1 /* The industrial I/O core
3 * Copyright (c) 2008 Jonathan Cameron
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
9 * Handling of buffer allocation / resizing.
12 * Things to look at here.
13 * - Better memory allocation techniques?
14 * - Alternative access techniques?
16 #include <linux/kernel.h>
17 #include <linux/export.h>
18 #include <linux/device.h>
20 #include <linux/cdev.h>
21 #include <linux/slab.h>
22 #include <linux/poll.h>
24 #include <linux/iio/iio.h>
26 #include <linux/iio/sysfs.h>
27 #include <linux/iio/buffer.h>
29 static const char * const iio_endian_prefix[] = {
34 static bool iio_buffer_is_active(struct iio_dev *indio_dev,
35 struct iio_buffer *buf)
39 list_for_each(p, &indio_dev->buffer_list)
40 if (p == &buf->buffer_list)
47 * iio_buffer_read_first_n_outer() - chrdev read for buffer access
49 * This function relies on all buffer implementations having an
50 * iio_buffer as their first element.
52 ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
53 size_t n, loff_t *f_ps)
55 struct iio_dev *indio_dev = filp->private_data;
56 struct iio_buffer *rb = indio_dev->buffer;
58 if (!rb || !rb->access->read_first_n)
60 return rb->access->read_first_n(rb, n, buf);
64 * iio_buffer_poll() - poll the buffer to find out if it has data
66 unsigned int iio_buffer_poll(struct file *filp,
67 struct poll_table_struct *wait)
69 struct iio_dev *indio_dev = filp->private_data;
70 struct iio_buffer *rb = indio_dev->buffer;
72 poll_wait(filp, &rb->pollq, wait);
74 return POLLIN | POLLRDNORM;
75 /* need a way of knowing if there may be enough data... */
79 void iio_buffer_init(struct iio_buffer *buffer)
81 INIT_LIST_HEAD(&buffer->demux_list);
82 init_waitqueue_head(&buffer->pollq);
84 EXPORT_SYMBOL(iio_buffer_init);
86 static ssize_t iio_show_scan_index(struct device *dev,
87 struct device_attribute *attr,
90 return sprintf(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
93 static ssize_t iio_show_fixed_type(struct device *dev,
94 struct device_attribute *attr,
97 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
98 u8 type = this_attr->c->scan_type.endianness;
100 if (type == IIO_CPU) {
101 #ifdef __LITTLE_ENDIAN
107 return sprintf(buf, "%s:%c%d/%d>>%u\n",
108 iio_endian_prefix[type],
109 this_attr->c->scan_type.sign,
110 this_attr->c->scan_type.realbits,
111 this_attr->c->scan_type.storagebits,
112 this_attr->c->scan_type.shift);
115 static ssize_t iio_scan_el_show(struct device *dev,
116 struct device_attribute *attr,
120 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
122 ret = test_bit(to_iio_dev_attr(attr)->address,
123 indio_dev->buffer->scan_mask);
125 return sprintf(buf, "%d\n", ret);
128 static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
130 clear_bit(bit, buffer->scan_mask);
134 static ssize_t iio_scan_el_store(struct device *dev,
135 struct device_attribute *attr,
141 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
142 struct iio_buffer *buffer = indio_dev->buffer;
143 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
145 ret = strtobool(buf, &state);
148 mutex_lock(&indio_dev->mlock);
149 if (iio_buffer_is_active(indio_dev, indio_dev->buffer)) {
153 ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
157 ret = iio_scan_mask_clear(buffer, this_attr->address);
160 } else if (state && !ret) {
161 ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
167 mutex_unlock(&indio_dev->mlock);
169 return ret < 0 ? ret : len;
173 static ssize_t iio_scan_el_ts_show(struct device *dev,
174 struct device_attribute *attr,
177 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
178 return sprintf(buf, "%d\n", indio_dev->buffer->scan_timestamp);
181 static ssize_t iio_scan_el_ts_store(struct device *dev,
182 struct device_attribute *attr,
