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path: root/drivers/iio/industrialio-buffer.c
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Diffstat (limited to 'drivers/iio/industrialio-buffer.c')
-rw-r--r--drivers/iio/industrialio-buffer.c66
1 files changed, 61 insertions, 5 deletions
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index e9f389b9da69..36c39dcad850 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -74,6 +74,7 @@ void iio_buffer_init(struct iio_buffer *buffer)
INIT_LIST_HEAD(&buffer->demux_list);
INIT_LIST_HEAD(&buffer->buffer_list);
init_waitqueue_head(&buffer->pollq);
+ kref_init(&buffer->ref);
}
EXPORT_SYMBOL(iio_buffer_init);
@@ -454,6 +455,19 @@ static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
return bytes;
}
+static void iio_buffer_activate(struct iio_dev *indio_dev,
+ struct iio_buffer *buffer)
+{
+ iio_buffer_get(buffer);
+ list_add(&buffer->buffer_list, &indio_dev->buffer_list);
+}
+
+static void iio_buffer_deactivate(struct iio_buffer *buffer)
+{
+ list_del_init(&buffer->buffer_list);
+ iio_buffer_put(buffer);
+}
+
void iio_disable_all_buffers(struct iio_dev *indio_dev)
{
struct iio_buffer *buffer, *_buffer;
@@ -466,7 +480,7 @@ void iio_disable_all_buffers(struct iio_dev *indio_dev)
list_for_each_entry_safe(buffer, _buffer,
&indio_dev->buffer_list, buffer_list)
- list_del_init(&buffer->buffer_list);
+ iio_buffer_deactivate(buffer);
indio_dev->currentmode = INDIO_DIRECT_MODE;
if (indio_dev->setup_ops->postdisable)
@@ -503,9 +517,9 @@ int iio_update_buffers(struct iio_dev *indio_dev,
indio_dev->active_scan_mask = NULL;
if (remove_buffer)
- list_del_init(&remove_buffer->buffer_list);
+ iio_buffer_deactivate(remove_buffer);
if (insert_buffer)
- list_add(&insert_buffer->buffer_list, &indio_dev->buffer_list);
+ iio_buffer_activate(indio_dev, insert_buffer);
/* If no buffers in list, we are done */
if (list_empty(&indio_dev->buffer_list)) {
@@ -540,7 +554,7 @@ int iio_update_buffers(struct iio_dev *indio_dev,
* Roll back.
* Note can only occur when adding a buffer.
*/
- list_del_init(&insert_buffer->buffer_list);
+ iio_buffer_deactivate(insert_buffer);
if (old_mask) {
indio_dev->active_scan_mask = old_mask;
success = -EINVAL;
@@ -631,7 +645,7 @@ error_run_postdisable:
error_remove_inserted:
if (insert_buffer)
- list_del_init(&insert_buffer->buffer_list);
+ iio_buffer_deactivate(insert_buffer);
indio_dev->active_scan_mask = old_mask;
kfree(compound_mask);
error_ret:
@@ -952,3 +966,45 @@ error_clear_mux_table:
return ret;
}
EXPORT_SYMBOL_GPL(iio_update_demux);
+
+/**
+ * iio_buffer_release() - Free a buffer's resources
+ * @ref: Pointer to the kref embedded in the iio_buffer struct
+ *
+ * This function is called when the last reference to the buffer has been
+ * dropped. It will typically free all resources allocated by the buffer. Do not
+ * call this function manually, always use iio_buffer_put() when done using a
+ * buffer.
+ */
+static void iio_buffer_release(struct kref *ref)
+{
+ struct iio_buffer *buffer = container_of(ref, struct iio_buffer, ref);
+
+ buffer->access->release(buffer);
+}
+
+/**
+ * iio_buffer_get() - Grab a reference to the buffer
+ * @buffer: The buffer to grab a reference for, may be NULL
+ *
+ * Returns the pointer to the buffer that was passed into the function.
+ */
+struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer)
+{
+ if (buffer)
+ kref_get(&buffer->ref);
+
+ return buffer;
+}
+EXPORT_SYMBOL_GPL(iio_buffer_get);
+
+/**
+ * iio_buffer_put() - Release the reference to the buffer
+ * @buffer: The buffer to release the reference for, may be NULL
+ */
+void iio_buffer_put(struct iio_buffer *buffer)
+{
+ if (buffer)
+ kref_put(&buffer->ref, iio_buffer_release);
+}
+EXPORT_SYMBOL_GPL(iio_buffer_put);