text: 
  /* The industrial I/O core
   *
   * 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 _INDUSTRIAL_IO_H_
  #define _INDUSTRIAL_IO_H_
  
  #include <linux/device.h>
  #include <linux/cdev.h>
  #include <linux/iio/types.h>
  /* IIO TODO LIST */
  /*
   * Provide means of adjusting timer accuracy.
   * Currently assumes nano seconds.
   */
  
  enum iio_chan_info_enum {
  	IIO_CHAN_INFO_RAW = 0,
  	IIO_CHAN_INFO_PROCESSED,
  	IIO_CHAN_INFO_SCALE,
  	IIO_CHAN_INFO_OFFSET,
  	IIO_CHAN_INFO_CALIBSCALE,
  	IIO_CHAN_INFO_CALIBBIAS,
  	IIO_CHAN_INFO_PEAK,
  	IIO_CHAN_INFO_PEAK_SCALE,
  	IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW,
  	IIO_CHAN_INFO_AVERAGE_RAW,
  	IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY,
  	IIO_CHAN_INFO_SAMP_FREQ,
  	IIO_CHAN_INFO_FREQUENCY,
  	IIO_CHAN_INFO_PHASE,
  	IIO_CHAN_INFO_HARDWAREGAIN,
  	IIO_CHAN_INFO_HYSTERESIS,
  };
  
  #define IIO_CHAN_INFO_SHARED_BIT(type) BIT(type*2)
  #define IIO_CHAN_INFO_SEPARATE_BIT(type) BIT(type*2 + 1)
  #define IIO_CHAN_INFO_BITS(type) (IIO_CHAN_INFO_SHARED_BIT(type) | \
  				    IIO_CHAN_INFO_SEPARATE_BIT(type))
  
  #define IIO_CHAN_INFO_RAW_SEPARATE_BIT			\
  	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_RAW)
  #define IIO_CHAN_INFO_PROCESSED_SEPARATE_BIT			\
  	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_PROCESSED)
  #define IIO_CHAN_INFO_SCALE_SEPARATE_BIT		\
  	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_SCALE)
  #define IIO_CHAN_INFO_SCALE_SHARED_BIT			\
  	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_SCALE)
  #define IIO_CHAN_INFO_OFFSET_SEPARATE_BIT			\
  	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_OFFSET)
  #define IIO_CHAN_INFO_OFFSET_SHARED_BIT			\
  	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_OFFSET)
  #define IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT			\
  	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_CALIBSCALE)
  #define IIO_CHAN_INFO_CALIBSCALE_SHARED_BIT			\
  	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_CALIBSCALE)
  #define IIO_CHAN_INFO_CALIBBIAS_SEPARATE_BIT			\
  	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_CALIBBIAS)
  #define IIO_CHAN_INFO_CALIBBIAS_SHARED_BIT			\
  	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_CALIBBIAS)
  #define IIO_CHAN_INFO_PEAK_SEPARATE_BIT			\
  	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_PEAK)
  #define IIO_CHAN_INFO_PEAK_SHARED_BIT			\
  	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_PEAK)
  #define IIO_CHAN_INFO_PEAKSCALE_SEPARATE_BIT			\
  	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_PEAKSCALE)
  #define IIO_CHAN_INFO_PEAKSCALE_SHARED_BIT			\
  	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_PEAKSCALE)
  #define IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW_SEPARATE_BIT	\
  	IIO_CHAN_INFO_SEPARATE_BIT(				\
  		IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW)
  #define IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW_SHARED_BIT	\
  	IIO_CHAN_INFO_SHARED_BIT(				\
  		IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW)
  #define IIO_CHAN_INFO_AVERAGE_RAW_SEPARATE_BIT			\
  	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_AVERAGE_RAW)
  #define IIO_CHAN_INFO_AVERAGE_RAW_SHARED_BIT			\
  	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_AVERAGE_RAW)
  #define IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY_SHARED_BIT \
  	IIO_CHAN_INFO_SHARED_BIT(			       \
  		IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY)
  #define IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY_SEPARATE_BIT \
  	IIO_CHAN_INFO_SEPARATE_BIT(			       \
  		IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY)
  #define IIO_CHAN_INFO_SAMP_FREQ_SEPARATE_BIT		\
  	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_SAMP_FREQ)
  #define IIO_CHAN_INFO_SAMP_FREQ_SHARED_BIT			\
  	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_SAMP_FREQ)
  #define IIO_CHAN_INFO_FREQUENCY_SEPARATE_BIT			\
  	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_FREQUENCY)
  #define IIO_CHAN_INFO_FREQUENCY_SHARED_BIT			\
  	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_FREQUENCY)
  #define IIO_CHAN_INFO_PHASE_SEPARATE_BIT			\
  	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_PHASE)
  #define IIO_CHAN_INFO_PHASE_SHARED_BIT			\
  	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_PHASE)
  #define IIO_CHAN_INFO_HARDWAREGAIN_SEPARATE_BIT			\
  	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_HARDWAREGAIN)
  #define IIO_CHAN_INFO_HARDWAREGAIN_SHARED_BIT			\
  	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_HARDWAREGAIN)
  #define IIO_CHAN_INFO_HYSTERESIS_SEPARATE_BIT			\
  	IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_HYSTERESIS)
  #define IIO_CHAN_INFO_HYSTERESIS_SHARED_BIT			\
  	IIO_CHAN_INFO_SHARED_BIT(IIO_CHAN_INFO_HYSTERESIS)
  
