1 /* The industrial I/O core - generic ring 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_RING_GENERIC_H_
11 #define _IIO_RING_GENERIC_H_
15 struct iio_ring_buffer
;
19 * iio_push_ring_event() - ring buffer specific push to event chrdev
20 * @ring_buf: ring buffer that is the event source
21 * @event_code: event indentification code
22 * @timestamp: time of event
24 int iio_push_ring_event(struct iio_ring_buffer
*ring_buf
,
28 * iio_push_or_escallate_ring_event() - escalate or add as appropriate
29 * @ring_buf: ring buffer that is the event source
30 * @event_code: event indentification code
31 * @timestamp: time of event
33 * Typical usecase is to escalate a 50% ring full to 75% full if noone has yet
34 * read the first event. Clearly the 50% full is no longer of interest in
37 int iio_push_or_escallate_ring_event(struct iio_ring_buffer
*ring_buf
,
42 * struct iio_ring_access_funcs - access functions for ring buffers.
43 * @mark_in_use: reference counting, typically to prevent module removal
44 * @unmark_in_use: reduce reference count when no longer using ring buffer
45 * @store_to: actually store stuff to the ring buffer
46 * @read_last: get the last element stored
47 * @rip_lots: try to get a specified number of elements (must exist)
48 * @mark_param_change: notify ring that some relevant parameter has changed
49 * Often this means the underlying storage may need to
51 * @request_update: if a parameter change has been marked, update underlying
53 * @get_bpd: get current bytes per datum
54 * @set_bpd: set number of bytes per datum
55 * @get_length: get number of datums in ring
56 * @set_length: set number of datums in ring
57 * @is_enabled: query if ring is currently being used
58 * @enable: enable the ring
60 * The purpose of this structure is to make the ring buffer element
61 * modular as event for a given driver, different usecases may require
62 * different ring designs (space efficiency vs speed for example).
64 * It is worth noting that a given ring implementation may only support a small
65 * proportion of these functions. The core code 'should' cope fine with any of
68 struct iio_ring_access_funcs
{
69 void (*mark_in_use
)(struct iio_ring_buffer
*ring
);
70 void (*unmark_in_use
)(struct iio_ring_buffer
*ring
);
72 int (*store_to
)(struct iio_ring_buffer
*ring
, u8
*data
, s64 timestamp
);
73 int (*read_last
)(struct iio_ring_buffer
*ring
, u8
*data
);
74 int (*rip_lots
)(struct iio_ring_buffer
*ring
,
79 int (*mark_param_change
)(struct iio_ring_buffer
*ring
);
80 int (*request_update
)(struct iio_ring_buffer
*ring
);
82 int (*get_bpd
)(struct iio_ring_buffer
*ring
);
83 int (*set_bpd
)(struct iio_ring_buffer
*ring
, size_t bpd
);
84 int (*get_length
)(struct iio_ring_buffer
*ring
);
85 int (*set_length
)(struct iio_ring_buffer
*ring
, int length
);
87 int (*is_enabled
)(struct iio_ring_buffer
*ring
);
88 int (*enable
)(struct iio_ring_buffer
*ring
);
92 * struct iio_ring_buffer - general ring buffer structure
93 * @dev: ring buffer device struct
94 * @access_dev: system device struct for the chrdev
95 * @indio_dev: industrial I/O device structure
96 * @owner: module that owns the ring buffer (for ref counting)
97 * @id: unique id number
98 * @access_id: device id number
99 * @length: [DEVICE] number of datums in ring
100 * @bpd: [DEVICE] size of individual datum including timestamp
101 * @loopcount: [INTERN] number of times the ring has looped
102 * @access_handler: [INTERN] chrdev access handling
103 * @ev_int: [INTERN] chrdev interface for the event chrdev
104 * @shared_ev_pointer: [INTERN] the shared event pointer to allow escalation of
106 * @access: [DRIVER] ring access functions associated with the
108 * @preenable: [DRIVER] function to run prior to marking ring enabled
109 * @postenable: [DRIVER] function to run after marking ring enabled
110 * @predisable: [DRIVER] function to run prior to marking ring disabled
111 * @postdisable: [DRIVER] function to run after marking ring disabled
113 struct iio_ring_buffer
{
115 struct device access_dev
;
116 struct iio_dev
*indio_dev
;
117 struct module
*owner
;
123 struct iio_handler access_handler
;
124 struct iio_event_interface ev_int
;
125 struct iio_shared_ev_pointer shared_ev_pointer
;
126 struct iio_ring_access_funcs access
;
127 int (*preenable
)(struct iio_dev
*);
128 int (*postenable
)(struct iio_dev
*);
129 int (*predisable
)(struct iio_dev
*);
130 int (*postdisable
)(struct iio_dev
*);
133 void iio_ring_buffer_init(struct iio_ring_buffer
*ring
,
134 struct iio_dev
*dev_info
);
137 * __iio_update_ring_buffer() - update common elements of ring buffers
138 * @ring: ring buffer that is the event source
139 * @bytes_per_datum: size of individual datum including timestamp
140 * @length: number of datums in ring
142 static inline void __iio_update_ring_buffer(struct iio_ring_buffer
*ring
,
143 int bytes_per_datum
, int length
)
145 ring
->bpd
= bytes_per_datum
;
146 ring
->length
= length
;
151 * struct iio_scan_el - an individual element of a scan
152 * @dev_attr: control attribute (if directly controllable)
153 * @number: unique identifier of element (used for bit mask)
154 * @bit_count: number of bits in scan element
155 * @label: useful data for the scan el (often reg address)
156 * @set_state: for some devices datardy signals are generated
157 * for any enabled lines. This allows unwanted lines
158 * to be disabled and hence not get in the way.
