480 lines
15 KiB
C
480 lines
15 KiB
C
/* The industrial I/O core - generic ring buffer interfaces.
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*
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* Copyright (c) 2008 Jonathan Cameron
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#ifndef _IIO_RING_GENERIC_H_
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#define _IIO_RING_GENERIC_H_
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#include "iio.h"
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#ifdef CONFIG_IIO_RING_BUFFER
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struct iio_ring_buffer;
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/**
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* struct iio_ring_access_funcs - access functions for ring buffers.
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* @mark_in_use: reference counting, typically to prevent module removal
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* @unmark_in_use: reduce reference count when no longer using ring buffer
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* @store_to: actually store stuff to the ring buffer
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* @read_last: get the last element stored
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* @read_first_n: try to get a specified number of elements (must exist)
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* @mark_param_change: notify ring that some relevant parameter has changed
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* Often this means the underlying storage may need to
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* change.
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* @request_update: if a parameter change has been marked, update underlying
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* storage.
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* @get_bytes_per_datum:get current bytes per datum
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* @set_bytes_per_datum:set number of bytes per datum
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* @get_length: get number of datums in ring
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* @set_length: set number of datums in ring
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* @is_enabled: query if ring is currently being used
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* @enable: enable the ring
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*
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* The purpose of this structure is to make the ring buffer element
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* modular as event for a given driver, different usecases may require
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* different ring designs (space efficiency vs speed for example).
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*
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* It is worth noting that a given ring implementation may only support a small
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* proportion of these functions. The core code 'should' cope fine with any of
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* them not existing.
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**/
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struct iio_ring_access_funcs {
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void (*mark_in_use)(struct iio_ring_buffer *ring);
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void (*unmark_in_use)(struct iio_ring_buffer *ring);
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int (*store_to)(struct iio_ring_buffer *ring, u8 *data, s64 timestamp);
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int (*read_last)(struct iio_ring_buffer *ring, u8 *data);
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int (*read_first_n)(struct iio_ring_buffer *ring,
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size_t n,
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char __user *buf);
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int (*mark_param_change)(struct iio_ring_buffer *ring);
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int (*request_update)(struct iio_ring_buffer *ring);
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int (*get_bytes_per_datum)(struct iio_ring_buffer *ring);
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int (*set_bytes_per_datum)(struct iio_ring_buffer *ring, size_t bpd);
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int (*get_length)(struct iio_ring_buffer *ring);
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int (*set_length)(struct iio_ring_buffer *ring, int length);
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int (*is_enabled)(struct iio_ring_buffer *ring);
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int (*enable)(struct iio_ring_buffer *ring);
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};
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/**
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* struct iio_ring_buffer - general ring buffer structure
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* @dev: ring buffer device struct
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* @indio_dev: industrial I/O device structure
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* @owner: module that owns the ring buffer (for ref counting)
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* @id: unique id number
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* @length: [DEVICE] number of datums in ring
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* @bytes_per_datum: [DEVICE] size of individual datum including timestamp
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* @bpe: [DEVICE] size of individual channel value
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* @loopcount: [INTERN] number of times the ring has looped
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* @scan_el_attrs: [DRIVER] control of scan elements if that scan mode
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* control method is used
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* @scan_count: [INTERN] the number of elements in the current scan mode
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* @scan_mask: [INTERN] bitmask used in masking scan mode elements
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* @scan_timestamp: [INTERN] does the scan mode include a timestamp
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* @access_handler: [INTERN] chrdev access handling
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* @access: [DRIVER] ring access functions associated with the
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* implementation.