  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;
  	bool 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)
   * @_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, _e) \
  { \
  	.name = (_name "_available"), \
  	.shared = true, \
  	.read = iio_enum_available_read, \
  	.private = (uintptr_t)(_e), \
  }
  
  /**
   * 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:		Sign:		's' or 'u' to specify signed or unsigned
   *			realbits:	Number of valid bits of data
   *			storage_bits:	Realbits + padding
   *			shift:		Shift right by this before masking out
   *					realbits.
   *			endianness:	little or big endian
   * @info_mask:		What information is to be exported about this channel.
   *			This includes calibbias, scale etc.
   * @event_mask:		What events can this channel produce.
   * @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.
   * @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.
   */
  struct iio_chan_spec {
  	enum iio_chan_type	type;
  	int			channel;
  	int			channel2;
  	unsigned long		address;
  	int			scan_index;
  	struct {
  		char	sign;
  		u8	realbits;
  		u8	storagebits;
  		u8	shift;
  		enum iio_endian endianness;
  	} scan_type;
  	long			info_mask;
  	long			event_mask;
  	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;
  };
  
  
  /**
   * 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 iio_channel_has_info(const struct iio_chan_spec *chan,
  	enum iio_chan_info_enum type)
  {
  	return chan->info_mask & IIO_CHAN_INFO_BITS(type);
  }
  
  #define IIO_ST(si, rb, sb, sh)						\
  	{ .sign = si, .realbits = rb, .storagebits = sb, .shift = sh }
  
  #define IIO_CHAN_SOFT_TIMESTAMP(_si)					\
  	{ .type = IIO_TIMESTAMP, .channel = -1,				\
  			.scan_index = _si, .scan_type = IIO_ST('s', 64, 64, 0) }
  
  /**
   * iio_get_time_ns() - utility function to get a time stamp for events etc
   **/
  static inline s64 iio_get_time_ns(void)
  {
  	struct timespec ts;
  	/*
  	 * calls getnstimeofday.
  	 * If hrtimers then up to ns accurate, if not microsecond.
  	 */
  	ktime_get_real_ts(&ts);
  
  	return timespec_to_ns(&ts);
  }
  
  /* Device operating modes */
  #define INDIO_DIRECT_MODE		0x01
  #define INDIO_BUFFER_TRIGGERED		0x02
  #define INDIO_BUFFER_HARDWARE		0x08
  
  #define INDIO_ALL_BUFFER_MODES					\
  	(INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE)
  
  struct iio_trigger; /* forward declaration */
  struct iio_dev;
  
