Staging: IIO: Add generic ring buffer support to the IIO core

This provides a unified interface for hardware and software
ring buffers.

Changes since V2:
* Moved to a more consistent structure.  Now the ring buffer
  has an associated struct device which is a child of the
  relevant iio_dev.  This in turn has two children, one
  for the event interface and one for the access interface.
  These two interfaces are now managed via cdev structures.

* Numerous minor cleanups

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Jonathan Cameron 2009-08-18 18:06:24 +01:00 committed by Greg Kroah-Hartman
parent e435bc191f
commit 7026ea4b52
4 changed files with 858 additions and 0 deletions

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@ -11,6 +11,12 @@ menuconfig IIO
Documentation/industrialio for more information.
if IIO
config IIO_RING_BUFFER
bool "Enable ring buffer support within IIO"
help
Provide core support for various ring buffer based data
acquisition methods.
source "drivers/staging/iio/accel/Kconfig"
source "drivers/staging/iio/adc/Kconfig"
source "drivers/staging/iio/light/Kconfig"

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@ -4,6 +4,7 @@
obj-$(CONFIG_IIO) += industrialio.o
industrialio-y := industrialio-core.o
industrialio-$(CONFIG_IIO_RING_BUFFER) += industrialio-ring.o
obj-y += accel/
obj-y += adc/

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@ -0,0 +1,568 @@
/* The industrial I/O core
*
* Copyright (c) 2008 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.
*
* Handling of ring allocation / resizing.
*
*
* Things to look at here.
* - Better memory allocation techniques?
* - Alternative access techniques?
*/
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/module.h>
#include <linux/cdev.h>
#include <linux/idr.h>
#include "iio.h"
#include "ring_generic.h"
/* IDR for ring buffer identifier */
static DEFINE_IDR(iio_ring_idr);
/* IDR for ring event identifier */
static DEFINE_IDR(iio_ring_event_idr);
/* IDR for ring access identifier */
static DEFINE_IDR(iio_ring_access_idr);
int iio_push_ring_event(struct iio_ring_buffer *ring_buf,
int event_code,
s64 timestamp)
{
return __iio_push_event(&ring_buf->ev_int,
event_code,
timestamp,
&ring_buf->shared_ev_pointer);
}
EXPORT_SYMBOL(iio_push_ring_event);
int iio_push_or_escallate_ring_event(struct iio_ring_buffer *ring_buf,
int event_code,
s64 timestamp)
{
if (ring_buf->shared_ev_pointer.ev_p)
__iio_change_event(ring_buf->shared_ev_pointer.ev_p,
event_code,
timestamp);
else
return iio_push_ring_event(ring_buf,
event_code,
timestamp);
return 0;
}
EXPORT_SYMBOL(iio_push_or_escallate_ring_event);
/**
* iio_ring_open() chrdev file open for ring buffer access
*
* This function relies on all ring buffer implementations having an
* iio_ring_buffer as their first element.
**/
int iio_ring_open(struct inode *inode, struct file *filp)
{
struct iio_handler *hand
= container_of(inode->i_cdev, struct iio_handler, chrdev);
struct iio_ring_buffer *rb = hand->private;
filp->private_data = hand->private;
if (rb->access.mark_in_use)
rb->access.mark_in_use(rb);
return 0;
}
/**
* iio_ring_release() -chrdev file close ring buffer access
*
* This function relies on all ring buffer implementations having an
* iio_ring_buffer as their first element.
**/
int iio_ring_release(struct inode *inode, struct file *filp)
{
struct cdev *cd = inode->i_cdev;
struct iio_handler *hand = iio_cdev_to_handler(cd);
struct iio_ring_buffer *rb = hand->private;
clear_bit(IIO_BUSY_BIT_POS, &rb->access_handler.flags);
if (rb->access.unmark_in_use)
rb->access.unmark_in_use(rb);
return 0;
}
/**
* iio_ring_rip_outer() chrdev read for ring buffer access
*
* This function relies on all ring buffer implementations having an
* iio_ring _bufer as their first element.
**/
ssize_t iio_ring_rip_outer(struct file *filp,
char *buf,
size_t count,
loff_t *f_ps)
{
struct iio_ring_buffer *rb = filp->private_data;
int ret, dead_offset, copied;
u8 *data;
/* rip lots must exist. */
if (!rb->access.rip_lots)
return -EINVAL;
copied = rb->access.rip_lots(rb, count, &data, &dead_offset);
if (copied < 0) {
ret = copied;
goto error_ret;
}
if (copy_to_user(buf, data + dead_offset, copied)) {
ret = -EFAULT;
goto error_free_data_cpy;
}
/* In clever ring buffer designs this may not need to be freed.
