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>
23 #include <linux/sched.h>
25 #include <linux/iio/iio.h>
27 #include <linux/iio/sysfs.h>
28 #include <linux/iio/buffer.h>
30 static const char * const iio_endian_prefix[] = {
35 static bool iio_buffer_is_active(struct iio_buffer *buf)
37 return !list_empty(&buf->buffer_list);
40 static bool iio_buffer_data_available(struct iio_buffer *buf)
42 if (buf->access->data_available)
43 return buf->access->data_available(buf);
45 return buf->stufftoread;
49 * iio_buffer_read_first_n_outer() - chrdev read for buffer access
51 * This function relies on all buffer implementations having an
52 * iio_buffer as their first element.
54 ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
55 size_t n, loff_t *f_ps)
57 struct iio_dev *indio_dev = filp->private_data;
58 struct iio_buffer *rb = indio_dev->buffer;
64 if (!rb || !rb->access->read_first_n)
68 if (!iio_buffer_data_available(rb)) {
69 if (filp->f_flags & O_NONBLOCK)
72 ret = wait_event_interruptible(rb->pollq,
73 iio_buffer_data_available(rb) ||
74 indio_dev->info == NULL);
77 if (indio_dev->info == NULL)
81 ret = rb->access->read_first_n(rb, n, buf);
82 if (ret == 0 && (filp->f_flags & O_NONBLOCK))
90 * iio_buffer_poll() - poll the buffer to find out if it has data
92 unsigned int iio_buffer_poll(struct file *filp,
93 struct poll_table_struct *wait)
95 struct iio_dev *indio_dev = filp->private_data;
96 struct iio_buffer *rb = indio_dev->buffer;
101 poll_wait(filp, &rb->pollq, wait);
102 if (iio_buffer_data_available(rb))
103 return POLLIN | POLLRDNORM;
104 /* need a way of knowing if there may be enough data... */
109 * iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
110 * @indio_dev: The IIO device
112 * Wakes up the event waitqueue used for poll(). Should usually
113 * be called when the device is unregistered.
115 void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
117 if (!indio_dev->buffer)
120 wake_up(&indio_dev->buffer->pollq);
123 void iio_buffer_init(struct iio_buffer *buffer)
125 INIT_LIST_HEAD(&buffer->demux_list);
126 INIT_LIST_HEAD(&buffer->buffer_list);
127 init_waitqueue_head(&buffer->pollq);
128 kref_init(&buffer->ref);
130 EXPORT_SYMBOL(iio_buffer_init);
132 static ssize_t iio_show_scan_index(struct device *dev,
133 struct device_attribute *attr,
136 return sprintf(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
139 static ssize_t iio_show_fixed_type(struct device *dev,
140 struct device_attribute *attr,
143 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
144 u8 type = this_attr->c->scan_type.endianness;
146 if (type == IIO_CPU) {
147 #ifdef __LITTLE_ENDIAN
153 return sprintf(buf, "%s:%c%d/%d>>%u\n",
154 iio_endian_prefix[type],
155 this_attr->c->scan_type.sign,
156 this_attr->c->scan_type.realbits,
157 this_attr->c->scan_type.storagebits,
158 this_attr->c->scan_type.shift);
161 static ssize_t iio_scan_el_show(struct device *dev,
162 struct device_attribute *attr,
166 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
168 /* Ensure ret is 0 or 1. */
169 ret = !!test_bit(to_iio_dev_attr(attr)->address,
170 indio_dev->buffer->scan_mask);
172 return sprintf(buf, "%d\n", ret);
175 static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
177 clear_bit(bit, buffer->scan_mask);
181 static ssize_t iio_scan_el_store(struct device *dev,
182 struct device_attribute *attr,
188 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
189 struct iio_buffer *buffer = indio_dev->buffer;
190 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
192 ret = strtobool(buf, &state);
195 mutex_lock(&indio_dev->mlock);
196 if (iio_buffer_is_active(indio_dev->buffer)) {
200 ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
204 ret = iio_scan_mask_clear(buffer, this_attr->address);
207 } else if (state && !ret) {
208 ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
214 mutex_unlock(&indio_dev->mlock);
216 return ret < 0 ? ret : len;
220 static ssize_t iio_scan_el_ts_show(struct device *dev,
221 struct device_attribute *attr,
224 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
225 return sprintf(buf, "%d\n", indio_dev->buffer->scan_timestamp);
228 static ssize_t iio_scan_el_ts_store(struct device *dev,
