[linux-2.6-block.git] / drivers / staging / iio / buffer.h

/* The industrial I/O core - generic 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_BUFFER_GENERIC_H_
#define _IIO_BUFFER_GENERIC_H_
#include <linux/sysfs.h>
#include "iio.h"

#ifdef CONFIG_IIO_BUFFER

struct iio_buffer;

/**
 * struct iio_buffer_access_funcs - access functions for buffers.
 * @store_to:		actually store stuff to the buffer
 * @read_first_n:	try to get a specified number of bytes (must exist)
 * @request_update:	if a parameter change has been marked, update underlying
 *			storage.
 * @get_bytes_per_datum:get current bytes per datum
 * @set_bytes_per_datum:set number of bytes per datum
 * @get_length:		get number of datums in buffer
 * @set_length:		set number of datums in buffer
 *
 * The purpose of this structure is to make the buffer element
 * modular as event for a given driver, different usecases may require
 * different buffer designs (space efficiency vs speed for example).
 *
 * It is worth noting that a given buffer implementation may only support a
 * small proportion of these functions.  The core code 'should' cope fine with
 * any of them not existing.
 **/
struct iio_buffer_access_funcs {
	int (*store_to)(struct iio_buffer *buffer, u8 *data, s64 timestamp);
	int (*read_first_n)(struct iio_buffer *buffer,
			    size_t n,
			    char __user *buf);

	int (*request_update)(struct iio_buffer *buffer);

	int (*get_bytes_per_datum)(struct iio_buffer *buffer);
	int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd);
	int (*get_length)(struct iio_buffer *buffer);
	int (*set_length)(struct iio_buffer *buffer, int length);
};

/**
 * struct iio_buffer - general buffer structure
 * @length:		[DEVICE] number of datums in buffer
 * @bytes_per_datum:	[DEVICE] size of individual datum including timestamp
 * @scan_el_attrs:	[DRIVER] control of scan elements if that scan mode
 *			control method is used
 * @scan_mask:		[INTERN] bitmask used in masking scan mode elements
 * @scan_timestamp:	[INTERN] does the scan mode include a timestamp
 * @access:		[DRIVER] buffer access functions associated with the
 *			implementation.
 * @scan_el_dev_attr_list:[INTERN] list of scan element related attributes.
 * @scan_el_group:	[DRIVER] attribute group for those attributes not
 *			created from the iio_chan_info array.
 * @pollq:		[INTERN] wait queue to allow for polling on the buffer.
 * @stufftoread:	[INTERN] flag to indicate new data.
 * @demux_list:		[INTERN] list of operations required to demux the scan.
 * @demux_bounce:	[INTERN] buffer for doing gather from incoming scan.
 **/
struct iio_buffer {
	int					length;
	int					bytes_per_datum;
	struct attribute_group			*scan_el_attrs;
	long					*scan_mask;
	bool					scan_timestamp;
	const struct iio_buffer_access_funcs	*access;
	struct list_head			scan_el_dev_attr_list;
	struct attribute_group			scan_el_group;
	wait_queue_head_t			pollq;
	bool					stufftoread;
	const struct attribute_group *attrs;
	struct list_head			demux_list;
	unsigned char				*demux_bounce;
};

/**
 * iio_buffer_init() - Initialize the buffer structure
 * @buffer: buffer to be initialized
 **/
void iio_buffer_init(struct iio_buffer *buffer);

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

int iio_scan_mask_query(struct iio_dev *indio_dev,
			struct iio_buffer *buffer, int bit);

/**
 * iio_scan_mask_set() - set particular bit in the scan mask
 * @buffer: the buffer whose scan mask we are interested in
 * @bit: the bit to be set.
 **/
int iio_scan_mask_set(struct iio_dev *indio_dev,
		      struct iio_buffer *buffer, int bit);

