drivers/media/cec/cec-core.c - linux - Git at Google

 /*
  * cec-core.c - HDMI Consumer Electronics Control framework - Core
  *
  * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
  *
  * This program is free software; you may redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; version 2 of the License.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */

 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/kmod.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
 #include <linux/string.h>
 #include <linux/types.h>

 #include "cec-priv.h"

 #define CEC_NUM_DEVICES	256
 #define CEC_NAME	"cec"

 int cec_debug;
 module_param_named(debug, cec_debug, int, 0644);
 MODULE_PARM_DESC(debug, "debug level (0-2)");

 static dev_t cec_dev_t;

 /* Active devices */
 static DEFINE_MUTEX(cec_devnode_lock);
 static DECLARE_BITMAP(cec_devnode_nums, CEC_NUM_DEVICES);

 static struct dentry *top_cec_dir;

 /* dev to cec_devnode */
 #define to_cec_devnode(cd) container_of(cd, struct cec_devnode, dev)

 int cec_get_device(struct cec_devnode *devnode)
 {
 	/*
 	 * Check if the cec device is available. This needs to be done with
 	 * the devnode->lock held to prevent an open/unregister race:
 	 * without the lock, the device could be unregistered and freed between
 	 * the devnode->registered check and get_device() calls, leading to
 	 * a crash.
 	 */
 	mutex_lock(&devnode->lock);
 	/*
 	 * return ENXIO if the cec device has been removed
 	 * already or if it is not registered anymore.
 	 */
 	if (!devnode->registered) {
 		mutex_unlock(&devnode->lock);
 		return -ENXIO;
 	}
 	/* and increase the device refcount */
 	get_device(&devnode->dev);
 	mutex_unlock(&devnode->lock);
 	return 0;
 }

 void cec_put_device(struct cec_devnode *devnode)
 {
 	put_device(&devnode->dev);
 }

 /* Called when the last user of the cec device exits. */
 static void cec_devnode_release(struct device *cd)
 {
 	struct cec_devnode *devnode = to_cec_devnode(cd);

 	mutex_lock(&cec_devnode_lock);
 	/* Mark device node number as free */
 	clear_bit(devnode->minor, cec_devnode_nums);
 	mutex_unlock(&cec_devnode_lock);

 	cec_delete_adapter(to_cec_adapter(devnode));
 }

 static struct bus_type cec_bus_type = {
 	.name = CEC_NAME,
 };

 /*
  * Register a cec device node
  *
  * The registration code assigns minor numbers and registers the new device node
  * with the kernel. An error is returned if no free minor number can be found,
  * or if the registration of the device node fails.
  *
  * Zero is returned on success.
  *
  * Note that if the cec_devnode_register call fails, the release() callback of
  * the cec_devnode structure is *not* called, so the caller is responsible for
  * freeing any data.
  */
 static int __must_check cec_devnode_register(struct cec_devnode *devnode,
 					     struct module *owner)
 {
 	int minor;
 	int ret;

 	/* Initialization */
 	INIT_LIST_HEAD(&devnode->fhs);
 	mutex_init(&devnode->lock);

 	/* Part 1: Find a free minor number */
 	mutex_lock(&cec_devnode_lock);
 	minor = find_next_zero_bit(cec_devnode_nums, CEC_NUM_DEVICES, 0);
 	if (minor == CEC_NUM_DEVICES) {
 		mutex_unlock(&cec_devnode_lock);
 		pr_err("could not get a free minor\n");
 		return -ENFILE;
 	}

 	set_bit(minor, cec_devnode_nums);
 	mutex_unlock(&cec_devnode_lock);

 	devnode->minor = minor;
 	devnode->dev.bus = &cec_bus_type;
 	devnode->dev.devt = MKDEV(MAJOR(cec_dev_t), minor);
 	devnode->dev.release = cec_devnode_release;
 	devnode->dev.parent = devnode->parent;
 	dev_set_name(&devnode->dev, "cec%d", devnode->minor);
 	device_initialize(&devnode->dev);