229 struct device_attribute *attr,
234 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
237 ret = strtobool(buf, &state);
241 mutex_lock(&indio_dev->mlock);
242 if (iio_buffer_is_active(indio_dev->buffer)) {
246 indio_dev->buffer->scan_timestamp = state;
248 mutex_unlock(&indio_dev->mlock);
250 return ret ? ret : len;
253 static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
254 const struct iio_chan_spec *chan)
256 int ret, attrcount = 0;
257 struct iio_buffer *buffer = indio_dev->buffer;
259 ret = __iio_add_chan_devattr("index",
261 &iio_show_scan_index,
266 &buffer->scan_el_dev_attr_list);
270 ret = __iio_add_chan_devattr("type",
272 &iio_show_fixed_type,
277 &buffer->scan_el_dev_attr_list);
281 if (chan->type != IIO_TIMESTAMP)
282 ret = __iio_add_chan_devattr("en",
289 &buffer->scan_el_dev_attr_list);
291 ret = __iio_add_chan_devattr("en",
293 &iio_scan_el_ts_show,
294 &iio_scan_el_ts_store,
298 &buffer->scan_el_dev_attr_list);
306 static const char * const iio_scan_elements_group_name = "scan_elements";
308 int iio_buffer_register(struct iio_dev *indio_dev,
309 const struct iio_chan_spec *channels,
312 struct iio_dev_attr *p;
313 struct attribute **attr;
314 struct iio_buffer *buffer = indio_dev->buffer;
315 int ret, i, attrn, attrcount, attrcount_orig = 0;
318 indio_dev->groups[indio_dev->groupcounter++] = buffer->attrs;
320 if (buffer->scan_el_attrs != NULL) {
321 attr = buffer->scan_el_attrs->attrs;
322 while (*attr++ != NULL)
325 attrcount = attrcount_orig;
326 INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
329 for (i = 0; i < num_channels; i++) {
330 if (channels[i].scan_index < 0)
333 /* Establish necessary mask length */
334 if (channels[i].scan_index >
335 (int)indio_dev->masklength - 1)
336 indio_dev->masklength
337 = channels[i].scan_index + 1;
339 ret = iio_buffer_add_channel_sysfs(indio_dev,
342 goto error_cleanup_dynamic;
344 if (channels[i].type == IIO_TIMESTAMP)
345 indio_dev->scan_index_timestamp =
346 channels[i].scan_index;
348 if (indio_dev->masklength && buffer->scan_mask == NULL) {
349 buffer->scan_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
350 sizeof(*buffer->scan_mask),
352 if (buffer->scan_mask == NULL) {
354 goto error_cleanup_dynamic;
359 buffer->scan_el_group.name = iio_scan_elements_group_name;
361 buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
362 sizeof(buffer->scan_el_group.attrs[0]),
364 if (buffer->scan_el_group.attrs == NULL) {
366 goto error_free_scan_mask;
368 if (buffer->scan_el_attrs)
369 memcpy(buffer->scan_el_group.attrs, buffer->scan_el_attrs,
370 sizeof(buffer->scan_el_group.attrs[0])*attrcount_orig);
371 attrn = attrcount_orig;
373 list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
374 buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
375 indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
379 error_free_scan_mask:
380 kfree(buffer->scan_mask);
381 error_cleanup_dynamic:
382 iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
386 EXPORT_SYMBOL(iio_buffer_register);
388 void iio_buffer_unregister(struct iio_dev *indio_dev)
390 kfree(indio_dev->buffer->scan_mask);
391 kfree(indio_dev->buffer->scan_el_group.attrs);
392 iio_free_chan_devattr_list(&indio_dev->buffer->scan_el_dev_attr_list);
394 EXPORT_SYMBOL(iio_buffer_unregister);
396 ssize_t iio_buffer_read_length(struct device *dev,
397 struct device_attribute *attr,
400 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
401 struct iio_buffer *buffer = indio_dev->buffer;
403 if (buffer->access->get_length)
404 return sprintf(buf, "%d\n",
405 buffer->access->get_length(buffer));
409 EXPORT_SYMBOL(iio_buffer_read_length);
411 ssize_t iio_buffer_write_length(struct device *dev,
412 struct device_attribute *attr,
416 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
417 struct iio_buffer *buffer = indio_dev->buffer;
421 ret = kstrtouint(buf, 10, &val);
425 if (buffer->access->get_length)
426 if (val == buffer->access->get_length(buffer))
429 mutex_lock(&indio_dev->mlock);
430 if (iio_buffer_is_active(indio_dev->buffer)) {
433 if (buffer->access->set_length)
434 buffer->access->set_length(buffer, val);
437 mutex_unlock(&indio_dev->mlock);
