1 // SPDX-License-Identifier: GPL-2.0-only
2 /* The industrial I/O core
4 * Copyright (c) 2008 Jonathan Cameron
6 * Handling of buffer allocation / resizing.
8 * Things to look at here.
9 * - Better memory allocation techniques?
10 * - Alternative access techniques?
12 #include <linux/anon_inodes.h>
13 #include <linux/kernel.h>
14 #include <linux/export.h>
15 #include <linux/device.h>
16 #include <linux/file.h>
18 #include <linux/cdev.h>
19 #include <linux/slab.h>
20 #include <linux/poll.h>
21 #include <linux/sched/signal.h>
23 #include <linux/iio/iio.h>
24 #include <linux/iio/iio-opaque.h>
26 #include "iio_core_trigger.h"
27 #include <linux/iio/sysfs.h>
28 #include <linux/iio/buffer.h>
29 #include <linux/iio/buffer_impl.h>
31 static const char * const iio_endian_prefix[] = {
36 static bool iio_buffer_is_active(struct iio_buffer *buf)
38 return !list_empty(&buf->buffer_list);
41 static size_t iio_buffer_data_available(struct iio_buffer *buf)
43 return buf->access->data_available(buf);
46 static int iio_buffer_flush_hwfifo(struct iio_dev *indio_dev,
47 struct iio_buffer *buf, size_t required)
49 if (!indio_dev->info->hwfifo_flush_to_buffer)
52 return indio_dev->info->hwfifo_flush_to_buffer(indio_dev, required);
55 static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
56 size_t to_wait, int to_flush)
61 /* wakeup if the device was unregistered */
65 /* drain the buffer if it was disabled */
66 if (!iio_buffer_is_active(buf)) {
67 to_wait = min_t(size_t, to_wait, 1);
71 avail = iio_buffer_data_available(buf);
73 if (avail >= to_wait) {
74 /* force a flush for non-blocking reads */
75 if (!to_wait && avail < to_flush)
76 iio_buffer_flush_hwfifo(indio_dev, buf,
82 flushed = iio_buffer_flush_hwfifo(indio_dev, buf,
87 if (avail + flushed >= to_wait)
94 * iio_buffer_read() - chrdev read for buffer access
95 * @filp: File structure pointer for the char device
96 * @buf: Destination buffer for iio buffer read
97 * @n: First n bytes to read
98 * @f_ps: Long offset provided by the user as a seek position
100 * This function relies on all buffer implementations having an
101 * iio_buffer as their first element.
103 * Return: negative values corresponding to error codes or ret != 0
104 * for ending the reading activity
106 static ssize_t iio_buffer_read(struct file *filp, char __user *buf,
107 size_t n, loff_t *f_ps)
109 struct iio_dev_buffer_pair *ib = filp->private_data;
110 struct iio_buffer *rb = ib->buffer;
111 struct iio_dev *indio_dev = ib->indio_dev;
112 DEFINE_WAIT_FUNC(wait, woken_wake_function);
117 if (!indio_dev->info)
120 if (!rb || !rb->access->read)
123 datum_size = rb->bytes_per_datum;
126 * If datum_size is 0 there will never be anything to read from the
127 * buffer, so signal end of file now.
132 if (filp->f_flags & O_NONBLOCK)
135 to_wait = min_t(size_t, n / datum_size, rb->watermark);
137 add_wait_queue(&rb->pollq, &wait);
139 if (!indio_dev->info) {
144 if (!iio_buffer_ready(indio_dev, rb, to_wait, n / datum_size)) {
145 if (signal_pending(current)) {
150 wait_woken(&wait, TASK_INTERRUPTIBLE,
151 MAX_SCHEDULE_TIMEOUT);
155 ret = rb->access->read(rb, n, buf);
156 if (ret == 0 && (filp->f_flags & O_NONBLOCK))
159 remove_wait_queue(&rb->pollq, &wait);
165 * iio_buffer_poll() - poll the buffer to find out if it has data
166 * @filp: File structure pointer for device access
167 * @wait: Poll table structure pointer for which the driver adds
170 * Return: (EPOLLIN | EPOLLRDNORM) if data is available for reading
171 * or 0 for other cases
173 static __poll_t iio_buffer_poll(struct file *filp,
174 struct poll_table_struct *wait)
176 struct iio_dev_buffer_pair *ib = filp->private_data;
177 struct iio_buffer *rb = ib->buffer;
178 struct iio_dev *indio_dev = ib->indio_dev;
180 if (!indio_dev->info || rb == NULL)
183 poll_wait(filp, &rb->pollq, wait);
184 if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
185 return EPOLLIN | EPOLLRDNORM;
189 ssize_t iio_buffer_read_wrapper(struct file *filp, char __user *buf,
190 size_t n, loff_t *f_ps)
192 struct iio_dev_buffer_pair *ib = filp->private_data;
193 struct iio_buffer *rb = ib->buffer;
195 /* check if buffer was opened through new API */
196 if (test_bit(IIO_BUSY_BIT_POS, &rb->flags))
199 return iio_buffer_read(filp, buf, n, f_ps);
202 __poll_t iio_buffer_poll_wrapper(struct file *filp,
203 struct poll_table_struct *wait)
205 struct iio_dev_buffer_pair *ib = filp->private_data;
206 struct iio_buffer *rb = ib->buffer;
208 /* check if buffer was opened through new API */
209 if (test_bit(IIO_BUSY_BIT_POS, &rb->flags))
212 return iio_buffer_poll(filp, wait);
216 * iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
217 * @indio_dev: The IIO device
219 * Wakes up the event waitqueue used for poll(). Should usually
220 * be called when the device is unregistered.