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* @preenable: [DRIVER] function to run prior to marking ring enabled
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* @postenable: [DRIVER] function to run after marking ring enabled
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* @predisable: [DRIVER] function to run prior to marking ring disabled
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* @postdisable: [DRIVER] function to run after marking ring disabled
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**/
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struct iio_ring_buffer {
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struct device dev;
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struct iio_dev *indio_dev;
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struct module *owner;
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int id;
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int length;
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int bytes_per_datum;
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int bpe;
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int loopcount;
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struct attribute_group *scan_el_attrs;
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int scan_count;
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u32 scan_mask;
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bool scan_timestamp;
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struct iio_handler access_handler;
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struct iio_ring_access_funcs access;
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int (*preenable)(struct iio_dev *);
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int (*postenable)(struct iio_dev *);
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int (*predisable)(struct iio_dev *);
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int (*postdisable)(struct iio_dev *);
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struct list_head scan_el_dev_attr_list;
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struct list_head scan_el_en_attr_list;
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wait_queue_head_t pollq;
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bool stufftoread;
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};
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/**
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* iio_ring_buffer_init() - Initialize the buffer structure
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* @ring: buffer to be initialized
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* @dev_info: the iio device the buffer is assocated with
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**/
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void iio_ring_buffer_init(struct iio_ring_buffer *ring,
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struct iio_dev *dev_info);
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/**
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* __iio_update_ring_buffer() - update common elements of ring buffers
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* @ring: ring buffer that is the event source
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* @bytes_per_datum: size of individual datum including timestamp
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* @length: number of datums in ring
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**/
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static inline void __iio_update_ring_buffer(struct iio_ring_buffer *ring,
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int bytes_per_datum, int length)
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{
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ring->bytes_per_datum = bytes_per_datum;
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ring->length = length;
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ring->loopcount = 0;
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}
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/**
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* struct iio_scan_el - an individual element of a scan
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* @dev_attr: control attribute (if directly controllable)
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* @number: unique identifier of element (used for bit mask)
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* @label: useful data for the scan el (often reg address)
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* @set_state: for some devices datardy signals are generated
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* for any enabled lines. This allows unwanted lines
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* to be disabled and hence not get in the way.
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**/
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struct iio_scan_el {
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struct device_attribute dev_attr;
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unsigned int number;
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unsigned int label;
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struct list_head l;
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int (*set_state)(struct iio_scan_el *scanel,
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struct iio_dev *dev_info,
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bool state);
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};
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#define to_iio_scan_el(_dev_attr) \
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container_of(_dev_attr, struct iio_scan_el, dev_attr);
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/**
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* iio_scan_el_store() - sysfs scan element selection interface
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* @dev: the target device
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* @attr: the device attribute that is being processed
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* @buf: input from userspace
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* @len: length of input
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*
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* A generic function used to enable various scan elements. In some
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* devices explicit read commands for each channel mean this is merely
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* a software switch. In others this must actively disable the channel.
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* Complexities occur when this interacts with data ready type triggers
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* which may not reset unless every channel that is enabled is explicitly
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* read.
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**/
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ssize_t iio_scan_el_store(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t len);
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/**
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* iio_scan_el_show() - sysfs interface to query whether a scan element
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* is enabled or not
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* @dev: the target device
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* @attr: the device attribute that is being processed
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* @buf: output buffer
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**/
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ssize_t iio_scan_el_show(struct device *dev, struct device_attribute *attr,
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char *buf);
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/**
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* iio_scan_el_ts_store() - sysfs interface to set whether a timestamp is included
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* in the scan.
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**/
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ssize_t iio_scan_el_ts_store(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t len);
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/**
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* iio_scan_el_ts_show() - sysfs interface to query if a timestamp is included
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* in the scan.
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**/
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ssize_t iio_scan_el_ts_show(struct device *dev, struct device_attribute *attr,
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char *buf);
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/**
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* IIO_SCAN_EL_C - declare and initialize a scan element with a control func
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*
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* @_name: identifying name. Resulting struct is iio_scan_el_##_name,
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* sysfs element, _name##_en.
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* @_number: unique id number for the scan element.
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* length devices).
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* @_label: indentification variable used by drivers. Often a reg address.
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* @_controlfunc: function used to notify hardware of whether state changes
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**/
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#define __IIO_SCAN_EL_C(_name, _number, _label, _controlfunc) \
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struct iio_scan_el iio_scan_el_##_name = { \
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.dev_attr = __ATTR(_name##_en, \
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S_IRUGO | S_IWUSR, \
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iio_scan_el_show, \
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iio_scan_el_store), \
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.number = _number, \
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.label = _label, \
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.set_state = _controlfunc, \
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}; \
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static IIO_CONST_ATTR(_name##_index, #_number)
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#define IIO_SCAN_EL_C(_name, _number, _label, _controlfunc) \
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__IIO_SCAN_EL_C(_name, _number, _label, _controlfunc)
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#define __IIO_SCAN_NAMED_EL_C(_name, _string, _number, _label, _cf) \
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struct iio_scan_el iio_scan_el_##_name = { \
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.dev_attr = __ATTR(_string##_en, \
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S_IRUGO | S_IWUSR, \
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iio_scan_el_show, \
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iio_scan_el_store), \
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.number = _number, \
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.label = _label, \
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.set_state = _cf, \
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}; \
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static struct iio_const_attr iio_const_attr_##_name##_index = { \
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.string = #_number, \
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.dev_attr = __ATTR(_string##_index, \
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S_IRUGO, iio_read_const_attr, NULL) \
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}
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#define IIO_SCAN_NAMED_EL_C(_name, _string, _number, _label, _cf) \
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__IIO_SCAN_NAMED_EL_C(_name, _string, _number, _label, _cf)
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/**
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* IIO_SCAN_EL_TIMESTAMP - declare a special scan element for timestamps
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* @number: specify where in the scan order this is stored.
