/* * 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. */ #ifndef _IIO_INKERN_CONSUMER_H_ #define _IIO_INKERN_CONSUMER_H_ #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_average_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. * * In opposit to the normal iio_read_channel_raw this function * returns the average of multiple reads. */ int iio_read_channel_average_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); #endif