439 return ret ? ret : len;
441 EXPORT_SYMBOL(iio_buffer_write_length);
443 ssize_t iio_buffer_show_enable(struct device *dev,
444 struct device_attribute *attr,
447 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
448 return sprintf(buf, "%d\n", iio_buffer_is_active(indio_dev->buffer));
450 EXPORT_SYMBOL(iio_buffer_show_enable);
452 /* Note NULL used as error indicator as it doesn't make sense. */
453 static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
454 unsigned int masklength,
455 const unsigned long *mask)
457 if (bitmap_empty(mask, masklength))
460 if (bitmap_subset(mask, av_masks, masklength))
462 av_masks += BITS_TO_LONGS(masklength);
467 static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
468 const unsigned long *mask, bool timestamp)
470 const struct iio_chan_spec *ch;
474 /* How much space will the demuxed element take? */
475 for_each_set_bit(i, mask,
476 indio_dev->masklength) {
477 ch = iio_find_channel_from_si(indio_dev, i);
478 length = ch->scan_type.storagebits / 8;
479 bytes = ALIGN(bytes, length);
483 ch = iio_find_channel_from_si(indio_dev,
484 indio_dev->scan_index_timestamp);
485 length = ch->scan_type.storagebits / 8;
486 bytes = ALIGN(bytes, length);
492 static void iio_buffer_activate(struct iio_dev *indio_dev,
493 struct iio_buffer *buffer)
495 iio_buffer_get(buffer);
496 list_add(&buffer->buffer_list, &indio_dev->buffer_list);
499 static void iio_buffer_deactivate(struct iio_buffer *buffer)
501 list_del_init(&buffer->buffer_list);
502 iio_buffer_put(buffer);
505 void iio_disable_all_buffers(struct iio_dev *indio_dev)
507 struct iio_buffer *buffer, *_buffer;
509 if (list_empty(&indio_dev->buffer_list))
512 if (indio_dev->setup_ops->predisable)
513 indio_dev->setup_ops->predisable(indio_dev);
515 list_for_each_entry_safe(buffer, _buffer,
516 &indio_dev->buffer_list, buffer_list)
517 iio_buffer_deactivate(buffer);
519 indio_dev->currentmode = INDIO_DIRECT_MODE;
520 if (indio_dev->setup_ops->postdisable)
521 indio_dev->setup_ops->postdisable(indio_dev);
523 if (indio_dev->available_scan_masks == NULL)
524 kfree(indio_dev->active_scan_mask);
527 static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev,
528 struct iio_buffer *buffer)
532 if (!buffer->access->set_bytes_per_datum)
535 bytes = iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
536 buffer->scan_timestamp);
538 buffer->access->set_bytes_per_datum(buffer, bytes);
541 static int __iio_update_buffers(struct iio_dev *indio_dev,
542 struct iio_buffer *insert_buffer,
543 struct iio_buffer *remove_buffer)
547 struct iio_buffer *buffer;
548 unsigned long *compound_mask;
549 const unsigned long *old_mask;
551 /* Wind down existing buffers - iff there are any */
552 if (!list_empty(&indio_dev->buffer_list)) {
553 if (indio_dev->setup_ops->predisable) {
554 ret = indio_dev->setup_ops->predisable(indio_dev);
558 indio_dev->currentmode = INDIO_DIRECT_MODE;
559 if (indio_dev->setup_ops->postdisable) {
560 ret = indio_dev->setup_ops->postdisable(indio_dev);
565 /* Keep a copy of current setup to allow roll back */
566 old_mask = indio_dev->active_scan_mask;
567 if (!indio_dev->available_scan_masks)
568 indio_dev->active_scan_mask = NULL;
571 iio_buffer_deactivate(remove_buffer);
573 iio_buffer_activate(indio_dev, insert_buffer);
575 /* If no buffers in list, we are done */
576 if (list_empty(&indio_dev->buffer_list)) {
577 indio_dev->currentmode = INDIO_DIRECT_MODE;
578 if (indio_dev->available_scan_masks == NULL)
583 /* What scan mask do we actually have? */
584 compound_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
585 sizeof(long), GFP_KERNEL);
586 if (compound_mask == NULL) {
587 if (indio_dev->available_scan_masks == NULL)
591 indio_dev->scan_timestamp = 0;
593 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
594 bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
595 indio_dev->masklength);
596 indio_dev->scan_timestamp |= buffer->scan_timestamp;
598 if (indio_dev->available_scan_masks) {
599 indio_dev->active_scan_mask =
600 iio_scan_mask_match(indio_dev->available_scan_masks,
601 indio_dev->masklength,
603 if (indio_dev->active_scan_mask == NULL) {
606 * Note can only occur when adding a buffer.
