[deliverable/linux.git] / drivers / staging / iio / ring_generic.h

/* The industrial I/O core - generic ring buffer interfaces.
 *
 * Copyright (c) 2008 Jonathan Cameron
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

#ifndef _IIO_RING_GENERIC_H_
#define _IIO_RING_GENERIC_H_
#include "iio.h"

struct iio_handler;
struct iio_ring_buffer;
struct iio_dev;

/**
 * iio_push_ring_event() - ring buffer specific push to event chrdev
 * @ring_buf:		ring buffer that is the event source
 * @event_code:		event indentification code
 * @timestamp:		time of event
 **/
int iio_push_ring_event(struct iio_ring_buffer *ring_buf,
			int event_code,
			s64 timestamp);
/**
 * iio_push_or_escallate_ring_event() -	escalate or add as appropriate
 * @ring_buf:		ring buffer that is the event source
 * @event_code:		event indentification code
 * @timestamp:		time of event
 *
 * Typical usecase is to escalate a 50% ring full to 75% full if noone has yet
 * read the first event. Clearly the 50% full is no longer of interest in
 * typical use case.
 **/
int iio_push_or_escallate_ring_event(struct iio_ring_buffer *ring_buf,
				     int event_code,
				     s64 timestamp);

/**
 * struct iio_ring_access_funcs - access functions for ring buffers.
 * @mark_in_use:	reference counting, typically to prevent module removal
 * @unmark_in_use:	reduce reference count when no longer using ring buffer
 * @store_to:		actually store stuff to the ring buffer
 * @read_last:		get the last element stored
 * @rip_lots:		try to get a specified number of elements (must exist)
 * @mark_param_change:	notify ring that some relevant parameter has changed
 *			Often this means the underlying storage may need to
 *			change.
 * @request_update:	if a parameter change has been marked, update underlying
 *			storage.
 * @get_bpd:		get current bytes per datum
 * @set_bpd:		set number of bytes per datum
 * @get_length:		get number of datums in ring
 * @set_length:		set number of datums in ring
 * @is_enabled:		query if ring is currently being used
 * @enable:		enable the ring
 *
 * The purpose of this structure is to make the ring buffer element
 * modular as event for a given driver, different usecases may require
 * different ring designs (space efficiency vs speed for example).
 *
 * It is worth noting that a given ring implementation may only support a small
 * proportion of these functions.  The core code 'should' cope fine with any of
 * them not existing.
 **/
struct iio_ring_access_funcs {
	void (*mark_in_use)(struct iio_ring_buffer *ring);
	void (*unmark_in_use)(struct iio_ring_buffer *ring);

	int (*store_to)(struct iio_ring_buffer *ring, u8 *data, s64 timestamp);
	int (*read_last)(struct iio_ring_buffer *ring, u8 *data);
	int (*rip_lots)(struct iio_ring_buffer *ring,
			size_t count,
			u8 **data,
			int *dead_offset);

	int (*mark_param_change)(struct iio_ring_buffer *ring);
	int (*request_update)(struct iio_ring_buffer *ring);

	int (*get_bpd)(struct iio_ring_buffer *ring);
	int (*set_bpd)(struct iio_ring_buffer *ring, size_t bpd);
	int (*get_length)(struct iio_ring_buffer *ring);
	int (*set_length)(struct iio_ring_buffer *ring, int length);

	int (*is_enabled)(struct iio_ring_buffer *ring);
	int (*enable)(struct iio_ring_buffer *ring);
};

