blob: 2752b1fd12be3ea8b41c58f64b408d88f1afddaa [file] [log] [blame]
* Industrial I/O in kernel consumer interface
* Copyright (c) 2011 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.
#include <linux/types.h>
#include <linux/iio/types.h>
struct iio_dev;
struct iio_chan_spec;
struct device;
* struct iio_channel - everything needed for a consumer to use a channel
* @indio_dev: Device on which the channel exists.
* @channel: Full description of the channel.
* @data: Data about the channel used by consumer.
struct iio_channel {
struct iio_dev *indio_dev;
const struct iio_chan_spec *channel;
void *data;
* iio_channel_get() - get description of all that is needed to access channel.
* @dev: Pointer to consumer device. Device name must match
* the name of the device as provided in the iio_map
* with which the desired provider to consumer mapping
* was registered.
* @consumer_channel: Unique name to identify the channel on the consumer
* side. This typically describes the channels use within
* the consumer. E.g. 'battery_voltage'
struct iio_channel *iio_channel_get(struct device *dev,
const char *consumer_channel);
* iio_channel_release() - release channels obtained via iio_channel_get
* @chan: The channel to be released.
void iio_channel_release(struct iio_channel *chan);
* iio_channel_get_all() - get all channels associated with a client
* @dev: Pointer to consumer device.
* Returns an array of iio_channel structures terminated with one with
* null iio_dev pointer.
* This function is used by fairly generic consumers to get all the
* channels registered as having this consumer.
struct iio_channel *iio_channel_get_all(struct device *dev);
* iio_channel_release_all() - reverse iio_channel_get_all
* @chan: Array of channels to be released.
void iio_channel_release_all(struct iio_channel *chan);
struct iio_cb_buffer;
* iio_channel_get_all_cb() - register callback for triggered capture
* @dev: Pointer to client device.
* @cb: Callback function.
* @private: Private data passed to callback.
* NB right now we have no ability to mux data from multiple devices.
* So if the channels requested come from different devices this will
* fail.
struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev,
int (*cb)(const void *data,
void *private),
void *private);
* iio_channel_release_all_cb() - release and unregister the callback.
* @cb_buffer: The callback buffer that was allocated.
void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buffer);
* iio_channel_start_all_cb() - start the flow of data through callback.
* @cb_buff: The callback buffer we are starting.
int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff);
* iio_channel_stop_all_cb() - stop the flow of data through the callback.
* @cb_buff: The callback buffer we are stopping.
void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff);
* iio_channel_cb_get_channels() - get access to the underlying channels.
* @cb_buff: The callback buffer from whom we want the channel
* information.
* This function allows one to obtain information about the channels.
* Whilst this may allow direct reading if all buffers are disabled, the
* primary aim is to allow drivers that are consuming a channel to query
* things like scaling of the channel.
struct iio_channel
*iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer);
* iio_read_channel_raw() - read from a given channel
* @chan: The channel being queried.
* @val: Value read back.
* Note raw reads from iio channels are in adc counts and hence
* scale will need to be applied if standard units required.
int iio_read_channel_raw(struct iio_channel *chan,
int *val);
* iio_read_channel_processed() - read processed value from a given channel
* @chan: The channel being queried.
* @val: Value read back.
* Returns an error code or 0.
* This function will read a processed value from a channel. A processed value
* means that this value will have the correct unit and not some device internal
* representation. If the device does not support reporting a processed value
* the function will query the raw value and the channels scale and offset and
* do the appropriate transformation.
int iio_read_channel_processed(struct iio_channel *chan, int *val);
* iio_get_channel_type() - get the type of a channel
* @channel: The channel being queried.
* @type: The type of the channel.
* returns the enum iio_chan_type of the channel
int iio_get_channel_type(struct iio_channel *channel,
enum iio_chan_type *type);
* iio_read_channel_scale() - read the scale value for a channel
* @chan: The channel being queried.
* @val: First part of value read back.
* @val2: Second part of value read back.
* Note returns a description of what is in val and val2, such
* as IIO_VAL_INT_PLUS_MICRO telling us we have a value of val
* + val2/1e6
int iio_read_channel_scale(struct iio_channel *chan, int *val,
int *val2);
* iio_convert_raw_to_processed() - Converts a raw value to a processed value
* @chan: The channel being queried
* @raw: The raw IIO to convert
* @processed: The result of the conversion
* @scale: Scale factor to apply during the conversion
* Returns an error code or 0.
* This function converts a raw value to processed value for a specific channel.
* A raw value is the device internal representation of a sample and the value
* returned by iio_read_channel_raw, so the unit of that value is device
* depended. A processed value on the other hand is value has a normed unit
* according with the IIO specification.
* The scale factor allows to increase the precession of the returned value. For
* a scale factor of 1 the function will return the result in the normal IIO
* unit for the channel type. E.g. millivolt for voltage channels, if you want
* nanovolts instead pass 1000 as the scale factor.
int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
int *processed, unsigned int scale);