1637db4441
Add general registration support for IIO triggers. These are currently only used to initialize a 'poll' of a given device. Examples include the lis3l02dq's data ready signal being used to initialize a read and gpio triggers being used to allow externally synchronized sensor reading. Each trigger can cause any number of 'consumer' devices to be polled with each storing data into a related ring buffer. Two stage triggering is supported with 'fast' and 'slow' paths. The first is used for things like pulling a data hold line high and the second for actual read which may take far longer. Changes since V2: * As with IIO triggers now use a registration approach much closer to that of input leading to cleaner code. Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
400 lines
10 KiB
C
400 lines
10 KiB
C
/* The industrial I/O core, trigger handling functions
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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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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/idr.h>
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#include <linux/err.h>
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#include <linux/device.h>
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#include <linux/interrupt.h>
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#include <linux/list.h>
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#include "iio.h"
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#include "trigger.h"
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/* RFC - Question of approach
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* Make the common case (single sensor single trigger)
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* simple by starting trigger capture from when first sensors
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* is added.
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*
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* Complex simultaneous start requires use of 'hold' functionality
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* of the trigger. (not implemented)
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*
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* Any other suggestions?
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*/
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static DEFINE_IDR(iio_trigger_idr);
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static DEFINE_SPINLOCK(iio_trigger_idr_lock);
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/* Single list of all available triggers */
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static LIST_HEAD(iio_trigger_list);
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static DEFINE_MUTEX(iio_trigger_list_lock);
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/**
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* iio_trigger_register_sysfs() - create a device for this trigger
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* @trig_info: the trigger
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*
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* Also adds any control attribute registered by the trigger driver
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**/
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static int iio_trigger_register_sysfs(struct iio_trigger *trig_info)
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{
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int ret = 0;
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if (trig_info->control_attrs)
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ret = sysfs_create_group(&trig_info->dev.kobj,
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trig_info->control_attrs);
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return ret;
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}
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static void iio_trigger_unregister_sysfs(struct iio_trigger *trig_info)
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{
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if (trig_info->control_attrs)
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sysfs_remove_group(&trig_info->dev.kobj,
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trig_info->control_attrs);
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}
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/**
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* iio_trigger_register_id() - get a unique id for this trigger
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* @trig_info: the trigger
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**/
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static int iio_trigger_register_id(struct iio_trigger *trig_info)
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{
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int ret = 0;
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idr_again:
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if (unlikely(idr_pre_get(&iio_trigger_idr, GFP_KERNEL) == 0))
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return -ENOMEM;
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spin_lock(&iio_trigger_idr_lock);
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ret = idr_get_new(&iio_trigger_idr, NULL, &trig_info->id);
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spin_unlock(&iio_trigger_idr_lock);
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if (unlikely(ret == -EAGAIN))
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goto idr_again;
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else if (likely(!ret))
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trig_info->id = trig_info->id & MAX_ID_MASK;
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return ret;
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}
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/**
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* iio_trigger_unregister_id() - free up unique id for use by another trigger
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* @trig_info: the trigger
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**/
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static void iio_trigger_unregister_id(struct iio_trigger *trig_info)
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{
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spin_lock(&iio_trigger_idr_lock);
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idr_remove(&iio_trigger_idr, trig_info->id);
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spin_unlock(&iio_trigger_idr_lock);
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}
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int iio_trigger_register(struct iio_trigger *trig_info)
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{
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int ret;
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ret = iio_trigger_register_id(trig_info);
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if (ret)
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goto error_ret;
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/* Set the name used for the sysfs directory etc */
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dev_set_name(&trig_info->dev, "trigger%ld",
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(unsigned long) trig_info->id);
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ret = device_add(&trig_info->dev);
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if (ret)
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goto error_unregister_id;
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ret = iio_trigger_register_sysfs(trig_info);
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if (ret)
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goto error_device_del;
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/* Add to list of available triggers held by the IIO core */
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mutex_lock(&iio_trigger_list_lock);
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list_add_tail(&trig_info->list, &iio_trigger_list);
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mutex_unlock(&iio_trigger_list_lock);
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return 0;
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error_device_del:
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device_del(&trig_info->dev);
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error_unregister_id:
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iio_trigger_unregister_id(trig_info);
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error_ret:
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return ret;
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}
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EXPORT_SYMBOL(iio_trigger_register);
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void iio_trigger_unregister(struct iio_trigger *trig_info)
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{
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struct iio_trigger *cursor;
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mutex_lock(&iio_trigger_list_lock);
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list_for_each_entry(cursor, &iio_trigger_list, list)