187 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
190 ret = strtobool(buf, &state);
194 mutex_lock(&indio_dev->mlock);
195 if (iio_buffer_is_active(indio_dev, indio_dev->buffer)) {
199 indio_dev->buffer->scan_timestamp = state;
201 mutex_unlock(&indio_dev->mlock);
203 return ret ? ret : len;
206 static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
207 const struct iio_chan_spec *chan)
209 int ret, attrcount = 0;
210 struct iio_buffer *buffer = indio_dev->buffer;
212 ret = __iio_add_chan_devattr("index",
214 &iio_show_scan_index,
219 &buffer->scan_el_dev_attr_list);
223 ret = __iio_add_chan_devattr("type",
225 &iio_show_fixed_type,
230 &buffer->scan_el_dev_attr_list);
234 if (chan->type != IIO_TIMESTAMP)
235 ret = __iio_add_chan_devattr("en",
242 &buffer->scan_el_dev_attr_list);
244 ret = __iio_add_chan_devattr("en",
246 &iio_scan_el_ts_show,
247 &iio_scan_el_ts_store,
251 &buffer->scan_el_dev_attr_list);
258 static void iio_buffer_remove_and_free_scan_dev_attr(struct iio_dev *indio_dev,
259 struct iio_dev_attr *p)
261 kfree(p->dev_attr.attr.name);
265 static void __iio_buffer_attr_cleanup(struct iio_dev *indio_dev)
267 struct iio_dev_attr *p, *n;
268 struct iio_buffer *buffer = indio_dev->buffer;
270 list_for_each_entry_safe(p, n,
271 &buffer->scan_el_dev_attr_list, l)
272 iio_buffer_remove_and_free_scan_dev_attr(indio_dev, p);
275 static const char * const iio_scan_elements_group_name = "scan_elements";
277 int iio_buffer_register(struct iio_dev *indio_dev,
278 const struct iio_chan_spec *channels,
281 struct iio_dev_attr *p;
282 struct attribute **attr;
283 struct iio_buffer *buffer = indio_dev->buffer;
284 int ret, i, attrn, attrcount, attrcount_orig = 0;
287 indio_dev->groups[indio_dev->groupcounter++] = buffer->attrs;
289 if (buffer->scan_el_attrs != NULL) {
290 attr = buffer->scan_el_attrs->attrs;
291 while (*attr++ != NULL)
294 attrcount = attrcount_orig;
295 INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
298 for (i = 0; i < num_channels; i++) {
299 if (channels[i].scan_index < 0)
302 /* Establish necessary mask length */
303 if (channels[i].scan_index >
304 (int)indio_dev->masklength - 1)
305 indio_dev->masklength
306 = channels[i].scan_index + 1;
308 ret = iio_buffer_add_channel_sysfs(indio_dev,
311 goto error_cleanup_dynamic;
313 if (channels[i].type == IIO_TIMESTAMP)
314 indio_dev->scan_index_timestamp =
315 channels[i].scan_index;
317 if (indio_dev->masklength && buffer->scan_mask == NULL) {
318 buffer->scan_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
319 sizeof(*buffer->scan_mask),
321 if (buffer->scan_mask == NULL) {
323 goto error_cleanup_dynamic;
328 buffer->scan_el_group.name = iio_scan_elements_group_name;
330 buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
331 sizeof(buffer->scan_el_group.attrs[0]),
333 if (buffer->scan_el_group.attrs == NULL) {
335 goto error_free_scan_mask;
337 if (buffer->scan_el_attrs)
338 memcpy(buffer->scan_el_group.attrs, buffer->scan_el_attrs,
339 sizeof(buffer->scan_el_group.attrs[0])*attrcount_orig);
340 attrn = attrcount_orig;
342 list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
343 buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
344 indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
348 error_free_scan_mask:
349 kfree(buffer->scan_mask);
350 error_cleanup_dynamic:
351 __iio_buffer_attr_cleanup(indio_dev);
355 EXPORT_SYMBOL(iio_buffer_register);
357 void iio_buffer_unregister(struct iio_dev *indio_dev)
359 kfree(indio_dev->buffer->scan_mask);
360 kfree(indio_dev->buffer->scan_el_group.attrs);
361 __iio_buffer_attr_cleanup(indio_dev);
363 EXPORT_SYMBOL(iio_buffer_unregister);
365 ssize_t iio_buffer_read_length(struct device *dev,
366 struct device_attribute *attr,
