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548 lines
14 KiB
548 lines
14 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* attribute_container.c - implementation of a simple container for classes |
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* |
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* Copyright (c) 2005 - James Bottomley <[email protected]> |
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* |
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* The basic idea here is to enable a device to be attached to an |
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* aritrary numer of classes without having to allocate storage for them. |
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* Instead, the contained classes select the devices they need to attach |
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* to via a matching function. |
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*/ |
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#include <linux/attribute_container.h> |
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#include <linux/device.h> |
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#include <linux/kernel.h> |
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#include <linux/slab.h> |
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#include <linux/list.h> |
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#include <linux/module.h> |
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#include <linux/mutex.h> |
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#include "base.h" |
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/* This is a private structure used to tie the classdev and the |
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* container .. it should never be visible outside this file */ |
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struct internal_container { |
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struct klist_node node; |
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struct attribute_container *cont; |
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struct device classdev; |
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}; |
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static void internal_container_klist_get(struct klist_node *n) |
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{ |
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struct internal_container *ic = |
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container_of(n, struct internal_container, node); |
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get_device(&ic->classdev); |
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} |
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static void internal_container_klist_put(struct klist_node *n) |
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{ |
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struct internal_container *ic = |
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container_of(n, struct internal_container, node); |
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put_device(&ic->classdev); |
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} |
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/** |
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* attribute_container_classdev_to_container - given a classdev, return the container |
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* |
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* @classdev: the class device created by attribute_container_add_device. |
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* |
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* Returns the container associated with this classdev. |
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*/ |
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struct attribute_container * |
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attribute_container_classdev_to_container(struct device *classdev) |
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{ |
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struct internal_container *ic = |
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container_of(classdev, struct internal_container, classdev); |
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return ic->cont; |
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} |
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EXPORT_SYMBOL_GPL(attribute_container_classdev_to_container); |
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static LIST_HEAD(attribute_container_list); |
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static DEFINE_MUTEX(attribute_container_mutex); |
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/** |
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* attribute_container_register - register an attribute container |
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* |
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* @cont: The container to register. This must be allocated by the |
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* callee and should also be zeroed by it. |
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*/ |
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int |
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attribute_container_register(struct attribute_container *cont) |
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{ |
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INIT_LIST_HEAD(&cont->node); |
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klist_init(&cont->containers, internal_container_klist_get, |
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internal_container_klist_put); |
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mutex_lock(&attribute_container_mutex); |
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list_add_tail(&cont->node, &attribute_container_list); |
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mutex_unlock(&attribute_container_mutex); |
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return 0; |
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} |
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EXPORT_SYMBOL_GPL(attribute_container_register); |
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/** |
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* attribute_container_unregister - remove a container registration |
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* |
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* @cont: previously registered container to remove |
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*/ |
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int |
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attribute_container_unregister(struct attribute_container *cont) |
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{ |
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int retval = -EBUSY; |
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mutex_lock(&attribute_container_mutex); |
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spin_lock(&cont->containers.k_lock); |
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if (!list_empty(&cont->containers.k_list)) |
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goto out; |
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retval = 0; |
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list_del(&cont->node); |
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out: |
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spin_unlock(&cont->containers.k_lock); |
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mutex_unlock(&attribute_container_mutex); |
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return retval; |
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} |
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EXPORT_SYMBOL_GPL(attribute_container_unregister); |
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/* private function used as class release */ |
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static void attribute_container_release(struct device *classdev) |
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{ |
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struct internal_container *ic |
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= container_of(classdev, struct internal_container, classdev); |
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struct device *dev = classdev->parent; |
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kfree(ic); |
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put_device(dev); |
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} |
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/** |
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* attribute_container_add_device - see if any container is interested in dev |
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* |
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* @dev: device to add attributes to |
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* @fn: function to trigger addition of class device. |
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* |
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* This function allocates storage for the class device(s) to be |
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* attached to dev (one for each matching attribute_container). If no |
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* fn is provided, the code will simply register the class device via |
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* device_add. If a function is provided, it is expected to add |
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* the class device at the appropriate time. One of the things that |
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* might be necessary is to allocate and initialise the classdev and |