/**
 * struct iio_ring_buffer - general ring buffer structure
 * @dev:		ring buffer device struct
 * @access_dev:		system device struct for the chrdev
 * @indio_dev:		industrial I/O device structure
 * @owner:		module that owns the ring buffer (for ref counting)
 * @id:			unique id number
 * @access_id:		device id number
 * @length:		[DEVICE] number of datums in ring
 * @bpd:		[DEVICE] size of individual datum including timestamp
 * @loopcount:		[INTERN] number of times the ring has looped
 * @access_handler:	[INTERN] chrdev access handling
 * @ev_int:		[INTERN] chrdev interface for the event chrdev
 * @shared_ev_pointer:	[INTERN] the shared event pointer to allow escalation of
 *			events
 * @access:		[DRIVER] ring access functions associated with the
 *			implementation.
 * @preenable:		[DRIVER] function to run prior to marking ring enabled
 * @postenable:		[DRIVER] function to run after marking ring enabled
 * @predisable:		[DRIVER] function to run prior to marking ring disabled
 * @postdisable:	[DRIVER] function to run after marking ring disabled
  **/
struct iio_ring_buffer {
	struct device dev;
	struct device access_dev;
	struct iio_dev *indio_dev;
	struct module *owner;
	int				id;
	int				access_id;
	int				length;
	int				bpd;
	int				loopcount;
	struct iio_handler		access_handler;
	struct iio_event_interface	ev_int;
	struct iio_shared_ev_pointer	shared_ev_pointer;
	struct iio_ring_access_funcs	access;
	int				(*preenable)(struct iio_dev *);
	int				(*postenable)(struct iio_dev *);
	int				(*predisable)(struct iio_dev *);
	int				(*postdisable)(struct iio_dev *);

};
void iio_ring_buffer_init(struct iio_ring_buffer *ring,
			  struct iio_dev *dev_info);

/**
 * __iio_update_ring_buffer() - update common elements of ring buffers
 * @ring:		ring buffer that is the event source
 * @bytes_per_datum:	size of individual datum including timestamp
 * @length:		number of datums in ring
 **/
static inline void __iio_update_ring_buffer(struct iio_ring_buffer *ring,
					    int bytes_per_datum, int length)
{
	ring->bpd = bytes_per_datum;
	ring->length = length;
	ring->loopcount = 0;
}

/**
 * struct iio_scan_el - an individual element of a scan
 * @dev_attr:		control attribute (if directly controllable)
 * @number:		unique identifier of element (used for bit mask)
 * @bit_count:		number of bits in scan element
 * @label:		useful data for the scan el (often reg address)
 * @set_state:		for some devices datardy signals are generated
 *			for any enabled lines.  This allows unwanted lines
 *			to be disabled and hence not get in the way.
 **/
struct iio_scan_el {
	struct device_attribute		dev_attr;
	unsigned int			number;
	int				bit_count;
	unsigned int			label;

	int (*set_state)(struct iio_scan_el *scanel,
			 struct iio_dev *dev_info,
			 bool state);
};

#define to_iio_scan_el(_dev_attr)				\
	container_of(_dev_attr, struct iio_scan_el, dev_attr);

/**
 * iio_scan_el_store() - sysfs scan element selection interface
 * @dev: the target device
 * @attr: the device attribute that is being processed
 * @buf: input from userspace
 * @len: length of input
 *
 * A generic function used to enable various scan elements.  In some
 * devices explicit read commands for each channel mean this is merely
 * a software switch.  In others this must actively disable the channel.
 * Complexities occur when this interacts with data ready type triggers
 * which may not reset unless every channel that is enabled is explicitly
 * read.
 **/
ssize_t iio_scan_el_store(struct device *dev, struct device_attribute *attr,
			  const char *buf, size_t len);
/**
 * iio_scal_el_show() -	sysfs interface to query whether a scan element is
 *			is enabled or not
 * @dev: the target device
 * @attr: the device attribute that is being processed
 * @buf: output buffer
 **/
ssize_t iio_scan_el_show(struct device *dev, struct device_attribute *attr,
			 char *buf);

ssize_t iio_scan_el_ts_store(struct device *dev, struct device_attribute *attr,
			     const char *buf, size_t len);