  /**
   * struct iio_info - constant information about device
   * @driver_module:	module structure used to ensure correct
   *			ownership of chrdevs etc
   * @event_attrs:	event control attributes
   * @attrs:		general purpose device attributes
   * @read_raw:		function to request a value from the device.
   *			mask specifies which value. Note 0 means a reading of
   *			the channel in question.  Return value will specify the
   *			type of value returned by the device. val and val2 will
   *			contain the elements making up the returned value.
   * @write_raw:		function to write a value to the device.
   *			Parameters are the same as for read_raw.
   * @write_raw_get_fmt:	callback function to query the expected
   *			format/precision. If not set by the driver, write_raw
   *			returns IIO_VAL_INT_PLUS_MICRO.
   * @read_event_config:	find out if the event is enabled.
   * @write_event_config:	set if the event is enabled.
   * @read_event_value:	read a value associated with the event. Meaning
   *			is event dependant. event_code specifies which event.
   * @write_event_value:	write the value associated with the event.
   *			Meaning is event dependent.
   * @validate_trigger:	function to validate the trigger when the
   *			current trigger gets changed.
   * @update_scan_mode:	function to configure device and scan buffer when
   *			channels have changed
   * @debugfs_reg_access:	function to read or write register value of device
   **/
  struct iio_info {
  	struct module			*driver_module;
  	struct attribute_group		*event_attrs;
  	const struct attribute_group	*attrs;
  
  	int (*read_raw)(struct iio_dev *indio_dev,
  			struct iio_chan_spec const *chan,
  			int *val,
  			int *val2,
  			long mask);
  
  	int (*write_raw)(struct iio_dev *indio_dev,
  			 struct iio_chan_spec const *chan,
  			 int val,
  			 int val2,
  			 long mask);
  
  	int (*write_raw_get_fmt)(struct iio_dev *indio_dev,
  			 struct iio_chan_spec const *chan,
  			 long mask);
  
  	int (*read_event_config)(struct iio_dev *indio_dev,
  				 u64 event_code);
  
  	int (*write_event_config)(struct iio_dev *indio_dev,
  				  u64 event_code,
  				  int state);
  
  	int (*read_event_value)(struct iio_dev *indio_dev,
  				u64 event_code,
  				int *val);
  	int (*write_event_value)(struct iio_dev *indio_dev,
  				 u64 event_code,
  				 int val);
  	int (*validate_trigger)(struct iio_dev *indio_dev,
  				struct iio_trigger *trig);
  	int (*update_scan_mode)(struct iio_dev *indio_dev,
  				const unsigned long *scan_mask);
  	int (*debugfs_reg_access)(struct iio_dev *indio_dev,
  				  unsigned reg, unsigned writeval,
  				  unsigned *readval);
  };
  
  /**
   * struct iio_buffer_setup_ops - buffer setup related callbacks
   * @preenable:		[DRIVER] function to run prior to marking buffer enabled
   * @postenable:		[DRIVER] function to run after marking buffer enabled
   * @predisable:		[DRIVER] function to run prior to marking buffer
   *			disabled
   * @postdisable:	[DRIVER] function to run after marking buffer disabled
   * @validate_scan_mask: [DRIVER] function callback to check whether a given
   *			scan mask is valid for the device.
   */
  struct iio_buffer_setup_ops {
  	int (*preenable)(struct iio_dev *);
  	int (*postenable)(struct iio_dev *);
  	int (*predisable)(struct iio_dev *);
  	int (*postdisable)(struct iio_dev *);
  	bool (*validate_scan_mask)(struct iio_dev *indio_dev,
  				   const unsigned long *scan_mask);
  };
  