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* then add it a later time. To do this, call this routine for |
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* allocation and initialisation and then use |
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* attribute_container_device_trigger() to call device_add() on |
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* it. Note: after this, the class device contains a reference to dev |
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* which is not relinquished until the release of the classdev. |
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*/ |
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void |
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attribute_container_add_device(struct device *dev, |
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int (*fn)(struct attribute_container *, |
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struct device *, |
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struct device *)) |
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{ |
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struct attribute_container *cont; |
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mutex_lock(&attribute_container_mutex); |
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list_for_each_entry(cont, &attribute_container_list, node) { |
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struct internal_container *ic; |
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if (attribute_container_no_classdevs(cont)) |
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continue; |
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if (!cont->match(cont, dev)) |
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continue; |
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ic = kzalloc(sizeof(*ic), GFP_KERNEL); |
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if (!ic) { |
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dev_err(dev, "failed to allocate class container\n"); |
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continue; |
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} |
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ic->cont = cont; |
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device_initialize(&ic->classdev); |
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ic->classdev.parent = get_device(dev); |
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ic->classdev.class = cont->class; |
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cont->class->dev_release = attribute_container_release; |
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dev_set_name(&ic->classdev, "%s", dev_name(dev)); |
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if (fn) |
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fn(cont, dev, &ic->classdev); |
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else |
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attribute_container_add_class_device(&ic->classdev); |
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klist_add_tail(&ic->node, &cont->containers); |
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} |
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mutex_unlock(&attribute_container_mutex); |
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} |
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/* FIXME: can't break out of this unless klist_iter_exit is also |
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* called before doing the break |
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*/ |
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#define klist_for_each_entry(pos, head, member, iter) \ |
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for (klist_iter_init(head, iter); (pos = ({ \ |
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struct klist_node *n = klist_next(iter); \ |
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n ? container_of(n, typeof(*pos), member) : \ |
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({ klist_iter_exit(iter) ; NULL; }); \ |
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})) != NULL;) |
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/** |
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* attribute_container_remove_device - make device eligible for removal. |
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* |
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* @dev: The generic device |
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* @fn: A function to call to remove the device |
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* |
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* This routine triggers device removal. If fn is NULL, then it is |
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* simply done via device_unregister (note that if something |
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* still has a reference to the classdev, then the memory occupied |
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* will not be freed until the classdev is released). If you want a |
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* two phase release: remove from visibility and then delete the |
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* device, then you should use this routine with a fn that calls |
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* device_del() and then use attribute_container_device_trigger() |
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* to do the final put on the classdev. |
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*/ |
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void |
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attribute_container_remove_device(struct device *dev, |
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void (*fn)(struct attribute_container *, |
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struct device *, |
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struct device *)) |
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{ |
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struct attribute_container *cont; |
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mutex_lock(&attribute_container_mutex); |
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list_for_each_entry(cont, &attribute_container_list, node) { |
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struct internal_container *ic; |
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struct klist_iter iter; |
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if (attribute_container_no_classdevs(cont)) |
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continue; |
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if (!cont->match(cont, dev)) |
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continue; |
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klist_for_each_entry(ic, &cont->containers, node, &iter) { |
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if (dev != ic->classdev.parent) |
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continue; |
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klist_del(&ic->node); |
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if (fn) |
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fn(cont, dev, &ic->classdev); |
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else { |
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attribute_container_remove_attrs(&ic->classdev); |
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device_unregister(&ic->classdev); |
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} |
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} |
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} |
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mutex_unlock(&attribute_container_mutex); |
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} |
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static int |
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do_attribute_container_device_trigger_safe(struct device *dev, |
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struct attribute_container *cont, |
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int (*fn)(struct attribute_container *, |
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struct device *, struct device *), |
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int (*undo)(struct attribute_container *, |
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struct device *, struct device *)) |
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{ |
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int ret; |
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struct internal_container *ic, *failed; |
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struct klist_iter iter; |
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if (attribute_container_no_classdevs(cont)) |
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return fn(cont, dev, NULL); |
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klist_for_each_entry(ic, &cont->containers, node, &iter) { |
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if (dev == ic->classdev.parent) { |
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ret = fn(cont, dev, &ic->classdev); |
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if (ret) { |
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failed = ic; |
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klist_iter_exit(&iter); |
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goto fail; |
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} |
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} |
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} |
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return 0; |
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fail: |
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if (!undo) |
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return ret; |