 	/* Part 2: Initialize and register the character device */
 	cdev_init(&devnode->cdev, &cec_devnode_fops);
 	devnode->cdev.kobj.parent = &devnode->dev.kobj;
 	devnode->cdev.owner = owner;

 	ret = cdev_add(&devnode->cdev, devnode->dev.devt, 1);
 	if (ret < 0) {
 		pr_err("%s: cdev_add failed\n", __func__);
 		goto clr_bit;
 	}

 	ret = device_add(&devnode->dev);
 	if (ret)
 		goto cdev_del;

 	devnode->registered = true;
 	return 0;

 cdev_del:
 	cdev_del(&devnode->cdev);
 clr_bit:
 	mutex_lock(&cec_devnode_lock);
 	clear_bit(devnode->minor, cec_devnode_nums);
 	mutex_unlock(&cec_devnode_lock);
 	return ret;
 }

 /*
  * Unregister a cec device node
  *
  * This unregisters the passed device. Future open calls will be met with
  * errors.
  *
  * This function can safely be called if the device node has never been
  * registered or has already been unregistered.
  */
 static void cec_devnode_unregister(struct cec_devnode *devnode)
 {
 	struct cec_fh *fh;

 	mutex_lock(&devnode->lock);

 	/* Check if devnode was never registered or already unregistered */
 	if (!devnode->registered || devnode->unregistered) {
 		mutex_unlock(&devnode->lock);
 		return;
 	}

 	list_for_each_entry(fh, &devnode->fhs, list)
 		wake_up_interruptible(&fh->wait);

 	devnode->registered = false;
 	devnode->unregistered = true;
 	mutex_unlock(&devnode->lock);

 	device_del(&devnode->dev);
 	cdev_del(&devnode->cdev);
 	put_device(&devnode->dev);
 }

 struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
 					 void *priv, const char *name, u32 caps,
 					 u8 available_las, struct device *parent)
 {
 	struct cec_adapter *adap;
 	int res;

 	if (WARN_ON(!parent))
 		return ERR_PTR(-EINVAL);
 	if (WARN_ON(!caps))
 		return ERR_PTR(-EINVAL);
 	if (WARN_ON(!ops))
 		return ERR_PTR(-EINVAL);
 	if (WARN_ON(!available_las || available_las > CEC_MAX_LOG_ADDRS))
 		return ERR_PTR(-EINVAL);
 	adap = kzalloc(sizeof(*adap), GFP_KERNEL);
 	if (!adap)
 		return ERR_PTR(-ENOMEM);
 	adap->owner = parent->driver->owner;
 	adap->devnode.parent = parent;
 	strlcpy(adap->name, name, sizeof(adap->name));
 	adap->phys_addr = CEC_PHYS_ADDR_INVALID;
 	adap->log_addrs.cec_version = CEC_OP_CEC_VERSION_2_0;
 	adap->log_addrs.vendor_id = CEC_VENDOR_ID_NONE;
 	adap->capabilities = caps;
 	adap->available_log_addrs = available_las;
 	adap->sequence = 0;
 	adap->ops = ops;
 	adap->priv = priv;
 	memset(adap->phys_addrs, 0xff, sizeof(adap->phys_addrs));
 	mutex_init(&adap->lock);
 	INIT_LIST_HEAD(&adap->transmit_queue);
 	INIT_LIST_HEAD(&adap->wait_queue);
 	init_waitqueue_head(&adap->kthread_waitq);

 	adap->kthread = kthread_run(cec_thread_func, adap, "cec-%s", name);
 	if (IS_ERR(adap->kthread)) {
 		pr_err("cec-%s: kernel_thread() failed\n", name);
 		res = PTR_ERR(adap->kthread);
 		kfree(adap);
 		return ERR_PTR(res);
 	}

 	if (!(caps & CEC_CAP_RC))
 		return adap;

