cec-notifier.c
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/*
* cec-notifier.c - notify CEC drivers of physical address changes
*
* Copyright 2016 Russell King <rmk+kernel@arm.linux.org.uk>
* Copyright 2016-2017 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/export.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/kref.h>
#include <media/cec.h>
#include <media/cec-notifier.h>
#include <drm/drm_edid.h>
struct cec_notifier {
struct mutex lock;
struct list_head head;
struct kref kref;
struct device *dev;
struct cec_adapter *cec_adap;
void (*callback)(struct cec_adapter *adap, u16 pa);
u16 phys_addr;
};
static LIST_HEAD(cec_notifiers);
static DEFINE_MUTEX(cec_notifiers_lock);
struct cec_notifier *cec_notifier_get(struct device *dev)
{
struct cec_notifier *n;
mutex_lock(&cec_notifiers_lock);
list_for_each_entry(n, &cec_notifiers, head) {
if (n->dev == dev) {
kref_get(&n->kref);
mutex_unlock(&cec_notifiers_lock);
return n;
}
}
n = kzalloc(sizeof(*n), GFP_KERNEL);
if (!n)
goto unlock;
n->dev = dev;
n->phys_addr = CEC_PHYS_ADDR_INVALID;
mutex_init(&n->lock);
kref_init(&n->kref);
list_add_tail(&n->head, &cec_notifiers);
unlock:
mutex_unlock(&cec_notifiers_lock);
return n;
}
EXPORT_SYMBOL_GPL(cec_notifier_get);
static void cec_notifier_release(struct kref *kref)
{
struct cec_notifier *n =
container_of(kref, struct cec_notifier, kref);
list_del(&n->head);
kfree(n);
}
void cec_notifier_put(struct cec_notifier *n)
{
mutex_lock(&cec_notifiers_lock);
kref_put(&n->kref, cec_notifier_release);
mutex_unlock(&cec_notifiers_lock);
}
EXPORT_SYMBOL_GPL(cec_notifier_put);
void cec_notifier_set_phys_addr(struct cec_notifier *n, u16 pa)
{
if (n == NULL)
return;
mutex_lock(&n->lock);
n->phys_addr = pa;
if (n->callback)
n->callback(n->cec_adap, n->phys_addr);
mutex_unlock(&n->lock);
}
EXPORT_SYMBOL_GPL(cec_notifier_set_phys_addr);
void cec_notifier_set_phys_addr_from_edid(struct cec_notifier *n,
const struct edid *edid)
{
u16 pa = CEC_PHYS_ADDR_INVALID;
if (n == NULL)
return;
if (edid && edid->extensions)
pa = cec_get_edid_phys_addr((const u8 *)edid,
EDID_LENGTH * (edid->extensions + 1), NULL);
cec_notifier_set_phys_addr(n, pa);
}
EXPORT_SYMBOL_GPL(cec_notifier_set_phys_addr_from_edid);
void cec_notifier_register(struct cec_notifier *n,
struct cec_adapter *adap,
void (*callback)(struct cec_adapter *adap, u16 pa))
{
kref_get(&n->kref);
mutex_lock(&n->lock);
n->cec_adap = adap;
n->callback = callback;
n->callback(adap, n->phys_addr);
mutex_unlock(&n->lock);
}
EXPORT_SYMBOL_GPL(cec_notifier_register);
void cec_notifier_unregister(struct cec_notifier *n)
{
mutex_lock(&n->lock);
n->callback = NULL;
mutex_unlock(&n->lock);
cec_notifier_put(n);
}
EXPORT_SYMBOL_GPL(cec_notifier_unregister);