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_init_ring_buffer() - initialize 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_init_ring_buffer(struct iio_ring_buffer *ring,
143 int bytes_per_datum, int length)
145 ring->bpd = bytes_per_datum;
146 ring->length = length;
148 ring->shared_ev_pointer.ev_p = 0;
149 ring->shared_ev_pointer.lock =
150 __SPIN_LOCK_UNLOCKED(ring->shared_ev_pointer->loc);
154 * struct iio_scan_el - an individual element of a scan
155 * @dev_attr: control attribute (if directly controllable)
156 * @number: unique identifier of element (used for bit mask)
157 * @bit_count: number of bits in scan element
158 * @label: useful data for the scan el (often reg address)
159 * @set_state: for some devices datardy signals are generated
160 * for any enabled lines. This allows unwanted lines
161 * to be disabled and hence not get in the way.
164 struct device_attribute dev_attr;
169 int (*set_state)(struct iio_scan_el *scanel,
170 struct iio_dev *dev_info,
174 #define to_iio_scan_el(_dev_attr) \
175 container_of(_dev_attr, struct iio_scan_el, dev_attr);
178 * iio_scan_el_store() - sysfs scan element selection interface
179 * @dev: the target device
180 * @attr: the device attribute that is being processed
181 * @buf: input from userspace
182 * @len: length of input
184 * A generic function used to enable various scan elements. In some
185 * devices explicit read commands for each channel mean this is merely
186 * a software switch. In others this must actively disable the channel.
187 * Complexities occur when this interacts with data ready type triggers
188 * which may not reset unless every channel that is enabled is explicitly
191 ssize_t iio_scan_el_store(struct device *dev, struct device_attribute *attr,
192 const char *buf, size_t len);
194 * iio_scal_el_show() - sysfs interface to query whether a scan element is
196 * @dev: the target device
197 * @attr: the device attribute that is being processed
198 * @buf: output buffer
200 ssize_t iio_scan_el_show(struct device *dev, struct device_attribute *attr,
203 * IIO_SCAN_EL - declare and initialize a scan element without control func
204 * @_name: identifying name. Resulting struct is iio_scan_el_##_name,
205 * sysfs element, scan_en_##_name.
206 * @_number: unique id number for the scan element.
207 * @_bits: number of bits in the scan element result (used in mixed bit
209 * @_label: indentification variable used by drivers. Often a reg address.
211 #define IIO_SCAN_EL(_name, _number, _bits, _label) \
212 struct iio_scan_el iio_scan_el_##_name = { \
213 .dev_attr = __ATTR(scan_en_##_name, \
216 iio_scan_el_store), \
217 .mask = (1 << _number), \
218 .bit_count = _bits, \
222 ssize_t iio_scan_el_ts_store(struct device *dev, struct device_attribute *attr,
223 const char *buf, size_t len);
225 ssize_t iio_scan_el_ts_show(struct device *dev, struct device_attribute *attr,
228 * IIO_SCAN_EL_C - declare and initialize a scan element with a control func
230 * @_name: identifying name. Resulting struct is iio_scan_el_##_name,
231 * sysfs element, scan_en_##_name.
232 * @_number: unique id number for the scan element.
233 * @_bits: number of bits in the scan element result (used in mixed bit
235 * @_label: indentification variable used by drivers. Often a reg address.
236 * @_controlfunc: function used to notify hardware of whether state changes
238 #define IIO_SCAN_EL_C(_name, _number, _bits, _label, _controlfunc) \
239 struct iio_scan_el iio_scan_el_##_name = { \
240 .dev_attr = __ATTR(scan_en_##_name, \
243 iio_scan_el_store), \
245 .bit_count = _bits, \
247 .set_state = _controlfunc, \
250 * IIO_SCAN_EL_TIMESTAMP - declare a special scan element for timestamps
252 * Odd one out. Handled slightly differently from other scan elements.
254 #define IIO_SCAN_EL_TIMESTAMP \
255 struct iio_scan_el iio_scan_el_timestamp = { \
256 .dev_attr = __ATTR(scan_en_timestamp, \
258 iio_scan_el_ts_show, \
259 iio_scan_el_ts_store), \
262 static inline void iio_put_ring_buffer(struct iio_ring_buffer *ring)
264 put_device(&ring->dev);
267 #define to_iio_ring_buffer(d) \
268 container_of(d, struct iio_ring_buffer, dev)
269 #define access_dev_to_iio_ring_buffer(d) \
270 container_of(d, struct iio_ring_buffer, access_dev)
271 int iio_ring_buffer_register(struct iio_ring_buffer *ring);
272 void iio_ring_buffer_unregister(struct iio_ring_buffer *ring);
274 ssize_t iio_read_ring_length(struct device *dev,
275 struct device_attribute *attr,
277 ssize_t iio_write_ring_length(struct device *dev,
278 struct device_attribute *attr,
281 ssize_t iio_read_ring_bps(struct device *dev,
282 struct device_attribute *attr,
284 ssize_t iio_store_ring_enable(struct device *dev,
285 struct device_attribute *attr,
288 ssize_t iio_show_ring_enable(struct device *dev,
289 struct device_attribute *attr,
291 #define IIO_RING_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \
292 iio_read_ring_length, \
293 iio_write_ring_length)
294 #define IIO_RING_BPS_ATTR DEVICE_ATTR(bps, S_IRUGO | S_IWUSR, \
295 iio_read_ring_bps, NULL)
296 #define IIO_RING_ENABLE_ATTR DEVICE_ATTR(ring_enable, S_IRUGO | S_IWUSR, \
297 iio_show_ring_enable, \
298 iio_store_ring_enable)
300 #endif /* _IIO_RING_GENERIC_H_ */