161 struct device_attribute dev_attr
;
166 int (*set_state
)(struct iio_scan_el
*scanel
,
167 struct iio_dev
*dev_info
,
171 #define to_iio_scan_el(_dev_attr) \
172 container_of(_dev_attr, struct iio_scan_el, dev_attr);
175 * iio_scan_el_store() - sysfs scan element selection interface
176 * @dev: the target device
177 * @attr: the device attribute that is being processed
178 * @buf: input from userspace
179 * @len: length of input
181 * A generic function used to enable various scan elements. In some
182 * devices explicit read commands for each channel mean this is merely
183 * a software switch. In others this must actively disable the channel.
184 * Complexities occur when this interacts with data ready type triggers
185 * which may not reset unless every channel that is enabled is explicitly
188 ssize_t
iio_scan_el_store(struct device
*dev
, struct device_attribute
*attr
,
189 const char *buf
, size_t len
);
191 * iio_scal_el_show() - sysfs interface to query whether a scan element is
193 * @dev: the target device
194 * @attr: the device attribute that is being processed
195 * @buf: output buffer
197 ssize_t
iio_scan_el_show(struct device
*dev
, struct device_attribute
*attr
,
200 ssize_t
iio_scan_el_ts_store(struct device
*dev
, struct device_attribute
*attr
,
201 const char *buf
, size_t len
);
203 ssize_t
iio_scan_el_ts_show(struct device
*dev
, struct device_attribute
*attr
,
206 * IIO_SCAN_EL_C - declare and initialize a scan element with a control func
208 * @_name: identifying name. Resulting struct is iio_scan_el_##_name,
209 * sysfs element, _name##_en.
210 * @_number: unique id number for the scan element.
211 * @_bits: number of bits in the scan element result (used in mixed bit
213 * @_label: indentification variable used by drivers. Often a reg address.
214 * @_controlfunc: function used to notify hardware of whether state changes
216 #define IIO_SCAN_EL_C(_name, _number, _bits, _label, _controlfunc) \
217 struct iio_scan_el iio_scan_el_##_name = { \
218 .dev_attr = __ATTR(_number##_##_name##_en, \
221 iio_scan_el_store), \
223 .bit_count = _bits, \
225 .set_state = _controlfunc, \
228 #define IIO_SCAN_NAMED_EL_C(_name, _string, _number, _bits, _label, _cf) \
229 struct iio_scan_el iio_scan_el_##_name = { \
230 .dev_attr = __ATTR(_number##_##_string##_en, \
233 iio_scan_el_store), \
235 .bit_count = _bits, \
241 * IIO_SCAN_EL_TIMESTAMP - declare a special scan element for timestamps
243 * Odd one out. Handled slightly differently from other scan elements.
245 #define IIO_SCAN_EL_TIMESTAMP(number) \
246 struct iio_scan_el iio_scan_el_timestamp = { \
247 .dev_attr = __ATTR(number##_timestamp_en, \
249 iio_scan_el_ts_show, \
250 iio_scan_el_ts_store), \
253 static inline void iio_put_ring_buffer(struct iio_ring_buffer
*ring
)
255 put_device(&ring
->dev
);
258 #define to_iio_ring_buffer(d) \
259 container_of(d, struct iio_ring_buffer, dev)
260 #define access_dev_to_iio_ring_buffer(d) \
261 container_of(d, struct iio_ring_buffer, access_dev)
262 int iio_ring_buffer_register(struct iio_ring_buffer
*ring
, int id
);
263 void iio_ring_buffer_unregister(struct iio_ring_buffer
*ring
);
265 ssize_t
iio_read_ring_length(struct device
*dev
,
266 struct device_attribute
*attr
,
268 ssize_t
iio_write_ring_length(struct device
*dev
,
269 struct device_attribute
*attr
,
272 ssize_t
iio_read_ring_bps(struct device
*dev
,
273 struct device_attribute
*attr
,
275 ssize_t
iio_store_ring_enable(struct device
*dev
,
276 struct device_attribute
*attr
,
279 ssize_t
iio_show_ring_enable(struct device
*dev
,
280 struct device_attribute
*attr
,
282 #define IIO_RING_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \
283 iio_read_ring_length, \
284 iio_write_ring_length)
285 #define IIO_RING_BPS_ATTR DEVICE_ATTR(bps, S_IRUGO | S_IWUSR, \
286 iio_read_ring_bps, NULL)
287 #define IIO_RING_ENABLE_ATTR DEVICE_ATTR(ring_enable, S_IRUGO | S_IWUSR, \
288 iio_show_ring_enable, \
289 iio_store_ring_enable)
291 #endif /* _IIO_RING_GENERIC_H_ */