222 void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
224 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
225 struct iio_buffer *buffer;
228 for (i = 0; i < iio_dev_opaque->attached_buffers_cnt; i++) {
229 buffer = iio_dev_opaque->attached_buffers[i];
230 wake_up(&buffer->pollq);
234 void iio_buffer_init(struct iio_buffer *buffer)
236 INIT_LIST_HEAD(&buffer->demux_list);
237 INIT_LIST_HEAD(&buffer->buffer_list);
238 init_waitqueue_head(&buffer->pollq);
239 kref_init(&buffer->ref);
240 if (!buffer->watermark)
241 buffer->watermark = 1;
243 EXPORT_SYMBOL(iio_buffer_init);
245 void iio_device_detach_buffers(struct iio_dev *indio_dev)
247 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
248 struct iio_buffer *buffer;
251 for (i = 0; i < iio_dev_opaque->attached_buffers_cnt; i++) {
252 buffer = iio_dev_opaque->attached_buffers[i];
253 iio_buffer_put(buffer);
256 kfree(iio_dev_opaque->attached_buffers);
259 static ssize_t iio_show_scan_index(struct device *dev,
260 struct device_attribute *attr,
263 return sysfs_emit(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
266 static ssize_t iio_show_fixed_type(struct device *dev,
267 struct device_attribute *attr,
270 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
271 u8 type = this_attr->c->scan_type.endianness;
273 if (type == IIO_CPU) {
274 #ifdef __LITTLE_ENDIAN
280 if (this_attr->c->scan_type.repeat > 1)
281 return sysfs_emit(buf, "%s:%c%d/%dX%d>>%u\n",
282 iio_endian_prefix[type],
283 this_attr->c->scan_type.sign,
284 this_attr->c->scan_type.realbits,
285 this_attr->c->scan_type.storagebits,
286 this_attr->c->scan_type.repeat,
287 this_attr->c->scan_type.shift);
289 return sysfs_emit(buf, "%s:%c%d/%d>>%u\n",
290 iio_endian_prefix[type],
291 this_attr->c->scan_type.sign,
292 this_attr->c->scan_type.realbits,
293 this_attr->c->scan_type.storagebits,
294 this_attr->c->scan_type.shift);
297 static ssize_t iio_scan_el_show(struct device *dev,
298 struct device_attribute *attr,
302 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
304 /* Ensure ret is 0 or 1. */
305 ret = !!test_bit(to_iio_dev_attr(attr)->address,
308 return sysfs_emit(buf, "%d\n", ret);
311 /* Note NULL used as error indicator as it doesn't make sense. */
312 static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
313 unsigned int masklength,
314 const unsigned long *mask,
317 if (bitmap_empty(mask, masklength))
321 if (bitmap_equal(mask, av_masks, masklength))
324 if (bitmap_subset(mask, av_masks, masklength))
327 av_masks += BITS_TO_LONGS(masklength);
332 static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
333 const unsigned long *mask)
335 if (!indio_dev->setup_ops->validate_scan_mask)
338 return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask);
342 * iio_scan_mask_set() - set particular bit in the scan mask
343 * @indio_dev: the iio device
344 * @buffer: the buffer whose scan mask we are interested in
345 * @bit: the bit to be set.
347 * Note that at this point we have no way of knowing what other
348 * buffers might request, hence this code only verifies that the
349 * individual buffers request is plausible.
351 static int iio_scan_mask_set(struct iio_dev *indio_dev,
352 struct iio_buffer *buffer, int bit)
354 const unsigned long *mask;
355 unsigned long *trialmask;
357 if (!indio_dev->masklength) {
358 WARN(1, "Trying to set scanmask prior to registering buffer\n");
362 trialmask = bitmap_alloc(indio_dev->masklength, GFP_KERNEL);
365 bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
366 set_bit(bit, trialmask);
368 if (!iio_validate_scan_mask(indio_dev, trialmask))
369 goto err_invalid_mask;
371 if (indio_dev->available_scan_masks) {
372 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
373 indio_dev->masklength,
376 goto err_invalid_mask;
378 bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
380 bitmap_free(trialmask);
385 bitmap_free(trialmask);
389 static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
391 clear_bit(bit, buffer->scan_mask);
395 static int iio_scan_mask_query(struct iio_dev *indio_dev,
396 struct iio_buffer *buffer, int bit)
398 if (bit > indio_dev->masklength)
401 if (!buffer->scan_mask)
404 /* Ensure return value is 0 or 1. */
405 return !!test_bit(bit, buffer->scan_mask);
408 static ssize_t iio_scan_el_store(struct device *dev,
409 struct device_attribute *attr,
415 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
416 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
417 struct iio_buffer *buffer = this_attr->buffer;
419 ret = strtobool(buf, &state);
422 mutex_lock(&indio_dev->mlock);
423 if (iio_buffer_is_active(buffer)) {
427 ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
431 ret = iio_scan_mask_clear(buffer, this_attr->address);
434 } else if (state && !ret) {
435 ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
441 mutex_unlock(&indio_dev->mlock);
443 return ret < 0 ? ret : len;
447 static ssize_t iio_scan_el_ts_show(struct device *dev,
448 struct device_attribute *attr,
451 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
453 return sysfs_emit(buf, "%d\n", buffer->scan_timestamp);
456 static ssize_t iio_scan_el_ts_store(struct device *dev,
457 struct device_attribute *attr,
462 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
463 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
466 ret = strtobool(buf, &state);
470 mutex_lock(&indio_dev->mlock);
471 if (iio_buffer_is_active(buffer)) {
475 buffer->scan_timestamp = state;
477 mutex_unlock(&indio_dev->mlock);
479 return ret ? ret : len;
482 static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
483 struct iio_buffer *buffer,
484 const struct iio_chan_spec *chan)
486 int ret, attrcount = 0;
488 ret = __iio_add_chan_devattr("index",
490 &iio_show_scan_index,
496 &buffer->buffer_attr_list);
500 ret = __iio_add_chan_devattr("type",
502 &iio_show_fixed_type,