ssize_t iio_scan_el_ts_show(struct device *dev, struct device_attribute *attr,
			    char *buf);
/**
 * IIO_SCAN_EL_C - declare and initialize a scan element with a control func
 *
 * @_name:	identifying name. Resulting struct is iio_scan_el_##_name,
 *		sysfs element, _name##_en.
 * @_number:	unique id number for the scan element.
 * @_bits:	number of bits in the scan element result (used in mixed bit
 *		length devices).
 * @_label:	indentification variable used by drivers.  Often a reg address.
 * @_controlfunc: function used to notify hardware of whether state changes
 **/
#define IIO_SCAN_EL_C(_name, _number, _bits, _label, _controlfunc)	\
	struct iio_scan_el iio_scan_el_##_name = {			\
		.dev_attr = __ATTR(_number##_##_name##_en,		\
				   S_IRUGO | S_IWUSR,			\
				   iio_scan_el_show,			\
				   iio_scan_el_store),			\
		.number =  _number,					\
		.bit_count = _bits,					\
		.label = _label,					\
		.set_state = _controlfunc,				\
	}

#define IIO_SCAN_NAMED_EL_C(_name, _string, _number, _bits, _label, _cf) \
	struct iio_scan_el iio_scan_el_##_name = {			\
		.dev_attr = __ATTR(_number##_##_string##_en,		\
				   S_IRUGO | S_IWUSR,			\
				   iio_scan_el_show,			\
				   iio_scan_el_store),			\
		.number =  _number,					\
		.bit_count = _bits,					\
		.label = _label,					\
		.set_state = _cf,					\
	}

/**
 * IIO_SCAN_EL_TIMESTAMP - declare a special scan element for timestamps
 *
 * Odd one out. Handled slightly differently from other scan elements.
 **/
#define IIO_SCAN_EL_TIMESTAMP(number)				\
	struct iio_scan_el iio_scan_el_timestamp = {		\
		.dev_attr = __ATTR(number##_timestamp_en,	\
				   S_IRUGO | S_IWUSR,		\
				   iio_scan_el_ts_show,		\
				   iio_scan_el_ts_store),	\
	}

static inline void iio_put_ring_buffer(struct iio_ring_buffer *ring)
{
	put_device(&ring->dev);
};

#define to_iio_ring_buffer(d)			\
	container_of(d, struct iio_ring_buffer, dev)
#define access_dev_to_iio_ring_buffer(d)			\
	container_of(d, struct iio_ring_buffer, access_dev)
int iio_ring_buffer_register(struct iio_ring_buffer *ring, int id);
void iio_ring_buffer_unregister(struct iio_ring_buffer *ring);

ssize_t iio_read_ring_length(struct device *dev,
			     struct device_attribute *attr,
			     char *buf);
ssize_t iio_write_ring_length(struct device *dev,
			      struct device_attribute *attr,
			      const char *buf,
			      size_t len);
ssize_t iio_read_ring_bps(struct device *dev,
			  struct device_attribute *attr,
			  char *buf);
ssize_t iio_store_ring_enable(struct device *dev,
			      struct device_attribute *attr,
			      const char *buf,
			      size_t len);
ssize_t iio_show_ring_enable(struct device *dev,
			     struct device_attribute *attr,
			     char *buf);
#define IIO_RING_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR,	\
					 iio_read_ring_length,		\
					 iio_write_ring_length)
#define IIO_RING_BPS_ATTR DEVICE_ATTR(bps, S_IRUGO | S_IWUSR,	\
				      iio_read_ring_bps, NULL)
#define IIO_RING_ENABLE_ATTR DEVICE_ATTR(ring_enable, S_IRUGO | S_IWUSR, \
					 iio_show_ring_enable,		\
					 iio_store_ring_enable)