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if (cursor == trig_info) {
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list_del(&cursor->list);
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break;
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}
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mutex_unlock(&iio_trigger_list_lock);
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iio_trigger_unregister_sysfs(trig_info);
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iio_trigger_unregister_id(trig_info);
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/* Possible issue in here */
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device_unregister(&trig_info->dev);
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}
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EXPORT_SYMBOL(iio_trigger_unregister);
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struct iio_trigger *iio_trigger_find_by_name(const char *name, size_t len)
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{
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struct iio_trigger *trig;
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bool found = false;
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mutex_lock(&iio_trigger_list_lock);
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list_for_each_entry(trig, &iio_trigger_list, list) {
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if (strncmp(trig->name, name, len) == 0) {
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found = true;
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break;
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}
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}
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mutex_unlock(&iio_trigger_list_lock);
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return found ? trig : NULL;
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};
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EXPORT_SYMBOL(iio_trigger_find_by_name);
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void iio_trigger_poll(struct iio_trigger *trig)
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{
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struct iio_poll_func *pf_cursor;
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list_for_each_entry(pf_cursor, &trig->pollfunc_list, list) {
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if (pf_cursor->poll_func_immediate) {
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pf_cursor->poll_func_immediate(pf_cursor->private_data);
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trig->use_count++;
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}
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}
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list_for_each_entry(pf_cursor, &trig->pollfunc_list, list) {
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if (pf_cursor->poll_func_main) {
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pf_cursor->poll_func_main(pf_cursor->private_data);
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trig->use_count++;
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}
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}
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}
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EXPORT_SYMBOL(iio_trigger_poll);
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void iio_trigger_notify_done(struct iio_trigger *trig)
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{
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trig->use_count--;
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if (trig->use_count == 0 && trig->try_reenable)
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if (trig->try_reenable(trig)) {
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/* Missed and interrupt so launch new poll now */
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trig->timestamp = 0;
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iio_trigger_poll(trig);
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}
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}
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EXPORT_SYMBOL(iio_trigger_notify_done);
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/**
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* iio_trigger_read_name() - retrieve useful identifying name
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**/
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ssize_t iio_trigger_read_name(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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struct iio_trigger *trig = dev_get_drvdata(dev);
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return sprintf(buf, "%s\n", trig->name);
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}
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EXPORT_SYMBOL(iio_trigger_read_name);
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/* Trigger Consumer related functions */
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/* Complexity in here. With certain triggers (datardy) an acknowledgement
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* may be needed if the pollfuncs do not include the data read for the
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* triggering device.
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* This is not currently handled. Alternative of not enabling trigger unless
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* the relevant function is in there may be the best option.
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*/
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/* Worth protecting against double additions?*/
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int iio_trigger_attach_poll_func(struct iio_trigger *trig,
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struct iio_poll_func *pf)
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{
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int ret = 0;
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unsigned long flags;
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spin_lock_irqsave(&trig->pollfunc_list_lock, flags);
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list_add_tail(&pf->list, &trig->pollfunc_list);
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spin_unlock_irqrestore(&trig->pollfunc_list_lock, flags);
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if (trig->set_trigger_state)
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ret = trig->set_trigger_state(trig, true);
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if (ret) {
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printk(KERN_ERR "set trigger state failed\n");
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list_del(&pf->list);
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}
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return ret;
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}
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EXPORT_SYMBOL(iio_trigger_attach_poll_func);
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int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
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struct iio_poll_func *pf)
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{
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struct iio_poll_func *pf_cursor;
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unsigned long flags;
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int ret = -EINVAL;
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spin_lock_irqsave(&trig->pollfunc_list_lock, flags);
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list_for_each_entry(pf_cursor, &trig->pollfunc_list, list)
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if (pf_cursor == pf) {
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ret = 0;
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break;
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}
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if (!ret) {
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if (list_is_singular(&trig->pollfunc_list)
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&& trig->set_trigger_state) {
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spin_unlock_irqrestore(&trig->pollfunc_list_lock,
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flags);
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/* May sleep hence cannot hold the spin lock */
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ret = trig->set_trigger_state(trig, false);
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if (ret)
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goto error_ret;
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spin_lock_irqsave(&trig->pollfunc_list_lock, flags);
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}
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/*
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* Now we can delete safe in the knowledge that, if this is
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* the last pollfunc then we have disabled the trigger anyway
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* and so nothing should be able to call the pollfunc.