608 iio_buffer_deactivate(insert_buffer);
610 indio_dev->active_scan_mask = old_mask;
614 kfree(compound_mask);
620 indio_dev->active_scan_mask = compound_mask;
623 iio_update_demux(indio_dev);
626 if (indio_dev->setup_ops->preenable) {
627 ret = indio_dev->setup_ops->preenable(indio_dev);
630 "Buffer not started: buffer preenable failed (%d)\n", ret);
631 goto error_remove_inserted;
634 indio_dev->scan_bytes =
635 iio_compute_scan_bytes(indio_dev,
636 indio_dev->active_scan_mask,
637 indio_dev->scan_timestamp);
638 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
639 iio_buffer_update_bytes_per_datum(indio_dev, buffer);
640 if (buffer->access->request_update) {
641 ret = buffer->access->request_update(buffer);
644 "Buffer not started: buffer parameter update failed (%d)\n", ret);
645 goto error_run_postdisable;
649 if (indio_dev->info->update_scan_mode) {
650 ret = indio_dev->info
651 ->update_scan_mode(indio_dev,
652 indio_dev->active_scan_mask);
654 printk(KERN_INFO "Buffer not started: update scan mode failed (%d)\n", ret);
655 goto error_run_postdisable;
658 /* Definitely possible for devices to support both of these. */
659 if (indio_dev->modes & INDIO_BUFFER_TRIGGERED) {
660 if (!indio_dev->trig) {
661 printk(KERN_INFO "Buffer not started: no trigger\n");
663 /* Can only occur on first buffer */
664 goto error_run_postdisable;
666 indio_dev->currentmode = INDIO_BUFFER_TRIGGERED;
667 } else if (indio_dev->modes & INDIO_BUFFER_HARDWARE) {
668 indio_dev->currentmode = INDIO_BUFFER_HARDWARE;
669 } else { /* Should never be reached */
671 goto error_run_postdisable;
674 if (indio_dev->setup_ops->postenable) {
675 ret = indio_dev->setup_ops->postenable(indio_dev);
678 "Buffer not started: postenable failed (%d)\n", ret);
679 indio_dev->currentmode = INDIO_DIRECT_MODE;
680 if (indio_dev->setup_ops->postdisable)
681 indio_dev->setup_ops->postdisable(indio_dev);
682 goto error_disable_all_buffers;
686 if (indio_dev->available_scan_masks)
687 kfree(compound_mask);
693 error_disable_all_buffers:
694 indio_dev->currentmode = INDIO_DIRECT_MODE;
695 error_run_postdisable:
696 if (indio_dev->setup_ops->postdisable)
697 indio_dev->setup_ops->postdisable(indio_dev);
698 error_remove_inserted:
700 iio_buffer_deactivate(insert_buffer);
701 indio_dev->active_scan_mask = old_mask;
702 kfree(compound_mask);
706 int iio_update_buffers(struct iio_dev *indio_dev,
707 struct iio_buffer *insert_buffer,
708 struct iio_buffer *remove_buffer)
712 if (insert_buffer == remove_buffer)
715 mutex_lock(&indio_dev->info_exist_lock);
716 mutex_lock(&indio_dev->mlock);
718 if (insert_buffer && iio_buffer_is_active(insert_buffer))
719 insert_buffer = NULL;
721 if (remove_buffer && !iio_buffer_is_active(remove_buffer))
722 remove_buffer = NULL;
724 if (!insert_buffer && !remove_buffer) {
729 if (indio_dev->info == NULL) {
734 ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
737 mutex_unlock(&indio_dev->mlock);
738 mutex_unlock(&indio_dev->info_exist_lock);
742 EXPORT_SYMBOL_GPL(iio_update_buffers);
744 ssize_t iio_buffer_store_enable(struct device *dev,
745 struct device_attribute *attr,
750 bool requested_state;
751 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
754 ret = strtobool(buf, &requested_state);
758 mutex_lock(&indio_dev->mlock);
760 /* Find out if it is in the list */
761 inlist = iio_buffer_is_active(indio_dev->buffer);
762 /* Already in desired state */
763 if (inlist == requested_state)
767 ret = __iio_update_buffers(indio_dev,
768 indio_dev->buffer, NULL);