 #if IS_REACHABLE(CONFIG_RC_CORE)
 	/* Prepare the RC input device */
 	adap->rc = rc_allocate_device();
 	if (!adap->rc) {
 		pr_err("cec-%s: failed to allocate memory for rc_dev\n",
 		       name);
 		kthread_stop(adap->kthread);
 		kfree(adap);
 		return ERR_PTR(-ENOMEM);
 	}

 	snprintf(adap->input_name, sizeof(adap->input_name),
 		 "RC for %s", name);
 	snprintf(adap->input_phys, sizeof(adap->input_phys),
 		 "%s/input0", name);

 	adap->rc->input_name = adap->input_name;
 	adap->rc->input_phys = adap->input_phys;
 	adap->rc->input_id.bustype = BUS_CEC;
 	adap->rc->input_id.vendor = 0;
 	adap->rc->input_id.product = 0;
 	adap->rc->input_id.version = 1;
 	adap->rc->dev.parent = parent;
 	adap->rc->driver_type = RC_DRIVER_SCANCODE;
 	adap->rc->driver_name = CEC_NAME;
 	adap->rc->allowed_protocols = RC_BIT_CEC;
 	adap->rc->priv = adap;
 	adap->rc->map_name = RC_MAP_CEC;
 	adap->rc->timeout = MS_TO_NS(100);
 #else
 	adap->capabilities &= ~CEC_CAP_RC;
 #endif
 	return adap;
 }
 EXPORT_SYMBOL_GPL(cec_allocate_adapter);

 int cec_register_adapter(struct cec_adapter *adap)
 {
 	int res;

 	if (IS_ERR_OR_NULL(adap))
 		return 0;

 #if IS_REACHABLE(CONFIG_RC_CORE)
 	if (adap->capabilities & CEC_CAP_RC) {
 		res = rc_register_device(adap->rc);

 		if (res) {
 			pr_err("cec-%s: failed to prepare input device\n",
 			       adap->name);
 			rc_free_device(adap->rc);
 			adap->rc = NULL;
 			return res;
 		}
 	}
 #endif

 	res = cec_devnode_register(&adap->devnode, adap->owner);
 	if (res) {
 #if IS_REACHABLE(CONFIG_RC_CORE)
 		/* Note: rc_unregister also calls rc_free */
 		rc_unregister_device(adap->rc);
 		adap->rc = NULL;
 #endif
 		return res;
 	}

 	dev_set_drvdata(&adap->devnode.dev, adap);
 #ifdef CONFIG_MEDIA_CEC_DEBUG
 	if (!top_cec_dir)
 		return 0;

 	adap->cec_dir = debugfs_create_dir(dev_name(&adap->devnode.dev), top_cec_dir);
 	if (IS_ERR_OR_NULL(adap->cec_dir)) {
 		pr_warn("cec-%s: Failed to create debugfs dir\n", adap->name);
 		return 0;
 	}
 	adap->status_file = debugfs_create_devm_seqfile(&adap->devnode.dev,
 		"status", adap->cec_dir, cec_adap_status);
 	if (IS_ERR_OR_NULL(adap->status_file)) {
 		pr_warn("cec-%s: Failed to create status file\n", adap->name);
 		debugfs_remove_recursive(adap->cec_dir);
 		adap->cec_dir = NULL;
 	}
 #endif
 	return 0;
 }
 EXPORT_SYMBOL_GPL(cec_register_adapter);

 void cec_unregister_adapter(struct cec_adapter *adap)
 {
 	if (IS_ERR_OR_NULL(adap))
 		return;

