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/align.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/cleanup.h>
#include <linux/compiler_types.h>
#include <linux/minmax.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;
                };
        };
        unsigned long                   info_mask_separate;
        unsigned long                   info_mask_separate_available;
        unsigned long                   info_mask_shared_by_type;
        unsigned long                   info_mask_shared_by_type_available;
        unsigned long                   info_mask_shared_by_dir;
        unsigned long                   info_mask_shared_by_dir_available;
        unsigned long                   info_mask_shared_by_all;
        unsigned 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 int            modified:1;
        unsigned int            indexed:1;
        unsigned int            output:1;
        unsigned int            differential:1;
        unsigned int            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 iio_channel_has_info(const struct iio_chan_spec *chan,
        enum iio_chan_info_enum type)
{
        return (chan->info_mask_separate & BIT(type)) |
                (chan->info_mask_shared_by_type & BIT(type)) |
                (chan->info_mask_shared_by_dir & BIT(type)) |
                (chan->info_mask_shared_by_all & BIT(type));
}

/**
 * iio_channel_has_available() - Checks if a channel has an available attribute
 * @chan: The channel to be queried
 * @type: Type of the available attribute to be checked
 *
 * Returns true if the channel supports reporting available values for the
 * given attribute type, false otherwise.
 */
static inline bool iio_channel_has_available(const struct iio_chan_spec *chan,
                                             enum iio_chan_info_enum type)
{
        return (chan->info_mask_separate_available & BIT(type)) |
                (chan->info_mask_shared_by_type_available & BIT(type)) |
                (chan->info_mask_shared_by_dir_available & BIT(type)) |
                (chan->info_mask_shared_by_all_available & BIT(type));
}

#define IIO_CHAN_SOFT_TIMESTAMP(_si) {                                  \
        .type = IIO_TIMESTAMP,                                          \
        .channel = -1,                                                  \
        .scan_index = _si,                                              \
        .scan_type = {                                                  \
                .sign = 's',                                            \
                .realbits = 64,                                 \
                .storagebits = 64,                                      \
                },                                                      \
}

s64 iio_get_time_ns(const struct iio_dev *indio_dev);

/*
 * Device operating modes
 * @INDIO_DIRECT_MODE: There is an access to either:
 * a) The last single value available for devices that do not provide
 *    on-demand reads.
 * b) A new value after performing an on-demand read otherwise.
 * On most devices, this is a single-shot read. On some devices with data
 * streams without an 'on-demand' function, this might also be the 'last value'
 * feature. Above all, this mode internally means that we are not in any of the
 * other modes, and sysfs reads should work.
 * Device drivers should inform the core if they support this mode.
 * @INDIO_BUFFER_TRIGGERED: Common mode when dealing with kfifo buffers.
 * It indicates that an explicit trigger is required. This requests the core to
 * attach a poll function when enabling the buffer, which is indicated by the
 * _TRIGGERED suffix.
 * The core will ensure this mode is set when registering a triggered buffer
 * with iio_triggered_buffer_setup().
 * @INDIO_BUFFER_SOFTWARE: Another kfifo buffer mode, but not event triggered.
 * No poll function can be attached because there is no triggered infrastructure
 * we can use to cause capture. There is a kfifo that the driver will fill, but
 * not "only one scan at a time". Typically, hardware will have a buffer that
 * can hold multiple scans. Software may read one or more scans at a single time
 * and push the available data to a Kfifo. This means the core will not attach
 * any poll function when enabling the buffer.
 * The core will ensure this mode is set when registering a simple kfifo buffer
 * with devm_iio_kfifo_buffer_setup().
 * @INDIO_BUFFER_HARDWARE: For specific hardware, if unsure do not use this mode.
 * Same as above but this time the buffer is not a kfifo where we have direct
 * access to the data. Instead, the consumer driver must access the data through
 * non software visible channels (or DMA when there is no demux possible in
 * software)
 * The core will ensure this mode is set when registering a dmaengine buffer
 * with devm_iio_dmaengine_buffer_setup().
 * @INDIO_EVENT_TRIGGERED: Very unusual mode.
 * Triggers usually refer to an external event which will start data capture.
 * Here it is kind of the opposite as, a particular state of the data might
 * produce an event which can be considered as an event. We don't necessarily
 * have access to the data itself, but to the event produced. For example, this
 * can be a threshold detector. The internal path of this mode is very close to
 * the INDIO_BUFFER_TRIGGERED mode.
 * The core will ensure this mode is set when registering a triggered event.
 * @INDIO_HARDWARE_TRIGGERED: Very unusual mode.
 * Here, triggers can result in data capture and can be routed to multiple
 * hardware components, which make them close to regular triggers in the way
 * they must be managed by the core, but without the entire interrupts/poll
 * functions burden. Interrupts are irrelevant as the data flow is hardware
 * mediated and distributed.
 */
#define INDIO_DIRECT_MODE               0x01
#define INDIO_BUFFER_TRIGGERED          0x02
#define INDIO_BUFFER_SOFTWARE           0x04
#define INDIO_BUFFER_HARDWARE           0x08
#define INDIO_EVENT_TRIGGERED           0x10
#define INDIO_HARDWARE_TRIGGERED        0x20