770 ret = __iio_update_buffers(indio_dev,
771 NULL, indio_dev->buffer);
776 mutex_unlock(&indio_dev->mlock);
777 return (ret < 0) ? ret : len;
779 EXPORT_SYMBOL(iio_buffer_store_enable);
782 * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
783 * @indio_dev: the iio device
784 * @mask: scan mask to be checked
786 * Return true if exactly one bit is set in the scan mask, false otherwise. It
787 * can be used for devices where only one channel can be active for sampling at
790 bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
791 const unsigned long *mask)
793 return bitmap_weight(mask, indio_dev->masklength) == 1;
795 EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
797 static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
798 const unsigned long *mask)
800 if (!indio_dev->setup_ops->validate_scan_mask)
803 return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask);
807 * iio_scan_mask_set() - set particular bit in the scan mask
808 * @indio_dev: the iio device
809 * @buffer: the buffer whose scan mask we are interested in
810 * @bit: the bit to be set.
812 * Note that at this point we have no way of knowing what other
813 * buffers might request, hence this code only verifies that the
814 * individual buffers request is plausible.
816 int iio_scan_mask_set(struct iio_dev *indio_dev,
817 struct iio_buffer *buffer, int bit)
819 const unsigned long *mask;
820 unsigned long *trialmask;
822 trialmask = kmalloc(sizeof(*trialmask)*
823 BITS_TO_LONGS(indio_dev->masklength),
826 if (trialmask == NULL)
828 if (!indio_dev->masklength) {
829 WARN_ON("Trying to set scanmask prior to registering buffer\n");
830 goto err_invalid_mask;
832 bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
833 set_bit(bit, trialmask);
835 if (!iio_validate_scan_mask(indio_dev, trialmask))
836 goto err_invalid_mask;
838 if (indio_dev->available_scan_masks) {
839 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
840 indio_dev->masklength,
843 goto err_invalid_mask;
845 bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
855 EXPORT_SYMBOL_GPL(iio_scan_mask_set);
857 int iio_scan_mask_query(struct iio_dev *indio_dev,
858 struct iio_buffer *buffer, int bit)
860 if (bit > indio_dev->masklength)
863 if (!buffer->scan_mask)
866 /* Ensure return value is 0 or 1. */
867 return !!test_bit(bit, buffer->scan_mask);
869 EXPORT_SYMBOL_GPL(iio_scan_mask_query);
872 * struct iio_demux_table() - table describing demux memcpy ops
873 * @from: index to copy from
874 * @to: index to copy to
875 * @length: how many bytes to copy
876 * @l: list head used for management
878 struct iio_demux_table {
885 static const void *iio_demux(struct iio_buffer *buffer,
888 struct iio_demux_table *t;
890 if (list_empty(&buffer->demux_list))
892 list_for_each_entry(t, &buffer->demux_list, l)
893 memcpy(buffer->demux_bounce + t->to,
894 datain + t->from, t->length);
896 return buffer->demux_bounce;
899 static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
901 const void *dataout = iio_demux(buffer, data);
903 return buffer->access->store_to(buffer, dataout);
906 static void iio_buffer_demux_free(struct iio_buffer *buffer)
908 struct iio_demux_table *p, *q;
909 list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
916 int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
919 struct iio_buffer *buf;
921 list_for_each_entry(buf, &indio_dev->buffer_list, buffer_list) {
922 ret = iio_push_to_buffer(buf, data);
929 EXPORT_SYMBOL_GPL(iio_push_to_buffers);
