg_size = indio_dev->channels[0].scan_type.realbits +
408 indio_dev->channels[0].scan_type.shift;
409 reg_size = DIV_ROUND_UP(reg_size, 8);
415 ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA,
419 /* We store 24 bit samples in a 32 bit word. Keep the upper
420 * byte set to zero. */
421 ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA,
426 iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp);
428 iio_trigger_notify_done(indio_dev->trig);
429 sigma_delta->irq_dis = false;
430 enable_irq(sigma_delta->spi->irq);
435 static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = {
436 .postenable = &ad_sd_buffer_postenable,
437 .predisable = &iio_triggered_buffer_predisable,
438 .postdisable = &ad_sd_buffer_postdisable,
439 .validate_scan_mask = &iio_validate_scan_mask_onehot,
442 static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private)
444 struct ad_sigma_delta *sigma_delta = private;
446 complete(&sigma_delta->completion);
447 disable_irq_nosync(irq);
448 sigma_delta->irq_dis = true;
449 iio_trigger_poll(sigma_delta->trig);
455 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices
456 * @indio_dev: The IIO device
457 * @trig: The new trigger
459 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta
460 * device, -EINVAL otherwise.
462 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig)
464 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
466 if (sigma_delta->trig != trig)
471 EXPORT_SYMBOL_GPL(ad_sd_validate_trigger);
473 static const struct iio_trigger_ops ad_sd_trigger_ops = {
476 static int ad_sd_probe_trigger(struct iio_dev *indio_dev)
478 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
481 sigma_delta->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name,
483 if (sigma_delta->trig == NULL) {
487 sigma_delta->trig->ops = &ad_sd_trigger_ops;
488 init_completion(&sigma_delta->completion);
490 ret = request_irq(sigma_delta->spi->irq,
491 ad_sd_data_rdy_trig_poll,
496 goto error_free_trig;
498 if (!sigma_delta->irq_dis) {
499 sigma_delta->irq_dis = true;
500 disable_irq_nosync(sigma_delta->spi->irq);
502 sigma_delta->trig->dev.parent = &sigma_delta->spi->dev;
503 iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta);
505 ret = iio_trigger_register(sigma_delta->trig);
509 /* select default trigger */
510 indio_dev->trig = iio_trigger_get(sigma_delta->trig);
515 free_irq(sigma_delta->spi->irq, sigma_delta);
517 iio_trigger_free(sigma_delta->trig);
522 static void ad_sd_remove_trigger(struct iio_dev *indio_dev)
524 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
526 iio_trigger_unregister(sigma_delta->trig);
527 free_irq(sigma_delta->spi->irq, sigma_delta);
528 iio_trigger_free(sigma_delta->trig);
532 * ad_sd_setup_buffer_and_trigger() -
533 * @indio_dev: The IIO device
535 int ad_sd_setup_buffer_and_trigger(struct iio_dev *indio_dev)
539 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
540 &ad_sd_trigger_handler, &ad_sd_buffer_setup_ops);
544 ret = ad_sd_probe_trigger(indio_dev);
546 iio_triggered_buffer_cleanup(indio_dev);
552 EXPORT_SYMBOL_GPL(ad_sd_setup_buffer_and_trigger);
555 * ad_sd_cleanup_buffer_and_trigger() -
556 * @indio_dev: The IIO device
558 void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev)
560 ad_sd_remove_trigger(indio_dev);
561 iio_triggered_buffer_cleanup(indio_dev);
563 EXPORT_SYMBOL_GPL(ad_sd_cleanup_buffer_and_trigger);
566 * ad_sd_init() - Initializes a ad_sigma_delta struct
567 * @sigma_delta: The ad_sigma_delta device
568 * @indio_dev: The IIO device which the Sigma Delta device is used for
569 * @spi: The SPI device for the ad_sigma_delta device
570 * @info: Device specific callbacks and options
572 * This function needs to be called before any other operations are performed on
573 * the ad_sigma_delta struct.
575 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
576 struct spi_device *spi, const struct ad_sigma_delta_info *info)
578 sigma_delta->spi = spi;
579 sigma_delta->info = info;
580 iio_device_set_drvdata(indio_dev, sigma_delta);
584 EXPORT_SYMBOL_GPL(ad_sd_init);
586 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
587 MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs");
588 MODULE_LICENSE("GPL v2");