/*
 * 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);

/**
 * devm_iio_channel_get() - Resource managed version of iio_channel_get().
 * @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'
 *
 * Returns a pointer to negative errno if it is not able to get the iio channel
 * otherwise returns valid pointer for iio channel.
 *
 * The allocated iio channel is automatically released when the device is
 * unbound.
 */
struct iio_channel *devm_iio_channel_get(struct device *dev,
                                         const char *consumer_channel);
/**
 * devm_iio_channel_release() - Resource managed version of
 *                              iio_channel_release().
 * @dev:                Pointer to consumer device for which resource
 *                      is allocared.
 * @chan:               The channel to be released.
 */
void devm_iio_channel_release(struct device *dev, 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);

/**
 * devm_iio_channel_get_all() - Resource managed version of
 *                              iio_channel_get_all().
 * @dev: Pointer to consumer device.
 *
 * Returns a pointer to negative errno if it is not able to get the iio channel
 * otherwise 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.
 *
 * The allocated iio channels are automatically released when the device is
 * unbounded.
 */
struct iio_channel *devm_iio_channel_get_all(struct device *dev);

/**
 * devm_iio_channel_release_all() - Resource managed version of
 *                                  iio_channel_release_all().
 * @dev:                Pointer to consumer device for which resource
 *                      is allocared.
 * @chan:               Array channel to be released.
 */
void devm_iio_channel_release_all(struct device *dev, 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_buffer:          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_channel_cb_get_iio_dev() - get access to the underlying device.
 * @cb_buffer:          The callback buffer from whom we want the device
 *                      information.
 *
 * This function allows one to obtain information about the device.
 * The primary aim is to allow drivers that are consuming a device to query
 * things like current trigger.
 */
struct iio_dev
*iio_channel_cb_get_iio_dev(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_write_channel_raw() - write to a given channel
 * @chan:               The channel being queried.
 * @val:                Value being written.
 *
 * Note raw writes to iio channels are in dac counts and hence
 * scale will need to be applied if standard units required.
 */
int iio_write_channel_raw(struct iio_channel *chan, int val);

/**
 * iio_read_max_channel_raw() - read maximum available raw value from a given
 *                              channel, i.e. the maximum possible value.
 * @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 are required.
 */
int iio_read_max_channel_raw(struct iio_channel *chan, int *val);

/**
 * iio_read_avail_channel_raw() - read available raw values from a given channel
 * @chan:               The channel being queried.
 * @vals:               Available values read back.
 * @length:             Number of entries in vals.
 *
 * Returns an error code, IIO_AVAIL_RANGE or IIO_AVAIL_LIST.
 *
 * For ranges, three vals are always returned; min, step and max.
 * For lists, all the possible values are enumerated.
 *
 * Note raw available values from iio channels are in adc counts and
 * hence scale will need to be applied if standard units are required.
 */
int iio_read_avail_channel_raw(struct iio_channel *chan,
                               const int **vals, int *length);

/**
 * 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_offset() - read the offset 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_offset(struct iio_channel *chan, int *val,
                           int *val2);

/**
 * 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 1000000 as the scale factor.
 */
int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
        int *processed, unsigned int scale);

/**
 * iio_get_channel_ext_info_count() - get number of ext_info attributes
 *                                    connected to the channel.
 * @chan:               The channel being queried
 *
 * Returns the number of ext_info attributes
 */
unsigned int iio_get_channel_ext_info_count(struct iio_channel *chan);

/**
 * iio_read_channel_ext_info() - read ext_info attribute from a given channel
 * @chan:               The channel being queried.
 * @attr:               The ext_info attribute to read.
 * @buf:                Where to store the attribute value. Assumed to hold
 *                      at least PAGE_SIZE bytes.
 *
 * Returns the number of bytes written to buf (perhaps w/o zero termination;
 * it need not even be a string), or an error code.
 */
ssize_t iio_read_channel_ext_info(struct iio_channel *chan,
                                  const char *attr, char *buf);

/**
 * iio_write_channel_ext_info() - write ext_info attribute from a given channel
 * @chan:               The channel being queried.
 * @attr:               The ext_info attribute to read.
 * @buf:                The new attribute value. Strings needs to be zero-
 *                      terminated, but the terminator should not be included
 *                      in the below len.
 * @len:                The size of the new attribute value.
 *
 * Returns the number of accepted bytes, which should be the same as len.
 * An error code can also be returned.
 */
ssize_t iio_write_channel_ext_info(struct iio_channel *chan, const char *attr,
                                   const char *buf, size_t len);

#endif