2 * cec-core.c - HDMI Consumer Electronics Control framework - Core
4 * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
6 * This program is free software; you may redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; version 2 of the License.
10 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
11 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
12 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
13 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
14 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
15 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
16 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
20 #include <linux/errno.h>
21 #include <linux/init.h>
22 #include <linux/module.h>
23 #include <linux/kernel.h>
24 #include <linux/kmod.h>
25 #include <linux/slab.h>
27 #include <linux/string.h>
28 #include <linux/types.h>
32 #define CEC_NUM_DEVICES 256
33 #define CEC_NAME "cec"
36 module_param_named(debug, cec_debug, int, 0644);
37 MODULE_PARM_DESC(debug, "debug level (0-2)");
39 static dev_t cec_dev_t;
42 static DEFINE_MUTEX(cec_devnode_lock);
43 static DECLARE_BITMAP(cec_devnode_nums, CEC_NUM_DEVICES);
45 static struct dentry *top_cec_dir;
47 /* dev to cec_devnode */
48 #define to_cec_devnode(cd) container_of(cd, struct cec_devnode, dev)
50 int cec_get_device(struct cec_devnode *devnode)
53 * Check if the cec device is available. This needs to be done with
54 * the devnode->lock held to prevent an open/unregister race:
55 * without the lock, the device could be unregistered and freed between
56 * the devnode->registered check and get_device() calls, leading to
59 mutex_lock(&devnode->lock);
61 * return ENXIO if the cec device has been removed
62 * already or if it is not registered anymore.
64 if (!devnode->registered) {
65 mutex_unlock(&devnode->lock);
68 /* and increase the device refcount */
69 get_device(&devnode->dev);
70 mutex_unlock(&devnode->lock);
74 void cec_put_device(struct cec_devnode *devnode)
76 put_device(&devnode->dev);
79 /* Called when the last user of the cec device exits. */
80 static void cec_devnode_release(struct device *cd)
82 struct cec_devnode *devnode = to_cec_devnode(cd);
84 mutex_lock(&cec_devnode_lock);
85 /* Mark device node number as free */
86 clear_bit(devnode->minor, cec_devnode_nums);
87 mutex_unlock(&cec_devnode_lock);
89 cec_delete_adapter(to_cec_adapter(devnode));
92 static struct bus_type cec_bus_type = {
97 * Register a cec device node
99 * The registration code assigns minor numbers and registers the new device node
100 * with the kernel. An error is returned if no free minor number can be found,
101 * or if the registration of the device node fails.
103 * Zero is returned on success.
105 * Note that if the cec_devnode_register call fails, the release() callback of
106 * the cec_devnode structure is *not* called, so the caller is responsible for
109 static int __must_check cec_devnode_register(struct cec_devnode *devnode,
110 struct module *owner)
116 INIT_LIST_HEAD(&devnode->fhs);
117 mutex_init(&devnode->lock);
119 /* Part 1: Find a free minor number */
120 mutex_lock(&cec_devnode_lock);
121 minor = find_next_zero_bit(cec_devnode_nums, CEC_NUM_DEVICES, 0);
122 if (minor == CEC_NUM_DEVICES) {
123 mutex_unlock(&cec_devnode_lock);
124 pr_err("could not get a free minor\n");
128 set_bit(minor, cec_devnode_nums);
129 mutex_unlock(&cec_devnode_lock);
131 devnode->minor = minor;
132 devnode->dev.bus = &cec_bus_type;
133 devnode->dev.devt = MKDEV(MAJOR(cec_dev_t), minor);
134 devnode->dev.release = cec_devnode_release;
135 dev_set_name(&devnode->dev, "cec%d", devnode->minor);
136 device_initialize(&devnode->dev);
138 /* Part 2: Initialize and register the character device */
139 cdev_init(&devnode->cdev, &cec_devnode_fops);
140 devnode->cdev.owner = owner;
142 ret = cdev_device_add(&devnode->cdev, &devnode->dev);
144 pr_err("%s: cdev_device_add failed\n", __func__);
148 devnode->registered = true;
152 mutex_lock(&cec_devnode_lock);
153 clear_bit(devnode->minor, cec_devnode_nums);
154 mutex_unlock(&cec_devnode_lock);
159 * Unregister a cec device node
161 * This unregisters the passed device. Future open calls will be met with
164 * This function can safely be called if the device node has never been
165 * registered or has already been unregistered.