369 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
370 struct iio_buffer *buffer = indio_dev->buffer;
372 if (buffer->access->get_length)
373 return sprintf(buf, "%d\n",
374 buffer->access->get_length(buffer));
378 EXPORT_SYMBOL(iio_buffer_read_length);
380 ssize_t iio_buffer_write_length(struct device *dev,
381 struct device_attribute *attr,
385 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
386 struct iio_buffer *buffer = indio_dev->buffer;
390 ret = kstrtouint(buf, 10, &val);
394 if (buffer->access->get_length)
395 if (val == buffer->access->get_length(buffer))
398 mutex_lock(&indio_dev->mlock);
399 if (iio_buffer_is_active(indio_dev, indio_dev->buffer)) {
402 if (buffer->access->set_length)
403 buffer->access->set_length(buffer, val);
406 mutex_unlock(&indio_dev->mlock);
408 return ret ? ret : len;
410 EXPORT_SYMBOL(iio_buffer_write_length);
412 ssize_t iio_buffer_show_enable(struct device *dev,
413 struct device_attribute *attr,
416 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
417 return sprintf(buf, "%d\n",
418 iio_buffer_is_active(indio_dev,
421 EXPORT_SYMBOL(iio_buffer_show_enable);
423 /* note NULL used as error indicator as it doesn't make sense. */
424 static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
425 unsigned int masklength,
426 const unsigned long *mask)
428 if (bitmap_empty(mask, masklength))
431 if (bitmap_subset(mask, av_masks, masklength))
433 av_masks += BITS_TO_LONGS(masklength);
438 static int iio_compute_scan_bytes(struct iio_dev *indio_dev, const long *mask,
441 const struct iio_chan_spec *ch;
445 /* How much space will the demuxed element take? */
446 for_each_set_bit(i, mask,
447 indio_dev->masklength) {
448 ch = iio_find_channel_from_si(indio_dev, i);
449 length = ch->scan_type.storagebits / 8;
450 bytes = ALIGN(bytes, length);
454 ch = iio_find_channel_from_si(indio_dev,
455 indio_dev->scan_index_timestamp);
456 length = ch->scan_type.storagebits / 8;
457 bytes = ALIGN(bytes, length);
463 int iio_update_buffers(struct iio_dev *indio_dev,
464 struct iio_buffer *insert_buffer,
465 struct iio_buffer *remove_buffer)
469 struct iio_buffer *buffer;
470 unsigned long *compound_mask;
471 const unsigned long *old_mask;
473 /* Wind down existing buffers - iff there are any */
474 if (!list_empty(&indio_dev->buffer_list)) {
475 if (indio_dev->setup_ops->predisable) {
476 ret = indio_dev->setup_ops->predisable(indio_dev);
480 indio_dev->currentmode = INDIO_DIRECT_MODE;
481 if (indio_dev->setup_ops->postdisable) {
482 ret = indio_dev->setup_ops->postdisable(indio_dev);
487 /* Keep a copy of current setup to allow roll back */
488 old_mask = indio_dev->active_scan_mask;
489 if (!indio_dev->available_scan_masks)
490 indio_dev->active_scan_mask = NULL;
493 list_del(&remove_buffer->buffer_list);
495 list_add(&insert_buffer->buffer_list, &indio_dev->buffer_list);
497 /* If no buffers in list, we are done */
498 if (list_empty(&indio_dev->buffer_list)) {
499 indio_dev->currentmode = INDIO_DIRECT_MODE;
500 if (indio_dev->available_scan_masks == NULL)
505 /* What scan mask do we actually have ?*/
506 compound_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
507 sizeof(long), GFP_KERNEL);
508 if (compound_mask == NULL) {
509 if (indio_dev->available_scan_masks == NULL)
513 indio_dev->scan_timestamp = 0;
515 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
516 bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
517 indio_dev->masklength);
518 indio_dev->scan_timestamp |= buffer->scan_timestamp;
520 if (indio_dev->available_scan_masks) {
521 indio_dev->active_scan_mask =
522 iio_scan_mask_match(indio_dev->available_scan_masks,
523 indio_dev->masklength,
525 if (indio_dev->active_scan_mask == NULL) {
528 * Note can only occur when adding a buffer.