508 &buffer->buffer_attr_list);
512 if (chan->type != IIO_TIMESTAMP)
513 ret = __iio_add_chan_devattr("en",
521 &buffer->buffer_attr_list);
523 ret = __iio_add_chan_devattr("en",
525 &iio_scan_el_ts_show,
526 &iio_scan_el_ts_store,
531 &buffer->buffer_attr_list);
539 static ssize_t iio_buffer_read_length(struct device *dev,
540 struct device_attribute *attr,
543 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
545 return sysfs_emit(buf, "%d\n", buffer->length);
548 static ssize_t iio_buffer_write_length(struct device *dev,
549 struct device_attribute *attr,
550 const char *buf, size_t len)
552 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
553 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
557 ret = kstrtouint(buf, 10, &val);
561 if (val == buffer->length)
564 mutex_lock(&indio_dev->mlock);
565 if (iio_buffer_is_active(buffer)) {
568 buffer->access->set_length(buffer, val);
573 if (buffer->length && buffer->length < buffer->watermark)
574 buffer->watermark = buffer->length;
576 mutex_unlock(&indio_dev->mlock);
578 return ret ? ret : len;
581 static ssize_t iio_buffer_show_enable(struct device *dev,
582 struct device_attribute *attr,
585 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
587 return sysfs_emit(buf, "%d\n", iio_buffer_is_active(buffer));
590 static unsigned int iio_storage_bytes_for_si(struct iio_dev *indio_dev,
591 unsigned int scan_index)
593 const struct iio_chan_spec *ch;
596 ch = iio_find_channel_from_si(indio_dev, scan_index);
597 bytes = ch->scan_type.storagebits / 8;
598 if (ch->scan_type.repeat > 1)
599 bytes *= ch->scan_type.repeat;
603 static unsigned int iio_storage_bytes_for_timestamp(struct iio_dev *indio_dev)
605 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
607 return iio_storage_bytes_for_si(indio_dev,
608 iio_dev_opaque->scan_index_timestamp);
611 static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
612 const unsigned long *mask, bool timestamp)
615 int length, i, largest = 0;
617 /* How much space will the demuxed element take? */
618 for_each_set_bit(i, mask,
619 indio_dev->masklength) {
620 length = iio_storage_bytes_for_si(indio_dev, i);
621 bytes = ALIGN(bytes, length);
623 largest = max(largest, length);
627 length = iio_storage_bytes_for_timestamp(indio_dev);
628 bytes = ALIGN(bytes, length);
630 largest = max(largest, length);
633 bytes = ALIGN(bytes, largest);
637 static void iio_buffer_activate(struct iio_dev *indio_dev,
638 struct iio_buffer *buffer)
640 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
642 iio_buffer_get(buffer);
643 list_add(&buffer->buffer_list, &iio_dev_opaque->buffer_list);
646 static void iio_buffer_deactivate(struct iio_buffer *buffer)
648 list_del_init(&buffer->buffer_list);
649 wake_up_interruptible(&buffer->pollq);
650 iio_buffer_put(buffer);
653 static void iio_buffer_deactivate_all(struct iio_dev *indio_dev)
655 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
656 struct iio_buffer *buffer, *_buffer;
658 list_for_each_entry_safe(buffer, _buffer,
659 &iio_dev_opaque->buffer_list, buffer_list)
660 iio_buffer_deactivate(buffer);
663 static int iio_buffer_enable(struct iio_buffer *buffer,
664 struct iio_dev *indio_dev)
666 if (!buffer->access->enable)
668 return buffer->access->enable(buffer, indio_dev);
671 static int iio_buffer_disable(struct iio_buffer *buffer,
672 struct iio_dev *indio_dev)
674 if (!buffer->access->disable)
676 return buffer->access->disable(buffer, indio_dev);
679 static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev,
680 struct iio_buffer *buffer)
684 if (!buffer->access->set_bytes_per_datum)
687 bytes = iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
688 buffer->scan_timestamp);
690 buffer->access->set_bytes_per_datum(buffer, bytes);
693 static int iio_buffer_request_update(struct iio_dev *indio_dev,
694 struct iio_buffer *buffer)
698 iio_buffer_update_bytes_per_datum(indio_dev, buffer);
699 if (buffer->access->request_update) {
700 ret = buffer->access->request_update(buffer);
702 dev_dbg(&indio_dev->dev,
703 "Buffer not started: buffer parameter update failed (%d)\n",
712 static void iio_free_scan_mask(struct iio_dev *indio_dev,
713 const unsigned long *mask)
715 /* If the mask is dynamically allocated free it, otherwise do nothing */
716 if (!indio_dev->available_scan_masks)
720 struct iio_device_config {
722 unsigned int watermark;
723 const unsigned long *scan_mask;
724 unsigned int scan_bytes;
728 static int iio_verify_update(struct iio_dev *indio_dev,
729 struct iio_buffer *insert_buffer, struct iio_buffer *remove_buffer,
730 struct iio_device_config *config)
732 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
733 unsigned long *compound_mask;
734 const unsigned long *scan_mask;
735 bool strict_scanmask = false;
736 struct iio_buffer *buffer;
741 bitmap_empty(insert_buffer->scan_mask, indio_dev->masklength)) {
742 dev_dbg(&indio_dev->dev,
743 "At least one scan element must be enabled first\n");
747 memset(config, 0, sizeof(*config));
748 config->watermark = ~0;
751 * If there is just one buffer and we are removing it there is nothing
754 if (remove_buffer && !insert_buffer &&
755 list_is_singular(&iio_dev_opaque->buffer_list))
758 modes = indio_dev->modes;
760 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
761 if (buffer == remove_buffer)
763 modes &= buffer->access->modes;
764 config->watermark = min(config->watermark, buffer->watermark);
768 modes &= insert_buffer->access->modes;
769 config->watermark = min(config->watermark,
770 insert_buffer->watermark);
773 /* Definitely possible for devices to support both of these. */
774 if ((modes & INDIO_BUFFER_TRIGGERED) && indio_dev->trig) {
775 config->mode = INDIO_BUFFER_TRIGGERED;
776 } else if (modes & INDIO_BUFFER_HARDWARE) {
778 * Keep things simple for now and only allow a single buffer to
779 * be connected in hardware mode.
