drivers/staging/iio/trigger.h

/* The industrial I/O core, trigger handling functions
 *
 * 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_TRIGGER_H_
#define _IIO_TRIGGER_H_
#define IIO_TRIGGER_NAME_LENGTH 20
#define IIO_TRIGGER_ID_PREFIX "iio:trigger"
#define IIO_TRIGGER_ID_FORMAT IIO_TRIGGER_ID_PREFIX "%d"


/**
 * struct iio_trigger - industrial I/O trigger device
 *
 * @id:			[INTERN] unique id number
 * @name:		[DRIVER] unique name
 * @dev:		[DRIVER] associated device (if relevant)
 * @private_data:	[DRIVER] device specific data
 * @list:		[INTERN] used in maintenance of global trigger list
 * @alloc_list:		[DRIVER] used for driver specific trigger list
 * @pollfunc_list_lock:	[INTERN] protection of the polling function list
 * @pollfunc_list:	[INTERN] list of functions to run on trigger.
 * @control_attrs:	[DRIVER] sysfs attributes relevant to trigger type
 * @timestamp:		[INTERN] timestamp usesd by some trigs (e.g. datardy)
 * @owner:		[DRIVER] used to monitor usage count of the trigger.
 * @use_count:		use count for the trigger
 * @set_trigger_state:	[DRIVER] switch on/off the trigger on demand
 * @try_reenable:	function to reenable the trigger when the
 *			use count is zero (may be NULL)
 **/
struct iio_trigger {
	int				id;
	const char			*name;
	struct device			dev;

	void				*private_data;
	struct list_head		list;
	struct list_head		alloc_list;
	spinlock_t			pollfunc_list_lock;
	struct list_head		pollfunc_list;
	const struct attribute_group	*control_attrs;
	s64				timestamp;
	struct module			*owner;
	int use_count;

	int (*set_trigger_state)(struct iio_trigger *trig, bool state);
	int (*try_reenable)(struct iio_trigger *trig);
};

static inline struct iio_trigger *to_iio_trigger(struct device *d)
{
	return container_of(d, struct iio_trigger, dev);
};

static inline void iio_put_trigger(struct iio_trigger *trig)
{
	put_device(&trig->dev);
	module_put(trig->owner);
};

static inline void iio_get_trigger(struct iio_trigger *trig)
{
	__module_get(trig->owner);
	get_device(&trig->dev);
};

/**
 * iio_trigger_read_name() - sysfs access function to get the trigger name
 * @dev: the system device
 * @attr: device attributes for the device
 * @buf: output buffer to store the trigger name
 **/
ssize_t iio_trigger_read_name(struct device *dev,
			      struct device_attribute *attr,
			      char *buf);

#define IIO_TRIGGER_NAME_ATTR DEVICE_ATTR(name, S_IRUGO,		\
					  iio_trigger_read_name,	\
					  NULL);

/**
 * iio_trigger_find_by_name() - search global trigger list
 * @name: trigger name to search for
 * @len: trigger name string length to compare
 **/
struct iio_trigger *iio_trigger_find_by_name(const char *name, size_t len);

/**
 * iio_trigger_register() - register a trigger with the IIO core
 * @trig_info:	trigger to be registered
 **/
int iio_trigger_register(struct iio_trigger *trig_info);

/**
 * iio_trigger_unregister() - unregister a trigger from the core
 * @trig_info:	trigger to be unregistered
 **/
void iio_trigger_unregister(struct iio_trigger *trig_info);

/**
 * iio_trigger_attach_poll_func() - add a function pair to be run on trigger
 * @trig:	trigger to which the function pair are being added
 * @pf:		poll function pair
 **/
int iio_trigger_attach_poll_func(struct iio_trigger *trig,
				 struct iio_poll_func *pf);

/**
 * iio_trigger_dettach_poll_func() -	remove function pair from those to be
 *					run on trigger
 * @trig:	trigger from which the function is being removed
 * @pf:		poll function pair
 **/
int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
				  struct iio_poll_func *pf);

/**
 * iio_trigger_poll() - called on a trigger occurring
 * @trig: trigger which occurred
 *
 * Typically called in relevant hardware interrupt handler.
 **/
void iio_trigger_poll(struct iio_trigger *trig);
void iio_trigger_notify_done(struct iio_trigger *trig);

/**
 * struct iio_poll_func - poll function pair
 *
 * @list:			associate this with a triggers pollfunc_list
 * @private_data:		data specific to device (passed into poll func)
 * @poll_func_immediate:	function in here is run first. They should be
 *				extremely lightweight.  Typically used for latch
 *				control on sensor supporting it.
 * @poll_func_main:		function in here is run after all immediates.
 *				Reading from sensor etc typically involves
 *				scheduling from here.
 *
 * The two stage approach used here is only important when multiple sensors are
 * being triggered by a single trigger. This really comes into its own with
 * simultaneous sampling devices where a simple latch command can be used to
 * make the device store the values on all inputs.
 **/
struct iio_poll_func {
	struct				list_head list;
	void				*private_data;
	void (*poll_func_immediate)(struct iio_dev *indio_dev);
	void (*poll_func_main)(struct iio_dev  *private_data);

};

struct iio_trigger *iio_allocate_trigger(void);

void iio_free_trigger(struct iio_trigger *trig);


#endif /* _IIO_TRIGGER_H_ */