1Buffer support within IIO
2
3This document is intended as a general overview of the functionality
4a buffer may supply and how it is specified within IIO.  For more
5specific information on a given buffer implementation, see the
6comments in the source code.  Note that some drivers allow buffer
7implementation to be selected at compile time via Kconfig options.
8
9A given buffer implementation typically embeds a struct
10iio_ring_buffer and it is a pointer to this that is provided to the
11IIO core. Access to the embedding structure is typically done via
12container_of functions.
13
14struct iio_ring_buffer contains a struct iio_ring_setup_ops *setup_ops
15which in turn contains the 4 function pointers
16(preenable, postenable, predisable and postdisable).
17These are used to perform device specific steps on either side
18of the core changing its current mode to indicate that the buffer
19is enabled or disabled (along with enabling triggering etc. as appropriate).
20
21Also in struct iio_ring_buffer is a struct iio_ring_access_funcs.
22The function pointers within here are used to allow the core to handle
23as much buffer functionality as possible. Note almost all of these
24are optional.
25
26store_to
27  If possible, push data to the buffer.
28
29read_last
30  If possible, get the most recent scan from the buffer (without removal).
31  This provides polling like functionality whilst the ring buffering is in
32  use without a separate read from the device.
33
34rip_first_n
35  The primary buffer reading function. Note that it may well not return
36  as much data as requested.
37
38request_update
39  If parameters have changed that require reinitialization or configuration of
40  the buffer this will trigger it.
41
42set_bytes_per_datum
43  Set the number of bytes for a complete scan. (All samples + timestamp)
44
45set_length
46  Set the number of complete scans that may be held by the buffer.
47
48