781 if (insert_buffer && !list_empty(&iio_dev_opaque->buffer_list))
783 config->mode = INDIO_BUFFER_HARDWARE;
784 strict_scanmask = true;
785 } else if (modes & INDIO_BUFFER_SOFTWARE) {
786 config->mode = INDIO_BUFFER_SOFTWARE;
788 /* Can only occur on first buffer */
789 if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
790 dev_dbg(&indio_dev->dev, "Buffer not started: no trigger\n");
794 /* What scan mask do we actually have? */
795 compound_mask = bitmap_zalloc(indio_dev->masklength, GFP_KERNEL);
796 if (compound_mask == NULL)
799 scan_timestamp = false;
801 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
802 if (buffer == remove_buffer)
804 bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
805 indio_dev->masklength);
806 scan_timestamp |= buffer->scan_timestamp;
810 bitmap_or(compound_mask, compound_mask,
811 insert_buffer->scan_mask, indio_dev->masklength);
812 scan_timestamp |= insert_buffer->scan_timestamp;
815 if (indio_dev->available_scan_masks) {
816 scan_mask = iio_scan_mask_match(indio_dev->available_scan_masks,
817 indio_dev->masklength,
820 bitmap_free(compound_mask);
821 if (scan_mask == NULL)
824 scan_mask = compound_mask;
827 config->scan_bytes = iio_compute_scan_bytes(indio_dev,
828 scan_mask, scan_timestamp);
829 config->scan_mask = scan_mask;
830 config->scan_timestamp = scan_timestamp;
836 * struct iio_demux_table - table describing demux memcpy ops
837 * @from: index to copy from
838 * @to: index to copy to
839 * @length: how many bytes to copy
840 * @l: list head used for management
842 struct iio_demux_table {
849 static void iio_buffer_demux_free(struct iio_buffer *buffer)
851 struct iio_demux_table *p, *q;
852 list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
858 static int iio_buffer_add_demux(struct iio_buffer *buffer,
859 struct iio_demux_table **p, unsigned int in_loc, unsigned int out_loc,
863 if (*p && (*p)->from + (*p)->length == in_loc &&
864 (*p)->to + (*p)->length == out_loc) {
865 (*p)->length += length;
867 *p = kmalloc(sizeof(**p), GFP_KERNEL);
872 (*p)->length = length;
873 list_add_tail(&(*p)->l, &buffer->demux_list);
879 static int iio_buffer_update_demux(struct iio_dev *indio_dev,
880 struct iio_buffer *buffer)
882 int ret, in_ind = -1, out_ind, length;
883 unsigned in_loc = 0, out_loc = 0;
884 struct iio_demux_table *p = NULL;
886 /* Clear out any old demux */
887 iio_buffer_demux_free(buffer);
888 kfree(buffer->demux_bounce);
889 buffer->demux_bounce = NULL;
891 /* First work out which scan mode we will actually have */
892 if (bitmap_equal(indio_dev->active_scan_mask,
894 indio_dev->masklength))
897 /* Now we have the two masks, work from least sig and build up sizes */
898 for_each_set_bit(out_ind,
900 indio_dev->masklength) {
901 in_ind = find_next_bit(indio_dev->active_scan_mask,
902 indio_dev->masklength,
904 while (in_ind != out_ind) {
905 length = iio_storage_bytes_for_si(indio_dev, in_ind);
906 /* Make sure we are aligned */
907 in_loc = roundup(in_loc, length) + length;
908 in_ind = find_next_bit(indio_dev->active_scan_mask,
909 indio_dev->masklength,
912 length = iio_storage_bytes_for_si(indio_dev, in_ind);
913 out_loc = roundup(out_loc, length);
914 in_loc = roundup(in_loc, length);
915 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
917 goto error_clear_mux_table;
921 /* Relies on scan_timestamp being last */
922 if (buffer->scan_timestamp) {
923 length = iio_storage_bytes_for_timestamp(indio_dev);
924 out_loc = roundup(out_loc, length);
925 in_loc = roundup(in_loc, length);
926 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
928 goto error_clear_mux_table;
931 buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
932 if (buffer->demux_bounce == NULL) {
934 goto error_clear_mux_table;
938 error_clear_mux_table:
939 iio_buffer_demux_free(buffer);
944 static int iio_update_demux(struct iio_dev *indio_dev)
946 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
947 struct iio_buffer *buffer;
950 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
951 ret = iio_buffer_update_demux(indio_dev, buffer);
953 goto error_clear_mux_table;
957 error_clear_mux_table:
958 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list)
959 iio_buffer_demux_free(buffer);
964 static int iio_enable_buffers(struct iio_dev *indio_dev,
965 struct iio_device_config *config)
967 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
968 struct iio_buffer *buffer;
971 indio_dev->active_scan_mask = config->scan_mask;
972 indio_dev->scan_timestamp = config->scan_timestamp;
973 indio_dev->scan_bytes = config->scan_bytes;
974 indio_dev->currentmode = config->mode;
976 iio_update_demux(indio_dev);
979 if (indio_dev->setup_ops->preenable) {
980 ret = indio_dev->setup_ops->preenable(indio_dev);
982 dev_dbg(&indio_dev->dev,
983 "Buffer not started: buffer preenable failed (%d)\n", ret);
984 goto err_undo_config;
988 if (indio_dev->info->update_scan_mode) {
989 ret = indio_dev->info
990 ->update_scan_mode(indio_dev,
991 indio_dev->active_scan_mask);
993 dev_dbg(&indio_dev->dev,
994 "Buffer not started: update scan mode failed (%d)\n",
996 goto err_run_postdisable;
1000 if (indio_dev->info->hwfifo_set_watermark)
1001 indio_dev->info->hwfifo_set_watermark(indio_dev,
1004 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
