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>
14 #include <linux/kref.h>
16 #ifdef CONFIG_IIO_BUFFER
21 * struct iio_buffer_access_funcs - access functions for buffers.
22 * @store_to: actually store stuff to the buffer
23 * @read_first_n: try to get a specified number of bytes (must exist)
24 * @request_update: if a parameter change has been marked, update underlying
26 * @get_bytes_per_datum:get current bytes per datum
27 * @set_bytes_per_datum:set number of bytes per datum
28 * @get_length: get number of datums in buffer
29 * @set_length: set number of datums in buffer
30 * @release: called when the last reference to the buffer is dropped,
31 * should free all resources allocated by the buffer.
33 * The purpose of this structure is to make the buffer element
34 * modular as event for a given driver, different usecases may require
35 * different buffer designs (space efficiency vs speed for example).
37 * It is worth noting that a given buffer implementation may only support a
38 * small proportion of these functions. The core code 'should' cope fine with
39 * any of them not existing.
41 struct iio_buffer_access_funcs
{
42 int (*store_to
)(struct iio_buffer
*buffer
, const void *data
);
43 int (*read_first_n
)(struct iio_buffer
*buffer
,
47 int (*request_update
)(struct iio_buffer
*buffer
);
49 int (*get_bytes_per_datum
)(struct iio_buffer
*buffer
);
50 int (*set_bytes_per_datum
)(struct iio_buffer
*buffer
, size_t bpd
);
51 int (*get_length
)(struct iio_buffer
*buffer
);
52 int (*set_length
)(struct iio_buffer
*buffer
, int length
);
54 void (*release
)(struct iio_buffer
*buffer
);
58 * struct iio_buffer - general buffer structure
59 * @length: [DEVICE] number of datums in buffer
60 * @bytes_per_datum: [DEVICE] size of individual datum including timestamp
61 * @scan_el_attrs: [DRIVER] control of scan elements if that scan mode
62 * control method is used
63 * @scan_mask: [INTERN] bitmask used in masking scan mode elements
64 * @scan_timestamp: [INTERN] does the scan mode include a timestamp
65 * @access: [DRIVER] buffer access functions associated with the
67 * @scan_el_dev_attr_list:[INTERN] list of scan element related attributes.
68 * @scan_el_group: [DRIVER] attribute group for those attributes not
69 * created from the iio_chan_info array.
70 * @pollq: [INTERN] wait queue to allow for polling on the buffer.
71 * @stufftoread: [INTERN] flag to indicate new data.
72 * @demux_list: [INTERN] list of operations required to demux the scan.
73 * @demux_bounce: [INTERN] buffer for doing gather from incoming scan.
74 * @buffer_list: [INTERN] entry in the devices list of current buffers.
75 * @ref: [INTERN] reference count of the buffer.
80 struct attribute_group
*scan_el_attrs
;
83 const struct iio_buffer_access_funcs
*access
;
84 struct list_head scan_el_dev_attr_list
;
85 struct attribute_group scan_el_group
;
86 wait_queue_head_t pollq
;
88 const struct attribute_group
*attrs
;
89 struct list_head demux_list
;
91 struct list_head buffer_list
;
96 * iio_update_buffers() - add or remove buffer from active list
97 * @indio_dev: device to add buffer to
98 * @insert_buffer: buffer to insert
99 * @remove_buffer: buffer_to_remove
101 * Note this will tear down the all buffering and build it up again
103 int iio_update_buffers(struct iio_dev
*indio_dev
,
104 struct iio_buffer
*insert_buffer
,
105 struct iio_buffer
*remove_buffer
);
108 * iio_buffer_init() - Initialize the buffer structure
109 * @buffer: buffer to be initialized
111 void iio_buffer_init(struct iio_buffer
*buffer
);
113 int iio_scan_mask_query(struct iio_dev
*indio_dev
,
114 struct iio_buffer
*buffer
, int bit
);
117 * iio_scan_mask_set() - set particular bit in the scan mask
118 * @indio_dev IIO device structure
119 * @buffer: the buffer whose scan mask we are interested in
120 * @bit: the bit to be set.
122 int iio_scan_mask_set(struct iio_dev
*indio_dev
,
123 struct iio_buffer
*buffer
, int bit
);
126 * iio_push_to_buffers() - push to a registered buffer.
