1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
|
/* The industrial I/O core - generic buffer interfaces.
*
* Copyright (c) 2008 Jonathan Cameron
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*/
#ifndef _IIO_BUFFER_GENERIC_H_
#define _IIO_BUFFER_GENERIC_H_
#include <linux/sysfs.h>
#include <linux/iio/iio.h>
#include <linux/kref.h>
#ifdef CONFIG_IIO_BUFFER
struct iio_buffer;
/**
* struct iio_buffer_access_funcs - access functions for buffers.
* @store_to: actually store stuff to the buffer
* @read_first_n: try to get a specified number of bytes (must exist)
* @request_update: if a parameter change has been marked, update underlying
* storage.
* @get_bytes_per_datum:get current bytes per datum
* @set_bytes_per_datum:set number of bytes per datum
* @get_length: get number of datums in buffer
* @set_length: set number of datums in buffer
* @release: called when the last reference to the buffer is dropped,
* should free all resources allocated by the buffer.
*
* The purpose of this structure is to make the buffer element
* modular as event for a given driver, different usecases may require
* different buffer designs (space efficiency vs speed for example).
*
* It is worth noting that a given buffer implementation may only support a
* small proportion of these functions. The core code 'should' cope fine with
* any of them not existing.
**/
struct iio_buffer_access_funcs {
int (*store_to)(struct iio_buffer *buffer, const void *data);
int (*read_first_n)(struct iio_buffer *buffer,
size_t n,
char __user *buf);
int (*request_update)(struct iio_buffer *buffer);
int (*get_bytes_per_datum)(struct iio_buffer *buffer);
int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd);
int (*get_length)(struct iio_buffer *buffer);
int (*set_length)(struct iio_buffer *buffer, int length);
void (*release)(struct iio_buffer *buffer);
};
/**
* struct iio_buffer - general buffer structure
* @length: [DEVICE] number of datums in buffer
* @bytes_per_datum: [DEVICE] size of individual datum including timestamp
* @scan_el_attrs: [DRIVER] control of scan elements if that scan mode
* control method is used
* @scan_mask: [INTERN] bitmask used in masking scan mode elements
* @scan_timestamp: [INTERN] does the scan mode include a timestamp
* @access: [DRIVER] buffer access functions associated with the
* implementation.
* @scan_el_dev_attr_list:[INTERN] list of scan element related attributes.
* @scan_el_group: [DRIVER] attribute group for those attributes not
* created from the iio_chan_info array.
* @pollq: [INTERN] wait queue to allow for polling on the buffer.
* @stufftoread: [INTERN] flag to indicate new data.
* @demux_list: [INTERN] list of operations required to demux the scan.
* @demux_bounce: [INTERN] buffer for doing gather from incoming scan.
* @buffer_list: [INTERN] entry in the devices list of current buffers.
* @ref: [INTERN] reference count of the buffer.
*/
struct iio_buffer {
int length;
int bytes_per_datum;
struct attribute_group *scan_el_attrs;
long *scan_mask;
bool scan_timestamp;
const struct iio_buffer_access_funcs *access;
struct list_head scan_el_dev_attr_list;
struct attribute_group scan_el_group;
wait_queue_head_t pollq;
bool stufftoread;
const struct attribute_group *attrs;
struct list_head demux_list;
void *demux_bounce;
struct list_head buffer_list;
struct kref ref;
};
/**
* iio_update_buffers() - add or remove buffer from active list
* @indio_dev: device to add buffer to
* @insert_buffer: buffer to insert
* @remove_buffer: buffer_to_remove
*
* Note this will tear down the all buffering and build it up again
*/
int iio_update_buffers(struct iio_dev *indio_dev,
struct iio_buffer *insert_buffer,
struct iio_buffer *remove_buffer);
/**
* iio_buffer_init() - Initialize the buffer structure
* @buffer: buffer to be initialized
**/
void iio_buffer_init(struct iio_buffer *buffer);
int iio_scan_mask_query(struct iio_dev *indio_dev,
struct iio_buffer *buffer, int bit);
/**
* iio_scan_mask_set() - set particular bit in the scan mask
* @indio_dev IIO device structure
* @buffer: the buffer whose scan mask we are interested in
* @bit: the bit to be set.
