kernel/drivers/iio/buffer/industrialio-buffer-cb.c

   1 /* The industrial I/O callback buffer
   2  *
   3  * This program is free software; you can redistribute it and/or modify it
   4  * under the terms of the GNU General Public License version 2 as published by
   5  * the Free Software Foundation.
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/slab.h>
  11 #include <linux/err.h>
  12 #include <linux/export.h>
  13 #include <linux/iio/buffer.h>
  14 #include <linux/iio/consumer.h>
  15
  16 struct iio_cb_buffer {
  17         struct iio_buffer buffer;
  18         int (*cb)(const void *data, void *private);
  19         void *private;
  20         struct iio_channel *channels;
  21 };
  22
  23 static struct iio_cb_buffer *buffer_to_cb_buffer(struct iio_buffer *buffer)
  24 {
  25         return container_of(buffer, struct iio_cb_buffer, buffer);
  26 }
  27
  28 static int iio_buffer_cb_store_to(struct iio_buffer *buffer, const void *data)
  29 {
  30         struct iio_cb_buffer *cb_buff = buffer_to_cb_buffer(buffer);
  31         return cb_buff->cb(data, cb_buff->private);
  32 }
  33
  34 static void iio_buffer_cb_release(struct iio_buffer *buffer)
  35 {
  36         struct iio_cb_buffer *cb_buff = buffer_to_cb_buffer(buffer);
  37         kfree(cb_buff->buffer.scan_mask);
  38         kfree(cb_buff);
  39 }
  40
  41 static const struct iio_buffer_access_funcs iio_cb_access = {
  42         .store_to = &iio_buffer_cb_store_to,
  43         .release = &iio_buffer_cb_release,
  44
  45         .modes = INDIO_BUFFER_SOFTWARE | INDIO_BUFFER_TRIGGERED,
  46 };
  47
  48 struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev,
  49                                              int (*cb)(const void *data,
  50                                                        void *private),
  51                                              void *private)
  52 {
  53         int ret;
  54         struct iio_cb_buffer *cb_buff;
  55         struct iio_dev *indio_dev;
  56         struct iio_channel *chan;
  57
  58         cb_buff = kzalloc(sizeof(*cb_buff), GFP_KERNEL);
  59         if (cb_buff == NULL)
  60                 return ERR_PTR(-ENOMEM);
  61
  62         iio_buffer_init(&cb_buff->buffer);
  63
  64         cb_buff->private = private;
  65         cb_buff->cb = cb;
  66         cb_buff->buffer.access = &iio_cb_access;
  67         INIT_LIST_HEAD(&cb_buff->buffer.demux_list);
  68
  69         cb_buff->channels = iio_channel_get_all(dev);
  70         if (IS_ERR(cb_buff->channels)) {
  71                 ret = PTR_ERR(cb_buff->channels);
  72                 goto error_free_cb_buff;
  73         }
  74
  75         indio_dev = cb_buff->channels[0].indio_dev;
  76         cb_buff->buffer.scan_mask
  77                 = kcalloc(BITS_TO_LONGS(indio_dev->masklength), sizeof(long),
  78                           GFP_KERNEL);
  79         if (cb_buff->buffer.scan_mask == NULL) {
  80                 ret = -ENOMEM;
  81                 goto error_release_channels;
  82         }
  83         chan = &cb_buff->channels[0];
  84         while (chan->indio_dev) {
  85                 if (chan->indio_dev != indio_dev) {
  86                         ret = -EINVAL;
  87                         goto error_free_scan_mask;
  88                 }
  89                 set_bit(chan->channel->scan_index,
  90                         cb_buff->buffer.scan_mask);
  91                 chan++;
  92         }
  93
  94         return cb_buff;
  95
  96 error_free_scan_mask:
  97         kfree(cb_buff->buffer.scan_mask);
  98 error_release_channels:
  99         iio_channel_release_all(cb_buff->channels);
 100 error_free_cb_buff:
 101         kfree(cb_buff);
 102         return ERR_PTR(ret);
 103 }
 104 EXPORT_SYMBOL_GPL(iio_channel_get_all_cb);
 105
 106 int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff)
 107 {
 108         return iio_update_buffers(cb_buff->channels[0].indio_dev,
 109                                   &cb_buff->buffer,
 110                                   NULL);
 111 }
 112 EXPORT_SYMBOL_GPL(iio_channel_start_all_cb);
 113
 114 void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff)
 115 {
 116         iio_update_buffers(cb_buff->channels[0].indio_dev,
 117                            NULL,
 118                            &cb_buff->buffer);
 119 }
 120 EXPORT_SYMBOL_GPL(iio_channel_stop_all_cb);
 121
 122 void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buff)
 123 {
 124         iio_channel_release_all(cb_buff->channels);
 125         iio_buffer_put(&cb_buff->buffer);
 126 }
 127 EXPORT_SYMBOL_GPL(iio_channel_release_all_cb);
 128
 129 struct iio_channel
 130 *iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer)
 131 {
 132         return cb_buffer->channels;
 133 }
 134 EXPORT_SYMBOL_GPL(iio_channel_cb_get_channels);
 135
 136 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
 137 MODULE_DESCRIPTION("Industrial I/O callback buffer");
 138 MODULE_LICENSE("GPL");