IIO device sysfs interface¶

Attributes are sysfs files used to expose chip info and also allowingapplications to set various configuration parameters. For device withindex X, attributes can be found under /sys/bus/iio/iio:deviceX/ directory.Common attributes are:

• name, description of the physical chip.
• dev, shows the major:minor pair associated with/dev/iio:deviceX node.
• sampling_frequency_available, available discrete set of samplingfrequency values for device.
• Available standard attributes for IIO devices are described in theDocumentation/ABI/testing/sysfs-bus-iio file in the Linux kernelsources.

IIO device channels¶

structiio_chan_spec - specification of a single channel

An IIO device channel is a representation of a data channel. An IIO device canhave one or multiple channels. For example:

• a thermometer sensor has one channel representing the temperature measurement.
• a light sensor with two channels indicating the measurements in the visibleand infrared spectrum.
• an accelerometer can have up to 3 channels representing acceleration on X, Yand Z axes.

An IIO channel is described by the structiio_chan_spec.A thermometer driver for the temperature sensor in the example above wouldhave to describe its channel as follows:

static const struct iio_chan_spec temp_channel[] = {     {         .type = IIO_TEMP,         .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),     },};

Channel sysfs attributes exposed to userspace are specified in the form ofbitmasks. Depending on their shared info, attributes can be set in one of thefollowing masks:

• info_mask_separate, attributes will be specific tothis channel
• info_mask_shared_by_type, attributes are shared by all channels of thesame type
• info_mask_shared_by_dir, attributes are shared by all channels of the samedirection
• info_mask_shared_by_all, attributes are shared by all channels

When there are multiple data channels per channel type we have two ways todistinguish between them:

• set.modified field ofiio_chan_spec to 1. Modifiers arespecified using.channel2 field of the sameiio_chan_specstructure and are used to indicate a physically unique characteristic of thechannel such as its direction or spectral response. For example, a lightsensor can have two channels, one for infrared light and one for bothinfrared and visible light.
• set.indexed field ofiio_chan_spec to 1. In this case thechannel is simply another instance with an index specified by the.channelfield.

Here is how we can make use of the channel’s modifiers:

static const struct iio_chan_spec light_channels[] = {        {                .type = IIO_INTENSITY,                .modified = 1,                .channel2 = IIO_MOD_LIGHT_IR,                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),                .info_mask_shared = BIT(IIO_CHAN_INFO_SAMP_FREQ),        },        {                .type = IIO_INTENSITY,                .modified = 1,                .channel2 = IIO_MOD_LIGHT_BOTH,                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),                .info_mask_shared = BIT(IIO_CHAN_INFO_SAMP_FREQ),        },        {                .type = IIO_LIGHT,                .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),                .info_mask_shared = BIT(IIO_CHAN_INFO_SAMP_FREQ),        },   }

This channel’s definition will generate two separate sysfs files for raw dataretrieval:

• /sys/bus/iio/iio:deviceX/in_intensity_ir_raw
• /sys/bus/iio/iio:deviceX/in_intensity_both_raw

one file for processed data:

• /sys/bus/iio/iio:deviceX/in_illuminance_input

and one shared sysfs file for sampling frequency:

• /sys/bus/iio/iio:deviceX/sampling_frequency.

Here is how we can make use of the channel’s indexing:

static const struct iio_chan_spec light_channels[] = {        {                .type = IIO_VOLTAGE,                .indexed = 1,                .channel = 0,                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),        },        {                .type = IIO_VOLTAGE,                .indexed = 1,                .channel = 1,                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),        },}

This will generate two separate attributes files for raw data retrieval:

• /sys/bus/iio/devices/iio:deviceX/in_voltage0_raw, representingvoltage measurement for channel 0.
• /sys/bus/iio/devices/iio:deviceX/in_voltage1_raw, representingvoltage measurement for channel 1.

More details¶

structiio_chan_spec_ext_info¶

Extended channel info attribute

Definition

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;};

Members

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.

structiio_enum¶

Enum channel info attribute

Definition

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 *);};

Members

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.