#endif /* _IIO_RING_GENERIC_H_ */
Commit	Line	Data
7026ea4b JC	1	/* The industrial I/O core - generic ring buffer interfaces.
	2	*
	3	* Copyright (c) 2008 Jonathan Cameron
	4	*
	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.
	8	*/
	9
	10	#ifndef _IIO_RING_GENERIC_H_
	11	#define _IIO_RING_GENERIC_H_
	12	#include "iio.h"
	13
	14	struct iio_handler;
	15	struct iio_ring_buffer;
	16	struct iio_dev;
	17
	18	/**
	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
	23	**/
	24	int iio_push_ring_event(struct iio_ring_buffer *ring_buf,
	25	int event_code,
	26	s64 timestamp);
	27	/**
4c572605 RD	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
7026ea4b	32	*
4c572605	33	* Typical usecase is to escalate a 50% ring full to 75% full if noone has yet
7026ea4b JC	34	* read the first event. Clearly the 50% full is no longer of interest in
	35	* typical use case.
	36	**/
	37	int iio_push_or_escallate_ring_event(struct iio_ring_buffer *ring_buf,
	38	int event_code,
	39	s64 timestamp);
	40
	41	/**
	42	* struct iio_ring_access_funcs - access functions for ring buffers.
7026ea4b JC	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
	50	* change.
	51	* @request_update: if a parameter change has been marked, update underlying
	52	* storage.
	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
	59	*
	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
4c572605	62	* different ring designs (space efficiency vs speed for example).
7026ea4b JC	63	*
	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
	66	* them not existing.
	67	**/
	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);
	71
	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,
	75	size_t count,
	76	u8 **data,
	77	int *dead_offset);
	78
	79	int (mark_param_change)(struct iio_ring_buffer ring);
	80	int (request_update)(struct iio_ring_buffer ring);
	81
	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);
	86
	87	int (is_enabled)(struct iio_ring_buffer ring);
	88	int (enable)(struct iio_ring_buffer ring);
	89	};
	90
	91	/**
	92	* struct iio_ring_buffer - general ring buffer structure
4c572605 RD	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
7026ea4b	105	* events
4c572605	106	* @access: [DRIVER] ring access functions associated with the
7026ea4b	107	* implementation.
4c572605 RD	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
7026ea4b JC	112	**/
	113	struct iio_ring_buffer {
	114	struct device dev;
	115	struct device access_dev;
	116	struct iio_dev *indio_dev;
	117	struct module *owner;
	118	int id;
	119	int access_id;
	120	int length;
	121	int bpd;
	122	int loopcount;
	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 );
	131
	132	};
	133	void iio_ring_buffer_init(struct iio_ring_buffer *ring,
	134	struct iio_dev *dev_info);
	135
	136	/**
6f2dfb31	137	* __iio_update_ring_buffer() - update common elements of ring buffers
4c572605 RD	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
7026ea4b	141	**/
6f2dfb31 JC	142	static inline void __iio_update_ring_buffer(struct iio_ring_buffer *ring,
6f2dfb31 JC	143	int bytes_per_datum, int length)
7026ea4b JC	144	{
	145	ring->bpd = bytes_per_datum;
	146	ring->length = length;
	147	ring->loopcount = 0;
7026ea4b JC	148	}
	149
	150	/**
	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.
	159	**/
	160	struct iio_scan_el {
	161	struct device_attribute dev_attr;
	162	unsigned int number;
	163	int bit_count;
	164	unsigned int label;
	165
	166	int (set_state)(struct iio_scan_el scanel,
	167	struct iio_dev *dev_info,
	168	bool state);
	169	};
	170
	171	#define to_iio_scan_el(_dev_attr) \
	172	container_of(_dev_attr, struct iio_scan_el, dev_attr);