  /**
   * struct iio_dev - industrial I/O device
   * @id:			[INTERN] used to identify device internally
   * @modes:		[DRIVER] operating modes supported by device
   * @currentmode:	[DRIVER] current operating mode
   * @dev:		[DRIVER] device structure, should be assigned a parent
   *			and owner
   * @event_interface:	[INTERN] event chrdevs associated with interrupt lines
   * @buffer:		[DRIVER] any buffer present
   * @scan_bytes:		[INTERN] num bytes captured to be fed to buffer demux
   * @mlock:		[INTERN] lock used to prevent simultaneous device state
   *			changes
   * @available_scan_masks: [DRIVER] optional array of allowed bitmasks
   * @masklength:		[INTERN] the length of the mask established from
   *			channels
   * @active_scan_mask:	[INTERN] union of all scan masks requested by buffers
   * @scan_timestamp:	[INTERN] set if any buffers have requested timestamp
   * @scan_index_timestamp:[INTERN] cache of the index to the timestamp
   * @trig:		[INTERN] current device trigger (buffer modes)
   * @pollfunc:		[DRIVER] function run on trigger being received
   * @channels:		[DRIVER] channel specification structure table
   * @num_channels:	[DRIVER] number of channels specified in @channels.
   * @channel_attr_list:	[INTERN] keep track of automatically created channel
   *			attributes
   * @chan_attr_group:	[INTERN] group for all attrs in base directory
   * @name:		[DRIVER] name of the device.
   * @info:		[DRIVER] callbacks and constant info from driver
   * @info_exist_lock:	[INTERN] lock to prevent use during removal
   * @setup_ops:		[DRIVER] callbacks to call before and after buffer
   *			enable/disable
   * @chrdev:		[INTERN] associated character device
   * @groups:		[INTERN] attribute groups
   * @groupcounter:	[INTERN] index of next attribute group
   * @flags:		[INTERN] file ops related flags including busy flag.
   * @debugfs_dentry:	[INTERN] device specific debugfs dentry.
   * @cached_reg_addr:	[INTERN] cached register address for debugfs reads.
   */
  struct iio_dev {
  	int				id;
  
  	int				modes;
  	int				currentmode;
  	struct device			dev;
  
  	struct iio_event_interface	*event_interface;
  
  	struct iio_buffer		*buffer;
  	int				scan_bytes;
  	struct mutex			mlock;
  
  	const unsigned long		*available_scan_masks;
  	unsigned			masklength;
  	const unsigned long		*active_scan_mask;
  	bool				scan_timestamp;
  	unsigned			scan_index_timestamp;
  	struct iio_trigger		*trig;
  	struct iio_poll_func		*pollfunc;
  
  	struct iio_chan_spec const	*channels;
  	int				num_channels;
  
  	struct list_head		channel_attr_list;
  	struct attribute_group		chan_attr_group;
  	const char			*name;
  	const struct iio_info		*info;
  	struct mutex			info_exist_lock;
  	const struct iio_buffer_setup_ops	*setup_ops;
  	struct cdev			chrdev;
  #define IIO_MAX_GROUPS 6
  	const struct attribute_group	*groups[IIO_MAX_GROUPS + 1];
  	int				groupcounter;
  
  	unsigned long			flags;
  #if defined(CONFIG_DEBUG_FS)
  	struct dentry			*debugfs_dentry;
  	unsigned			cached_reg_addr;
  #endif
  };
  
  /**
   * iio_find_channel_from_si() - get channel from its scan index
   * @indio_dev:		device
   * @si:			scan index to match
   */
  const struct iio_chan_spec
  *iio_find_channel_from_si(struct iio_dev *indio_dev, int si);
  
  /**
   * iio_device_register() - register a device with the IIO subsystem
   * @indio_dev:		Device structure filled by the device driver
   **/
  int iio_device_register(struct iio_dev *indio_dev);
  
  /**
   * iio_device_unregister() - unregister a device from the IIO subsystem
   * @indio_dev:		Device structure representing the device.
   **/
  void iio_device_unregister(struct iio_dev *indio_dev);
  
  /**
   * iio_push_event() - try to add event to the list for userspace reading
   * @indio_dev:		IIO device structure
   * @ev_code:		What event
   * @timestamp:		When the event occurred
   **/
  int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp);
  
  extern struct bus_type iio_bus_type;
  