#define INDIO_ALL_BUFFER_MODES                                  \
        (INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE | INDIO_BUFFER_SOFTWARE)

#define INDIO_ALL_TRIGGERED_MODES       \
        (INDIO_BUFFER_TRIGGERED         \
         | INDIO_EVENT_TRIGGERED        \
         | INDIO_HARDWARE_TRIGGERED)

#define INDIO_MAX_RAW_ELEMENTS          4

struct iio_val_int_plus_micro {
        int integer;
        int micro;
};

struct iio_trigger; /* forward declaration */

/**
 * struct iio_info - constant information about device
 * @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.
 * @read_raw_multi:     function to return values 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. vals pointer
 *                      contain the elements making up the returned value.
 *                      max_len specifies maximum number of elements
 *                      vals pointer can contain. val_len is used to return
 *                      length of valid elements in vals.
 * @read_avail:         function to return the available values from the device.
 *                      mask specifies which value. Note 0 means the available
 *                      values for the channel in question.  Return value
 *                      specifies if a IIO_AVAIL_LIST or a IIO_AVAIL_RANGE is
 *                      returned in vals. The type of the vals are returned in
 *                      type and the number of vals is returned in length. For
 *                      ranges, there are always three vals returned; min, step
 *                      and max. For lists, all possible values are enumerated.
 * @write_raw:          function to write a value to the device.
 *                      Parameters are the same as for read_raw.
 * @read_label:         function to request label name for a specified label,
 *                      for better channel identification.
 * @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 configuration value associated with the event.
 * @write_event_value:  write a configuration value for the event.
 * @read_event_label:   function to request label name for a specified label,
 *                      for better event identification.
 * @validate_trigger:   function to validate the trigger when the
 *                      current trigger gets changed.
 * @get_current_scan_type: must be implemented by drivers that use ext_scan_type
 *                      in the channel spec to return the index of the currently
 *                      active ext_scan type for a channel.
 * @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
 * @fwnode_xlate:       fwnode based function pointer to obtain channel specifier index.
 * @hwfifo_set_watermark: function pointer to set the current hardware
 *                      fifo watermark level; see hwfifo_* entries in
 *                      Documentation/ABI/testing/sysfs-bus-iio for details on
 *                      how the hardware fifo operates
 * @hwfifo_flush_to_buffer: function pointer to flush the samples stored
 *                      in the hardware fifo to the device buffer. The driver
 *                      should not flush more than count samples. The function
 *                      must return the number of samples flushed, 0 if no
 *                      samples were flushed or a negative integer if no samples
 *                      were flushed and there was an error.
 **/
struct iio_info {
        const 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 (*read_raw_multi)(struct iio_dev *indio_dev,
                        struct iio_chan_spec const *chan,
                        int max_len,
                        int *vals,
                        int *val_len,
                        long mask);

        int (*read_avail)(struct iio_dev *indio_dev,
                          struct iio_chan_spec const *chan,
                          const int **vals,
                          int *type,
                          int *length,
                          long mask);

        int (*write_raw)(struct iio_dev *indio_dev,
                         struct iio_chan_spec const *chan,
                         int val,
                         int val2,
                         long mask);

        int (*read_label)(struct iio_dev *indio_dev,
                         struct iio_chan_spec const *chan,
                         char *label);