/**
 * iio_push_to_buffer() - push to a registered buffer.
 * @buffer:		IIO buffer structure for device
 * @scan:		Full scan.
 * @timestamp:
 */
int iio_push_to_buffer(struct iio_buffer *buffer, unsigned char *data,
		       s64 timestamp);

int iio_update_demux(struct iio_dev *indio_dev);

/**
 * iio_buffer_register() - register the buffer with IIO core
 * @indio_dev: device with the buffer to be registered
 **/
int iio_buffer_register(struct iio_dev *indio_dev,
			const struct iio_chan_spec *channels,
			int num_channels);

/**
 * iio_buffer_unregister() - unregister the buffer from IIO core
 * @indio_dev: the device with the buffer to be unregistered
 **/
void iio_buffer_unregister(struct iio_dev *indio_dev);

/**
 * iio_buffer_read_length() - attr func to get number of datums in the buffer
 **/
ssize_t iio_buffer_read_length(struct device *dev,
			       struct device_attribute *attr,
			       char *buf);
/**
 * iio_buffer_write_length() - attr func to set number of datums in the buffer
 **/
ssize_t iio_buffer_write_length(struct device *dev,
			      struct device_attribute *attr,
			      const char *buf,
			      size_t len);
/**
 * iio_buffer_store_enable() - attr to turn the buffer on
 **/
ssize_t iio_buffer_store_enable(struct device *dev,
				struct device_attribute *attr,
				const char *buf,
				size_t len);
/**
 * iio_buffer_show_enable() - attr to see if the buffer is on
 **/
ssize_t iio_buffer_show_enable(struct device *dev,
			       struct device_attribute *attr,
			       char *buf);
#define IIO_BUFFER_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR,	\
					   iio_buffer_read_length,	\
					   iio_buffer_write_length)

#define IIO_BUFFER_ENABLE_ATTR DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,	\
					   iio_buffer_show_enable,	\
					   iio_buffer_store_enable)

int iio_sw_buffer_preenable(struct iio_dev *indio_dev);

#else /* CONFIG_IIO_BUFFER */

static inline int iio_buffer_register(struct iio_dev *indio_dev,
					   struct iio_chan_spec *channels,
					   int num_channels)
{
	return 0;
}

static inline void iio_buffer_unregister(struct iio_dev *indio_dev)
{};

