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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);
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 * @buffer_list: [INTERN] entry in the devices list of current buffers.
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 const struct iio_buffer_access_funcs *access;
78 struct list_head scan_el_dev_attr_list;
79 struct attribute_group scan_el_group;
80 wait_queue_head_t pollq;
81 bool stufftoread;
82 const struct attribute_group *attrs;
83 struct list_head demux_list;
84 unsigned char *demux_bounce;
85 struct list_head buffer_list;
86};
87
88/**
89 * iio_update_buffers() - add or remove buffer from active list
90 * @indio_dev: device to add buffer to
91 * @insert_buffer: buffer to insert
92 * @remove_buffer: buffer_to_remove
93 *
94 * Note this will tear down the all buffering and build it up again
95 */
96int iio_update_buffers(struct iio_dev *indio_dev,
97 struct iio_buffer *insert_buffer,
98 struct iio_buffer *remove_buffer);
99
100/**
101 * iio_buffer_init() - Initialize the buffer structure
102 * @buffer: buffer to be initialized
103 **/
104void iio_buffer_init(struct iio_buffer *buffer);
105
106/**
107 * __iio_update_buffer() - update common elements of buffers
108 * @buffer: buffer that is the event source
109 * @bytes_per_datum: size of individual datum including timestamp
110 * @length: number of datums in buffer
111 **/
112static inline void __iio_update_buffer(struct iio_buffer *buffer,
113 int bytes_per_datum, int length)
114{
115 buffer->bytes_per_datum = bytes_per_datum;
116 buffer->length = length;
117}
118
119int iio_scan_mask_query(struct iio_dev *indio_dev,
120 struct iio_buffer *buffer, int bit);
121
122/**
123 * iio_scan_mask_set() - set particular bit in the scan mask
124 * @indio_dev IIO device structure
125 * @buffer: the buffer whose scan mask we are interested in
126 * @bit: the bit to be set.
127 **/
128int iio_scan_mask_set(struct iio_dev *indio_dev,
129 struct iio_buffer *buffer, int bit);
130
131/**
132 * iio_push_to_buffers() - push to a registered buffer.
133 * @indio_dev: iio_dev structure for device.
134 * @data: Full scan.
135 */
136int iio_push_to_buffers(struct iio_dev *indio_dev, unsigned char *data);
137
138int iio_update_demux(struct iio_dev *indio_dev);
139
140/**
141 * iio_buffer_register() - register the buffer with IIO core
142 * @indio_dev: device with the buffer to be registered
143 * @channels: the channel descriptions used to construct buffer
144 * @num_channels: the number of channels
145 **/
146int iio_buffer_register(struct iio_dev *indio_dev,
147 const struct iio_chan_spec *channels,
148 int num_channels);
149
150/**
151 * iio_buffer_unregister() - unregister the buffer from IIO core
152 * @indio_dev: the device with the buffer to be unregistered
153 **/
154void iio_buffer_unregister(struct iio_dev *indio_dev);
155
156/**
157 * iio_buffer_read_length() - attr func to get number of datums in the buffer
158 **/
159ssize_t iio_buffer_read_length(struct device *dev,
160 struct device_attribute *attr,
161 char *buf);
162/**
163 * iio_buffer_write_length() - attr func to set number of datums in the buffer
164 **/
165ssize_t iio_buffer_write_length(struct device *dev,
166 struct device_attribute *attr,
167 const char *buf,
168 size_t len);
169/**
170 * iio_buffer_store_enable() - attr to turn the buffer on
171 **/
172ssize_t iio_buffer_store_enable(struct device *dev,
173 struct device_attribute *attr,
174 const char *buf,
175 size_t len);
176/**
177 * iio_buffer_show_enable() - attr to see if the buffer is on
178 **/
179ssize_t iio_buffer_show_enable(struct device *dev,
180 struct device_attribute *attr,
181 char *buf);
182#define IIO_BUFFER_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \
183 iio_buffer_read_length, \
184 iio_buffer_write_length)
185
186#define IIO_BUFFER_ENABLE_ATTR DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, \
187 iio_buffer_show_enable, \
188 iio_buffer_store_enable)
189
190int iio_sw_buffer_preenable(struct iio_dev *indio_dev);
191
192bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
193 const unsigned long *mask);
194
195#else /* CONFIG_IIO_BUFFER */
196
197static inline int iio_buffer_register(struct iio_dev *indio_dev,
198 const struct iio_chan_spec *channels,
199 int num_channels)
200{
201 return 0;
202}
203
204static inline void iio_buffer_unregister(struct iio_dev *indio_dev)
205{}
206
207#endif /* CONFIG_IIO_BUFFER */
208
209#endif /* _IIO_BUFFER_GENERIC_H_ */