        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,
                                 const struct iio_chan_spec *chan,
                                 enum iio_event_type type,
                                 enum iio_event_direction dir);

        int (*write_event_config)(struct iio_dev *indio_dev,
                                  const struct iio_chan_spec *chan,
                                  enum iio_event_type type,
                                  enum iio_event_direction dir,
                                  bool state);

        int (*read_event_value)(struct iio_dev *indio_dev,
                                const struct iio_chan_spec *chan,
                                enum iio_event_type type,
                                enum iio_event_direction dir,
                                enum iio_event_info info, int *val, int *val2);

        int (*write_event_value)(struct iio_dev *indio_dev,
                                 const struct iio_chan_spec *chan,
                                 enum iio_event_type type,
                                 enum iio_event_direction dir,
                                 enum iio_event_info info, int val, int val2);

        int (*read_event_label)(struct iio_dev *indio_dev,
                                struct iio_chan_spec const *chan,
                                enum iio_event_type type,
                                enum iio_event_direction dir,
                                char *label);

        int (*validate_trigger)(struct iio_dev *indio_dev,
                                struct iio_trigger *trig);
        int (*get_current_scan_type)(const struct iio_dev *indio_dev,
                                     const struct iio_chan_spec *chan);
        int (*update_scan_mode)(struct iio_dev *indio_dev,
                                const unsigned long *scan_mask);
        int (*debugfs_reg_access)(struct iio_dev *indio_dev,
                                  unsigned int reg, unsigned int writeval,
                                  unsigned int *readval);
        int (*fwnode_xlate)(struct iio_dev *indio_dev,
                            const struct fwnode_reference_args *iiospec);
        int (*hwfifo_set_watermark)(struct iio_dev *indio_dev, unsigned int val);
        int (*hwfifo_flush_to_buffer)(struct iio_dev *indio_dev,
                                      unsigned int count);
};

/**
 * 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
 * @modes:              [DRIVER] bitmask listing all the operating modes
 *                      supported by the IIO device. This list should be
 *                      initialized before registering the IIO device. It can
 *                      also be filed up by the IIO core, as a result of
 *                      enabling particular features in the driver
 *                      (see iio_triggered_event_setup()).
 * @dev:                [DRIVER] device structure, should be assigned a parent
 *                      and owner
 * @buffer:             [DRIVER] any buffer present
 * @scan_bytes:         [INTERN] num bytes captured to be fed to buffer demux
 * @available_scan_masks: [DRIVER] optional array of allowed bitmasks. Sort the
 *                         array in order of preference, the most preferred
 *                         masks first.
 * @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
 * @trig:               [INTERN] current device trigger (buffer modes)
 * @pollfunc:           [DRIVER] function run on trigger being received
 * @pollfunc_event:     [DRIVER] function run on events trigger being received
 * @channels:           [DRIVER] channel specification structure table
 * @num_channels:       [DRIVER] number of channels specified in @channels.
 * @name:               [DRIVER] name of the device.
 * @label:              [DRIVER] unique name to identify which device this is
 * @info:               [DRIVER] callbacks and constant info from driver
 * @setup_ops:          [DRIVER] callbacks to call before and after buffer
 *                      enable/disable
 * @priv:               [DRIVER] reference to driver's private information
 *                      **MUST** be accessed **ONLY** via iio_priv() helper
 */
struct iio_dev {
        int                             modes;
        struct device                   dev;