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*
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* Odd one out. Handled slightly differently from other scan elements.
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**/
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#define IIO_SCAN_EL_TIMESTAMP(number) \
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struct iio_scan_el iio_scan_el_timestamp = { \
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.dev_attr = __ATTR(timestamp_en, \
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S_IRUGO | S_IWUSR, \
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iio_scan_el_ts_show, \
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iio_scan_el_ts_store), \
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}; \
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static IIO_CONST_ATTR(timestamp_index, #number)
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/**
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* IIO_CONST_ATTR_SCAN_EL_TYPE - attr to specify the data format of a scan el
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* @name: the scan el name (may be more general and cover a set of scan elements
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* @_sign: either s or u for signed or unsigned
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* @_bits: number of actual bits occuplied by the value
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* @_storagebits: number of bits _bits is padded to when read out of buffer
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**/
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#define IIO_CONST_ATTR_SCAN_EL_TYPE(_name, _sign, _bits, _storagebits) \
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IIO_CONST_ATTR(_name##_type, #_sign#_bits"/"#_storagebits);
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/**
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* IIO_CONST_ATTR_SCAN_EL_TYPE_WITH_SHIFT - attr to specify the data format of a scan el
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* @name: the scan el name (may be more general and cover a set of scan elements
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* @_sign: either s or u for signed or unsigned
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* @_bits: number of actual bits occuplied by the value
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* @_storagebits: number of bits _bits is padded to when read out of buffer
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* @_shiftbits: number of bits _shiftbits the result must be shifted
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**/
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#define IIO_CONST_ATTR_SCAN_EL_TYPE_WITH_SHIFT(_name, _sign, _bits, \
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_storagebits, _shiftbits) \
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IIO_CONST_ATTR(_name##_type, #_sign#_bits"/"#_storagebits \
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">>"#_shiftbits);
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#define IIO_SCAN_EL_TYPE_SIGNED 's'
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#define IIO_SCAN_EL_TYPE_UNSIGNED 'u'
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/*
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* These are mainly provided to allow for a change of implementation if a device
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* has a large number of scan elements
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*/
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#define IIO_MAX_SCAN_LENGTH 31
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/* note 0 used as error indicator as it doesn't make sense. */
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static inline u32 iio_scan_mask_match(u32 *av_masks, u32 mask)
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{
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while (*av_masks) {
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if (!(~*av_masks & mask))
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return *av_masks;
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av_masks++;
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}
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return 0;
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}
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static inline int iio_scan_mask_query(struct iio_ring_buffer *ring, int bit)
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{
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struct iio_dev *dev_info = ring->indio_dev;
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u32 mask;
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if (bit > IIO_MAX_SCAN_LENGTH)
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return -EINVAL;
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if (!ring->scan_mask)
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return 0;
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if (dev_info->available_scan_masks)
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mask = iio_scan_mask_match(dev_info->available_scan_masks,
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ring->scan_mask);
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else
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mask = ring->scan_mask;
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if (!mask)
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return -EINVAL;
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return !!(mask & (1 << bit));
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};
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/**
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* iio_scan_mask_set() - set particular bit in the scan mask
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* @ring: the ring buffer whose scan mask we are interested in
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* @bit: the bit to be set.
