path: root/include/linux/iio/iio.h

/* SPDX-License-Identifier: GPL-2.0-only */

/* The industrial I/O core
 *
 * Copyright (c) 2008 Jonathan Cameron
 */
#ifndef _INDUSTRIAL_IO_H_
#define _INDUSTRIAL_IO_H_

#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/cleanup.h>
#include <linux/slab.h>
#include <linux/iio/types.h>
/* IIO TODO LIST */
/*
 * Provide means of adjusting timer accuracy.
 * Currently assumes nano seconds.
 */

struct fwnode_reference_args;

enum iio_shared_by {
	IIO_SEPARATE,
	IIO_SHARED_BY_TYPE,
	IIO_SHARED_BY_DIR,
	IIO_SHARED_BY_ALL
};

enum iio_endian {
	IIO_CPU,
	IIO_BE,
	IIO_LE,
};

struct iio_chan_spec;
struct iio_dev;

/**
 * struct iio_chan_spec_ext_info - Extended channel info attribute
 * @name:	Info attribute name
 * @shared:	Whether this attribute is shared between all channels.
 * @read:	Read callback for this info attribute, may be NULL.
 * @write:	Write callback for this info attribute, may be NULL.
 * @private:	Data private to the driver.
 */
struct iio_chan_spec_ext_info {
	const char *name;
	enum iio_shared_by shared;
	ssize_t (*read)(struct iio_dev *, uintptr_t private,
			struct iio_chan_spec const *, char *buf);
	ssize_t (*write)(struct iio_dev *, uintptr_t private,
			 struct iio_chan_spec const *, const char *buf,
			 size_t len);
	uintptr_t private;
};

/**
 * struct iio_enum - Enum channel info attribute
 * @items:	An array of strings.
 * @num_items:	Length of the item array.
 * @set:	Set callback function, may be NULL.
 * @get:	Get callback function, may be NULL.
 *
 * The iio_enum struct can be used to implement enum style channel attributes.
 * Enum style attributes are those which have a set of strings which map to
 * unsigned integer values. The IIO enum helper code takes care of mapping
 * between value and string as well as generating a "_available" file which
 * contains a list of all available items. The set callback will be called when
 * the attribute is updated. The last parameter is the index to the newly
 * activated item. The get callback will be used to query the currently active
 * item and is supposed to return the index for it.
 */
struct iio_enum {
	const char * const *items;
	unsigned int num_items;
	int (*set)(struct iio_dev *, const struct iio_chan_spec *, unsigned int);
	int (*get)(struct iio_dev *, const struct iio_chan_spec *);
};

ssize_t iio_enum_available_read(struct iio_dev *indio_dev,
	uintptr_t priv, const struct iio_chan_spec *chan, char *buf);
ssize_t iio_enum_read(struct iio_dev *indio_dev,
	uintptr_t priv, const struct iio_chan_spec *chan, char *buf);
ssize_t iio_enum_write(struct iio_dev *indio_dev,
	uintptr_t priv, const struct iio_chan_spec *chan, const char *buf,
	size_t len);

/**
 * IIO_ENUM() - Initialize enum extended channel attribute
 * @_name:	Attribute name
 * @_shared:	Whether the attribute is shared between all channels
 * @_e:		Pointer to an iio_enum struct
 *
 * This should usually be used together with IIO_ENUM_AVAILABLE()
 */
#define IIO_ENUM(_name, _shared, _e) \
{ \
	.name = (_name), \
	.shared = (_shared), \
	.read = iio_enum_read, \
	.write = iio_enum_write, \
	.private = (uintptr_t)(_e), \
}

/**
 * IIO_ENUM_AVAILABLE() - Initialize enum available extended channel attribute
 * @_name:	Attribute name ("_available" will be appended to the name)
 * @_shared:	Whether the attribute is shared between all channels
 * @_e:		Pointer to an iio_enum struct
 *
 * Creates a read only attribute which lists all the available enum items in a
 * space separated list. This should usually be used together with IIO_ENUM()
 */
#define IIO_ENUM_AVAILABLE(_name, _shared, _e) \
{ \
	.name = (_name "_available"), \
	.shared = _shared, \
	.read = iio_enum_available_read, \
	.private = (uintptr_t)(_e), \
}

/**
 * struct iio_mount_matrix - iio mounting matrix
 * @rotation: 3 dimensional space rotation matrix defining sensor alignment with
 *            main hardware
 */
struct iio_mount_matrix {
	const char *rotation[9];
};

ssize_t iio_show_mount_matrix(struct iio_dev *indio_dev, uintptr_t priv,
			      const struct iio_chan_spec *chan, char *buf);
int iio_read_mount_matrix(struct device *dev, struct iio_mount_matrix *matrix);

typedef const struct iio_mount_matrix *
	(iio_get_mount_matrix_t)(const struct iio_dev *indio_dev,
				 const struct iio_chan_spec *chan);

/**
 * IIO_MOUNT_MATRIX() - Initialize mount matrix extended channel attribute
 * @_shared:	Whether the attribute is shared between all channels
 * @_get:	Pointer to an iio_get_mount_matrix_t accessor
 */
#define IIO_MOUNT_MATRIX(_shared, _get) \
{ \
	.name = "mount_matrix", \
	.shared = (_shared), \
	.read = iio_show_mount_matrix, \
	.private = (uintptr_t)(_get), \
}