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/* Attempt to undo the work partially done. */ |
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klist_for_each_entry(ic, &cont->containers, node, &iter) { |
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if (ic == failed) { |
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klist_iter_exit(&iter); |
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break; |
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} |
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if (dev == ic->classdev.parent) |
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undo(cont, dev, &ic->classdev); |
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} |
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return ret; |
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} |
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/** |
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* attribute_container_device_trigger_safe - execute a trigger for each |
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* matching classdev or fail all of them. |
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* |
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* @dev: The generic device to run the trigger for |
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* @fn: the function to execute for each classdev. |
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* @undo: A function to undo the work previously done in case of error |
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* |
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* This function is a safe version of |
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* attribute_container_device_trigger. It stops on the first error and |
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* undo the partial work that has been done, on previous classdev. It |
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* is guaranteed that either they all succeeded, or none of them |
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* succeeded. |
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*/ |
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int |
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attribute_container_device_trigger_safe(struct device *dev, |
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int (*fn)(struct attribute_container *, |
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struct device *, |
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struct device *), |
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int (*undo)(struct attribute_container *, |
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struct device *, |
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struct device *)) |
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{ |
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struct attribute_container *cont, *failed = NULL; |
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int ret = 0; |
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mutex_lock(&attribute_container_mutex); |
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list_for_each_entry(cont, &attribute_container_list, node) { |
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if (!cont->match(cont, dev)) |
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continue; |
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ret = do_attribute_container_device_trigger_safe(dev, cont, |
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fn, undo); |
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if (ret) { |
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failed = cont; |
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break; |
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} |
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} |
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if (ret && !WARN_ON(!undo)) { |
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list_for_each_entry(cont, &attribute_container_list, node) { |
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if (failed == cont) |
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break; |
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if (!cont->match(cont, dev)) |
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continue; |
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do_attribute_container_device_trigger_safe(dev, cont, |
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undo, NULL); |
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} |
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} |
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mutex_unlock(&attribute_container_mutex); |
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return ret; |
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} |
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/** |
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* attribute_container_device_trigger - execute a trigger for each matching classdev |
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* |
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* @dev: The generic device to run the trigger for |
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* @fn: the function to execute for each classdev. |
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* |
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* This function is for executing a trigger when you need to know both |
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* the container and the classdev. If you only care about the |
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* container, then use attribute_container_trigger() instead. |
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*/ |
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void |
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attribute_container_device_trigger(struct device *dev, |
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int (*fn)(struct attribute_container *, |
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struct device *, |
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struct device *)) |
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{ |
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struct attribute_container *cont; |
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mutex_lock(&attribute_container_mutex); |
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list_for_each_entry(cont, &attribute_container_list, node) { |
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struct internal_container *ic; |
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struct klist_iter iter; |
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if (!cont->match(cont, dev)) |
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continue; |
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if (attribute_container_no_classdevs(cont)) { |
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fn(cont, dev, NULL); |
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continue; |
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} |
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klist_for_each_entry(ic, &cont->containers, node, &iter) { |
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if (dev == ic->classdev.parent) |
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fn(cont, dev, &ic->classdev); |
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} |
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} |
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mutex_unlock(&attribute_container_mutex); |
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} |
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/** |
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* attribute_container_trigger - trigger a function for each matching container |
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* |
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* @dev: The generic device to activate the trigger for |
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* @fn: the function to trigger |
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* |
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* This routine triggers a function that only needs to know the |
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* matching containers (not the classdev) associated with a device. |
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* It is more lightweight than attribute_container_device_trigger, so |
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* should be used in preference unless the triggering function |
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* actually needs to know the classdev. |
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*/ |
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void |
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attribute_container_trigger(struct device *dev, |
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int (*fn)(struct attribute_container *, |
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struct device *)) |
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{ |
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struct attribute_container *cont; |
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mutex_lock(&attribute_container_mutex); |
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list_for_each_entry(cont, &attribute_container_list, node) { |
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if (cont->match(cont, dev)) |
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fn(cont, dev); |
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} |
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mutex_unlock(&attribute_container_mutex); |
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} |
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/** |