1005 ret = iio_buffer_enable(buffer, indio_dev);
1007 goto err_disable_buffers;
1010 if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
1011 ret = iio_trigger_attach_poll_func(indio_dev->trig,
1012 indio_dev->pollfunc);
1014 goto err_disable_buffers;
1017 if (indio_dev->setup_ops->postenable) {
1018 ret = indio_dev->setup_ops->postenable(indio_dev);
1020 dev_dbg(&indio_dev->dev,
1021 "Buffer not started: postenable failed (%d)\n", ret);
1022 goto err_detach_pollfunc;
1028 err_detach_pollfunc:
1029 if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
1030 iio_trigger_detach_poll_func(indio_dev->trig,
1031 indio_dev->pollfunc);
1033 err_disable_buffers:
1034 list_for_each_entry_continue_reverse(buffer, &iio_dev_opaque->buffer_list,
1036 iio_buffer_disable(buffer, indio_dev);
1037 err_run_postdisable:
1038 if (indio_dev->setup_ops->postdisable)
1039 indio_dev->setup_ops->postdisable(indio_dev);
1041 indio_dev->currentmode = INDIO_DIRECT_MODE;
1042 indio_dev->active_scan_mask = NULL;
1047 static int iio_disable_buffers(struct iio_dev *indio_dev)
1049 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1050 struct iio_buffer *buffer;
1054 /* Wind down existing buffers - iff there are any */
1055 if (list_empty(&iio_dev_opaque->buffer_list))
1059 * If things go wrong at some step in disable we still need to continue
1060 * to perform the other steps, otherwise we leave the device in a
1061 * inconsistent state. We return the error code for the first error we
1065 if (indio_dev->setup_ops->predisable) {
1066 ret2 = indio_dev->setup_ops->predisable(indio_dev);
1071 if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
1072 iio_trigger_detach_poll_func(indio_dev->trig,
1073 indio_dev->pollfunc);
1076 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
1077 ret2 = iio_buffer_disable(buffer, indio_dev);
1082 if (indio_dev->setup_ops->postdisable) {
1083 ret2 = indio_dev->setup_ops->postdisable(indio_dev);
1088 iio_free_scan_mask(indio_dev, indio_dev->active_scan_mask);
1089 indio_dev->active_scan_mask = NULL;
1090 indio_dev->currentmode = INDIO_DIRECT_MODE;
1095 static int __iio_update_buffers(struct iio_dev *indio_dev,
1096 struct iio_buffer *insert_buffer,
1097 struct iio_buffer *remove_buffer)
1099 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1100 struct iio_device_config new_config;
1103 ret = iio_verify_update(indio_dev, insert_buffer, remove_buffer,
1108 if (insert_buffer) {
1109 ret = iio_buffer_request_update(indio_dev, insert_buffer);
1111 goto err_free_config;
1114 ret = iio_disable_buffers(indio_dev);
1116 goto err_deactivate_all;
1119 iio_buffer_deactivate(remove_buffer);
1121 iio_buffer_activate(indio_dev, insert_buffer);
1123 /* If no buffers in list, we are done */
1124 if (list_empty(&iio_dev_opaque->buffer_list))
1127 ret = iio_enable_buffers(indio_dev, &new_config);
1129 goto err_deactivate_all;
1135 * We've already verified that the config is valid earlier. If things go
1136 * wrong in either enable or disable the most likely reason is an IO
1137 * error from the device. In this case there is no good recovery
1138 * strategy. Just make sure to disable everything and leave the device
1139 * in a sane state. With a bit of luck the device might come back to
1140 * life again later and userspace can try again.
1142 iio_buffer_deactivate_all(indio_dev);
1145 iio_free_scan_mask(indio_dev, new_config.scan_mask);
1149 int iio_update_buffers(struct iio_dev *indio_dev,
1150 struct iio_buffer *insert_buffer,
1151 struct iio_buffer *remove_buffer)
1153 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1156 if (insert_buffer == remove_buffer)
1159 mutex_lock(&iio_dev_opaque->info_exist_lock);
1160 mutex_lock(&indio_dev->mlock);
1162 if (insert_buffer && iio_buffer_is_active(insert_buffer))
1163 insert_buffer = NULL;
1165 if (remove_buffer && !iio_buffer_is_active(remove_buffer))
1166 remove_buffer = NULL;
1168 if (!insert_buffer && !remove_buffer) {
1173 if (indio_dev->info == NULL) {
1178 ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
1181 mutex_unlock(&indio_dev->mlock);
1182 mutex_unlock(&iio_dev_opaque->info_exist_lock);
1186 EXPORT_SYMBOL_GPL(iio_update_buffers);
1188 void iio_disable_all_buffers(struct iio_dev *indio_dev)
1190 iio_disable_buffers(indio_dev);
1191 iio_buffer_deactivate_all(indio_dev);
1194 static ssize_t iio_buffer_store_enable(struct device *dev,
1195 struct device_attribute *attr,
1200 bool requested_state;
1201 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1202 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
1205 ret = strtobool(buf, &requested_state);
1209 mutex_lock(&indio_dev->mlock);
1211 /* Find out if it is in the list */
1212 inlist = iio_buffer_is_active(buffer);
1213 /* Already in desired state */
1214 if (inlist == requested_state)
1217 if (requested_state)
1218 ret = __iio_update_buffers(indio_dev, buffer, NULL);
1220 ret = __iio_update_buffers(indio_dev, NULL, buffer);
1223 mutex_unlock(&indio_dev->mlock);
1224 return (ret < 0) ? ret : len;
1227 static ssize_t iio_buffer_show_watermark(struct device *dev,
1228 struct device_attribute *attr,
1231 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
1233 return sysfs_emit(buf, "%u\n", buffer->watermark);
1236 static ssize_t iio_buffer_store_watermark(struct device *dev,