/**
 * struct iio_event_spec - specification for a channel event
 * @type:		    Type of the event
 * @dir:		    Direction of the event
 * @mask_separate:	    Bit mask of enum iio_event_info values. Attributes
 *			    set in this mask will be registered per channel.
 * @mask_shared_by_type:    Bit mask of enum iio_event_info values. Attributes
 *			    set in this mask will be shared by channel type.
 * @mask_shared_by_dir:	    Bit mask of enum iio_event_info values. Attributes
 *			    set in this mask will be shared by channel type and
 *			    direction.
 * @mask_shared_by_all:	    Bit mask of enum iio_event_info values. Attributes
 *			    set in this mask will be shared by all channels.
 */
struct iio_event_spec {
	enum iio_event_type type;
	enum iio_event_direction dir;
	unsigned long mask_separate;
	unsigned long mask_shared_by_type;
	unsigned long mask_shared_by_dir;
	unsigned long mask_shared_by_all;
};

/**
 * struct iio_scan_type - specification for channel data format in buffer
 * @sign:		's' or 'u' to specify signed or unsigned
 * @realbits:		Number of valid bits of data
 * @storagebits:	Realbits + padding
 * @shift:		Shift right by this before masking out realbits.
 * @repeat:		Number of times real/storage bits repeats. When the
 *			repeat element is more than 1, then the type element in
 *			sysfs will show a repeat value. Otherwise, the number
 *			of repetitions is omitted.
 * @endianness:		little or big endian
 */
struct iio_scan_type {
	char	sign;
	u8	realbits;
	u8	storagebits;
	u8	shift;
	u8	repeat;
	enum iio_endian endianness;
};

/**
 * struct iio_chan_spec - specification of a single channel
 * @type:		What type of measurement is the channel making.
 * @channel:		What number do we wish to assign the channel.
 * @channel2:		If there is a second number for a differential
 *			channel then this is it. If modified is set then the
 *			value here specifies the modifier.
 * @address:		Driver specific identifier.
 * @scan_index:		Monotonic index to give ordering in scans when read
 *			from a buffer.
 * @scan_type:		struct describing the scan type - mutually exclusive
 *			with ext_scan_type.
 * @ext_scan_type:	Used in rare cases where there is more than one scan
 *			format for a channel. When this is used, the flag
 *			has_ext_scan_type must be set and the driver must
 *			implement get_current_scan_type in struct iio_info.
 * @num_ext_scan_type:	Number of elements in ext_scan_type.
 * @info_mask_separate: What information is to be exported that is specific to
 *			this channel.
 * @info_mask_separate_available: What availability information is to be
 *			exported that is specific to this channel.
 * @info_mask_shared_by_type: What information is to be exported that is shared
 *			by all channels of the same type.
 * @info_mask_shared_by_type_available: What availability information is to be
 *			exported that is shared by all channels of the same
 *			type.
 * @info_mask_shared_by_dir: What information is to be exported that is shared
 *			by all channels of the same direction.
 * @info_mask_shared_by_dir_available: What availability information is to be
 *			exported that is shared by all channels of the same
 *			direction.
 * @info_mask_shared_by_all: What information is to be exported that is shared
 *			by all channels.
 * @info_mask_shared_by_all_available: What availability information is to be
 *			exported that is shared by all channels.
 * @event_spec:		Array of events which should be registered for this
 *			channel.
 * @num_event_specs:	Size of the event_spec array.
 * @ext_info:		Array of extended info attributes for this channel.
 *			The array is NULL terminated, the last element should
 *			have its name field set to NULL.
 * @extend_name:	Allows labeling of channel attributes with an
 *			informative name. Note this has no effect codes etc,
 *			unlike modifiers.
 *			This field is deprecated in favour of providing
 *			iio_info->read_label() to override the label, which
 *			unlike @extend_name does not affect sysfs filenames.
 * @datasheet_name:	A name used in in-kernel mapping of channels. It should
 *			correspond to the first name that the channel is referred
 *			to by in the datasheet (e.g. IND), or the nearest
 *			possible compound name (e.g. IND-INC).
 * @modified:		Does a modifier apply to this channel. What these are
 *			depends on the channel type.  Modifier is set in
 *			channel2. Examples are IIO_MOD_X for axial sensors about
 *			the 'x' axis.
 * @indexed:		Specify the channel has a numerical index. If not,
 *			the channel index number will be suppressed for sysfs
 *			attributes but not for event codes.
 * @output:		Channel is output.
 * @differential:	Channel is differential.
 * @has_ext_scan_type:	True if ext_scan_type is used instead of scan_type.
 */
struct iio_chan_spec {
	enum iio_chan_type	type;
	int			channel;
	int			channel2;
	unsigned long		address;
	int			scan_index;
	union {
		struct iio_scan_type scan_type;
		struct {
			const struct iio_scan_type *ext_scan_type;
			unsigned int num_ext_scan_type;
		};
	};
	long			info_mask_separate;
	long			info_mask_separate_available;
	long			info_mask_shared_by_type;
	long			info_mask_shared_by_type_available;
	long			info_mask_shared_by_dir;
	long			info_mask_shared_by_dir_available;
	long			info_mask_shared_by_all;
	long			info_mask_shared_by_all_available;
	const struct iio_event_spec *event_spec;
	unsigned int		num_event_specs;
	const struct iio_chan_spec_ext_info *ext_info;
	const char		*extend_name;
	const char		*datasheet_name;
	unsigned		modified:1;
	unsigned		indexed:1;
	unsigned		output:1;
	unsigned		differential:1;
	unsigned		has_ext_scan_type:1;
};


/**
 * iio_channel_has_info() - Checks whether a channel supports a info attribute
 * @chan: The channel to be queried
 * @type: Type of the info attribute to be checked
 *
 * Returns true if the channels supports reporting values for the given info
 * attribute type, false otherwise.
 */
static inline bool <