Description

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 tounsigned integer values. The IIO enum helper code takes care of mappingbetween value and string as well as generating a “_available” file whichcontains a list of all available items. The set callback will be called whenthe attribute is updated. The last parameter is the index to the newlyactivated item. The get callback will be used to query the currently activeitem and is supposed to return the index for it.

IIO_ENUM(_name,_shared,_e)¶

Initialize enum extended channel attribute

Parameters

_name

Attribute name

_shared

Whether the attribute is shared between all channels

_e

Pointer to an iio_enum struct

Description

This should usually be used together withIIO_ENUM_AVAILABLE()

IIO_ENUM_AVAILABLE(_name,_e)¶

Initialize enum available extended channel attribute

Parameters

_name

Attribute name (“_available” will be appended to the name)

_e

Pointer to an iio_enum struct

Description

Creates a read only attribute which lists all the available enum items in aspace separated list. This should usually be used together withIIO_ENUM()

structiio_mount_matrix¶

iio mounting matrix

Definition

struct iio_mount_matrix {  const char *rotation[9];};

Members

rotation

3 dimensional space rotation matrix defining sensor alignment withmain hardware

IIO_MOUNT_MATRIX(_shared,_get)¶

Initialize mount matrix extended channel attribute

Parameters

_shared

Whether the attribute is shared between all channels

_get

Pointer to an iio_get_mount_matrix_t accessor

structiio_event_spec¶

specification for a channel event

Definition

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;};

Members

type

Type of the event

dir

Direction of the event

mask_separate

Bit mask of enum iio_event_info values. Attributesset in this mask will be registered per channel.

mask_shared_by_type

Bit mask of enum iio_event_info values. Attributesset in this mask will be shared by channel type.

mask_shared_by_dir

Bit mask of enum iio_event_info values. Attributesset in this mask will be shared by channel type anddirection.

mask_shared_by_all

Bit mask of enum iio_event_info values. Attributesset in this mask will be shared by all channels.

structiio_chan_spec¶

specification of a single channel

Definition

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;    u8 repeat;    enum iio_endian endianness;  } 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;};

Members

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 differentialchannel then this is it. If modified is set then thevalue here specifies the modifier.

address

Driver specific identifier.

scan_index

Monotonic index to give ordering in scans when readfrom a buffer.

scan_type

struct describing the scan type

scan_type.sign

‘s’ or ‘u’ to specify signed or unsigned

scan_type.realbits

Number of valid bits of data

scan_type.storagebits

Realbits + padding

scan_type.shift

Shift right by this before masking outrealbits.

scan_type.repeat

Number of times real/storage bits repeats.When the repeat element is more than 1, thenthe type element in sysfs will show a repeatvalue. Otherwise, the number of repetitionsis omitted.

scan_type.endianness

little or big endian

info_mask_separate

What information is to be exported that is specific tothis channel.

info_mask_separate_available

What availability information is to beexported that is specific to this channel.

info_mask_shared_by_type

What information is to be exported that is sharedby all channels of the same type.

info_mask_shared_by_type_available

What availability information is to beexported that is shared by all channels of the sametype.

info_mask_shared_by_dir

What information is to be exported that is sharedby all channels of the same direction.

info_mask_shared_by_dir_available

What availability information is to beexported that is shared by all channels of the samedirection.

info_mask_shared_by_all

What information is to be exported that is sharedby all channels.

info_mask_shared_by_all_available

What availability information is to beexported that is shared by all channels.

event_spec

Array of events which should be registered for thischannel.