* When such a design exists I'll add this to ring access funcs.
*/
kfree(data);
return copied;
error_free_data_cpy:
kfree(data);
error_ret:
return ret;
}
static const struct file_operations iio_ring_fileops = {
.read = iio_ring_rip_outer,
.release = iio_ring_release,
.open = iio_ring_open,
.owner = THIS_MODULE,
};
/**
* __iio_request_ring_buffer_event_chrdev() allocate ring event chrdev
* @buf: ring buffer whose event chrdev we are allocating
* @owner: the module who owns the ring buffer (for ref counting)
* @dev: device with which the chrdev is associated
**/
static inline int
__iio_request_ring_buffer_event_chrdev(struct iio_ring_buffer *buf,
int id,
struct module *owner,
struct device *dev)
{
int ret;
ret = iio_get_new_idr_val(&iio_ring_event_idr);
if (ret < 0)
goto error_ret;
else
buf->ev_int.id = ret;
snprintf(buf->ev_int._name, 20,
"ring_event_line%d",
buf->ev_int.id);
ret = iio_setup_ev_int(&(buf->ev_int),
buf->ev_int._name,
owner,
dev);
if (ret)
goto error_free_id;
return 0;
error_free_id:
iio_free_idr_val(&iio_ring_event_idr, buf->ev_int.id);
error_ret:
return ret;
}
static inline void
__iio_free_ring_buffer_event_chrdev(struct iio_ring_buffer *buf)
{
iio_free_ev_int(&(buf->ev_int));
iio_free_idr_val(&iio_ring_event_idr, buf->ev_int.id);
}
static void iio_ring_access_release(struct device *dev)
{
struct iio_ring_buffer *buf
= access_dev_to_iio_ring_buffer(dev);
cdev_del(&buf->access_handler.chrdev);
iio_device_free_chrdev_minor(MINOR(dev->devt));
}
static struct device_type iio_ring_access_type = {
.release = iio_ring_access_release,
};
static inline int
__iio_request_ring_buffer_access_chrdev(struct iio_ring_buffer *buf,
int id,
struct module *owner)
{
int ret, minor;
buf->access_handler.flags = 0;
buf->access_dev.parent = &buf->dev;
buf->access_dev.class = &iio_class;
buf->access_dev.type = &iio_ring_access_type;
device_initialize(&buf->access_dev);
minor = iio_device_get_chrdev_minor();
if (minor < 0) {
ret = minor;
goto error_device_put;
}
buf->access_dev.devt = MKDEV(MAJOR(iio_devt), minor);
ret = iio_get_new_idr_val(&iio_ring_access_idr);
if (ret < 0)
goto error_device_put;
else
buf->access_id = ret;
dev_set_name(&buf->access_dev, "ring_access%d", buf->access_id);
ret = device_add(&buf->access_dev);
if (ret < 0) {
printk(KERN_ERR "failed to add the ring access dev\n");
goto error_free_idr;
}
cdev_init(&buf->access_handler.chrdev, &iio_ring_fileops);
buf->access_handler.chrdev.owner = owner;
ret = cdev_add(&buf->access_handler.chrdev, buf->access_dev.devt, 1);
if (ret) {
printk(KERN_ERR "failed to allocate ring access chrdev\n");
goto error_device_unregister;
}
return 0;
error_device_unregister:
device_unregister(&buf->access_dev);
error_free_idr:
iio_free_idr_val(&iio_ring_access_idr, buf->access_id);
error_device_put:
put_device(&buf->access_dev);
return ret;
}
static void __iio_free_ring_buffer_access_chrdev(struct iio_ring_buffer *buf)
{
iio_free_idr_val(&iio_ring_access_idr, buf->access_id);
device_unregister(&buf->access_dev);
}
void iio_ring_buffer_init(struct iio_ring_buffer *ring,
struct iio_dev *dev_info)
{
if (ring->access.mark_param_change)
ring->access.mark_param_change(ring);
ring->indio_dev = dev_info;
ring->ev_int.private = ring;
ring->access_handler.private = ring;
}
EXPORT_SYMBOL(iio_ring_buffer_init);
int iio_ring_buffer_register(struct iio_ring_buffer *ring)
{
int ret;
ret = iio_get_new_idr_val(&iio_ring_idr);
if (ret < 0)
goto error_ret;
else
ring->id = ret;
dev_set_name(&ring->dev, "ring_buffer%d", ring->id);
ret = device_add(&ring->dev);
if (ret)
goto error_free_id;