931 static int iio_buffer_update_demux(struct iio_dev *indio_dev,
932 struct iio_buffer *buffer)
934 const struct iio_chan_spec *ch;
935 int ret, in_ind = -1, out_ind, length;
936 unsigned in_loc = 0, out_loc = 0;
937 struct iio_demux_table *p;
939 /* Clear out any old demux */
940 iio_buffer_demux_free(buffer);
941 kfree(buffer->demux_bounce);
942 buffer->demux_bounce = NULL;
944 /* First work out which scan mode we will actually have */
945 if (bitmap_equal(indio_dev->active_scan_mask,
947 indio_dev->masklength))
950 /* Now we have the two masks, work from least sig and build up sizes */
951 for_each_set_bit(out_ind,
952 indio_dev->active_scan_mask,
953 indio_dev->masklength) {
954 in_ind = find_next_bit(indio_dev->active_scan_mask,
955 indio_dev->masklength,
957 while (in_ind != out_ind) {
958 in_ind = find_next_bit(indio_dev->active_scan_mask,
959 indio_dev->masklength,
961 ch = iio_find_channel_from_si(indio_dev, in_ind);
962 length = ch->scan_type.storagebits/8;
963 /* Make sure we are aligned */
966 in_loc += length - in_loc % length;
968 p = kmalloc(sizeof(*p), GFP_KERNEL);
971 goto error_clear_mux_table;
973 ch = iio_find_channel_from_si(indio_dev, in_ind);
974 length = ch->scan_type.storagebits/8;
975 if (out_loc % length)
976 out_loc += length - out_loc % length;
978 in_loc += length - in_loc % length;
982 list_add_tail(&p->l, &buffer->demux_list);
986 /* Relies on scan_timestamp being last */
987 if (buffer->scan_timestamp) {
988 p = kmalloc(sizeof(*p), GFP_KERNEL);
991 goto error_clear_mux_table;
993 ch = iio_find_channel_from_si(indio_dev,
994 indio_dev->scan_index_timestamp);
995 length = ch->scan_type.storagebits/8;
996 if (out_loc % length)
997 out_loc += length - out_loc % length;
999 in_loc += length - in_loc % length;
1003 list_add_tail(&p->l, &buffer->demux_list);
1007 buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
1008 if (buffer->demux_bounce == NULL) {
1010 goto error_clear_mux_table;
1014 error_clear_mux_table:
1015 iio_buffer_demux_free(buffer);
1020 int iio_update_demux(struct iio_dev *indio_dev)
1022 struct iio_buffer *buffer;
1025 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
1026 ret = iio_buffer_update_demux(indio_dev, buffer);
1028 goto error_clear_mux_table;
1032 error_clear_mux_table:
1033 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
1034 iio_buffer_demux_free(buffer);
1038 EXPORT_SYMBOL_GPL(iio_update_demux);
1041 * iio_buffer_release() - Free a buffer's resources
1042 * @ref: Pointer to the kref embedded in the iio_buffer struct
1044 * This function is called when the last reference to the buffer has been
1045 * dropped. It will typically free all resources allocated by the buffer. Do not
1046 * call this function manually, always use iio_buffer_put() when done using a
1049 static void iio_buffer_release(struct kref *ref)
1051 struct iio_buffer *buffer = container_of(ref, struct iio_buffer, ref);
1053 buffer->access->release(buffer);
1057 * iio_buffer_get() - Grab a reference to the buffer
1058 * @buffer: The buffer to grab a reference for, may be NULL
1060 * Returns the pointer to the buffer that was passed into the function.
1062 struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer)
1065 kref_get(&buffer->ref);
1069 EXPORT_SYMBOL_GPL(iio_buffer_get);
1072 * iio_buffer_put() - Release the reference to the buffer
1073 * @buffer: The buffer to release the reference for, may be NULL
1075 void iio_buffer_put(struct iio_buffer *buffer)
1078 kref_put(&buffer->ref, iio_buffer_release);
1080 EXPORT_SYMBOL_GPL(iio_buffer_put);