  /**
   * iio_device_put() - reference counted deallocation of struct device
   * @indio_dev: 		IIO device structure containing the device
   **/
  static inline void iio_device_put(struct iio_dev *indio_dev)
  {
  	if (indio_dev)
  		put_device(&indio_dev->dev);
  };
  
  /**
   * dev_to_iio_dev() - Get IIO device struct from a device struct
   * @dev: 		The device embedded in the IIO device
   *
   * Note: The device must be a IIO device, otherwise the result is undefined.
   */
  static inline struct iio_dev *dev_to_iio_dev(struct device *dev)
  {
  	return container_of(dev, struct iio_dev, dev);
  }
  
  /**
   * iio_device_get() - increment reference count for the device
   * @indio_dev: 		IIO device structure
   *
   * Returns: The passed IIO device
   **/
  static inline struct iio_dev *iio_device_get(struct iio_dev *indio_dev)
  {
  	return indio_dev ? dev_to_iio_dev(get_device(&indio_dev->dev)) : NULL;
  }
  
  
  /**
   * iio_device_set_drvdata() - Set device driver data
   * @indio_dev: IIO device structure
   * @data: Driver specific data
   *
   * Allows to attach an arbitrary pointer to an IIO device, which can later be
   * retrieved by iio_device_get_drvdata().
   */
  static inline void iio_device_set_drvdata(struct iio_dev *indio_dev, void *data)
  {
  	dev_set_drvdata(&indio_dev->dev, data);
  }
  
  /**
   * iio_device_get_drvdata() - Get device driver data
   * @indio_dev: IIO device structure
   *
   * Returns the data previously set with iio_device_set_drvdata()
   */
  static inline void *iio_device_get_drvdata(struct iio_dev *indio_dev)
  {
  	return dev_get_drvdata(&indio_dev->dev);
  }
  
  /* Can we make this smaller? */
  #define IIO_ALIGN L1_CACHE_BYTES
  /**
   * iio_device_alloc() - allocate an iio_dev from a driver
   * @sizeof_priv: 	Space to allocate for private structure.
   **/
  struct iio_dev *iio_device_alloc(int sizeof_priv);
  
  static inline void *iio_priv(const struct iio_dev *indio_dev)
  {
  	return (char *)indio_dev + ALIGN(sizeof(struct iio_dev), IIO_ALIGN);
  }
  
  static inline struct iio_dev *iio_priv_to_dev(void *priv)
  {
  	return (struct iio_dev *)((char *)priv -
  				  ALIGN(sizeof(struct iio_dev), IIO_ALIGN));
  }
  
  /**
   * iio_device_free() - free an iio_dev from a driver
   * @indio_dev: 		the iio_dev associated with the device
   **/
  void iio_device_free(struct iio_dev *indio_dev);
  
  /**
   * iio_buffer_enabled() - helper function to test if the buffer is enabled
   * @indio_dev:		IIO device structure for device
   **/
  static inline bool iio_buffer_enabled(struct iio_dev *indio_dev)
  {
  	return indio_dev->currentmode
  		& (INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE);
  };
  
  /**
   * iio_get_debugfs_dentry() - helper function to get the debugfs_dentry
   * @indio_dev:		IIO device structure for device
   **/
  #if defined(CONFIG_DEBUG_FS)
  static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
  {
  	return indio_dev->debugfs_dentry;
  };
  #else
  static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
  {
  	return NULL;
  };
  #endif
  
  /**
   * IIO_DEGREE_TO_RAD() - Convert degree to rad
   * @deg: A value in degree
   *
   * Returns the given value converted from degree to rad
   */
  #define IIO_DEGREE_TO_RAD(deg) (((deg) * 314159ULL + 9000000ULL) / 18000000ULL)
  
  /**
   * IIO_G_TO_M_S_2() - Convert g to meter / second**2
   * @g: A value in g
   *
   * Returns the given value converted from g to meter / second**2
   */
  #define IIO_G_TO_M_S_2(g) ((g) * 980665ULL / 100000ULL)
  
  #endif /* _INDUSTRIAL_IO_H_ */
  