ret = __iio_request_ring_buffer_event_chrdev(ring,
0,
ring->owner,
&ring->dev);
if (ret)
goto error_remove_device;
ret = __iio_request_ring_buffer_access_chrdev(ring,
0,
ring->owner);
if (ret)
goto error_free_ring_buffer_event_chrdev;
return ret;
error_free_ring_buffer_event_chrdev:
__iio_free_ring_buffer_event_chrdev(ring);
error_remove_device:
device_del(&ring->dev);
error_free_id:
iio_free_idr_val(&iio_ring_idr, ring->id);
error_ret:
return ret;
}
EXPORT_SYMBOL(iio_ring_buffer_register);
void iio_ring_buffer_unregister(struct iio_ring_buffer *ring)
{
__iio_free_ring_buffer_access_chrdev(ring);
__iio_free_ring_buffer_event_chrdev(ring);
device_del(&ring->dev);
iio_free_idr_val(&iio_ring_idr, ring->id);
}
EXPORT_SYMBOL(iio_ring_buffer_unregister);
ssize_t iio_read_ring_length(struct device *dev,
struct device_attribute *attr,
char *buf)
{
int len = 0;
struct iio_ring_buffer *ring = dev_get_drvdata(dev);
if (ring->access.get_length)
len = sprintf(buf, "%d\n",
ring->access.get_length(ring));
return len;
}
EXPORT_SYMBOL(iio_read_ring_length);
ssize_t iio_write_ring_length(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
int ret;
ulong val;
struct iio_ring_buffer *ring = dev_get_drvdata(dev);
ret = strict_strtoul(buf, 10, &val);
if (ret)
return ret;
if (ring->access.get_length)
if (val == ring->access.get_length(ring))
return len;
if (ring->access.set_length) {
ring->access.set_length(ring, val);
if (ring->access.mark_param_change)
ring->access.mark_param_change(ring);
}
return len;
}
EXPORT_SYMBOL(iio_write_ring_length);
ssize_t iio_read_ring_bps(struct device *dev,
struct device_attribute *attr,
char *buf)
{
int len = 0;
struct iio_ring_buffer *ring = dev_get_drvdata(dev);
if (ring->access.get_bpd)
len = sprintf(buf, "%d\n",
ring->access.get_bpd(ring));
return len;
}
EXPORT_SYMBOL(iio_read_ring_bps);
ssize_t iio_store_ring_enable(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
int ret;
bool requested_state, current_state;
int previous_mode;
struct iio_ring_buffer *ring = dev_get_drvdata(dev);
struct iio_dev *dev_info = ring->indio_dev;
mutex_lock(&dev_info->mlock);
previous_mode = dev_info->currentmode;
requested_state = !(buf[0] == '0');
current_state = !!(previous_mode & INDIO_ALL_RING_MODES);
if (current_state == requested_state) {
printk(KERN_INFO "iio-ring, current state requested again\n");
goto done;
}
if (requested_state) {
if (ring->preenable) {
ret = ring->preenable(dev_info);
if (ret) {
printk(KERN_ERR
"Buffer not started:"
"ring preenable failed\n");
goto error_ret;
}
}
if (ring->access.request_update) {
ret = ring->access.request_update(ring);
if (ret) {
printk(KERN_INFO
"Buffer not started:"
"ring parameter update failed\n");
goto error_ret;
}
}
if (ring->access.mark_in_use)
ring->access.mark_in_use(ring);
/* Definitely possible for devices to support both of these.*/
if (dev_info->modes & INDIO_RING_TRIGGERED) {
if (!dev_info->trig) {
printk(KERN_INFO
"Buffer not started: no trigger\n");
ret = -EINVAL;
if (ring->access.unmark_in_use)
ring->access.unmark_in_use(ring);
goto error_ret;
}
dev_info->currentmode = INDIO_RING_TRIGGERED;
} else if (dev_info->modes & INDIO_RING_HARDWARE_BUFFER)
dev_info->currentmode = INDIO_RING_HARDWARE_BUFFER;
else { /* should never be reached */
ret = -EINVAL;
goto error_ret;
}
if (ring->postenable) {
ret = ring->postenable(dev_info);
if (ret) {
printk(KERN_INFO
"Buffer not started:"
"postenable failed\n");
if (ring->access.unmark_in_use)
ring->access.unmark_in_use(ring);
dev_info->currentmode = previous_mode;
if (ring->postdisable)