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 shouldhave its name field set to NULL.

extend_name

Allows labeling of channel attributes with aninformative name. Note this has no effect codes etc,unlike modifiers.

datasheet_name

A name used in in-kernel mapping of channels. It shouldcorrespond to the first name that the channel is referredto by in the datasheet (e.g. IND), or the nearestpossible compound name (e.g. IND-INC).

modified

Does a modifier apply to this channel. What these aredepends on the channel type. Modifier is set inchannel2. Examples are IIO_MOD_X for axial sensors aboutthe ‘x’ axis.

indexed

Specify the channel has a numerical index. If not,the channel index number will be suppressed for sysfsattributes but not for event codes.

output

Channel is output.

differential

Channel is differential.

booliio_channel_has_info(const structiio_chan_spec * chan, enum iio_chan_info_enum type)¶

Checks whether a channel supports a info attribute

Parameters

conststructiio_chan_spec*chan

The channel to be queried

enumiio_chan_info_enumtype

Type of the info attribute to be checked

Description

Returns true if the channels supports reporting values for the given infoattribute type, false otherwise.

booliio_channel_has_available(const structiio_chan_spec * chan, enum iio_chan_info_enum type)¶

Checks if a channel has an available attribute

Parameters

conststructiio_chan_spec*chan

The channel to be queried

enumiio_chan_info_enumtype

Type of the available attribute to be checked

Description

Returns true if the channel supports reporting available values for thegiven attribute type, false otherwise.

structiio_info¶

constant information about device

Definition

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 (*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, int 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 (*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);  int (*of_xlate)(struct iio_dev *indio_dev, const struct of_phandle_args *iiospec);  int (*hwfifo_set_watermark)(struct iio_dev *indio_dev, unsigned val);  int (*hwfifo_flush_to_buffer)(struct iio_dev *indio_dev, unsigned count);};

Members

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 ofthe channel in question. Return value will specify thetype of value returned by the device. val and val2 willcontain 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 ofthe channel in question. Return value will specify thetype of value returned by the device. vals pointercontain the elements making up the returned value.max_len specifies maximum number of elementsvals pointer can contain. val_len is used to returnlength of valid elements in vals.

read_avail

function to return the available values from the device.mask specifies which value. Note 0 means the availablevalues for the channel in question. Return valuespecifies if a IIO_AVAIL_LIST or a IIO_AVAIL_RANGE isreturned in vals. The type of the vals are returned intype and the number of vals is returned in length. Forranges, there are always three vals returned; min, stepand 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.

write_raw_get_fmt

callback function to query the expectedformat/precision. If not set by the driver, write_rawreturns 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.

validate_trigger

function to validate the trigger when thecurrent trigger gets changed.

update_scan_mode

function to configure device and scan buffer whenchannels have changed

debugfs_reg_access

function to read or write register value of device

of_xlate

function pointer to obtain channel specifier index.When #iio-cells is greater than ‘0’, the driver couldprovide a custom of_xlate function that reads theargs and returns the appropriate index in registeredIIO channels array.

hwfifo_set_watermark

function pointer to set the current hardwarefifo watermark level; see hwfifo_* entries inDocumentation/ABI/testing/sysfs-bus-iio for details onhow the hardware fifo operates

hwfifo_flush_to_buffer

function pointer to flush the samples storedin the hardware fifo to the device buffer. The drivershould not flush more than count samples. The functionmust return the number of samples flushed, 0 if nosamples were flushed or a negative integer if no sampleswere flushed and there was an error.

structiio_buffer_setup_ops¶

buffer setup related callbacks

Definition

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);};

Members

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 bufferdisabled

postdisable

[DRIVER] function to run after marking buffer disabled

validate_scan_mask

[DRIVER] function callback to check whether a givenscan mask is valid for the device.

structiio_dev¶

industrial I/O device

Definition

struct iio_dev {  int id;  struct module                   *driver_module;  int modes;  int currentmode;  struct device                   dev;  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;  bool trig_readonly;  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;  clockid_t clock_id;  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;  void *priv;};

Members

id

[INTERN] used to identify device internally

driver_module

[INTERN] used to make it harder to undercut users

modes

[DRIVER] operating modes supported by device

currentmode

[DRIVER] current operating mode

dev

[DRIVER] device structure, should be assigned a parentand owner

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 statechanges

available_scan_masks

[DRIVER] optional array of allowed bitmasks

masklength

[INTERN] the length of the mask established fromchannels

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)

trig_readonly

[INTERN] mark the current trigger immutable

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 inchannels.