167 static void cec_devnode_unregister(struct cec_devnode *devnode)
171 mutex_lock(&devnode->lock);
173 /* Check if devnode was never registered or already unregistered */
174 if (!devnode->registered || devnode->unregistered) {
175 mutex_unlock(&devnode->lock);
179 list_for_each_entry(fh, &devnode->fhs, list)
180 wake_up_interruptible(&fh->wait);
182 devnode->registered = false;
183 devnode->unregistered = true;
184 mutex_unlock(&devnode->lock);
186 cdev_device_del(&devnode->cdev, &devnode->dev);
187 put_device(&devnode->dev);
190 #ifdef CONFIG_MEDIA_CEC_NOTIFIER
191 static void cec_cec_notify(struct cec_adapter *adap, u16 pa)
193 cec_s_phys_addr(adap, pa, false);
196 void cec_register_cec_notifier(struct cec_adapter *adap,
197 struct cec_notifier *notifier)
199 if (WARN_ON(!adap->devnode.registered))
202 adap->notifier = notifier;
203 cec_notifier_register(adap->notifier, adap, cec_cec_notify);
205 EXPORT_SYMBOL_GPL(cec_register_cec_notifier);
208 struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
209 void *priv, const char *name, u32 caps,
212 struct cec_adapter *adap;
215 #ifndef CONFIG_MEDIA_CEC_RC
220 return ERR_PTR(-EINVAL);
222 return ERR_PTR(-EINVAL);
223 if (WARN_ON(!available_las || available_las > CEC_MAX_LOG_ADDRS))
224 return ERR_PTR(-EINVAL);
225 adap = kzalloc(sizeof(*adap), GFP_KERNEL);
227 return ERR_PTR(-ENOMEM);
228 strlcpy(adap->name, name, sizeof(adap->name));
229 adap->phys_addr = CEC_PHYS_ADDR_INVALID;
230 adap->log_addrs.cec_version = CEC_OP_CEC_VERSION_2_0;
231 adap->log_addrs.vendor_id = CEC_VENDOR_ID_NONE;
232 adap->capabilities = caps;
233 adap->available_log_addrs = available_las;
237 memset(adap->phys_addrs, 0xff, sizeof(adap->phys_addrs));
238 mutex_init(&adap->lock);
239 INIT_LIST_HEAD(&adap->transmit_queue);
240 INIT_LIST_HEAD(&adap->wait_queue);
241 init_waitqueue_head(&adap->kthread_waitq);
243 adap->kthread = kthread_run(cec_thread_func, adap, "cec-%s", name);
244 if (IS_ERR(adap->kthread)) {
245 pr_err("cec-%s: kernel_thread() failed\n", name);
246 res = PTR_ERR(adap->kthread);
251 #ifdef CONFIG_MEDIA_CEC_RC
252 if (!(caps & CEC_CAP_RC))
255 /* Prepare the RC input device */
256 adap->rc = rc_allocate_device(RC_DRIVER_SCANCODE);
258 pr_err("cec-%s: failed to allocate memory for rc_dev\n",
260 kthread_stop(adap->kthread);
262 return ERR_PTR(-ENOMEM);
265 snprintf(adap->input_name, sizeof(adap->input_name),
267 snprintf(adap->input_phys, sizeof(adap->input_phys),
270 adap->rc->input_name = adap->input_name;
271 adap->rc->input_phys = adap->input_phys;
272 adap->rc->input_id.bustype = BUS_CEC;
273 adap->rc->input_id.vendor = 0;
274 adap->rc->input_id.product = 0;
275 adap->rc->input_id.version = 1;
276 adap->rc->driver_name = CEC_NAME;
277 adap->rc->allowed_protocols = RC_BIT_CEC;
278 adap->rc->priv = adap;
279 adap->rc->map_name = RC_MAP_CEC;
280 adap->rc->timeout = MS_TO_NS(100);
284 EXPORT_SYMBOL_GPL(cec_allocate_adapter);
286 int cec_register_adapter(struct cec_adapter *adap,
287 struct device *parent)
