1 /* The industrial I/O core - generic buffer interfaces.
3 * Copyright (c) 2008 Jonathan Cameron
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.
10 #ifndef _IIO_BUFFER_GENERIC_H_
11 #define _IIO_BUFFER_GENERIC_H_
12 #include <linux/sysfs.h>
15 #ifdef CONFIG_IIO_BUFFER
20 * struct iio_buffer_access_funcs - access functions for buffers.
21 * @mark_in_use: reference counting, typically to prevent module removal
22 * @unmark_in_use: reduce reference count when no longer using buffer
23 * @store_to: actually store stuff to the buffer
24 * @read_first_n: try to get a specified number of bytes (must exist)
25 * @mark_param_change: notify buffer that some relevant parameter has changed
26 * Often this means the underlying storage may need to
28 * @request_update: if a parameter change has been marked, update underlying
30 * @get_bytes_per_datum:get current bytes per datum
31 * @set_bytes_per_datum:set number of bytes per datum
32 * @get_length: get number of datums in buffer
33 * @set_length: set number of datums in buffer
34 * @is_enabled: query if buffer is currently being used
35 * @enable: enable the buffer
37 * The purpose of this structure is to make the buffer element
38 * modular as event for a given driver, different usecases may require
39 * different buffer designs (space efficiency vs speed for example).
41 * It is worth noting that a given buffer implementation may only support a
42 * small proportion of these functions. The core code 'should' cope fine with
43 * any of them not existing.
45 struct iio_buffer_access_funcs {
46 void (*mark_in_use)(struct iio_buffer *buffer);
47 void (*unmark_in_use)(struct iio_buffer *buffer);
49 int (*store_to)(struct iio_buffer *buffer, u8 *data, s64 timestamp);
50 int (*read_first_n)(struct iio_buffer *buffer,
54 int (*mark_param_change)(struct iio_buffer *buffer);
55 int (*request_update)(struct iio_buffer *buffer);
57 int (*get_bytes_per_datum)(struct iio_buffer *buffer);
58 int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd);
59 int (*get_length)(struct iio_buffer *buffer);
60 int (*set_length)(struct iio_buffer *buffer, int length);
62 int (*is_enabled)(struct iio_buffer *buffer);
63 int (*enable)(struct iio_buffer *buffer);
67 * struct iio_buffer - general buffer structure
68 * @length: [DEVICE] number of datums in buffer
69 * @bytes_per_datum: [DEVICE] size of individual datum including timestamp
70 * @scan_el_attrs: [DRIVER] control of scan elements if that scan mode
71 * control method is used
72 * @scan_mask: [INTERN] bitmask used in masking scan mode elements
73 * @scan_index_timestamp:[INTERN] cache of the index to the timestamp
74 * @scan_timestamp: [INTERN] does the scan mode include a timestamp
75 * @access: [DRIVER] buffer access functions associated with the
77 * @scan_el_dev_attr_list:[INTERN] list of scan element related attributes.
78 * @scan_el_group: [DRIVER] attribute group for those attributes not
79 * created from the iio_chan_info array.
80 * @pollq: [INTERN] wait queue to allow for polling on the buffer.
81 * @stufftoread: [INTERN] flag to indicate new data.
82 * @demux_list: [INTERN] list of operations required to demux the scan.
83 * @demux_bounce: [INTERN] buffer for doing gather from incoming scan.
88 struct attribute_group *scan_el_attrs;
91 unsigned scan_index_timestamp;
92 const struct iio_buffer_access_funcs *access;
93 struct list_head scan_el_dev_attr_list;
94 struct attribute_group scan_el_group;
95 wait_queue_head_t pollq;
97 const struct attribute_group *attrs;
98 struct list_head demux_list;
99 unsigned char *demux_bounce;
103 * iio_buffer_init() - Initialize the buffer structure
104 * @buffer: buffer to be initialized
106 void iio_buffer_init(struct iio_buffer *buffer);
108 void iio_buffer_deinit(struct iio_buffer *buffer);
111 * __iio_update_buffer() - update common elements of buffers
112 * @buffer: buffer that is the event source
113 * @bytes_per_datum: size of individual datum including timestamp
114 * @length: number of datums in buffer
116 static inline void __iio_update_buffer(struct iio_buffer *buffer,
117 int bytes_per_datum, int length)
119 buffer->bytes_per_datum = bytes_per_datum;
120 buffer->length = length;
123 int iio_scan_mask_query(struct iio_dev *indio_dev,
124 struct iio_buffer *buffer, int bit);
127 * iio_scan_mask_set() - set particular bit in the scan mask
128 * @buffer: the buffer whose scan mask we are interested in
129 * @bit: the bit to be set.
131 int iio_scan_mask_set(struct iio_dev *indio_dev,
132 struct iio_buffer *buffer, int bit);
135 * iio_push_to_buffer() - push to a registered buffer.
136 * @buffer: IIO buffer structure for device
140 int iio_push_to_buffer(struct iio_buffer *buffer, unsigned char *data,
143 int iio_update_demux(struct iio_dev *indio_dev);
146 * iio_buffer_register() - register the buffer with IIO core
147 * @indio_dev: device with the buffer to be registered
149 int iio_buffer_register(struct iio_dev *indio_dev,
150 const struct iio_chan_spec *channels,
154 * iio_buffer_unregister() - unregister the buffer from IIO core
155 * @indio_dev: the device with the buffer to be unregistered
157 void iio_buffer_unregister(struct iio_dev *indio_dev);
160 * iio_buffer_read_length() - attr func to get number of datums in the buffer
162 ssize_t iio_buffer_read_length(struct device *dev,
163 struct device_attribute *attr,
166 * iio_buffer_write_length() - attr func to set number of datums in the buffer
168 ssize_t iio_buffer_write_length(struct device *dev,
169 struct device_attribute *attr,
173 * iio_buffer_store_enable() - attr to turn the buffer on
175 ssize_t iio_buffer_store_enable(struct device *dev,
176 struct device_attribute *attr,
180 * iio_buffer_show_enable() - attr to see if the buffer is on
182 ssize_t iio_buffer_show_enable(struct device *dev,
183 struct device_attribute *attr,
185 #define IIO_BUFFER_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \
186 iio_buffer_read_length, \
187 iio_buffer_write_length)
189 #define IIO_BUFFER_ENABLE_ATTR DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, \
190 iio_buffer_show_enable, \
191 iio_buffer_store_enable)
193 int iio_sw_buffer_preenable(struct iio_dev *indio_dev);
195 #else /* CONFIG_IIO_BUFFER */
197 static inline int iio_buffer_register(struct iio_dev *indio_dev,
198 struct iio_chan_spec *channels,
204 static inline void iio_buffer_unregister(struct iio_dev *indio_dev)
207 #endif /* CONFIG_IIO_BUFFER */
209 #endif /* _IIO_BUFFER_GENERIC_H_ */