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* attribute_container_add_attrs - add attributes |
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* |
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* @classdev: The class device |
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* |
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* This simply creates all the class device sysfs files from the |
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* attributes listed in the container |
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*/ |
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int |
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attribute_container_add_attrs(struct device *classdev) |
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{ |
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struct attribute_container *cont = |
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attribute_container_classdev_to_container(classdev); |
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struct device_attribute **attrs = cont->attrs; |
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int i, error; |
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BUG_ON(attrs && cont->grp); |
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if (!attrs && !cont->grp) |
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return 0; |
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if (cont->grp) |
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return sysfs_create_group(&classdev->kobj, cont->grp); |
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for (i = 0; attrs[i]; i++) { |
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sysfs_attr_init(&attrs[i]->attr); |
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error = device_create_file(classdev, attrs[i]); |
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if (error) |
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return error; |
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} |
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return 0; |
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} |
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/** |
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* attribute_container_add_class_device - same function as device_add |
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* |
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* @classdev: the class device to add |
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* |
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* This performs essentially the same function as device_add except for |
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* attribute containers, namely add the classdev to the system and then |
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* create the attribute files |
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*/ |
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int |
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attribute_container_add_class_device(struct device *classdev) |
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{ |
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int error = device_add(classdev); |
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if (error) |
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return error; |
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return attribute_container_add_attrs(classdev); |
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} |
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/** |
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* attribute_container_add_class_device_adapter - simple adapter for triggers |
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* |
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* @cont: the container to register. |
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* @dev: the generic device to activate the trigger for |
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* @classdev: the class device to add |
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* |
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* This function is identical to attribute_container_add_class_device except |
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* that it is designed to be called from the triggers |
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*/ |
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int |
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attribute_container_add_class_device_adapter(struct attribute_container *cont, |
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struct device *dev, |
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struct device *classdev) |
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{ |
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return attribute_container_add_class_device(classdev); |
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} |
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/** |
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* attribute_container_remove_attrs - remove any attribute files |
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* |
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* @classdev: The class device to remove the files from |
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* |
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*/ |
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void |
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attribute_container_remove_attrs(struct device *classdev) |
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{ |
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struct attribute_container *cont = |
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attribute_container_classdev_to_container(classdev); |
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struct device_attribute **attrs = cont->attrs; |
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int i; |
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if (!attrs && !cont->grp) |
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return; |
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if (cont->grp) { |
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sysfs_remove_group(&classdev->kobj, cont->grp); |
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return ; |
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} |
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for (i = 0; attrs[i]; i++) |
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device_remove_file(classdev, attrs[i]); |
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} |
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/** |
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* attribute_container_class_device_del - equivalent of class_device_del |
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* |
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* @classdev: the class device |
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* |
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* This function simply removes all the attribute files and then calls |
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* device_del. |
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*/ |
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void |
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attribute_container_class_device_del(struct device *classdev) |
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{ |
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attribute_container_remove_attrs(classdev); |
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device_del(classdev); |
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} |
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/** |
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* attribute_container_find_class_device - find the corresponding class_device |
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* |
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* @cont: the container |
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* @dev: the generic device |
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* |
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* Looks up the device in the container's list of class devices and returns |
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* the corresponding class_device. |
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*/ |
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struct device * |
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attribute_container_find_class_device(struct attribute_container *cont, |
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struct device *dev) |
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{ |
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struct device *cdev = NULL; |
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struct internal_container *ic; |
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struct klist_iter iter; |
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klist_for_each_entry(ic, &cont->containers, node, &iter) { |
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if (ic->classdev.parent == dev) { |
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cdev = &ic->classdev; |
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/* FIXME: must exit iterator then break */ |
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klist_iter_exit(&iter); |
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break; |
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} |
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} |
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return cdev; |
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} |
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EXPORT_SYMBOL_GPL(attribute_container_find_class_device);
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