	173
	174	/**
4c572605 RD	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
7026ea4b JC	180	*
	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
	186	* read.
	187	**/
	188	ssize_t iio_scan_el_store(struct device dev, struct device_attribute attr,
	189	const char *buf, size_t len);
	190	/**
	191	* iio_scal_el_show() - sysfs interface to query whether a scan element is
4c572605 RD	192	* is enabled or not
	193	* @dev: the target device
	194	* @attr: the device attribute that is being processed
	195	* @buf: output buffer
7026ea4b JC	196	**/
	197	ssize_t iio_scan_el_show(struct device dev, struct device_attribute attr,
	198	char *buf);
7026ea4b JC	199
	200	ssize_t iio_scan_el_ts_store(struct device dev, struct device_attribute attr,
	201	const char *buf, size_t len);
	202
	203	ssize_t iio_scan_el_ts_show(struct device dev, struct device_attribute attr,
	204	char *buf);
	205	/**
4c572605	206	* IIO_SCAN_EL_C - declare and initialize a scan element with a control func
7026ea4b	207	*
4c572605	208	* @_name: identifying name. Resulting struct is iio_scan_el_##_name,
1722762c	209	* sysfs element, _name##_en.
4c572605 RD	210	* @_number: unique id number for the scan element.
	211	* @_bits: number of bits in the scan element result (used in mixed bit
	212	* length devices).
	213	* @_label: indentification variable used by drivers. Often a reg address.
7026ea4b JC	214	* @_controlfunc: function used to notify hardware of whether state changes
	215	**/
	216	#define IIO_SCAN_EL_C(_name, _number, _bits, _label, _controlfunc) \
	217	struct iio_scan_el iio_scan_el_##_name = { \
1722762c	218	.dev_attr = __ATTR(_number##_##_name##_en, \
7026ea4b JC	219	S_IRUGO \| S_IWUSR, \
	220	iio_scan_el_show, \
	221	iio_scan_el_store), \
	222	.number = _number, \
	223	.bit_count = _bits, \
	224	.label = _label, \
	225	.set_state = _controlfunc, \
	226	}
1722762c JC	227
	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, \
	231	S_IRUGO \| S_IWUSR, \
	232	iio_scan_el_show, \
	233	iio_scan_el_store), \
	234	.number = _number, \
	235	.bit_count = _bits, \
	236	.label = _label, \
	237	.set_state = _cf, \
	238	}
	239
7026ea4b	240	/**
4c572605	241	* IIO_SCAN_EL_TIMESTAMP - declare a special scan element for timestamps
7026ea4b JC	242	*
	243	* Odd one out. Handled slightly differently from other scan elements.
	244	**/
f3fb0011	245	#define IIO_SCAN_EL_TIMESTAMP(number) \
7026ea4b	246	struct iio_scan_el iio_scan_el_timestamp = { \
f3fb0011	247	.dev_attr = __ATTR(number##_timestamp_en, \
7026ea4b JC	248	S_IRUGO \| S_IWUSR, \
	249	iio_scan_el_ts_show, \
	250	iio_scan_el_ts_store), \
	251	}
	252
	253	static inline void iio_put_ring_buffer(struct iio_ring_buffer *ring)
	254	{
	255	put_device(&ring->dev);
	256	};
	257
	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)
758d988c	262	int iio_ring_buffer_register(struct iio_ring_buffer *ring, int id);
7026ea4b JC	263	void iio_ring_buffer_unregister(struct iio_ring_buffer *ring);
	264
	265	ssize_t iio_read_ring_length(struct device *dev,
	266	struct device_attribute *attr,
	267	char *buf);
	268	ssize_t iio_write_ring_length(struct device *dev,
	269	struct device_attribute *attr,
	270	const char *buf,
	271	size_t len);
	272	ssize_t iio_read_ring_bps(struct device *dev,
	273	struct device_attribute *attr,
	274	char *buf);
	275	ssize_t iio_store_ring_enable(struct device *dev,
	276	struct device_attribute *attr,
	277	const char *buf,
	278	size_t len);
	279	ssize_t iio_show_ring_enable(struct device *dev,
	280	struct device_attribute *attr,
	281	char *buf);
	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)
	290
	291	#endif /* _IIO_RING_GENERIC_H_ */