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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 <linux/iio/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_timestamp: [INTERN] does the scan mode include a timestamp
60 * @access: [DRIVER] buffer access functions associated with the
61 * implementation.
62 * @scan_el_dev_attr_list:[INTERN] list of scan element related attributes.
63 * @scan_el_group: [DRIVER] attribute group for those attributes not
64 * created from the iio_chan_info array.
65 * @pollq: [INTERN] wait queue to allow for polling on the buffer.
66 * @stufftoread: [INTERN] flag to indicate new data.
67 * @demux_list: [INTERN] list of operations required to demux the scan.
68 * @demux_bounce: [INTERN] buffer for doing gather from incoming scan.
69 **/
70struct iio_buffer {
71 int length;
72 int bytes_per_datum;
73 struct attribute_group *scan_el_attrs;
74 long *scan_mask;
75 bool scan_timestamp;
76 const struct iio_buffer_access_funcs *access;
77 struct list_head scan_el_dev_attr_list;
78 struct attribute_group scan_el_group;
79 wait_queue_head_t pollq;
80 bool stufftoread;
81 const struct attribute_group *attrs;
82 struct list_head demux_list;
83 unsigned char *demux_bounce;
84};
85
86/**
87 * iio_buffer_init() - Initialize the buffer structure
88 * @buffer: buffer to be initialized
89 **/
90void iio_buffer_init(struct iio_buffer *buffer);
91
92/**
93 * __iio_update_buffer() - update common elements of buffers
94 * @buffer: buffer that is the event source
95 * @bytes_per_datum: size of individual datum including timestamp
96 * @length: number of datums in buffer
97 **/
98static inline void __iio_update_buffer(struct iio_buffer *buffer,
99 int bytes_per_datum, int length)
100{
101 buffer->bytes_per_datum = bytes_per_datum;
102 buffer->length = length;
103}
104
105int iio_scan_mask_query(struct iio_dev *indio_dev,
106 struct iio_buffer *buffer, int bit);
107
108/**
109 * iio_scan_mask_set() - set particular bit in the scan mask
110 * @buffer: the buffer whose scan mask we are interested in
111 * @bit: the bit to be set.
112 **/
113int iio_scan_mask_set(struct iio_dev *indio_dev,
114 struct iio_buffer *buffer, int bit);
115
116/**
117 * iio_push_to_buffer() - push to a registered buffer.
118 * @buffer: IIO buffer structure for device
119 * @scan: Full scan.
120 * @timestamp:
121 */
122int iio_push_to_buffer(struct iio_buffer *buffer, unsigned char *data,
123 s64 timestamp);
124
125int iio_update_demux(struct iio_dev *indio_dev);
126
127/**
128 * iio_buffer_register() - register the buffer with IIO core
129 * @indio_dev: device with the buffer to be registered
130 **/
131int iio_buffer_register(struct iio_dev *indio_dev,
132 const struct iio_chan_spec *channels,
133 int num_channels);
134
135/**
136 * iio_buffer_unregister() - unregister the buffer from IIO core
137 * @indio_dev: the device with the buffer to be unregistered
138 **/
139void iio_buffer_unregister(struct iio_dev *indio_dev);
140
141/**
142 * iio_buffer_read_length() - attr func to get number of datums in the buffer
143 **/
144ssize_t iio_buffer_read_length(struct device *dev,
145 struct device_attribute *attr,
146 char *buf);
147/**
148 * iio_buffer_write_length() - attr func to set number of datums in the buffer
149 **/
150ssize_t iio_buffer_write_length(struct device *dev,
151 struct device_attribute *attr,
152 const char *buf,
153 size_t len);
154/**
155 * iio_buffer_store_enable() - attr to turn the buffer on
156 **/
157ssize_t iio_buffer_store_enable(struct device *dev,
158 struct device_attribute *attr,
159 const char *buf,
160 size_t len);
161/**
162 * iio_buffer_show_enable() - attr to see if the buffer is on
163 **/
164ssize_t iio_buffer_show_enable(struct device *dev,
165 struct device_attribute *attr,
166 char *buf);
167#define IIO_BUFFER_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \
168 iio_buffer_read_length, \
169 iio_buffer_write_length)
170
171#define IIO_BUFFER_ENABLE_ATTR DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, \
172 iio_buffer_show_enable, \
173 iio_buffer_store_enable)
174
175int iio_sw_buffer_preenable(struct iio_dev *indio_dev);
176
177#else /* CONFIG_IIO_BUFFER */
178
179static inline int iio_buffer_register(struct iio_dev *indio_dev,
180 struct iio_chan_spec *channels,
181 int num_channels)
182{
183 return 0;
184}
185
186static inline void iio_buffer_unregister(struct iio_dev *indio_dev)
187{};
188
189#endif /* CONFIG_IIO_BUFFER */
190
191#endif /* _IIO_BUFFER_GENERIC_H_ */