163 lines
5.1 KiB
C
163 lines
5.1 KiB
C
#ifndef _IIO_BUFFER_GENERIC_IMPL_H_
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#define _IIO_BUFFER_GENERIC_IMPL_H_
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#include <linux/sysfs.h>
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#include <linux/kref.h>
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#ifdef CONFIG_IIO_BUFFER
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struct iio_dev;
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struct iio_buffer;
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/**
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* INDIO_BUFFER_FLAG_FIXED_WATERMARK - Watermark level of the buffer can not be
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* configured. It has a fixed value which will be buffer specific.
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*/
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#define INDIO_BUFFER_FLAG_FIXED_WATERMARK BIT(0)
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/**
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* struct iio_buffer_access_funcs - access functions for buffers.
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* @store_to: actually store stuff to the buffer
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* @read_first_n: try to get a specified number of bytes (must exist)
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* @data_available: indicates how much data is available for reading from
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* the buffer.
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* @request_update: if a parameter change has been marked, update underlying
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* storage.
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* @set_bytes_per_datum:set number of bytes per datum
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* @set_length: set number of datums in buffer
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* @enable: called if the buffer is attached to a device and the
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* device starts sampling. Calls are balanced with
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* @disable.
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* @disable: called if the buffer is attached to a device and the
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* device stops sampling. Calles are balanced with @enable.
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* @release: called when the last reference to the buffer is dropped,
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* should free all resources allocated by the buffer.
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* @modes: Supported operating modes by this buffer type
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* @flags: A bitmask combination of INDIO_BUFFER_FLAG_*
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*
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* The purpose of this structure is to make the buffer element
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* modular as event for a given driver, different usecases may require
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* different buffer designs (space efficiency vs speed for example).
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*
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* It is worth noting that a given buffer implementation may only support a
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* small proportion of these functions. The core code 'should' cope fine with
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* any of them not existing.
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**/
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struct iio_buffer_access_funcs {
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int (*store_to)(struct iio_buffer *buffer, const void *data);
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int (*read_first_n)(struct iio_buffer *buffer,
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size_t n,
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char __user *buf);
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size_t (*data_available)(struct iio_buffer *buffer);
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int (*request_update)(struct iio_buffer *buffer);
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int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd);
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int (*set_length)(struct iio_buffer *buffer, int length);
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int (*enable)(struct iio_buffer *buffer, struct iio_dev *indio_dev);
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int (*disable)(struct iio_buffer *buffer, struct iio_dev *indio_dev);
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void (*release)(struct iio_buffer *buffer);
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unsigned int modes;
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unsigned int flags;
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};
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/**
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* struct iio_buffer - general buffer structure
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*
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* Note that the internals of this structure should only be of interest to
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* those writing new buffer implementations.
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*/
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struct iio_buffer {
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/** @length: Number of datums in buffer. */
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int length;
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/** @bytes_per_datum: Size of individual datum including timestamp. */
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int bytes_per_datum;
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/**
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* @access: Buffer access functions associated with the
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* implementation.
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*/
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const struct iio_buffer_access_funcs *access;
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/** @scan_mask: Bitmask used in masking scan mode elements. */
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long *scan_mask;
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/** @demux_list: List of operations required to demux the scan. */
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struct list_head demux_list;
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/** @pollq: Wait queue to allow for polling on the buffer. */
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wait_queue_head_t pollq;
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/** @watermark: Number of datums to wait for poll/read. */
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unsigned int watermark;
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/* private: */
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/*
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* @scan_el_attrs: Control of scan elements if that scan mode
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* control method is used.
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*/
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struct attribute_group *scan_el_attrs;
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/* @scan_timestamp: Does the scan mode include a timestamp. */
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bool scan_timestamp;
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/* @scan_el_dev_attr_list: List of scan element related attributes. */
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struct list_head scan_el_dev_attr_list;
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/* @buffer_group: Attributes of the buffer group. */
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struct attribute_group buffer_group;
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/*
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* @scan_el_group: Attribute group for those attributes not
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* created from the iio_chan_info array.
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*/
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struct attribute_group scan_el_group;
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/* @stufftoread: Flag to indicate new data. */
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bool stufftoread;
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/* @attrs: Standard attributes of the buffer. */
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const struct attribute **attrs;
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/* @demux_bounce: Buffer for doing gather from incoming scan. */
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void *demux_bounce;
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/* @buffer_list: Entry in the devices list of current buffers. */
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struct list_head buffer_list;
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/* @ref: Reference count of the buffer. */
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struct kref ref;
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};
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/**
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* iio_update_buffers() - add or remove buffer from active list
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* @indio_dev: device to add buffer to
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* @insert_buffer: buffer to insert
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* @remove_buffer: buffer_to_remove
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*
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* Note this will tear down the all buffering and build it up again
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*/
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int iio_update_buffers(struct iio_dev *indio_dev,
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struct iio_buffer *insert_buffer,
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struct iio_buffer *remove_buffer);
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/**
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* iio_buffer_init() - Initialize the buffer structure
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* @buffer: buffer to be initialized
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**/
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void iio_buffer_init(struct iio_buffer *buffer);
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struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer);
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void iio_buffer_put(struct iio_buffer *buffer);
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#else /* CONFIG_IIO_BUFFER */
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static inline void iio_buffer_get(struct iio_buffer *buffer) {}
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static inline void iio_buffer_put(struct iio_buffer *buffer) {}
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#endif /* CONFIG_IIO_BUFFER */
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#endif /* _IIO_BUFFER_GENERIC_IMPL_H_ */
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