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->bus_locked,
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 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 reinit_completion(&sigma_delta->completion);
222 ret = ad_sigma_delta_set_mode(sigma_delta, mode);
226 sigma_delta->irq_dis = false;
227 enable_irq(sigma_delta->spi->irq);
228 timeout = wait_for_completion_timeout(&sigma_delta->completion, 2 * HZ);
230 sigma_delta->irq_dis = true;
231 disable_irq_nosync(sigma_delta->spi->irq);
237 sigma_delta->bus_locked = false;
238 spi_bus_unlock(sigma_delta->spi->master);
239 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
245 * ad_sd_calibrate_all() - Performs channel calibration
246 * @sigma_delta: The sigma delta device
247 * @cb: Array of channels and calibration type to perform
248 * @n: Number of items in cb
250 * Returns 0 on success, an error code otherwise.
252 int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
253 const struct ad_sd_calib_data *cb, unsigned int n)
258 for (i = 0; i < n; i++) {
259 ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel);
266 EXPORT_SYMBOL_GPL(ad_sd_calibrate_all);
269 * ad_sigma_delta_single_conversion() - Performs a single data conversion
270 * @indio_dev: The IIO device
271 * @chan: The conversion is done for this channel
272 * @val: Pointer to the location where to store the read value
274 * Returns: 0 on success, an error value otherwise.
276 int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
277 const struct iio_chan_spec *chan, int *val)
279 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
280 unsigned int sample, raw_sample;
283 if (iio_buffer_enabled(indio_dev))
286 mutex_lock(&indio_dev->mlock);
287 ad_sigma_delta_set_channel(sigma_delta, chan->address);
289 spi_bus_lock(sigma_delta->spi->master);
290 sigma_delta->bus_locked = true;
291 reinit_completion(&sigma_delta->completion);
293 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE);
295 sigma_delta->irq_dis = false;
296 enable_irq(sigma_delta->spi->irq);
297 ret = wait_for_completion_interruptible_timeout(
298 &sigma_delta->completion, HZ);
300 sigma_delta->bus_locked = false;
301 spi_bus_unlock(sigma_delta->spi->master);
308 ret = ad_sd_read_reg(sigma_delta, AD_SD_REG_DATA,
309 DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8),
313 if (!sigma_delta->irq_dis) {
314 disable_irq_nosync(sigma_delta->spi->irq);
315 sigma_delta->irq_dis = true;
318 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
319 mutex_unlock(&indio_dev->mlock);
324 sample = raw_sample >> chan->scan_type.shift;
325 sample &= (1 << chan->scan_type.realbits) - 1;
328 ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample);
334 EXPORT_SYMBOL_GPL(ad_sigma_delta_single_conversion);
336 static int ad_sd_buffer_postenable(struct iio_dev *indio_dev)
338 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
339 unsigned int channel;
342 ret = iio_triggered_buffer_postenable(indio_dev);
346 channel = find_first_bit(indio_dev->active_scan_mask,
347 indio_dev->masklength);
348 ret = ad_sigma_delta_set_channel(sigma_delta,
349 indio_dev->channels[channel].address);
353 spi_bus_lock(sigma_delta->spi->master);
354 sigma_delta->bus_locked = true;
355 ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS);
359 sigma_delta->irq_dis = false;
360 enable_irq(sigma_delta->spi->irq);
365 spi_bus_unlock(sigma_delta->spi->master);
371 static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev)
373 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
375 reinit_completion(&sigma_delta->completion);
376 wait_for_completion_timeout(&sigma_delta->completion, HZ);
378 if (!sigma_delta->irq_dis) {
379 disable_irq_nosync(sigma_delta->spi->irq);
380 sigma_delta->irq_dis = true;
383 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
385 sigma_delta->bus_locked = false;
386 return spi_bus_unlock(sigma_delta->spi->master);
389 static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
391 struct iio_poll_func *pf = p;
392 struct iio_dev *indio_dev = pf->indio_dev;
393 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
394 unsigned int reg_size;
398 memset(data, 0x00, 16);
400 reg_size = indio_dev->channels[0].scan_type.realbits +
401 indio_dev->channels[0].scan_type.shift;
402 reg_size = DIV_ROUND_UP(reg_size, 8);
408 ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA,
412 /* We store 24 bit samples in a 32 bit word. Keep the upper
413 * byte set to zero. */
414 ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA,
419 iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp);
421 iio_trigger_notify_done(indio_dev->trig);
422 sigma_delta->irq_dis = false;
423 enable_irq(sigma_delta->spi->irq);
428 static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = {
429 .postenable = &ad_sd_buffer_postenable,
430 .predisable = &iio_triggered_buffer_predisable,
431 .postdisable = &ad_sd_buffer_postdisable,
432 .validate_scan_mask = &iio_validate_scan_mask_onehot,
435 static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private)
437 struct ad_sigma_delta *sigma_delta = private;
439 complete(&sigma_delta->completion);
440 disable_irq_nosync(irq);
441 sigma_delta->irq_dis = true;
442 iio_trigger_poll(sigma_delta->trig);
448 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices
449 * @indio_dev: The IIO device
450 * @trig: The new trigger
452 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta
453 * device, -EINVAL otherwise.