 #if IS_REACHABLE(CONFIG_RC_CORE)
 	/* Note: rc_unregister also calls rc_free */
 	rc_unregister_device(adap->rc);
 	adap->rc = NULL;
 #endif
 	debugfs_remove_recursive(adap->cec_dir);
 	cec_devnode_unregister(&adap->devnode);
 }
 EXPORT_SYMBOL_GPL(cec_unregister_adapter);

 void cec_delete_adapter(struct cec_adapter *adap)
 {
 	if (IS_ERR_OR_NULL(adap))
 		return;
 	mutex_lock(&adap->lock);
 	__cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false);
 	mutex_unlock(&adap->lock);
 	kthread_stop(adap->kthread);
 	if (adap->kthread_config)
 		kthread_stop(adap->kthread_config);
 #if IS_REACHABLE(CONFIG_RC_CORE)
 	rc_free_device(adap->rc);
 #endif
 	kfree(adap);
 }
 EXPORT_SYMBOL_GPL(cec_delete_adapter);

 /*
  *	Initialise cec for linux
  */
 static int __init cec_devnode_init(void)
 {
 	int ret;

 	pr_info("Linux cec interface: v0.10\n");
 	ret = alloc_chrdev_region(&cec_dev_t, 0, CEC_NUM_DEVICES,
 				  CEC_NAME);
 	if (ret < 0) {
 		pr_warn("cec: unable to allocate major\n");
 		return ret;
 	}

 #ifdef CONFIG_MEDIA_CEC_DEBUG
 	top_cec_dir = debugfs_create_dir("cec", NULL);
 	if (IS_ERR_OR_NULL(top_cec_dir)) {
 		pr_warn("cec: Failed to create debugfs cec dir\n");
 		top_cec_dir = NULL;
 	}
 #endif

 	ret = bus_register(&cec_bus_type);
 	if (ret < 0) {
 		unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES);
 		pr_warn("cec: bus_register failed\n");
 		return -EIO;
 	}

 	return 0;
 }

 static void __exit cec_devnode_exit(void)
 {
 	debugfs_remove_recursive(top_cec_dir);
 	bus_unregister(&cec_bus_type);
 	unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES);
 }

 subsys_initcall(cec_devnode_init);
 module_exit(cec_devnode_exit)

 MODULE_AUTHOR("Hans Verkuil <hans.verkuil@cisco.com>");
 MODULE_DESCRIPTION("Device node registration for cec drivers");
 MODULE_LICENSE("GPL");
	/*
	* cec-core.c - HDMI Consumer Electronics Control framework - Core
	*
	* Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
	*
	* This program is free software; you may redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; version 2 of the License.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
	* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
	* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
	* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
	* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
	* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	* SOFTWARE.
	*/

	#include <linux/errno.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/kmod.h>
	#include <linux/slab.h>
	#include <linux/mm.h>
	#include <linux/string.h>
	#include <linux/types.h>

	#include "cec-priv.h"

	#define CEC_NUM_DEVICES 256
	#define CEC_NAME "cec"

	int cec_debug;
	module_param_named(debug, cec_debug, int, 0644);
	MODULE_PARM_DESC(debug, "debug level (0-2)");

	static dev_t cec_dev_t;

	/* Active devices */
	static DEFINE_MUTEX(cec_devnode_lock);
	static DECLARE_BITMAP(cec_devnode_nums, CEC_NUM_DEVICES);

	static struct dentry *top_cec_dir;

	/* dev to cec_devnode */
	#define to_cec_devnode(cd) container_of(cd, struct cec_devnode, dev)

	int cec_get_device(struct cec_devnode *devnode)
	{
	/*
	* Check if the cec device is available. This needs to be done with
	* the devnode->lock held to prevent an open/unregister race:
	* without the lock, the device could be unregistered and freed between
	* the devnode->registered check and get_device() calls, leading to
	* a crash.
	*/
	mutex_lock(&devnode->lock);
	/*
	* return ENXIO if the cec device has been removed
	* already or if it is not registered anymore.
	*/
	if (!devnode->registered) {
	mutex_unlock(&devnode->lock);
	return -ENXIO;
	}
	/* and increase the device refcount */
	get_device(&devnode->dev);
	mutex_unlock(&devnode->lock);
	return 0;
	}

	void cec_put_device(struct cec_devnode *devnode)
	{
	put_device(&devnode->dev);
	}