530 list_del(&insert_buffer->buffer_list);
532 indio_dev->active_scan_mask = old_mask;
536 kfree(compound_mask);
542 indio_dev->active_scan_mask = compound_mask;
545 iio_update_demux(indio_dev);
548 if (indio_dev->setup_ops->preenable) {
549 ret = indio_dev->setup_ops->preenable(indio_dev);
552 "Buffer not started: buffer preenable failed (%d)\n", ret);
553 goto error_remove_inserted;
556 indio_dev->scan_bytes =
557 iio_compute_scan_bytes(indio_dev,
558 indio_dev->active_scan_mask,
559 indio_dev->scan_timestamp);
560 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
561 if (buffer->access->request_update) {
562 ret = buffer->access->request_update(buffer);
565 "Buffer not started: buffer parameter update failed (%d)\n", ret);
566 goto error_run_postdisable;
569 if (indio_dev->info->update_scan_mode) {
570 ret = indio_dev->info
571 ->update_scan_mode(indio_dev,
572 indio_dev->active_scan_mask);
574 printk(KERN_INFO "Buffer not started: update scan mode failed (%d)\n", ret);
575 goto error_run_postdisable;
578 /* Definitely possible for devices to support both of these.*/
579 if (indio_dev->modes & INDIO_BUFFER_TRIGGERED) {
580 if (!indio_dev->trig) {
581 printk(KERN_INFO "Buffer not started: no trigger\n");
583 /* Can only occur on first buffer */
584 goto error_run_postdisable;
586 indio_dev->currentmode = INDIO_BUFFER_TRIGGERED;
587 } else if (indio_dev->modes & INDIO_BUFFER_HARDWARE) {
588 indio_dev->currentmode = INDIO_BUFFER_HARDWARE;
589 } else { /* should never be reached */
591 goto error_run_postdisable;
594 if (indio_dev->setup_ops->postenable) {
595 ret = indio_dev->setup_ops->postenable(indio_dev);
598 "Buffer not started: postenable failed (%d)\n", ret);
599 indio_dev->currentmode = INDIO_DIRECT_MODE;
600 if (indio_dev->setup_ops->postdisable)
601 indio_dev->setup_ops->postdisable(indio_dev);
602 goto error_disable_all_buffers;
606 if (indio_dev->available_scan_masks)
607 kfree(compound_mask);
613 error_disable_all_buffers:
614 indio_dev->currentmode = INDIO_DIRECT_MODE;
615 error_run_postdisable:
616 if (indio_dev->setup_ops->postdisable)
617 indio_dev->setup_ops->postdisable(indio_dev);
618 error_remove_inserted:
621 list_del(&insert_buffer->buffer_list);
622 indio_dev->active_scan_mask = old_mask;
623 kfree(compound_mask);
628 EXPORT_SYMBOL_GPL(iio_update_buffers);
630 ssize_t iio_buffer_store_enable(struct device *dev,
631 struct device_attribute *attr,
636 bool requested_state;
637 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
638 struct iio_buffer *pbuf = indio_dev->buffer;
641 ret = strtobool(buf, &requested_state);
645 mutex_lock(&indio_dev->mlock);
647 /* Find out if it is in the list */
648 inlist = iio_buffer_is_active(indio_dev, pbuf);
649 /* Already in desired state */
650 if (inlist == requested_state)
654 ret = iio_update_buffers(indio_dev,
655 indio_dev->buffer, NULL);
657 ret = iio_update_buffers(indio_dev,
658 NULL, indio_dev->buffer);
663 mutex_unlock(&indio_dev->mlock);
664 return (ret < 0) ? ret : len;
666 EXPORT_SYMBOL(iio_buffer_store_enable);
668 int iio_sw_buffer_preenable(struct iio_dev *indio_dev)
670 struct iio_buffer *buffer;
672 dev_dbg(&indio_dev->dev, "%s\n", __func__);
674 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
675 if (buffer->access->set_bytes_per_datum) {
676 bytes = iio_compute_scan_bytes(indio_dev,
678 buffer->scan_timestamp);
680 buffer->access->set_bytes_per_datum(buffer, bytes);
684 EXPORT_SYMBOL(iio_sw_buffer_preenable);
687 * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
688 * @indio_dev: the iio device
689 * @mask: scan mask to be checked
691 * Return true if exactly one bit is set in the scan mask, false otherwise. It
692 * can be used for devices where only one channel can be active for sampling at
695 bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
696 const unsigned long *mask)
698 return bitmap_weight(mask, indio_dev->masklength) == 1;
700 EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
702 static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
703 const unsigned long *mask)
705 if (!indio_dev->setup_ops->validate_scan_mask)
708 return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask);
712 * iio_scan_mask_set() - set particular bit in the scan mask
713 * @buffer: the buffer whose scan mask we are interested in
714 * @bit: the bit to be set.
716 * Note that at this point we have no way of knowing what other
717 * buffers might request, hence this code only verifies that the
718 * individual buffers request is plausible.