        struct iio_buffer               *buffer;
        int                             scan_bytes;

        const unsigned long             *available_scan_masks;
        unsigned int                    __private masklength;
        const unsigned long             *active_scan_mask;
        bool                            __private scan_timestamp;
        struct iio_trigger              *trig;
        struct iio_poll_func            *pollfunc;
        struct iio_poll_func            *pollfunc_event;

        struct iio_chan_spec const      *channels;
        int                             num_channels;

        const char                      *name;
        const char                      *label;
        const struct iio_info           *info;
        const struct iio_buffer_setup_ops       *setup_ops;

        void                            *__private priv;
};

int iio_device_id(struct iio_dev *indio_dev);
int iio_device_get_current_mode(struct iio_dev *indio_dev);
bool iio_buffer_enabled(struct iio_dev *indio_dev);

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
 **/
#define iio_device_register(indio_dev) \
        __iio_device_register((indio_dev), THIS_MODULE)
int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod);
void iio_device_unregister(struct iio_dev *indio_dev);
/**
 * devm_iio_device_register - Resource-managed iio_device_register()
 * @dev:        Device to allocate iio_dev for
 * @indio_dev:  Device structure filled by the device driver
 *
 * Managed iio_device_register.  The IIO device registered with this
 * function is automatically unregistered on driver detach. This function
 * calls iio_device_register() internally. Refer to that function for more
 * information.
 *
 * RETURNS:
 * 0 on success, negative error number on failure.
 */
#define devm_iio_device_register(dev, indio_dev) \
        __devm_iio_device_register((dev), (indio_dev), THIS_MODULE)
int __devm_iio_device_register(struct device *dev, struct iio_dev *indio_dev,
                               struct module *this_mod);
int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp);

void __iio_dev_mode_lock(struct iio_dev *indio_dev) __acquires(indio_dev);
void __iio_dev_mode_unlock(struct iio_dev *indio_dev) __releases(indio_dev);

/*
 * Helper functions that allow claim and release of direct mode
 * in a fashion that doesn't generate many false positives from sparse.
 * Note this must remain static inline in the header so that sparse
 * can see the __acquires() and __releases() annotations.
 */

/**
 * iio_device_claim_direct() - Keep device in direct mode
 * @indio_dev:  the iio_dev associated with the device
 *
 * If the device is in direct mode it is guaranteed to stay
 * that way until iio_device_release_direct() is called.
 *
 * Use with iio_device_release_direct().
 *
 * Returns: true on success, false on failure.
 */
static inline bool iio_device_claim_direct(struct iio_dev *indio_dev)
{
        __iio_dev_mode_lock(indio_dev);

        if (iio_buffer_enabled(indio_dev)) {
                __iio_dev_mode_unlock(indio_dev);
                return false;
        }

        return true;
}

/**
 * iio_device_release_direct() - Releases claim on direct mode
 * @indio_dev:  the iio_dev associated with the device
 *
 * Release the claim. Device is no longer guaranteed to stay
 * in direct mode.
 *
 * Use with iio_device_claim_direct().
 */
#define iio_device_release_direct(indio_dev) __iio_dev_mode_unlock(indio_dev)

/**
 * iio_device_try_claim_buffer_mode() - Keep device in buffer mode
 * @indio_dev:  the iio_dev associated with the device
 *
 * If the device is in buffer mode it is guaranteed to stay
 * that way until iio_device_release_buffer_mode() is called.
 *
 * Use with iio_device_release_buffer_mode().
 *
 * Returns: true on success, false on failure.
 */
static inline bool iio_device_try_claim_buffer_mode(struct iio_dev *indio_dev)
{
        __iio_dev_mode_lock(indio_dev);

        if (!iio_buffer_enabled(indio_dev)) {
                __iio_dev_mode_unlock(indio_dev);
                return false;
        }

        return true;
}

/**
 * iio_device_release_buffer_mode() - releases claim on buffer mode
 * @indio_dev:  the iio_dev associated with the device
 *
 * Release the claim. Device is no longer guaranteed to stay
 * in buffer mode.
 *
 * Use with iio_device_try_claim_buffer_mode().
 */
#define iio_device_release_buffer_mode(indio_dev) __iio_dev_mode_unlock(indio_dev)