1237 struct device_attribute *attr,
1241 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1242 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
1246 ret = kstrtouint(buf, 10, &val);
1252 mutex_lock(&indio_dev->mlock);
1254 if (val > buffer->length) {
1259 if (iio_buffer_is_active(buffer)) {
1264 buffer->watermark = val;
1266 mutex_unlock(&indio_dev->mlock);
1268 return ret ? ret : len;
1271 static ssize_t iio_dma_show_data_available(struct device *dev,
1272 struct device_attribute *attr,
1275 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
1277 return sysfs_emit(buf, "%zu\n", iio_buffer_data_available(buffer));
1280 static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length,
1281 iio_buffer_write_length);
1282 static struct device_attribute dev_attr_length_ro = __ATTR(length,
1283 S_IRUGO, iio_buffer_read_length, NULL);
1284 static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
1285 iio_buffer_show_enable, iio_buffer_store_enable);
1286 static DEVICE_ATTR(watermark, S_IRUGO | S_IWUSR,
1287 iio_buffer_show_watermark, iio_buffer_store_watermark);
1288 static struct device_attribute dev_attr_watermark_ro = __ATTR(watermark,
1289 S_IRUGO, iio_buffer_show_watermark, NULL);
1290 static DEVICE_ATTR(data_available, S_IRUGO,
1291 iio_dma_show_data_available, NULL);
1293 static struct attribute *iio_buffer_attrs[] = {
1294 &dev_attr_length.attr,
1295 &dev_attr_enable.attr,
1296 &dev_attr_watermark.attr,
1297 &dev_attr_data_available.attr,
1300 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
1302 static struct attribute *iio_buffer_wrap_attr(struct iio_buffer *buffer,
1303 struct attribute *attr)
1305 struct device_attribute *dattr = to_dev_attr(attr);
1306 struct iio_dev_attr *iio_attr;
1308 iio_attr = kzalloc(sizeof(*iio_attr), GFP_KERNEL);
1312 iio_attr->buffer = buffer;
1313 memcpy(&iio_attr->dev_attr, dattr, sizeof(iio_attr->dev_attr));
1314 iio_attr->dev_attr.attr.name = kstrdup_const(attr->name, GFP_KERNEL);
1315 if (!iio_attr->dev_attr.attr.name) {
1320 sysfs_attr_init(&iio_attr->dev_attr.attr);
1322 list_add(&iio_attr->l, &buffer->buffer_attr_list);
1324 return &iio_attr->dev_attr.attr;
1327 static int iio_buffer_register_legacy_sysfs_groups(struct iio_dev *indio_dev,
1328 struct attribute **buffer_attrs,
1329 int buffer_attrcount,
1330 int scan_el_attrcount)
1332 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1333 struct attribute_group *group;
1334 struct attribute **attrs;
1337 attrs = kcalloc(buffer_attrcount + 1, sizeof(*attrs), GFP_KERNEL);
1341 memcpy(attrs, buffer_attrs, buffer_attrcount * sizeof(*attrs));
1343 group = &iio_dev_opaque->legacy_buffer_group;
1344 group->attrs = attrs;
1345 group->name = "buffer";
1347 ret = iio_device_register_sysfs_group(indio_dev, group);
1349 goto error_free_buffer_attrs;
1351 attrs = kcalloc(scan_el_attrcount + 1, sizeof(*attrs), GFP_KERNEL);
1354 goto error_free_buffer_attrs;
1357 memcpy(attrs, &buffer_attrs[buffer_attrcount],
1358 scan_el_attrcount * sizeof(*attrs));
1360 group = &iio_dev_opaque->legacy_scan_el_group;
1361 group->attrs = attrs;
1362 group->name = "scan_elements";
1364 ret = iio_device_register_sysfs_group(indio_dev, group);
1366 goto error_free_scan_el_attrs;
1370 error_free_scan_el_attrs:
1371 kfree(iio_dev_opaque->legacy_scan_el_group.attrs);
1372 error_free_buffer_attrs:
1373 kfree(iio_dev_opaque->legacy_buffer_group.attrs);
1378 static void iio_buffer_unregister_legacy_sysfs_groups(struct iio_dev *indio_dev)
1380 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1382 kfree(iio_dev_opaque->legacy_buffer_group.attrs);
1383 kfree(iio_dev_opaque->legacy_scan_el_group.attrs);
1386 static int iio_buffer_chrdev_release(struct inode *inode, struct file *filep)
1388 struct iio_dev_buffer_pair *ib = filep->private_data;
1389 struct iio_dev *indio_dev = ib->indio_dev;
1390 struct iio_buffer *buffer = ib->buffer;
1392 wake_up(&buffer->pollq);
1395 clear_bit(IIO_BUSY_BIT_POS, &buffer->flags);
1396 iio_device_put(indio_dev);
1401 static const struct file_operations iio_buffer_chrdev_fileops = {
1402 .owner = THIS_MODULE,
1403 .llseek = noop_llseek,
1404 .read = iio_buffer_read,
1405 .poll = iio_buffer_poll,
1406 .release = iio_buffer_chrdev_release,
1409 static long iio_device_buffer_getfd(struct iio_dev *indio_dev, unsigned long arg)
1411 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1412 int __user *ival = (int __user *)arg;
1413 struct iio_dev_buffer_pair *ib;
1414 struct iio_buffer *buffer;
1417 if (copy_from_user(&idx, ival, sizeof(idx)))
1420 if (idx >= iio_dev_opaque->attached_buffers_cnt)
1423 iio_device_get(indio_dev);
1425 buffer = iio_dev_opaque->attached_buffers[idx];
1427 if (test_and_set_bit(IIO_BUSY_BIT_POS, &buffer->flags)) {
1429 goto error_iio_dev_put;
1432 ib = kzalloc(sizeof(*ib), GFP_KERNEL);
1435 goto error_clear_busy_bit;
1438 ib->indio_dev = indio_dev;
1439 ib->buffer = buffer;
1441 fd = anon_inode_getfd("iio:buffer", &iio_buffer_chrdev_fileops,
1442 ib, O_RDWR | O_CLOEXEC);
1448 if (copy_to_user(ival, &fd, sizeof(fd))) {
1450 * "Leak" the fd, as there's not much we can do about this
1451 * anyway. 'fd' might have been closed already, as
1452 * anon_inode_getfd() called fd_install() on it, which made
1453 * it reachable by userland.