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*/
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list_del(&pf_cursor->list);
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}
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spin_unlock_irqrestore(&trig->pollfunc_list_lock, flags);
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error_ret:
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return ret;
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}
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EXPORT_SYMBOL(iio_trigger_dettach_poll_func);
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/**
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* iio_trigger_read_currrent() trigger consumer sysfs query which trigger
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*
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* For trigger consumers the current_trigger interface allows the trigger
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* used by the device to be queried.
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**/
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static ssize_t iio_trigger_read_current(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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struct iio_dev *dev_info = dev_get_drvdata(dev);
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int len = 0;
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if (dev_info->trig)
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len = snprintf(buf,
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IIO_TRIGGER_NAME_LENGTH,
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"%s\n",
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dev_info->trig->name);
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return len;
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}
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/**
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* iio_trigger_write_current() trigger consumer sysfs set current trigger
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*
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* For trigger consumers the current_trigger interface allows the trigger
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* used for this device to be specified at run time based on the triggers
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* name.
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**/
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static ssize_t iio_trigger_write_current(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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struct iio_dev *dev_info = dev_get_drvdata(dev);
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struct iio_trigger *oldtrig = dev_info->trig;
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mutex_lock(&dev_info->mlock);
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if (dev_info->currentmode == INDIO_RING_TRIGGERED) {
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mutex_unlock(&dev_info->mlock);
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return -EBUSY;
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}
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mutex_unlock(&dev_info->mlock);
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len = len < IIO_TRIGGER_NAME_LENGTH ? len : IIO_TRIGGER_NAME_LENGTH;
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dev_info->trig = iio_trigger_find_by_name(buf, len);
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if (oldtrig && dev_info->trig != oldtrig)
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iio_put_trigger(oldtrig);
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if (dev_info->trig)
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iio_get_trigger(dev_info->trig);
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return len;
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}
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DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
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iio_trigger_read_current,
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iio_trigger_write_current);
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static struct attribute *iio_trigger_consumer_attrs[] = {
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&dev_attr_current_trigger.attr,
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NULL,
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};
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static const struct attribute_group iio_trigger_consumer_attr_group = {
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.name = "trigger",
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.attrs = iio_trigger_consumer_attrs,
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};
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static void iio_trig_release(struct device *device)
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{
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struct iio_trigger *trig = to_iio_trigger(device);
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kfree(trig);
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iio_put();
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}
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static struct device_type iio_trig_type = {
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.release = iio_trig_release,
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};
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struct iio_trigger *iio_allocate_trigger(void)
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{
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struct iio_trigger *trig;
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trig = kzalloc(sizeof *trig, GFP_KERNEL);
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if (trig) {
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trig->dev.type = &iio_trig_type;
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trig->dev.class = &iio_class;
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device_initialize(&trig->dev);
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dev_set_drvdata(&trig->dev, (void *)trig);
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spin_lock_init(&trig->pollfunc_list_lock);
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INIT_LIST_HEAD(&trig->list);
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INIT_LIST_HEAD(&trig->pollfunc_list);
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iio_get();
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}
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return trig;
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}
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EXPORT_SYMBOL(iio_allocate_trigger);
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void iio_free_trigger(struct iio_trigger *trig)
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{
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if (trig)
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put_device(&trig->dev);
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}
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EXPORT_SYMBOL(iio_free_trigger);
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int iio_device_register_trigger_consumer(struct iio_dev *dev_info)
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{
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int ret;
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ret = sysfs_create_group(&dev_info->dev.kobj,
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&iio_trigger_consumer_attr_group);
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return ret;
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}
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EXPORT_SYMBOL(iio_device_register_trigger_consumer);
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int iio_device_unregister_trigger_consumer(struct iio_dev *dev_info)
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{
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sysfs_remove_group(&dev_info->dev.kobj,
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&iio_trigger_consumer_attr_group);
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return 0;
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}
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EXPORT_SYMBOL(iio_device_unregister_trigger_consumer);
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