name

[DRIVER] name of the device.

label

[DRIVER] unique name to identify which device this is

info

[DRIVER] callbacks and constant info from driver

clock_id

[INTERN] timestamping clock posix identifier

info_exist_lock

[INTERN] lock to prevent use during removal

setup_ops

[DRIVER] callbacks to call before and after bufferenable/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.

priv

[DRIVER] reference to driver’s private informationMUST be accessedONLY via iio_priv() helper

iio_device_register(indio_dev)¶

register a device with the IIO subsystem

Parameters

indio_dev

Device structure filled by the device driver

devm_iio_device_register(dev,indio_dev)¶

Resource-managediio_device_register()

Parameters

dev

Device to allocate iio_dev for

indio_dev

Device structure filled by the device driver

Description

Managed iio_device_register. The IIO device registered with thisfunction is automatically unregistered on driver detach. This functioncallsiio_device_register() internally. Refer to that function for moreinformation.

Return

0 on success, negative error number on failure.

voidiio_device_put(structiio_dev * indio_dev)¶

reference counted deallocation of struct device

Parameters

structiio_dev*indio_dev

IIO device structure containing the device

clockid_tiio_device_get_clock(const structiio_dev * indio_dev)¶

Retrieve current timestamping clock for the device

Parameters

conststructiio_dev*indio_dev

IIO device structure containing the device

structiio_dev *dev_to_iio_dev(structdevice * dev)¶

Get IIO device struct from a device struct

Parameters

structdevice*dev

The device embedded in the IIO device

Note

The device must be a IIO device, otherwise the result is undefined.

structiio_dev *iio_device_get(structiio_dev * indio_dev)¶

increment reference count for the device

Parameters

structiio_dev*indio_dev

IIO device structure

Return

The passed IIO device

voidiio_device_set_parent(structiio_dev * indio_dev, structdevice * parent)¶

assign parent device to the IIO device object

Parameters

structiio_dev*indio_dev

IIO device structure

structdevice*parent

reference to parent device object

Description

This utility must be called between IIO device allocation(viadevm_iio_device_alloc()) & IIO device registration(via {devm_}iio_device_register()).By default, the device allocation will also assign a parent device tothe IIO device object. In cases wheredevm_iio_device_alloc() is used,sometimes the parent device must be different than the device used tomanage the allocation.In that case, this helper should be used to change the parent, hence therequirement to call this between allocation & registration.

voidiio_device_set_drvdata(structiio_dev * indio_dev, void * data)¶

Set device driver data

Parameters

structiio_dev*indio_dev

IIO device structure

void*data

Driver specific data

Description

Allows to attach an arbitrary pointer to an IIO device, which can later beretrieved byiio_device_get_drvdata().

void *iio_device_get_drvdata(const structiio_dev * indio_dev)¶

Get device driver data

Parameters

conststructiio_dev*indio_dev

IIO device structure

Description

Returns the data previously set withiio_device_set_drvdata()

booliio_buffer_enabled(structiio_dev * indio_dev)¶

helper function to test if the buffer is enabled

Parameters

structiio_dev*indio_dev

IIO device structure for device

struct dentry *iio_get_debugfs_dentry(structiio_dev * indio_dev)¶

helper function to get the debugfs_dentry

Parameters

structiio_dev*indio_dev

IIO device structure for device

IIO_DEGREE_TO_RAD(deg)¶

Convert degree to rad

Parameters

deg

A value in degree

Description

Returns the given value converted from degree to rad

IIO_RAD_TO_DEGREE(rad)¶

Convert rad to degree

Parameters

rad

A value in rad

Description

Returns the given value converted from rad to degree

IIO_G_TO_M_S_2(g)¶

Convert g to meter / second**2

Parameters

g

A value in g

Description

Returns the given value converted from g to meter / second**2

IIO_M_S_2_TO_G(ms2)¶

Convert meter / second**2 to g

Parameters

ms2

A value in meter / second**2

Description

Returns the given value converted from meter / second**2 to g

struct dentry *iio_get_debugfs_dentry(structiio_dev * indio_dev)