455 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig)
457 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
459 if (sigma_delta->trig != trig)
464 EXPORT_SYMBOL_GPL(ad_sd_validate_trigger);
466 static const struct iio_trigger_ops ad_sd_trigger_ops = {
469 static int ad_sd_probe_trigger(struct iio_dev *indio_dev)
471 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
474 sigma_delta->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name,
476 if (sigma_delta->trig == NULL) {
480 sigma_delta->trig->ops = &ad_sd_trigger_ops;
481 init_completion(&sigma_delta->completion);
483 ret = request_irq(sigma_delta->spi->irq,
484 ad_sd_data_rdy_trig_poll,
489 goto error_free_trig;
491 if (!sigma_delta->irq_dis) {
492 sigma_delta->irq_dis = true;
493 disable_irq_nosync(sigma_delta->spi->irq);
495 sigma_delta->trig->dev.parent = &sigma_delta->spi->dev;
496 iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta);
498 ret = iio_trigger_register(sigma_delta->trig);
502 /* select default trigger */
503 indio_dev->trig = iio_trigger_get(sigma_delta->trig);
508 free_irq(sigma_delta->spi->irq, sigma_delta);
510 iio_trigger_free(sigma_delta->trig);
515 static void ad_sd_remove_trigger(struct iio_dev *indio_dev)
517 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
519 iio_trigger_unregister(sigma_delta->trig);
520 free_irq(sigma_delta->spi->irq, sigma_delta);
521 iio_trigger_free(sigma_delta->trig);
525 * ad_sd_setup_buffer_and_trigger() -
526 * @indio_dev: The IIO device
528 int ad_sd_setup_buffer_and_trigger(struct iio_dev *indio_dev)
532 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
533 &ad_sd_trigger_handler, &ad_sd_buffer_setup_ops);
537 ret = ad_sd_probe_trigger(indio_dev);
539 iio_triggered_buffer_cleanup(indio_dev);
545 EXPORT_SYMBOL_GPL(ad_sd_setup_buffer_and_trigger);
548 * ad_sd_cleanup_buffer_and_trigger() -
549 * @indio_dev: The IIO device
551 void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev)
553 ad_sd_remove_trigger(indio_dev);
554 iio_triggered_buffer_cleanup(indio_dev);
556 EXPORT_SYMBOL_GPL(ad_sd_cleanup_buffer_and_trigger);
559 * ad_sd_init() - Initializes a ad_sigma_delta struct
560 * @sigma_delta: The ad_sigma_delta device
561 * @indio_dev: The IIO device which the Sigma Delta device is used for
562 * @spi: The SPI device for the ad_sigma_delta device
563 * @info: Device specific callbacks and options
565 * This function needs to be called before any other operations are performed on
566 * the ad_sigma_delta struct.
568 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
569 struct spi_device *spi, const struct ad_sigma_delta_info *info)
571 sigma_delta->spi = spi;
572 sigma_delta->info = info;
573 iio_device_set_drvdata(indio_dev, sigma_delta);
577 EXPORT_SYMBOL_GPL(ad_sd_init);
579 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
580 MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs");
581 MODULE_LICENSE("GPL v2");