#endif /* CONFIG_IIO_BUFFER */

#endif /* _IIO_BUFFER_GENERIC_H_ */
Commit	Line	Data
	1	/* The industrial I/O core - generic 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_BUFFER_GENERIC_H_
	11	#define _IIO_BUFFER_GENERIC_H_
	12	#include <linux/sysfs.h>
	13	#include "iio.h"
	14
	15	#ifdef CONFIG_IIO_BUFFER
	16
	17	struct iio_buffer;
	18
	19	/**
	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
	24	* storage.
	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
	29	*
	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).
	33	*
	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.
	37	**/
	38	struct iio_buffer_access_funcs {
	39	int (store_to)(struct iio_buffer buffer, u8 *data, s64 timestamp);
	40	int (read_first_n)(struct iio_buffer buffer,
	41	size_t n,
	42	char __user *buf);
	43
	44	int (request_update)(struct iio_buffer buffer);
	45
	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);
	50	};
	51
	52	/**
	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
	61	* implementation.
	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	**/
	70	struct iio_buffer {
	71	int length;
	72	int bytes_per_datum;
	73	struct attribute_group *scan_el_attrs;
	74	long *scan_mask;
	75	bool scan_timestamp;
	76	const struct iio_buffer_access_funcs *access;
	77	struct list_head scan_el_dev_attr_list;
	78	struct attribute_group scan_el_group;
	79	wait_queue_head_t pollq;
	80	bool stufftoread;
	81	const struct attribute_group *attrs;
	82	struct list_head demux_list;
	83	unsigned char *demux_bounce;
	84	};
	85
	86	/**
	87	* iio_buffer_init() - Initialize the buffer structure
	88	* @buffer: buffer to be initialized
	89	**/
	90	void iio_buffer_init(struct iio_buffer *buffer);
	91
	92	/**
	93	* __iio_update_buffer() - update common elements of buffers
	94	* @buffer: buffer that is the event source
	95	* @bytes_per_datum: size of individual datum including timestamp
	96	* @length: number of datums in buffer
	97	**/
	98	static inline void __iio_update_buffer(struct iio_buffer *buffer,
	99	int bytes_per_datum, int length)
	100	{
	101	buffer->bytes_per_datum = bytes_per_datum;
	102	buffer->length = length;
	103	}
	104
	105	int iio_scan_mask_query(struct iio_dev *indio_dev,
	106	struct iio_buffer *buffer, int bit);
	107
	108	/**
	109	* iio_scan_mask_set() - set particular bit in the scan mask
	110	* @buffer: the buffer whose scan mask we are interested in
	111	* @bit: the bit to be set.
	112	**/
	113	int iio_scan_mask_set(struct iio_dev *indio_dev,
	114	struct iio_buffer *buffer, int bit);
	115
	116	/**
	117	* iio_push_to_buffer() - push to a registered buffer.
	118	* @buffer: IIO buffer structure for device
	119	* @scan: Full scan.
	120	* @timestamp:
	121	*/
	122	int iio_push_to_buffer(struct iio_buffer buffer, unsigned char data,
	123	s64 timestamp);
	124
	125	int iio_update_demux(struct iio_dev *indio_dev);
	126
	127	/**
	128	* iio_buffer_register() - register the buffer with IIO core
	129	* @indio_dev: device with the buffer to be registered
	130	**/
	131	int iio_buffer_register(struct iio_dev *indio_dev,
	132	const struct iio_chan_spec *channels,
	133	int num_channels);
	134
	135	/**
	136	* iio_buffer_unregister() - unregister the buffer from IIO core
	137	* @indio_dev: the device with the buffer to be unregistered
	138	**/
	139	void iio_buffer_unregister(struct iio_dev *indio_dev);
	140
	141	/**
	142	* iio_buffer_read_length() - attr func to get number of datums in the buffer
	143	**/
	144	ssize_t iio_buffer_read_length(struct device *dev,
	145	struct device_attribute *attr,
	146	char *buf);
	147	/**
	148	* iio_buffer_write_length() - attr func to set number of datums in the buffer
	149	**/
	150	ssize_t iio_buffer_write_length(struct device *dev,
	151	struct device_attribute *attr,
	152	const char *buf,
	153	size_t len);
	154	/**
	155	* iio_buffer_store_enable() - attr to turn the buffer on
	156	**/
	157	ssize_t iio_buffer_store_enable(struct device *dev,
	158	struct device_attribute *attr,
	159	const char *buf,
	160	size_t len);
	161	/**
	162	* iio_buffer_show_enable() - attr to see if the buffer is on
	163	**/
	164	ssize_t iio_buffer_show_enable(struct device *dev,
	165	struct device_attribute *attr,
	166	char *buf);
	167	#define IIO_BUFFER_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO \| S_IWUSR, \
	168	iio_buffer_read_length, \
	169	iio_buffer_write_length)
	170
	171	#define IIO_BUFFER_ENABLE_ATTR DEVICE_ATTR(enable, S_IRUGO \| S_IWUSR, \
	172	iio_buffer_show_enable, \
	173	iio_buffer_store_enable)
	174
	175	int iio_sw_buffer_preenable(struct iio_dev *indio_dev);
	176
	177	#else /* CONFIG_IIO_BUFFER */
	178
	179	static inline int iio_buffer_register(struct iio_dev *indio_dev,
	180	struct iio_chan_spec *channels,
	181	int num_channels)
	182	{
	183	return 0;
	184	}
	185
	186	static inline void iio_buffer_unregister(struct iio_dev *indio_dev)
	187	{};
	188
	189	#endif /* CONFIG_IIO_BUFFER */
	190
	191	#endif /* _IIO_BUFFER_GENERIC_H_ */