720 int iio_scan_mask_set(struct iio_dev *indio_dev,
721 struct iio_buffer *buffer, int bit)
723 const unsigned long *mask;
724 unsigned long *trialmask;
726 trialmask = kmalloc(sizeof(*trialmask)*
727 BITS_TO_LONGS(indio_dev->masklength),
730 if (trialmask == NULL)
732 if (!indio_dev->masklength) {
733 WARN_ON("trying to set scanmask prior to registering buffer\n");
734 goto err_invalid_mask;
736 bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
737 set_bit(bit, trialmask);
739 if (!iio_validate_scan_mask(indio_dev, trialmask))
740 goto err_invalid_mask;
742 if (indio_dev->available_scan_masks) {
743 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
744 indio_dev->masklength,
747 goto err_invalid_mask;
749 bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
759 EXPORT_SYMBOL_GPL(iio_scan_mask_set);
761 int iio_scan_mask_query(struct iio_dev *indio_dev,
762 struct iio_buffer *buffer, int bit)
764 if (bit > indio_dev->masklength)
767 if (!buffer->scan_mask)
770 return test_bit(bit, buffer->scan_mask);
772 EXPORT_SYMBOL_GPL(iio_scan_mask_query);
775 * struct iio_demux_table() - table describing demux memcpy ops
776 * @from: index to copy from
777 * @to: index to copy to
778 * @length: how many bytes to copy
779 * @l: list head used for management
781 struct iio_demux_table {
788 static unsigned char *iio_demux(struct iio_buffer *buffer,
789 unsigned char *datain)
791 struct iio_demux_table *t;
793 if (list_empty(&buffer->demux_list))
795 list_for_each_entry(t, &buffer->demux_list, l)
796 memcpy(buffer->demux_bounce + t->to,
797 datain + t->from, t->length);
799 return buffer->demux_bounce;
802 static int iio_push_to_buffer(struct iio_buffer *buffer, unsigned char *data)
804 unsigned char *dataout = iio_demux(buffer, data);
806 return buffer->access->store_to(buffer, dataout);
809 static void iio_buffer_demux_free(struct iio_buffer *buffer)
811 struct iio_demux_table *p, *q;
812 list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
819 int iio_push_to_buffers(struct iio_dev *indio_dev, unsigned char *data)
822 struct iio_buffer *buf;
824 list_for_each_entry(buf, &indio_dev->buffer_list, buffer_list) {
825 ret = iio_push_to_buffer(buf, data);
832 EXPORT_SYMBOL_GPL(iio_push_to_buffers);
834 static int iio_buffer_update_demux(struct iio_dev *indio_dev,
835 struct iio_buffer *buffer)
837 const struct iio_chan_spec *ch;
838 int ret, in_ind = -1, out_ind, length;
839 unsigned in_loc = 0, out_loc = 0;
840 struct iio_demux_table *p;
842 /* Clear out any old demux */
843 iio_buffer_demux_free(buffer);
844 kfree(buffer->demux_bounce);
845 buffer->demux_bounce = NULL;
847 /* First work out which scan mode we will actually have */
848 if (bitmap_equal(indio_dev->active_scan_mask,
850 indio_dev->masklength))
853 /* Now we have the two masks, work from least sig and build up sizes */
854 for_each_set_bit(out_ind,
855 indio_dev->active_scan_mask,
856 indio_dev->masklength) {
857 in_ind = find_next_bit(indio_dev->active_scan_mask,
858 indio_dev->masklength,
860 while (in_ind != out_ind) {
861 in_ind = find_next_bit(indio_dev->active_scan_mask,
862 indio_dev->masklength,
864 ch = iio_find_channel_from_si(indio_dev, in_ind);
865 length = ch->scan_type.storagebits/8;
866 /* Make sure we are aligned */
869 in_loc += length - in_loc % length;
871 p = kmalloc(sizeof(*p), GFP_KERNEL);
874 goto error_clear_mux_table;
876 ch = iio_find_channel_from_si(indio_dev, in_ind);
877 length = ch->scan_type.storagebits/8;
878 if (out_loc % length)
879 out_loc += length - out_loc % length;
881 in_loc += length - in_loc % length;
885 list_add_tail(&p->l, &buffer->demux_list);
889 /* Relies on scan_timestamp being last */
890 if (buffer->scan_timestamp) {
891 p = kmalloc(sizeof(*p), GFP_KERNEL);
894 goto error_clear_mux_table;
896 ch = iio_find_channel_from_si(indio_dev,
897 indio_dev->scan_index_timestamp);
898 length = ch->scan_type.storagebits/8;
899 if (out_loc % length)
900 out_loc += length - out_loc % length;
902 in_loc += length - in_loc % length;
906 list_add_tail(&p->l, &buffer->demux_list);
910 buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
911 if (buffer->demux_bounce == NULL) {
913 goto error_clear_mux_table;
917 error_clear_mux_table:
918 iio_buffer_demux_free(buffer);
923 int iio_update_demux(struct iio_dev *indio_dev)
925 struct iio_buffer *buffer;
928 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
929 ret = iio_buffer_update_demux(indio_dev, buffer);
931 goto error_clear_mux_table;
935 error_clear_mux_table:
936 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
937 iio_buffer_demux_free(buffer);
941 EXPORT_SYMBOL_GPL(iio_update_demux);