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**/
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static inline int iio_scan_mask_set(struct iio_ring_buffer *ring, int bit)
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{
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struct iio_dev *dev_info = ring->indio_dev;
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u32 mask;
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u32 trialmask = ring->scan_mask | (1 << bit);
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if (bit > IIO_MAX_SCAN_LENGTH)
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return -EINVAL;
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if (dev_info->available_scan_masks) {
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mask = iio_scan_mask_match(dev_info->available_scan_masks,
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trialmask);
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if (!mask)
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return -EINVAL;
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}
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ring->scan_mask = trialmask;
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ring->scan_count++;
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return 0;
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};
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/**
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* iio_scan_mask_clear() - clear a particular element from the scan mask
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* @ring: the ring buffer whose scan mask we are interested in
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* @bit: the bit to clear
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**/
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static inline int iio_scan_mask_clear(struct iio_ring_buffer *ring, int bit)
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{
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if (bit > IIO_MAX_SCAN_LENGTH)
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return -EINVAL;
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ring->scan_mask &= ~(1 << bit);
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ring->scan_count--;
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return 0;
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};
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/**
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* iio_scan_mask_count_to_right() - how many scan elements occur before here
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* @ring: the ring buffer whose scan mask we interested in
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* @bit: which number scan element is this
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**/
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static inline int iio_scan_mask_count_to_right(struct iio_ring_buffer *ring,
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int bit)
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{
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int count = 0;
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int mask = (1 << bit);
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if (bit > IIO_MAX_SCAN_LENGTH)
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return -EINVAL;
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while (mask) {
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mask >>= 1;
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if (mask & ring->scan_mask)
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count++;
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}
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return count;
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}
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/**
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* iio_put_ring_buffer() - notify done with buffer
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* @ring: the buffer we are done with.
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**/
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static inline void iio_put_ring_buffer(struct iio_ring_buffer *ring)
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{
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put_device(&ring->dev);
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};
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#define to_iio_ring_buffer(d) \
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container_of(d, struct iio_ring_buffer, dev)
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/**
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* iio_ring_buffer_register() - register the buffer with IIO core
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* @ring: the buffer to be registered
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* @id: the id of the buffer (typically 0)
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**/
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int iio_ring_buffer_register(struct iio_ring_buffer *ring, int id);
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/** iio_ring_buffer_register_ex() - register the buffer with IIO core
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* @ring: the buffer to be registered
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* @id: the id of the buffer (typically 0)
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**/
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int iio_ring_buffer_register_ex(struct iio_ring_buffer *ring, int id,
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const struct iio_chan_spec *channels,
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int num_channels);
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void iio_ring_access_release(struct device *dev);
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/**
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* iio_ring_buffer_unregister() - unregister the buffer from IIO core
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* @ring: the buffer to be unregistered
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**/
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void iio_ring_buffer_unregister(struct iio_ring_buffer *ring);
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/**
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* iio_read_ring_length() - attr func to get number of datums in the buffer
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**/
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ssize_t iio_read_ring_length(struct device *dev,
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struct device_attribute *attr,
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char *buf);
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/**
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* iio_write_ring_length() - attr func to set number of datums in the buffer
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**/
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ssize_t iio_write_ring_length(struct device *dev,
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struct device_attribute *attr,
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const char *buf,
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size_t len);
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/**
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* iio_read_ring_bytes_per_datum() - attr for number of bytes in whole datum
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**/
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ssize_t iio_read_ring_bytes_per_datum(struct device *dev,
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struct device_attribute *attr,
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char *buf);
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/**
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* iio_store_ring_enable() - attr to turn the buffer on
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**/
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ssize_t iio_store_ring_enable(struct device *dev,
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struct device_attribute *attr,
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const char *buf,
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size_t len);
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/**
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* iio_show_ring_enable() - attr to see if the buffer is on
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**/
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ssize_t iio_show_ring_enable(struct device *dev,
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struct device_attribute *attr,
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char *buf);
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#define IIO_RING_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \
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iio_read_ring_length, \
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iio_write_ring_length)
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#define IIO_RING_BYTES_PER_DATUM_ATTR DEVICE_ATTR(bytes_per_datum, S_IRUGO | S_IWUSR, \
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iio_read_ring_bytes_per_datum, NULL)
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#define IIO_RING_ENABLE_ATTR DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, \
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iio_show_ring_enable, \
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iio_store_ring_enable)
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#else /* CONFIG_IIO_RING_BUFFER */
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static inline int iio_ring_buffer_register(struct iio_ring_buffer *ring, int id)
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{
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return 0;
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};
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static inline int iio_ring_buffer_register_ex(struct iio_ring_buffer *ring,
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int id,
|
|
struct iio_chan_spec *channels,
|
|
int num_channels)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline void iio_ring_buffer_unregister(struct iio_ring_buffer *ring)
|
|
{};
|
|
|
|
#endif /* CONFIG_IIO_RING_BUFFER */
|
|
|
|
#endif /* _IIO_RING_GENERIC_H_ */
|