	/* Called when the last user of the cec device exits. */
	static void cec_devnode_release(struct device *cd)
	{
	struct cec_devnode *devnode = to_cec_devnode(cd);

	mutex_lock(&cec_devnode_lock);
	/* Mark device node number as free */
	clear_bit(devnode->minor, cec_devnode_nums);
	mutex_unlock(&cec_devnode_lock);

	cec_delete_adapter(to_cec_adapter(devnode));
	}

	static struct bus_type cec_bus_type = {
	.name = CEC_NAME,
	};

	/*
	* Register a cec device node
	*
	* The registration code assigns minor numbers and registers the new device node
	* with the kernel. An error is returned if no free minor number can be found,
	* or if the registration of the device node fails.
	*
	* Zero is returned on success.
	*
	* Note that if the cec_devnode_register call fails, the release() callback of
	* the cec_devnode structure is not called, so the caller is responsible for
	* freeing any data.
	*/
	static int __must_check cec_devnode_register(struct cec_devnode *devnode,
	struct module *owner)
	{
	int minor;
	int ret;

	/* Initialization */
	INIT_LIST_HEAD(&devnode->fhs);
	mutex_init(&devnode->lock);

	/* Part 1: Find a free minor number */
	mutex_lock(&cec_devnode_lock);
	minor = find_next_zero_bit(cec_devnode_nums, CEC_NUM_DEVICES, 0);
	if (minor == CEC_NUM_DEVICES) {
	mutex_unlock(&cec_devnode_lock);
	pr_err("could not get a free minor\n");
	return -ENFILE;
	}

	set_bit(minor, cec_devnode_nums);
	mutex_unlock(&cec_devnode_lock);

	devnode->minor = minor;
	devnode->dev.bus = &cec_bus_type;
	devnode->dev.devt = MKDEV(MAJOR(cec_dev_t), minor);
	devnode->dev.release = cec_devnode_release;
	devnode->dev.parent = devnode->parent;
	dev_set_name(&devnode->dev, "cec%d", devnode->minor);
	device_initialize(&devnode->dev);

	/* Part 2: Initialize and register the character device */
	cdev_init(&devnode->cdev, &cec_devnode_fops);
	devnode->cdev.kobj.parent = &devnode->dev.kobj;
	devnode->cdev.owner = owner;

	ret = cdev_add(&devnode->cdev, devnode->dev.devt, 1);
	if (ret < 0) {
	pr_err("%s: cdev_add failed\n", __func__);
	goto clr_bit;
	}

	ret = device_add(&devnode->dev);
	if (ret)
	goto cdev_del;

	devnode->registered = true;
	return 0;

	cdev_del:
	cdev_del(&devnode->cdev);
	clr_bit:
	mutex_lock(&cec_devnode_lock);
	clear_bit(devnode->minor, cec_devnode_nums);
	mutex_unlock(&cec_devnode_lock);
	return ret;
	}

	/*
	* Unregister a cec device node
	*
	* This unregisters the passed device. Future open calls will be met with
	* errors.
	*
	* This function can safely be called if the device node has never been
	* registered or has already been unregistered.
	*/
	static void cec_devnode_unregister(struct cec_devnode *devnode)
	{
	struct cec_fh *fh;

	mutex_lock(&devnode->lock);