/*
 * These classes are not meant to be used directly by drivers (hence the
 * __priv__ prefix). Instead, documented wrapper macros are provided below to
 * enforce the use of ACQUIRE() or guard() semantics and avoid the problematic
 * scoped guard variants.
 */
DEFINE_GUARD(__priv__iio_dev_mode_lock, struct iio_dev *,
             __iio_dev_mode_lock(_T), __iio_dev_mode_unlock(_T));
DEFINE_GUARD_COND(__priv__iio_dev_mode_lock, _try_direct,
                  iio_device_claim_direct(_T));

/**
 * IIO_DEV_ACQUIRE_DIRECT_MODE() - Tries to acquire the direct mode lock with
 *                                 automatic release
 * @dev: IIO device instance
 * @claim: Variable identifier to store acquire result
 *
 * Tries to acquire the direct mode lock with cleanup ACQUIRE() semantics and
 * automatically releases it at the end of the scope. It most be always paired
 * with IIO_DEV_ACQUIRE_ERR(), for example (notice the scope braces)::
 *
 *      switch() {
 *      case IIO_CHAN_INFO_RAW: {
 *              IIO_DEV_ACQUIRE_DIRECT_MODE(indio_dev, claim);
 *              if (IIO_DEV_ACQUIRE_FAILED(claim))
 *                      return -EBUSY;
 *
 *              ...
 *      }
 *      case IIO_CHAN_INFO_SCALE:
 *              ...
 *      ...
 *      }
 *
 * Context: Can sleep
 */
#define IIO_DEV_ACQUIRE_DIRECT_MODE(dev, claim) \
        ACQUIRE(__priv__iio_dev_mode_lock_try_direct, claim)(dev)

/**
 * IIO_DEV_ACQUIRE_FAILED() - ACQUIRE_ERR() wrapper
 * @claim: The claim variable passed to IIO_DEV_ACQUIRE_*_MODE()
 *
 * Return: true if failed to acquire the mode, otherwise false.
 */
#define IIO_DEV_ACQUIRE_FAILED(claim) \
        ACQUIRE_ERR(__priv__iio_dev_mode_lock_try_direct, &(claim))

/**
 * IIO_DEV_GUARD_CURRENT_MODE() - Acquires the mode lock with automatic release
 * @dev: IIO device instance
 *
 * Acquires the mode lock with cleanup guard() semantics. It is usually paired
 * with iio_buffer_enabled().
 *
 * This should *not* be used to protect internal driver state and it's use in
 * general is *strongly* discouraged. Use any of the IIO_DEV_ACQUIRE_*_MODE()
 * variants.
 *
 * Context: Can sleep
 */
#define IIO_DEV_GUARD_CURRENT_MODE(dev) \
        guard(__priv__iio_dev_mode_lock)(dev)

extern const 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);
}

clockid_t iio_device_get_clock(const struct iio_dev *indio_dev);
int iio_device_set_clock(struct iio_dev *indio_dev, clockid_t clock_id);

/**
 * 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_parent() - assign parent device to the IIO device object
 * @indio_dev:          IIO device structure
 * @parent:             reference to parent device object
 *
 * This utility must be called between IIO device allocation
 * (via devm_iio_device_alloc()) & IIO device registration
 * (via iio_device_register() and devm_iio_device_register())).
 * By default, the device allocation will also assign a parent device to
 * the IIO device object. In cases where devm_iio_device_alloc() is used,
 * sometimes the parent device must be different than the device used to
 * manage the allocation.
 * In that case, this helper should be used to change the parent, hence the
 * requirement to call this between allocation & registration.
 **/
static inline void iio_device_set_parent(struct iio_dev *indio_dev,
                                         struct device *parent)
{
        indio_dev->dev.parent = parent;
}