ring->postdisable(dev_info);
goto error_ret;
}
}
} else {
if (ring->predisable) {
ret = ring->predisable(dev_info);
if (ret)
goto error_ret;
}
if (ring->access.unmark_in_use)
ring->access.unmark_in_use(ring);
dev_info->currentmode = INDIO_DIRECT_MODE;
if (ring->postdisable) {
ret = ring->postdisable(dev_info);
if (ret)
goto error_ret;
}
}
done:
mutex_unlock(&dev_info->mlock);
return len;
error_ret:
mutex_unlock(&dev_info->mlock);
return ret;
}
EXPORT_SYMBOL(iio_store_ring_enable);
ssize_t iio_show_ring_enable(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_ring_buffer *ring = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", !!(ring->indio_dev->currentmode
& INDIO_ALL_RING_MODES));
}
EXPORT_SYMBOL(iio_show_ring_enable);
ssize_t iio_scan_el_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
int ret;
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct iio_scan_el *this_el = to_iio_scan_el(attr);
ret = iio_scan_mask_query(indio_dev, this_el->number);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", ret);
}
EXPORT_SYMBOL(iio_scan_el_show);
ssize_t iio_scan_el_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
int ret = 0;
bool state;
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct iio_scan_el *this_el = to_iio_scan_el(attr);
state = !(buf[0] == '0');
mutex_lock(&indio_dev->mlock);
if (indio_dev->currentmode == INDIO_RING_TRIGGERED) {
ret = -EBUSY;
goto error_ret;
}
ret = iio_scan_mask_query(indio_dev, this_el->number);
if (ret < 0)
goto error_ret;
if (!state && ret) {
ret = iio_scan_mask_clear(indio_dev, this_el->number);
if (ret)
goto error_ret;
indio_dev->scan_count--;
} else if (state && !ret) {
ret = iio_scan_mask_set(indio_dev, this_el->number);
if (ret)
goto error_ret;
indio_dev->scan_count++;
}
if (this_el->set_state)
ret = this_el->set_state(this_el, indio_dev, state);
error_ret:
mutex_unlock(&indio_dev->mlock);
return ret ? ret : len;
}
EXPORT_SYMBOL(iio_scan_el_store);
ssize_t iio_scan_el_ts_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", indio_dev->scan_timestamp);
}
EXPORT_SYMBOL(iio_scan_el_ts_show);
ssize_t iio_scan_el_ts_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
int ret = 0;
struct iio_dev *indio_dev = dev_get_drvdata(dev);
bool state;
state = !(buf[0] == '0');
mutex_lock(&indio_dev->mlock);
if (indio_dev->currentmode == INDIO_RING_TRIGGERED) {
ret = -EBUSY;
goto error_ret;
}
indio_dev->scan_timestamp = state;
error_ret:
mutex_unlock(&indio_dev->mlock);
return ret ? ret : len;
}
EXPORT_SYMBOL(iio_scan_el_ts_store);

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@ -0,0 +1,283 @@
/* The industrial I/O core - generic ring buffer interfaces.
*
* Copyright (c) 2008 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_RING_GENERIC_H_
#define _IIO_RING_GENERIC_H_
#include "iio.h"
struct iio_handler;
struct iio_ring_buffer;
struct iio_dev;
/**
* iio_push_ring_event() - ring buffer specific push to event chrdev
* @ring_buf: ring buffer that is the event source
* @event_code: event indentification code
* @timestamp: time of event
**/
int iio_push_ring_event(struct iio_ring_buffer *ring_buf,
int event_code,
s64 timestamp);
/**
* iio_push_or_escallate_ring_event() - escallate or add as appropriate
*
* Typical usecase is to escallate a 50% ring full to 75% full if noone has yet
* read the first event. Clearly the 50% full is no longer of interest in
* typical use case.
**/
int iio_push_or_escallate_ring_event(struct iio_ring_buffer *ring_buf,
int event_code,
s64 timestamp);
/**
* struct iio_ring_access_funcs - access functions for ring buffers.