	/* Check if devnode was never registered or already unregistered */
	if (!devnode->registered \|\| devnode->unregistered) {
	mutex_unlock(&devnode->lock);
	return;
	}

	list_for_each_entry(fh, &devnode->fhs, list)
	wake_up_interruptible(&fh->wait);

	devnode->registered = false;
	devnode->unregistered = true;
	mutex_unlock(&devnode->lock);

	device_del(&devnode->dev);
	cdev_del(&devnode->cdev);
	put_device(&devnode->dev);
	}

	struct cec_adapter cec_allocate_adapter(const struct cec_adap_ops ops,
	void priv, const char name, u32 caps,
	u8 available_las, struct device *parent)
	{
	struct cec_adapter *adap;
	int res;

	if (WARN_ON(!parent))
	return ERR_PTR(-EINVAL);
	if (WARN_ON(!caps))
	return ERR_PTR(-EINVAL);
	if (WARN_ON(!ops))
	return ERR_PTR(-EINVAL);
	if (WARN_ON(!available_las \|\| available_las > CEC_MAX_LOG_ADDRS))
	return ERR_PTR(-EINVAL);
	adap = kzalloc(sizeof(*adap), GFP_KERNEL);
	if (!adap)
	return ERR_PTR(-ENOMEM);
	adap->owner = parent->driver->owner;
	adap->devnode.parent = parent;
	strlcpy(adap->name, name, sizeof(adap->name));
	adap->phys_addr = CEC_PHYS_ADDR_INVALID;
	adap->log_addrs.cec_version = CEC_OP_CEC_VERSION_2_0;
	adap->log_addrs.vendor_id = CEC_VENDOR_ID_NONE;
	adap->capabilities = caps;
	adap->available_log_addrs = available_las;
	adap->sequence = 0;
	adap->ops = ops;
	adap->priv = priv;
	memset(adap->phys_addrs, 0xff, sizeof(adap->phys_addrs));
	mutex_init(&adap->lock);
	INIT_LIST_HEAD(&adap->transmit_queue);
	INIT_LIST_HEAD(&adap->wait_queue);
	init_waitqueue_head(&adap->kthread_waitq);

	adap->kthread = kthread_run(cec_thread_func, adap, "cec-%s", name);
	if (IS_ERR(adap->kthread)) {
	pr_err("cec-%s: kernel_thread() failed\n", name);
	res = PTR_ERR(adap->kthread);
	kfree(adap);
	return ERR_PTR(res);
	}

	if (!(caps & CEC_CAP_RC))
	return adap;

	#if IS_REACHABLE(CONFIG_RC_CORE)
	/* Prepare the RC input device */
	adap->rc = rc_allocate_device();
	if (!adap->rc) {
	pr_err("cec-%s: failed to allocate memory for rc_dev\n",
	name);
	kthread_stop(adap->kthread);
	kfree(adap);
	return ERR_PTR(-ENOMEM);
	}

	snprintf(adap->input_name, sizeof(adap->input_name),
	"RC for %s", name);
	snprintf(adap->input_phys, sizeof(adap->input_phys),
	"%s/input0", name);

	adap->rc->input_name = adap->input_name;
	adap->rc->input_phys = adap->input_phys;
	adap->rc->input_id.bustype = BUS_CEC;
	adap->rc->input_id.vendor = 0;
	adap->rc->input_id.product = 0;
	adap->rc->input_id.version = 1;
	adap->rc->dev.parent = parent;
	adap->rc->driver_type = RC_DRIVER_SCANCODE;
	adap->rc->driver_name = CEC_NAME;
	adap->rc->allowed_protocols = RC_BIT_CEC;
	adap->rc->priv = adap;
	adap->rc->map_name = RC_MAP_CEC;
	adap->rc->timeout = MS_TO_NS(100);
	#else
	adap->capabilities &= ~CEC_CAP_RC;
	#endif
	return adap;
	}
	EXPORT_SYMBOL_GPL(cec_allocate_adapter);

	int cec_register_adapter(struct cec_adapter *adap)
	{
	int res;

	if (IS_ERR_OR_NULL(adap))
	return 0;