**/
int iio_scan_mask_set(struct iio_dev *indio_dev,
struct iio_buffer *buffer, int bit);
/**
* iio_push_to_buffers() - push to a registered buffer.
* @indio_dev: iio_dev structure for device.
* @data: Full scan.
*/
int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data);
/*
* iio_push_to_buffers_with_timestamp() - push data and timestamp to buffers
* @indio_dev: iio_dev structure for device.
* @data: sample data
* @timestamp: timestamp for the sample data
*
* Pushes data to the IIO device's buffers. If timestamps are enabled for the
* device the function will store the supplied timestamp as the last element in
* the sample data buffer before pushing it to the device buffers. The sample
* data buffer needs to be large enough to hold the additional timestamp
* (usually the buffer should be indio->scan_bytes bytes large).
*
* Returns 0 on success, a negative error code otherwise.
*/
static inline int iio_push_to_buffers_with_timestamp(struct iio_dev *indio_dev,
void *data, int64_t timestamp)
{
if (indio_dev->scan_timestamp) {
size_t ts_offset = indio_dev->scan_bytes / sizeof(int64_t) - 1;
((int64_t *)data)[ts_offset] = timestamp;
}
return iio_push_to_buffers(indio_dev, data);
}
int iio_update_demux(struct iio_dev *indio_dev);
/**
* iio_buffer_register() - register the buffer with IIO core
* @indio_dev: device with the buffer to be registered
* @channels: the channel descriptions used to construct buffer
* @num_channels: the number of channels
**/
int iio_buffer_register(struct iio_dev *indio_dev,
const struct iio_chan_spec *channels,
int num_channels);
/**
* iio_buffer_unregister() - unregister the buffer from IIO core
* @indio_dev: the device with the buffer to be unregistered
**/
void iio_buffer_unregister(struct iio_dev *indio_dev);
/**
* iio_buffer_read_length() - attr func to get number of datums in the buffer
**/
ssize_t iio_buffer_read_length(struct device *dev,
struct device_attribute *attr,
char *buf);
/**
* iio_buffer_write_length() - attr func to set number of datums in the buffer
**/
ssize_t iio_buffer_write_length(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len);
/**
* iio_buffer_store_enable() - attr to turn the buffer on
**/
ssize_t iio_buffer_store_enable(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len);
/**
* iio_buffer_show_enable() - attr to see if the buffer is on
**/
ssize_t iio_buffer_show_enable(struct device *dev,
struct device_attribute *attr,
char *buf);
#define IIO_BUFFER_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \
iio_buffer_read_length, \
iio_buffer_write_length)
#define IIO_BUFFER_ENABLE_ATTR DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, \
iio_buffer_show_enable, \
iio_buffer_store_enable)
bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
const unsigned long *mask);
struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer);
void iio_buffer_put(struct iio_buffer *buffer);
/**
* iio_device_attach_buffer - Attach a buffer to a IIO device
* @indio_dev: The device the buffer should be attached to
* @buffer: The buffer to attach to the device
*
* This function attaches a buffer to a IIO device. The buffer stays attached to
* the device until the device is freed. The function should only be called at
* most once per device.
*/
static inline void iio_device_attach_buffer(struct iio_dev *indio_dev,
struct iio_buffer *buffer)
{
indio_dev->buffer = iio_buffer_get(buffer);
}
#else /* CONFIG_IIO_BUFFER */
static inline int iio_buffer_register(struct iio_dev *indio_dev,
const struct iio_chan_spec *channels,
int num_channels)
{
return 0;
}
static inline void iio_buffer_unregister(struct iio_dev *indio_dev)
{}
static inline void iio_buffer_get(struct iio_buffer *buffer) {}
static inline void iio_buffer_put(struct iio_buffer *buffer) {}
#endif /* CONFIG_IIO_BUFFER */
#endif /* _IIO_BUFFER_GENERIC_H_ */
|