/**
 * 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(const struct iio_dev *indio_dev)
{
        return dev_get_drvdata(&indio_dev->dev);
}

/*
 * Used to ensure the iio_priv() structure is aligned to allow that structure
 * to in turn include IIO_DMA_MINALIGN'd elements such as buffers which
 * must not share  cachelines with the rest of the structure, thus making
 * them safe for use with non-coherent DMA.
 *
 * A number of drivers also use this on buffers that include a 64-bit timestamp
 * that is used with iio_push_to_buffers_with_ts(). Therefore, in the case where
 * DMA alignment is not sufficient for proper timestamp alignment, we align to
 * 8 bytes instead.
 */
#define IIO_DMA_MINALIGN MAX(ARCH_DMA_MINALIGN, sizeof(s64))

#define __IIO_DECLARE_BUFFER_WITH_TS(type, name, count) \
        type name[ALIGN((count), sizeof(s64) / sizeof(type)) + sizeof(s64) / sizeof(type)]

/**
 * IIO_DECLARE_BUFFER_WITH_TS() - Declare a buffer with timestamp
 * @type: element type of the buffer
 * @name: identifier name of the buffer
 * @count: number of elements in the buffer
 *
 * Declares a buffer that is safe to use with iio_push_to_buffers_with_ts(). In
 * addition to allocating enough space for @count elements of @type, it also
 * allocates space for a s64 timestamp at the end of the buffer and ensures
 * proper alignment of the timestamp.
 */
#define IIO_DECLARE_BUFFER_WITH_TS(type, name, count) \
        __IIO_DECLARE_BUFFER_WITH_TS(type, name, count) __aligned(sizeof(s64))

/**
 * IIO_DECLARE_DMA_BUFFER_WITH_TS() - Declare a DMA-aligned buffer with timestamp
 * @type: element type of the buffer
 * @name: identifier name of the buffer
 * @count: number of elements in the buffer
 *
 * Same as IIO_DECLARE_BUFFER_WITH_TS(), but is uses __aligned(IIO_DMA_MINALIGN)
 * to ensure that the buffer doesn't share cachelines with anything that comes
 * before it in a struct. This should not be used for stack-allocated buffers
 * as stack memory cannot generally be used for DMA.
 */
#define IIO_DECLARE_DMA_BUFFER_WITH_TS(type, name, count) \
        __IIO_DECLARE_BUFFER_WITH_TS(type, name, count) __aligned(IIO_DMA_MINALIGN)

/**
 * IIO_DECLARE_QUATERNION() - Declare a quaternion element
 * @type: element type of the individual vectors
 * @name: identifier name
 *
 * Quaternions are a vector composed of 4 elements (W, X, Y, Z). Use this macro
 * to declare a quaternion element in a struct to ensure proper alignment in
 * an IIO buffer.
 */
#define IIO_DECLARE_QUATERNION(type, name) \
        type name[4] __aligned(sizeof(type) * 4)

struct iio_dev *iio_device_alloc(struct device *parent, int sizeof_priv);

/* The information at the returned address is guaranteed to be cacheline aligned */
static inline void *iio_priv(const struct iio_dev *indio_dev)
{
        return ACCESS_PRIVATE(indio_dev, priv);
}

void iio_device_free(struct iio_dev *indio_dev);
struct iio_dev *devm_iio_device_alloc(struct device *parent, int sizeof_priv);

#define devm_iio_trigger_alloc(parent, fmt, ...) \
        __devm_iio_trigger_alloc((parent), THIS_MODULE, (fmt), ##__VA_ARGS__)
__printf(3, 4)
struct iio_trigger *__devm_iio_trigger_alloc(struct device *parent,
                                             struct module *this_mod,
                                             const char *fmt, ...);
/**
 * iio_get_debugfs_dentry() - helper function to get the debugfs_dentry
 * @indio_dev:          IIO device structure for device
 **/
#if defined(CONFIG_DEBUG_FS)
struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev);
#else
static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
{
        return NULL;
}
#endif