1455 * Instead of allowing a malicious user to play tricks with
1456 * us, rely on the process exit path to do any necessary
1457 * cleanup, as in releasing the file, if still needed.
1466 error_clear_busy_bit:
1467 clear_bit(IIO_BUSY_BIT_POS, &buffer->flags);
1469 iio_device_put(indio_dev);
1473 static long iio_device_buffer_ioctl(struct iio_dev *indio_dev, struct file *filp,
1474 unsigned int cmd, unsigned long arg)
1477 case IIO_BUFFER_GET_FD_IOCTL:
1478 return iio_device_buffer_getfd(indio_dev, arg);
1480 return IIO_IOCTL_UNHANDLED;
1484 static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
1485 struct iio_dev *indio_dev,
1488 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1489 struct iio_dev_attr *p;
1490 struct attribute **attr;
1491 int ret, i, attrn, scan_el_attrcount, buffer_attrcount;
1492 const struct iio_chan_spec *channels;
1494 buffer_attrcount = 0;
1495 if (buffer->attrs) {
1496 while (buffer->attrs[buffer_attrcount] != NULL)
1500 scan_el_attrcount = 0;
1501 INIT_LIST_HEAD(&buffer->buffer_attr_list);
1502 channels = indio_dev->channels;
1505 for (i = 0; i < indio_dev->num_channels; i++) {
1506 if (channels[i].scan_index < 0)
1509 ret = iio_buffer_add_channel_sysfs(indio_dev, buffer,
1512 goto error_cleanup_dynamic;
1513 scan_el_attrcount += ret;
1514 if (channels[i].type == IIO_TIMESTAMP)
1515 iio_dev_opaque->scan_index_timestamp =
1516 channels[i].scan_index;
1518 if (indio_dev->masklength && buffer->scan_mask == NULL) {
1519 buffer->scan_mask = bitmap_zalloc(indio_dev->masklength,
1521 if (buffer->scan_mask == NULL) {
1523 goto error_cleanup_dynamic;
1528 attrn = buffer_attrcount + scan_el_attrcount + ARRAY_SIZE(iio_buffer_attrs);
1529 attr = kcalloc(attrn + 1, sizeof(* attr), GFP_KERNEL);
1532 goto error_free_scan_mask;
1535 memcpy(attr, iio_buffer_attrs, sizeof(iio_buffer_attrs));
1536 if (!buffer->access->set_length)
1537 attr[0] = &dev_attr_length_ro.attr;
1539 if (buffer->access->flags & INDIO_BUFFER_FLAG_FIXED_WATERMARK)
1540 attr[2] = &dev_attr_watermark_ro.attr;
1543 memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs,
1544 sizeof(struct attribute *) * buffer_attrcount);
1546 buffer_attrcount += ARRAY_SIZE(iio_buffer_attrs);
1547 buffer->buffer_group.attrs = attr;
1549 for (i = 0; i < buffer_attrcount; i++) {
1550 struct attribute *wrapped;
1552 wrapped = iio_buffer_wrap_attr(buffer, attr[i]);
1555 goto error_free_buffer_attrs;
1561 list_for_each_entry(p, &buffer->buffer_attr_list, l)
1562 attr[attrn++] = &p->dev_attr.attr;
1564 buffer->buffer_group.name = kasprintf(GFP_KERNEL, "buffer%d", index);
1565 if (!buffer->buffer_group.name) {
1567 goto error_free_buffer_attrs;
1570 ret = iio_device_register_sysfs_group(indio_dev, &buffer->buffer_group);
1572 goto error_free_buffer_attr_group_name;
1574 /* we only need to register the legacy groups for the first buffer */
1578 ret = iio_buffer_register_legacy_sysfs_groups(indio_dev, attr,
1582 goto error_free_buffer_attr_group_name;
1586 error_free_buffer_attr_group_name:
1587 kfree(buffer->buffer_group.name);
1588 error_free_buffer_attrs:
1589 kfree(buffer->buffer_group.attrs);
1590 error_free_scan_mask:
1591 bitmap_free(buffer->scan_mask);
1592 error_cleanup_dynamic:
1593 iio_free_chan_devattr_list(&buffer->buffer_attr_list);
1598 static void __iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer,
1599 struct iio_dev *indio_dev,
1603 iio_buffer_unregister_legacy_sysfs_groups(indio_dev);
1604 bitmap_free(buffer->scan_mask);
1605 kfree(buffer->buffer_group.name);
1606 kfree(buffer->buffer_group.attrs);
1607 iio_free_chan_devattr_list(&buffer->buffer_attr_list);
1610 int iio_buffers_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
1612 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1613 const struct iio_chan_spec *channels;
1614 struct iio_buffer *buffer;
1619 channels = indio_dev->channels;
1621 int ml = indio_dev->masklength;
1623 for (i = 0; i < indio_dev->num_channels; i++)
1624 ml = max(ml, channels[i].scan_index + 1);
1625 indio_dev->masklength = ml;
1628 if (!iio_dev_opaque->attached_buffers_cnt)
1631 for (i = 0; i < iio_dev_opaque->attached_buffers_cnt; i++) {
1632 buffer = iio_dev_opaque->attached_buffers[i];
1633 ret = __iio_buffer_alloc_sysfs_and_mask(buffer, indio_dev, i);
1636 goto error_unwind_sysfs_and_mask;
1639 unwind_idx = iio_dev_opaque->attached_buffers_cnt - 1;
1641 sz = sizeof(*(iio_dev_opaque->buffer_ioctl_handler));
1642 iio_dev_opaque->buffer_ioctl_handler = kzalloc(sz, GFP_KERNEL);
1643 if (!iio_dev_opaque->buffer_ioctl_handler) {
1645 goto error_unwind_sysfs_and_mask;
1648 iio_dev_opaque->buffer_ioctl_handler->ioctl = iio_device_buffer_ioctl;
1649 iio_device_ioctl_handler_register(indio_dev,
1650 iio_dev_opaque->buffer_ioctl_handler);
1654 error_unwind_sysfs_and_mask:
1655 for (; unwind_idx >= 0; unwind_idx--) {
1656 buffer = iio_dev_opaque->attached_buffers[unwind_idx];
1657 __iio_buffer_free_sysfs_and_mask(buffer, indio_dev, unwind_idx);
1662 void iio_buffers_free_sysfs_and_mask(struct iio_dev *indio_dev)
1664 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1665 struct iio_buffer *buffer;
1668 if (!iio_dev_opaque->attached_buffers_cnt)
1671 iio_device_ioctl_handler_unregister(iio_dev_opaque->buffer_ioctl_handler);
1672 kfree(iio_dev_opaque->buffer_ioctl_handler);
1674 for (i = iio_dev_opaque->attached_buffers_cnt - 1; i >= 0; i--) {
1675 buffer = iio_dev_opaque->attached_buffers[i];
1676 __iio_buffer_free_sysfs_and_mask(buffer, indio_dev, i);
1681 * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
1682 * @indio_dev: the iio device
1683 * @mask: scan mask to be checked
1685 * Return true if exactly one bit is set in the scan mask, false otherwise. It
1686 * can be used for devices where only one channel can be active for sampling at
1689 bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
1690 const unsigned long *mask)
1692 return bitmap_weight(mask, indio_dev->masklength) == 1;
1694 EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
1696 static const void *iio_demux(struct iio_buffer *buffer,
1699 struct iio_demux_table *t;
1701 if (list_empty(&buffer->demux_list))
1703 list_for_each_entry(t, &buffer->demux_list, l)
1704 memcpy(buffer->demux_bounce + t->to,
1705 datain + t->from, t->length);
1707 return buffer->demux_bounce;
1710 static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
1712 const void *dataout = iio_demux(buffer, data);
1715 ret = buffer->access->store_to(buffer, dataout);
1720 * We can't just test for watermark to decide if we wake the poll queue
1721 * because read may request less samples than the watermark.
1723 wake_up_interruptible_poll(&buffer->pollq, EPOLLIN | EPOLLRDNORM);
1728 * iio_push_to_buffers() - push to a registered buffer.
1729 * @indio_dev: iio_dev structure for device.
1732 int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
1734 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1736 struct iio_buffer *buf;
1738 list_for_each_entry(buf, &iio_dev_opaque->buffer_list, buffer_list) {
1739 ret = iio_push_to_buffer(buf, data);
1746 EXPORT_SYMBOL_GPL(iio_push_to_buffers);
1749 * iio_buffer_release() - Free a buffer's resources
1750 * @ref: Pointer to the kref embedded in the iio_buffer struct
1752 * This function is called when the last reference to the buffer has been
1753 * dropped. It will typically free all resources allocated by the buffer. Do not
1754 * call this function manually, always use iio_buffer_put() when done using a
1757 static void iio_buffer_release(struct kref *ref)
1759 struct iio_buffer *buffer = container_of(ref, struct iio_buffer, ref);
1761 buffer->access->release(buffer);
1765 * iio_buffer_get() - Grab a reference to the buffer
1766 * @buffer: The buffer to grab a reference for, may be NULL
1768 * Returns the pointer to the buffer that was passed into the function.
1770 struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer)
1773 kref_get(&buffer->ref);
1777 EXPORT_SYMBOL_GPL(iio_buffer_get);
1780 * iio_buffer_put() - Release the reference to the buffer
1781 * @buffer: The buffer to release the reference for, may be NULL
1783 void iio_buffer_put(struct iio_buffer *buffer)
1786 kref_put(&buffer->ref, iio_buffer_release);
1788 EXPORT_SYMBOL_GPL(iio_buffer_put);
1791 * iio_device_attach_buffer - Attach a buffer to a IIO device
1792 * @indio_dev: The device the buffer should be attached to
1793 * @buffer: The buffer to attach to the device
1795 * Return 0 if successful, negative if error.
1797 * This function attaches a buffer to a IIO device. The buffer stays attached to
1798 * the device until the device is freed. For legacy reasons, the first attached
1799 * buffer will also be assigned to 'indio_dev->buffer'.
1800 * The array allocated here, will be free'd via the iio_device_detach_buffers()
1801 * call which is handled by the iio_device_free().
1803 int iio_device_attach_buffer(struct iio_dev *indio_dev,
1804 struct iio_buffer *buffer)
1806 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1807 struct iio_buffer **new, **old = iio_dev_opaque->attached_buffers;
1808 unsigned int cnt = iio_dev_opaque->attached_buffers_cnt;
1812 new = krealloc(old, sizeof(*new) * cnt, GFP_KERNEL);
1815 iio_dev_opaque->attached_buffers = new;
1817 buffer = iio_buffer_get(buffer);
1819 /* first buffer is legacy; attach it to the IIO device directly */
1820 if (!indio_dev->buffer)
1821 indio_dev->buffer = buffer;
1823 iio_dev_opaque->attached_buffers[cnt - 1] = buffer;
1824 iio_dev_opaque->attached_buffers_cnt = cnt;
1828 EXPORT_SYMBOL_GPL(iio_device_attach_buffer);