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>
13 #include <linux/iio/iio.h>
15 #ifdef CONFIG_IIO_BUFFER
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
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
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).
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.
38 struct iio_buffer_access_funcs
{
39 int (*store_to
)(struct iio_buffer
*buffer
, u8
*data
);
40 int (*read_first_n
)(struct iio_buffer
*buffer
,
44 int (*request_update
)(struct iio_buffer
*buffer
);
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
);
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
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.
74 struct attribute_group
*scan_el_attrs
;
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
;
82 const struct attribute_group
*attrs
;
83 struct list_head demux_list
;
84 unsigned char *demux_bounce
;
85 struct list_head buffer_list
;
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
94 * Note this will tear down the all buffering and build it up again
96 int iio_update_buffers(struct iio_dev
*indio_dev
,
97 struct iio_buffer
*insert_buffer
,
98 struct iio_buffer
*remove_buffer
);
101 * iio_buffer_init() - Initialize the buffer structure
102 * @buffer: buffer to be initialized
104 void iio_buffer_init(struct iio_buffer
*buffer
);
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
112 static inline void __iio_update_buffer(struct iio_buffer
*buffer
,
113 int bytes_per_datum
, int length
)
115 buffer
->bytes_per_datum
= bytes_per_datum
;
116 buffer
->length
= length
;
119 int iio_scan_mask_query(struct iio_dev
*indio_dev
,
120 struct iio_buffer
*buffer
, int bit
);
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.
128 int iio_scan_mask_set(struct iio_dev
*indio_dev
,
129 struct iio_buffer
*buffer
, int bit
);
132 * iio_push_to_buffers() - push to a registered buffer.
133 * @indio_dev: iio_dev structure for device.
136 int iio_push_to_buffers(struct iio_dev
*indio_dev
, unsigned char *data
);
138 int iio_update_demux(struct iio_dev
*indio_dev
);
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
146 int iio_buffer_register(struct iio_dev
*indio_dev
,
147 const struct iio_chan_spec
*channels
,
151 * iio_buffer_unregister() - unregister the buffer from IIO core
152 * @indio_dev: the device with the buffer to be unregistered
154 void iio_buffer_unregister(struct iio_dev
*indio_dev
);
157 * iio_buffer_read_length() - attr func to get number of datums in the buffer
159 ssize_t
iio_buffer_read_length(struct device
*dev
,
160 struct device_attribute
*attr
,
163 * iio_buffer_write_length() - attr func to set number of datums in the buffer
165 ssize_t
iio_buffer_write_length(struct device
*dev
,
166 struct device_attribute
*attr
,
170 * iio_buffer_store_enable() - attr to turn the buffer on
172 ssize_t
iio_buffer_store_enable(struct device
*dev
,
173 struct device_attribute
*attr
,
177 * iio_buffer_show_enable() - attr to see if the buffer is on
179 ssize_t
iio_buffer_show_enable(struct device
*dev
,
180 struct device_attribute
*attr
,
182 #define IIO_BUFFER_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \
183 iio_buffer_read_length, \
184 iio_buffer_write_length)
186 #define IIO_BUFFER_ENABLE_ATTR DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, \
187 iio_buffer_show_enable, \
188 iio_buffer_store_enable)
190 int iio_sw_buffer_preenable(struct iio_dev
*indio_dev
);
192 bool iio_validate_scan_mask_onehot(struct iio_dev
*indio_dev
,
193 const unsigned long *mask
);
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_ */