Parameters

structiio_dev*indio_dev

undescribed

Description

iio_get_debugfs_dentry() to make it inline if CONFIG_DEBUG_FS is undefined

intiio_device_set_clock(structiio_dev * indio_dev, clockid_t clock_id)¶

Set current timestamping clock for the device

Parameters

structiio_dev*indio_dev

IIO device structure containing the device

clockid_tclock_id

timestamping clock posix identifier to set.

s64iio_get_time_ns(const structiio_dev * indio_dev)¶

utility function to get a time stamp for events etc

Parameters

conststructiio_dev*indio_dev

device

unsigned intiio_get_time_res(const structiio_dev * indio_dev)¶

utility function to get time stamp clock resolution in nano seconds.

Parameters

conststructiio_dev*indio_dev

device

intiio_read_mount_matrix(structdevice * dev, const char * propname, structiio_mount_matrix * matrix)¶

retrieve iio device mounting matrix from device “mount-matrix” property

Parameters

structdevice*dev

device the mounting matrix property is assigned to

constchar*propname

device specific mounting matrix property name

structiio_mount_matrix*matrix

where to store retrieved matrix

Description

If device is assigned no mounting matrix property, a default 3x3 identitymatrix will be filled in.

Return

0 if success, or a negative error code on failure.

ssize_tiio_format_value(char * buf, unsigned int type, int size, int * vals)¶

Formats a IIO value into its string representation

Parameters

char*buf

The buffer to which the formatted value gets writtenwhich is assumed to be big enough (i.e. PAGE_SIZE).

unsignedinttype

One of the IIO_VAL_* constants. This decides how the valand val2 parameters are formatted.

intsize

Number of IIO value entries contained in vals

int*vals

Pointer to the values, exact meaning depends on thetype parameter.

Return

0 by default, a negative number on failure or the

total number of characters written for a type that belongsto the IIO_VAL_* constant.

intiio_str_to_fixpoint(const char * str, int fract_mult, int * integer, int * fract)¶

Parse a fixed-point number from a string

Parameters

constchar*str

The string to parse

intfract_mult

Multiplier for the first decimal place, should be a power of 10

int*integer

The integer part of the number

int*fract

The fractional part of the number

Description

Returns 0 on success, or a negative error code if the string could not beparsed.

structiio_dev *iio_device_alloc(structdevice * parent, int sizeof_priv)¶

allocate an iio_dev from a driver

Parameters

structdevice*parent

undescribed

intsizeof_priv

Space to allocate for private structure.

voidiio_device_free(structiio_dev * dev)¶

free an iio_dev from a driver

Parameters

structiio_dev*dev

the iio_dev associated with the device

structiio_dev *devm_iio_device_alloc(structdevice * parent, int sizeof_priv)¶

Resource-managediio_device_alloc()

Parameters

structdevice*parent

Device to allocate iio_dev for, and parent for this IIO device

intsizeof_priv

Space to allocate for private structure.

Description

Managed iio_device_alloc. iio_dev allocated with this function isautomatically freed on driver detach.

Return

Pointer to allocated iio_dev on success, NULL on failure.

voidiio_device_unregister(structiio_dev * indio_dev)¶

unregister a device from the IIO subsystem

Parameters

structiio_dev*indio_dev

Device structure representing the device.

intiio_device_claim_direct_mode(structiio_dev * indio_dev)¶

Keep device in direct mode

Parameters

structiio_dev*indio_dev

the iio_dev associated with the device

Description

If the device is in direct mode it is guaranteed to staythat way untiliio_device_release_direct_mode() is called.

Use withiio_device_release_direct_mode()

Return

0 on success, -EBUSY on failure

voidiio_device_release_direct_mode(structiio_dev * indio_dev)¶

releases claim on direct mode

Parameters

structiio_dev*indio_dev

the iio_dev associated with the device

Description

Release the claim. Device is no longer guaranteed to stayin direct mode.

Use withiio_device_claim_direct_mode()