/**
 * iio_device_suspend_triggering() - suspend trigger attached to an iio_dev
 * @indio_dev: iio_dev associated with the device that will have triggers suspended
 *
 * Return 0 if successful, negative otherwise
 **/
int iio_device_suspend_triggering(struct iio_dev *indio_dev);

/**
 * iio_device_resume_triggering() - resume trigger attached to an iio_dev
 *      that was previously suspended with iio_device_suspend_triggering()
 * @indio_dev: iio_dev associated with the device that will have triggers resumed
 *
 * Return 0 if successful, negative otherwise
 **/
int iio_device_resume_triggering(struct iio_dev *indio_dev);

#ifdef CONFIG_ACPI
bool iio_read_acpi_mount_matrix(struct device *dev,
                                struct iio_mount_matrix *orientation,
                                char *acpi_method);
const char *iio_get_acpi_device_name_and_data(struct device *dev, const void **data);
#else
static inline bool iio_read_acpi_mount_matrix(struct device *dev,
                                              struct iio_mount_matrix *orientation,
                                              char *acpi_method)
{
        return false;
}
static inline const char *
iio_get_acpi_device_name_and_data(struct device *dev, const void **data)
{
        return NULL;
}
#endif
static inline const char *iio_get_acpi_device_name(struct device *dev)
{
        return iio_get_acpi_device_name_and_data(dev, NULL);
}

/**
 * iio_get_current_scan_type - Get the current scan type for a channel
 * @indio_dev:  the IIO device to get the scan type for
 * @chan:       the channel to get the scan type for
 *
 * Most devices only have one scan type per channel and can just access it
 * directly without calling this function. Core IIO code and drivers that
 * implement ext_scan_type in the channel spec should use this function to
 * get the current scan type for a channel.
 *
 * Returns: the current scan type for the channel or error.
 */
static inline const struct iio_scan_type
*iio_get_current_scan_type(const struct iio_dev *indio_dev,
                           const struct iio_chan_spec *chan)
{
        int ret;

        if (chan->has_ext_scan_type) {
                ret = indio_dev->info->get_current_scan_type(indio_dev, chan);
                if (ret < 0)
                        return ERR_PTR(ret);

                if (ret >= chan->num_ext_scan_type)
                        return ERR_PTR(-EINVAL);

                return &chan->ext_scan_type[ret];
        }

        return &chan->scan_type;
}

/**
 * iio_get_masklength - Get length of the channels mask
 * @indio_dev: the IIO device to get the masklength for
 */
static inline unsigned int iio_get_masklength(const struct iio_dev *indio_dev)
{
        return ACCESS_PRIVATE(indio_dev, masklength);
}

int iio_active_scan_mask_index(struct iio_dev *indio_dev);

/**
 * iio_for_each_active_channel - Iterated over active channels
 * @indio_dev: the IIO device
 * @chan: Holds the index of the enabled channel
 */
#define iio_for_each_active_channel(indio_dev, chan) \
        for_each_set_bit((chan), (indio_dev)->active_scan_mask, \
                         iio_get_masklength(indio_dev))

ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals);

int iio_str_to_fixpoint(const char *str, int fract_mult, int *integer,
        int *fract);

/**
 * 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_RAD_TO_DEGREE() - Convert rad to degree
 * @rad: A value in rad
 *
 * Returns the given value converted from rad to degree
 */
#define IIO_RAD_TO_DEGREE(rad) \
        (((rad) * 18000000ULL + 314159ULL / 2) / 314159ULL)

/**
 * 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)

/**
 * IIO_M_S_2_TO_G() - Convert meter / second**2 to g
 * @ms2: A value in meter / second**2
 *
 * Returns the given value converted from meter / second**2 to g
 */
#define IIO_M_S_2_TO_G(ms2) (((ms2) * 100000ULL + 980665ULL / 2) / 980665ULL)

#endif /* _INDUSTRIAL_IO_H_ */