	#if IS_REACHABLE(CONFIG_RC_CORE)
	if (adap->capabilities & CEC_CAP_RC) {
	res = rc_register_device(adap->rc);

	if (res) {
	pr_err("cec-%s: failed to prepare input device\n",
	adap->name);
	rc_free_device(adap->rc);
	adap->rc = NULL;
	return res;
	}
	}
	#endif

	res = cec_devnode_register(&adap->devnode, adap->owner);
	if (res) {
	#if IS_REACHABLE(CONFIG_RC_CORE)
	/* Note: rc_unregister also calls rc_free */
	rc_unregister_device(adap->rc);
	adap->rc = NULL;
	#endif
	return res;
	}

	dev_set_drvdata(&adap->devnode.dev, adap);
	#ifdef CONFIG_MEDIA_CEC_DEBUG
	if (!top_cec_dir)
	return 0;

	adap->cec_dir = debugfs_create_dir(dev_name(&adap->devnode.dev), top_cec_dir);
	if (IS_ERR_OR_NULL(adap->cec_dir)) {
	pr_warn("cec-%s: Failed to create debugfs dir\n", adap->name);
	return 0;
	}
	adap->status_file = debugfs_create_devm_seqfile(&adap->devnode.dev,
	"status", adap->cec_dir, cec_adap_status);
	if (IS_ERR_OR_NULL(adap->status_file)) {
	pr_warn("cec-%s: Failed to create status file\n", adap->name);
	debugfs_remove_recursive(adap->cec_dir);
	adap->cec_dir = NULL;
	}
	#endif
	return 0;
	}
	EXPORT_SYMBOL_GPL(cec_register_adapter);

	void cec_unregister_adapter(struct cec_adapter *adap)
	{
	if (IS_ERR_OR_NULL(adap))
	return;

	#if IS_REACHABLE(CONFIG_RC_CORE)
	/* Note: rc_unregister also calls rc_free */
	rc_unregister_device(adap->rc);
	adap->rc = NULL;
	#endif
	debugfs_remove_recursive(adap->cec_dir);
	cec_devnode_unregister(&adap->devnode);
	}
	EXPORT_SYMBOL_GPL(cec_unregister_adapter);

	void cec_delete_adapter(struct cec_adapter *adap)
	{
	if (IS_ERR_OR_NULL(adap))
	return;
	mutex_lock(&adap->lock);
	__cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false);
	mutex_unlock(&adap->lock);
	kthread_stop(adap->kthread);
	if (adap->kthread_config)
	kthread_stop(adap->kthread_config);
	#if IS_REACHABLE(CONFIG_RC_CORE)
	rc_free_device(adap->rc);
	#endif
	kfree(adap);
	}
	EXPORT_SYMBOL_GPL(cec_delete_adapter);

	/*
	* Initialise cec for linux
	*/
	static int __init cec_devnode_init(void)
	{
	int ret;

	pr_info("Linux cec interface: v0.10\n");
	ret = alloc_chrdev_region(&cec_dev_t, 0, CEC_NUM_DEVICES,
	CEC_NAME);
	if (ret < 0) {
	pr_warn("cec: unable to allocate major\n");
	return ret;
	}

	#ifdef CONFIG_MEDIA_CEC_DEBUG
	top_cec_dir = debugfs_create_dir("cec", NULL);
	if (IS_ERR_OR_NULL(top_cec_dir)) {
	pr_warn("cec: Failed to create debugfs cec dir\n");
	top_cec_dir = NULL;
	}
	#endif

	ret = bus_register(&cec_bus_type);
	if (ret < 0) {
	unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES);
	pr_warn("cec: bus_register failed\n");
	return -EIO;
	}

	return 0;
	}

	static void __exit cec_devnode_exit(void)
	{
	debugfs_remove_recursive(top_cec_dir);
	bus_unregister(&cec_bus_type);
	unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES);
	}

	subsys_initcall(cec_devnode_init);
	module_exit(cec_devnode_exit)

	MODULE_AUTHOR("Hans Verkuil <hans.verkuil@cisco.com>");
	MODULE_DESCRIPTION("Device node registration for cec drivers");
	MODULE_LICENSE("GPL");