Quelle  industrialio-buffer-cb.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/* The industrial I/O callback buffer
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer_impl.h>
#include <linux/iio/consumer.h>

struct iio_cb_buffer {
 struct iio_buffer buffer;
 int (*cb)(const void *data, void *private);
 void *private;
 struct iio_channel *channels;
 struct iio_dev *indio_dev;
};

static struct iio_cb_buffer *buffer_to_cb_buffer(struct iio_buffer *buffer)
{
 return container_of(buffer, struct iio_cb_buffer, buffer);
}

static int iio_buffer_cb_store_to(struct iio_buffer *buffer, const void *data)
{
 struct iio_cb_buffer *cb_buff = buffer_to_cb_buffer(buffer);
 return cb_buff->cb(data, cb_buff->private);
}

static void iio_buffer_cb_release(struct iio_buffer *buffer)
{
 struct iio_cb_buffer *cb_buff = buffer_to_cb_buffer(buffer);

 bitmap_free(cb_buff->buffer.scan_mask);
 kfree(cb_buff);
}

static const struct iio_buffer_access_funcs iio_cb_access = {
 .store_to = &iio_buffer_cb_store_to,
 .release = &iio_buffer_cb_release,

 .modes = INDIO_BUFFER_SOFTWARE | INDIO_BUFFER_TRIGGERED,
};

struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev,
          int (*cb)(const void *data,
             void *private),
          void *private)
{
 int ret;
 struct iio_cb_buffer *cb_buff;
 struct iio_channel *chan;

 if (!cb) {
  dev_err(dev, "Invalid arguments: A callback must be provided!\n");
  return ERR_PTR(-EINVAL);
 }

 cb_buff = kzalloc(sizeof(*cb_buff), GFP_KERNEL);
 if (cb_buff == NULL)
  return ERR_PTR(-ENOMEM);

 iio_buffer_init(&cb_buff->buffer);

 cb_buff->private = private;
 cb_buff->cb = cb;
 cb_buff->buffer.access = &iio_cb_access;
 INIT_LIST_HEAD(&cb_buff->buffer.demux_list);

 cb_buff->channels = iio_channel_get_all(dev);
 if (IS_ERR(cb_buff->channels)) {
  ret = PTR_ERR(cb_buff->channels);
  goto error_free_cb_buff;
 }

 cb_buff->indio_dev = cb_buff->channels[0].indio_dev;
 cb_buff->buffer.scan_mask = bitmap_zalloc(iio_get_masklength(cb_buff->indio_dev),
        GFP_KERNEL);
 if (cb_buff->buffer.scan_mask == NULL) {
  ret = -ENOMEM;
  goto error_release_channels;
 }
 chan = &cb_buff->channels[0];
 while (chan->indio_dev) {
  if (chan->indio_dev != cb_buff->indio_dev) {
   ret = -EINVAL;
   goto error_free_scan_mask;
  }
  set_bit(chan->channel->scan_index,
   cb_buff->buffer.scan_mask);
  chan++;
 }

 return cb_buff;

error_free_scan_mask:
 bitmap_free(cb_buff->buffer.scan_mask);
error_release_channels:
 iio_channel_release_all(cb_buff->channels);
error_free_cb_buff:
 kfree(cb_buff);
 return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(iio_channel_get_all_cb);

int iio_channel_cb_set_buffer_watermark(struct iio_cb_buffer *cb_buff,
     size_t watermark)
{
 if (!watermark)
  return -EINVAL;
 cb_buff->buffer.watermark = watermark;

 return 0;
}
EXPORT_SYMBOL_GPL(iio_channel_cb_set_buffer_watermark);

int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff)
{
 return iio_update_buffers(cb_buff->indio_dev, &cb_buff->buffer,
      NULL);
}
EXPORT_SYMBOL_GPL(iio_channel_start_all_cb);

void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff)
{
 iio_update_buffers(cb_buff->indio_dev, NULL, &cb_buff->buffer);
}
EXPORT_SYMBOL_GPL(iio_channel_stop_all_cb);

void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buff)
{
 iio_channel_release_all(cb_buff->channels);
 iio_buffer_put(&cb_buff->buffer);
}
EXPORT_SYMBOL_GPL(iio_channel_release_all_cb);

struct iio_channel
*iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer)
{
 return cb_buffer->channels;
}
EXPORT_SYMBOL_GPL(iio_channel_cb_get_channels);

struct iio_dev
*iio_channel_cb_get_iio_dev(const struct iio_cb_buffer *cb_buffer)
{
 return cb_buffer->indio_dev;
}
EXPORT_SYMBOL_GPL(iio_channel_cb_get_iio_dev);

MODULE_AUTHOR("Jonathan Cameron ");
MODULE_DESCRIPTION("Industrial I/O callback buffer");
MODULE_LICENSE("GPL");