* @create: perform allocation
* @init: get ring buffer ready for use
* @_exit: reverse steps in init
* @_free: deallocate ring buffer
* @mark_in_use: reference counting, typically to prevent module removal
* @unmark_in_use: reduce reference count when no longer using ring buffer
* @store_to: actually store stuff to the ring buffer
* @read_last: get the last element stored
* @rip_lots: try to get a specified number of elements (must exist)
* @mark_param_change: notify ring that some relevant parameter has changed
* Often this means the underlying storage may need to
* change.
* @request_update: if a parameter change has been marked, update underlying
* storage.
* @get_bpd: get current bytes per datum
* @set_bpd: set number of bytes per datum
* @get_length: get number of datums in ring
* @set_length: set number of datums in ring
* @is_enabled: query if ring is currently being used
* @enable: enable the ring
*
* The purpose of this structure is to make the ring buffer element
* modular as event for a given driver, different usecases may require
* different ring designs (space efficiency vs speed for example.
*
* It is worth noting that a given ring implementation may only support a small
* proportion of these functions. The core code 'should' cope fine with any of
* them not existing.
**/
struct iio_ring_access_funcs {
void (*mark_in_use)(struct iio_ring_buffer *ring);
void (*unmark_in_use)(struct iio_ring_buffer *ring);
int (*store_to)(struct iio_ring_buffer *ring, u8 *data, s64 timestamp);
int (*read_last)(struct iio_ring_buffer *ring, u8 *data);
int (*rip_lots)(struct iio_ring_buffer *ring,
size_t count,
u8 **data,
int *dead_offset);
int (*mark_param_change)(struct iio_ring_buffer *ring);
int (*request_update)(struct iio_ring_buffer *ring);
int (*get_bpd)(struct iio_ring_buffer *ring);
int (*set_bpd)(struct iio_ring_buffer *ring, size_t bpd);
int (*get_length)(struct iio_ring_buffer *ring);
int (*set_length)(struct iio_ring_buffer *ring, int length);
int (*is_enabled)(struct iio_ring_buffer *ring);
int (*enable)(struct iio_ring_buffer *ring);
};
/**
* struct iio_ring_buffer - general ring buffer structure
* @length: [DEVICE]number of datums in ring
* @bpd: [DEVICE]size of individual datum including timestamp
* @loopcount: [INTERN]number of times the ring has looped
* @access_minor_name: [INTERN]store of name of the access chrdev minor number
* sysfs attribute
* @access_handler: [INTERN]chrdev access handling
* @event_minor_name: [INTERN]store of name of the event chrdev minor number
* sysfs attribute
* @ev_int: [INTERN]chrdev interface for the event chrdev
* @shared_ev_pointer: [INTERN]the shared event pointer to allow escalation of
* events
* @ring_access: [DRIVER]ring access functions associated with the
* implementation.
* @ring_prenable: [DRIVER] function to run prior to marking ring enabled
* @ring_postenable: [DRIVER] function to run after marking ring enabled
* @ring_predisable: [DRIVER] function to run prior to marking ring disabled
* @ring_postdisable: [DRIVER] function to run after marking ring disabled
**/
struct iio_ring_buffer {
struct device dev;
struct device access_dev;
struct iio_dev *indio_dev;
struct module *owner;
int id;
int access_id;
int length;
int bpd;
int loopcount;
struct iio_handler access_handler;
struct iio_event_interface ev_int;
struct iio_shared_ev_pointer shared_ev_pointer;
struct iio_ring_access_funcs access;
int (*preenable)(struct iio_dev *);
int (*postenable)(struct iio_dev *);
int (*predisable)(struct iio_dev *);
int (*postdisable)(struct iio_dev *);
};
void iio_ring_buffer_init(struct iio_ring_buffer *ring,
struct iio_dev *dev_info);
/**
* __iio_init_ring_buffer() - initialize common elements of ring buffers.
**/
static inline void __iio_init_ring_buffer(struct iio_ring_buffer *ring,
int bytes_per_datum, int length)
{
ring->bpd = bytes_per_datum;
ring->length = length;
ring->loopcount = 0;
ring->shared_ev_pointer.ev_p = 0;
ring->shared_ev_pointer.lock =
__SPIN_LOCK_UNLOCKED(ring->shared_ev_pointer->loc);
}
/**
* struct iio_scan_el - an individual element of a scan
* @dev_attr: control attribute (if directly controllable)
* @number: unique identifier of element (used for bit mask)
* @bit_count: number of bits in scan element
* @label: useful data for the scan el (often reg address)
* @set_state: for some devices datardy signals are generated
* for any enabled lines. This allows unwanted lines
* to be disabled and hence not get in the way.
