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1/* The industrial I/O core - generic buffer interfaces.
2 *
3 * Copyright (c) 2008 Jonathan Cameron
4 *
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.
8 */
9
10#ifndef _IIO_BUFFER_GENERIC_H_
11#define _IIO_BUFFER_GENERIC_H_
12#include <linux/sysfs.h>
13#include "iio.h"
14
15#ifdef CONFIG_IIO_BUFFER
16
17struct iio_buffer;
18
19/**
20 * struct iio_buffer_access_funcs - access functions for buffers.
21 * @store_to: actually store stuff to the buffer
22 * @read_first_n: try to get a specified number of bytes (must exist)
23 * @request_update: if a parameter change has been marked, update underlying
24 * storage.
25 * @get_bytes_per_datum:get current bytes per datum
26 * @set_bytes_per_datum:set number of bytes per datum
27 * @get_length: get number of datums in buffer
28 * @set_length: set number of datums in buffer
29 *
30 * The purpose of this structure is to make the buffer element
31 * modular as event for a given driver, different usecases may require
32 * different buffer designs (space efficiency vs speed for example).
33 *
34 * It is worth noting that a given buffer implementation may only support a
35 * small proportion of these functions. The core code 'should' cope fine with
36 * any of them not existing.
37 **/
38struct iio_buffer_access_funcs {
39 int (*store_to)(struct iio_buffer *buffer, u8 *data, s64 timestamp);
40 int (*read_first_n)(struct iio_buffer *buffer,
41 size_t n,
42 char __user *buf);
43
44 int (*request_update)(struct iio_buffer *buffer);
45
46 int (*get_bytes_per_datum)(struct iio_buffer *buffer);
47 int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd);
48 int (*get_length)(struct iio_buffer *buffer);
49 int (*set_length)(struct iio_buffer *buffer, int length);
50};
51
52/**
53 * struct iio_buffer - general buffer structure
54 * @length: [DEVICE] number of datums in buffer
55 * @bytes_per_datum: [DEVICE] size of individual datum including timestamp
56 * @scan_el_attrs: [DRIVER] control of scan elements if that scan mode
57 * control method is used
58 * @scan_mask: [INTERN] bitmask used in masking scan mode elements
59 * @scan_index_timestamp:[INTERN] cache of the index to the timestamp
60 * @scan_timestamp: [INTERN] does the scan mode include a timestamp
61 * @access: [DRIVER] buffer access functions associated with the
62 * implementation.
63 * @scan_el_dev_attr_list:[INTERN] list of scan element related attributes.
64 * @scan_el_group: [DRIVER] attribute group for those attributes not
65 * created from the iio_chan_info array.
66 * @pollq: [INTERN] wait queue to allow for polling on the buffer.
67 * @stufftoread: [INTERN] flag to indicate new data.
68 * @demux_list: [INTERN] list of operations required to demux the scan.
69 * @demux_bounce: [INTERN] buffer for doing gather from incoming scan.
70 **/
71struct iio_buffer {
72 int length;
73 int bytes_per_datum;
74 struct attribute_group *scan_el_attrs;
75 long *scan_mask;
76 bool scan_timestamp;
77 unsigned scan_index_timestamp;
78 const struct iio_buffer_access_funcs *access;
79 struct list_head scan_el_dev_attr_list;
80 struct attribute_group scan_el_group;
81 wait_queue_head_t pollq;
82 bool stufftoread;
83 const struct attribute_group *attrs;
84 struct list_head demux_list;
85 unsigned char *demux_bounce;
86};
87
88/**
89 * iio_buffer_init() - Initialize the buffer structure
90 * @buffer: buffer to be initialized
91 **/
92void iio_buffer_init(struct iio_buffer *buffer);
93
94void iio_buffer_deinit(struct iio_buffer *buffer);
95
96/**
97 * __iio_update_buffer() - update common elements of buffers
98 * @buffer: buffer that is the event source
99 * @bytes_per_datum: size of individual datum including timestamp
100 * @length: number of datums in buffer
101 **/
102static inline void __iio_update_buffer(struct iio_buffer *buffer,
103 int bytes_per_datum, int length)
104{
105 buffer->bytes_per_datum = bytes_per_datum;
106 buffer->length = length;
107}
108
109int iio_scan_mask_query(struct iio_dev *indio_dev,
110 struct iio_buffer *buffer, int bit);
111
112/**
113 * iio_scan_mask_set() - set particular bit in the scan mask
114 * @buffer: the buffer whose scan mask we are interested in
115 * @bit: the bit to be set.
116 **/
117int iio_scan_mask_set(struct iio_dev *indio_dev,
118 struct iio_buffer *buffer, int bit);
119
120/**
121 * iio_push_to_buffer() - push to a registered buffer.
122 * @buffer: IIO buffer structure for device
123 * @scan: Full scan.
124 * @timestamp:
125 */
126int iio_push_to_buffer(struct iio_buffer *buffer, unsigned char *data,
127 s64 timestamp);
128
129int iio_update_demux(struct iio_dev *indio_dev);
130
131/**
132 * iio_buffer_register() - register the buffer with IIO core
133 * @indio_dev: device with the buffer to be registered
134 **/
135int iio_buffer_register(struct iio_dev *indio_dev,
136 const struct iio_chan_spec *channels,
137 int num_channels);
138
139/**
140 * iio_buffer_unregister() - unregister the buffer from IIO core
141 * @indio_dev: the device with the buffer to be unregistered
142 **/
143void iio_buffer_unregister(struct iio_dev *indio_dev);
144
145/**
146 * iio_buffer_read_length() - attr func to get number of datums in the buffer
147 **/
148ssize_t iio_buffer_read_length(struct device *dev,
149 struct device_attribute *attr,
150 char *buf);
151/**
152 * iio_buffer_write_length() - attr func to set number of datums in the buffer
153 **/
154ssize_t iio_buffer_write_length(struct device *dev,
155 struct device_attribute *attr,
156 const char *buf,
157 size_t len);
158/**
159 * iio_buffer_store_enable() - attr to turn the buffer on
160 **/
161ssize_t iio_buffer_store_enable(struct device *dev,
162 struct device_attribute *attr,
163 const char *buf,
164 size_t len);
165/**
166 * iio_buffer_show_enable() - attr to see if the buffer is on
167 **/
168ssize_t iio_buffer_show_enable(struct device *dev,
169 struct device_attribute *attr,
170 char *buf);
171#define IIO_BUFFER_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \
172 iio_buffer_read_length, \
173 iio_buffer_write_length)
174
175#define IIO_BUFFER_ENABLE_ATTR DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, \
176 iio_buffer_show_enable, \
177 iio_buffer_store_enable)
178
179int iio_sw_buffer_preenable(struct iio_dev *indio_dev);
180
181#else /* CONFIG_IIO_BUFFER */
182
183static inline int iio_buffer_register(struct iio_dev *indio_dev,
184 struct iio_chan_spec *channels,
185 int num_channels)
186{
187 return 0;
188}
189
190static inline void iio_buffer_unregister(struct iio_dev *indio_dev)
191{};
192
193#endif /* CONFIG_IIO_BUFFER */
194
195#endif /* _IIO_BUFFER_GENERIC_H_ */