291 if (IS_ERR_OR_NULL(adap))
294 if (WARN_ON(!parent))
297 adap->owner = parent->driver->owner;
298 adap->devnode.dev.parent = parent;
300 #ifdef CONFIG_MEDIA_CEC_RC
301 if (adap->capabilities & CEC_CAP_RC) {
302 adap->rc->dev.parent = parent;
303 res = rc_register_device(adap->rc);
306 pr_err("cec-%s: failed to prepare input device\n",
308 rc_free_device(adap->rc);
315 res = cec_devnode_register(&adap->devnode, adap->owner);
317 #ifdef CONFIG_MEDIA_CEC_RC
318 /* Note: rc_unregister also calls rc_free */
319 rc_unregister_device(adap->rc);
325 dev_set_drvdata(&adap->devnode.dev, adap);
326 #ifdef CONFIG_MEDIA_CEC_DEBUG
330 adap->cec_dir = debugfs_create_dir(dev_name(&adap->devnode.dev), top_cec_dir);
331 if (IS_ERR_OR_NULL(adap->cec_dir)) {
332 pr_warn("cec-%s: Failed to create debugfs dir\n", adap->name);
335 adap->status_file = debugfs_create_devm_seqfile(&adap->devnode.dev,
336 "status", adap->cec_dir, cec_adap_status);
337 if (IS_ERR_OR_NULL(adap->status_file)) {
338 pr_warn("cec-%s: Failed to create status file\n", adap->name);
339 debugfs_remove_recursive(adap->cec_dir);
340 adap->cec_dir = NULL;
345 EXPORT_SYMBOL_GPL(cec_register_adapter);
347 void cec_unregister_adapter(struct cec_adapter *adap)
349 if (IS_ERR_OR_NULL(adap))
352 #ifdef CONFIG_MEDIA_CEC_RC
353 /* Note: rc_unregister also calls rc_free */
354 rc_unregister_device(adap->rc);
357 debugfs_remove_recursive(adap->cec_dir);
358 #ifdef CONFIG_MEDIA_CEC_NOTIFIER
360 cec_notifier_unregister(adap->notifier);
362 cec_devnode_unregister(&adap->devnode);
364 EXPORT_SYMBOL_GPL(cec_unregister_adapter);
366 void cec_delete_adapter(struct cec_adapter *adap)
368 if (IS_ERR_OR_NULL(adap))
370 mutex_lock(&adap->lock);
371 __cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false);
372 mutex_unlock(&adap->lock);
373 kthread_stop(adap->kthread);
374 if (adap->kthread_config)
375 kthread_stop(adap->kthread_config);
376 #ifdef CONFIG_MEDIA_CEC_RC
377 rc_free_device(adap->rc);
381 EXPORT_SYMBOL_GPL(cec_delete_adapter);
384 * Initialise cec for linux
386 static int __init cec_devnode_init(void)
390 pr_info("Linux cec interface: v0.10\n");
391 ret = alloc_chrdev_region(&cec_dev_t, 0, CEC_NUM_DEVICES,
394 pr_warn("cec: unable to allocate major\n");
398 #ifdef CONFIG_MEDIA_CEC_DEBUG
399 top_cec_dir = debugfs_create_dir("cec", NULL);
400 if (IS_ERR_OR_NULL(top_cec_dir)) {
401 pr_warn("cec: Failed to create debugfs cec dir\n");
406 ret = bus_register(&cec_bus_type);
408 unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES);
409 pr_warn("cec: bus_register failed\n");
416 static void __exit cec_devnode_exit(void)
418 debugfs_remove_recursive(top_cec_dir);
419 bus_unregister(&cec_bus_type);
420 unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES);
423 subsys_initcall(cec_devnode_init);
424 module_exit(cec_devnode_exit)
426 MODULE_AUTHOR("Hans Verkuil <hans.verkuil@cisco.com>");
427 MODULE_DESCRIPTION("Device node registration for cec drivers");
428 MODULE_LICENSE("GPL");