**/
struct iio_scan_el {
struct device_attribute dev_attr;
unsigned int number;
int bit_count;
unsigned int label;
int (*set_state)(struct iio_scan_el *scanel,
struct iio_dev *dev_info,
bool state);
};
#define to_iio_scan_el(_dev_attr) \
container_of(_dev_attr, struct iio_scan_el, dev_attr);
/**
* iio_scan_el_store() - sysfs scan element selection interface.
*
* A generic function used to enable various scan elements. In some
* devices explicit read commands for each channel mean this is merely
* a software switch. In others this must actively disable the channel.
* Complexities occur when this interacts with data ready type triggers
* which may not reset unless every channel that is enabled is explicitly
* read.
**/
ssize_t iio_scan_el_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t len);
/**
* iio_scal_el_show() - sysfs interface to query whether a scan element is
* is enabled or not.
**/
ssize_t iio_scan_el_show(struct device *dev, struct device_attribute *attr,
char *buf);
/**
* IIO_SCAN_EL: - declare and initialize a scan element without control func
* @_name: identifying name. Resulting struct is iio_scan_el_##_name,
* sysfs element, scan_en_##_name.
* @_number: unique id number for the scan element.
* @_bits: number of bits in the scan element result (used in mixed bit
* length devices).
* @_label: indentification variable used by drivers. Often a reg address.
**/
#define IIO_SCAN_EL(_name, _number, _bits, _label) \
struct iio_scan_el iio_scan_el_##_name = { \
.dev_attr = __ATTR(scan_en_##_name, \
S_IRUGO | S_IWUSR, \
iio_scan_el_show, \
iio_scan_el_store), \
.mask = (1 << _number), \
.bit_count = _bits, \
.label = _label, \
}
ssize_t iio_scan_el_ts_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t len);
ssize_t iio_scan_el_ts_show(struct device *dev, struct device_attribute *attr,
char *buf);
/**
* IIO_SCAN_EL_C: - declare and initialize a scan element with a control func
*
* @_controlfunc: function used to notify hardware of whether state changes
**/
#define IIO_SCAN_EL_C(_name, _number, _bits, _label, _controlfunc) \
struct iio_scan_el iio_scan_el_##_name = { \
.dev_attr = __ATTR(scan_en_##_name, \
S_IRUGO | S_IWUSR, \
iio_scan_el_show, \
iio_scan_el_store), \
.number = _number, \
.bit_count = _bits, \
.label = _label, \
.set_state = _controlfunc, \
}
/**
* IIO_SCAN_EL_TIMESTAMP: - declare a special scan element for timestamps
*
* Odd one out. Handled slightly differently from other scan elements.
**/
#define IIO_SCAN_EL_TIMESTAMP \
struct iio_scan_el iio_scan_el_timestamp = { \
.dev_attr = __ATTR(scan_en_timestamp, \
S_IRUGO | S_IWUSR, \
iio_scan_el_ts_show, \
iio_scan_el_ts_store), \
}
static inline void iio_put_ring_buffer(struct iio_ring_buffer *ring)
{
put_device(&ring->dev);
};
#define to_iio_ring_buffer(d) \
container_of(d, struct iio_ring_buffer, dev)
#define access_dev_to_iio_ring_buffer(d) \
container_of(d, struct iio_ring_buffer, access_dev)
int iio_ring_buffer_register(struct iio_ring_buffer *ring);
void iio_ring_buffer_unregister(struct iio_ring_buffer *ring);
ssize_t iio_read_ring_length(struct device *dev,
struct device_attribute *attr,
char *buf);
ssize_t iio_write_ring_length(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len);
ssize_t iio_read_ring_bps(struct device *dev,
struct device_attribute *attr,
char *buf);
ssize_t iio_store_ring_enable(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len);
ssize_t iio_show_ring_enable(struct device *dev,
struct device_attribute *attr,
char *buf);
#define IIO_RING_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \
iio_read_ring_length, \
iio_write_ring_length)
#define IIO_RING_BPS_ATTR DEVICE_ATTR(bps, S_IRUGO | S_IWUSR, \
iio_read_ring_bps, NULL)
#define IIO_RING_ENABLE_ATTR DEVICE_ATTR(ring_enable, S_IRUGO | S_IWUSR, \
iio_show_ring_enable, \
iio_store_ring_enable)
#endif /* _IIO_RING_GENERIC_H_ */