127 * @indio_dev: iio_dev structure for device.
130 int iio_push_to_buffers(struct iio_dev
*indio_dev
, const void *data
);
133 * iio_push_to_buffers_with_timestamp() - push data and timestamp to buffers
134 * @indio_dev: iio_dev structure for device.
136 * @timestamp: timestamp for the sample data
138 * Pushes data to the IIO device's buffers. If timestamps are enabled for the
139 * device the function will store the supplied timestamp as the last element in
140 * the sample data buffer before pushing it to the device buffers. The sample
141 * data buffer needs to be large enough to hold the additional timestamp
142 * (usually the buffer should be indio->scan_bytes bytes large).
144 * Returns 0 on success, a negative error code otherwise.
146 static inline int iio_push_to_buffers_with_timestamp(struct iio_dev
*indio_dev
,
147 void *data
, int64_t timestamp
)
149 if (indio_dev
->scan_timestamp
) {
150 size_t ts_offset
= indio_dev
->scan_bytes
/ sizeof(int64_t) - 1;
151 ((int64_t *)data
)[ts_offset
] = timestamp
;
154 return iio_push_to_buffers(indio_dev
, data
);
157 int iio_update_demux(struct iio_dev
*indio_dev
);
160 * iio_buffer_register() - register the buffer with IIO core
161 * @indio_dev: device with the buffer to be registered
162 * @channels: the channel descriptions used to construct buffer
163 * @num_channels: the number of channels
165 int iio_buffer_register(struct iio_dev
*indio_dev
,
166 const struct iio_chan_spec
*channels
,
170 * iio_buffer_unregister() - unregister the buffer from IIO core
171 * @indio_dev: the device with the buffer to be unregistered
173 void iio_buffer_unregister(struct iio_dev
*indio_dev
);
176 * iio_buffer_read_length() - attr func to get number of datums in the buffer
178 ssize_t
iio_buffer_read_length(struct device
*dev
,
179 struct device_attribute
*attr
,
182 * iio_buffer_write_length() - attr func to set number of datums in the buffer
184 ssize_t
iio_buffer_write_length(struct device
*dev
,
185 struct device_attribute
*attr
,
189 * iio_buffer_store_enable() - attr to turn the buffer on
191 ssize_t
iio_buffer_store_enable(struct device
*dev
,
192 struct device_attribute
*attr
,
196 * iio_buffer_show_enable() - attr to see if the buffer is on
198 ssize_t
iio_buffer_show_enable(struct device
*dev
,
199 struct device_attribute
*attr
,
201 #define IIO_BUFFER_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \
202 iio_buffer_read_length, \
203 iio_buffer_write_length)
205 #define IIO_BUFFER_ENABLE_ATTR DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, \
206 iio_buffer_show_enable, \
207 iio_buffer_store_enable)
209 bool iio_validate_scan_mask_onehot(struct iio_dev
*indio_dev
,
210 const unsigned long *mask
);
212 struct iio_buffer
*iio_buffer_get(struct iio_buffer
*buffer
);
213 void iio_buffer_put(struct iio_buffer
*buffer
);
216 * iio_device_attach_buffer - Attach a buffer to a IIO device
217 * @indio_dev: The device the buffer should be attached to
218 * @buffer: The buffer to attach to the device
220 * This function attaches a buffer to a IIO device. The buffer stays attached to
221 * the device until the device is freed. The function should only be called at
222 * most once per device.
224 static inline void iio_device_attach_buffer(struct iio_dev
*indio_dev
,
225 struct iio_buffer
*buffer
)
227 indio_dev
->buffer
= iio_buffer_get(buffer
);
230 #else /* CONFIG_IIO_BUFFER */
232 static inline int iio_buffer_register(struct iio_dev
*indio_dev
,
233 const struct iio_chan_spec
*channels
,
239 static inline void iio_buffer_unregister(struct iio_dev
*indio_dev
)
242 static inline void iio_buffer_get(struct iio_buffer
*buffer
) {}
243 static inline void iio_buffer_put(struct iio_buffer
*buffer
) {}
245 #endif /* CONFIG_IIO_BUFFER */
247 #endif /* _IIO_BUFFER_GENERIC_H_ */