forked from luck/tmp_suning_uos_patched
fbbd403b32
Add helper function to parse the DT for the hdmi-phandle property and return the corresponding struct device pointer. It takes care to avoid increasing the device refcount since all we need is the device pointer. This pointer is used in the notifier list as a key, but it is never accessed by the CEC driver. Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Reported-by: Wen Yang <wen.yang99@zte.com.cn> Acked-by: Wen Yang <wen.yang99@zte.com.cn> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
160 lines
3.7 KiB
C
160 lines
3.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* cec-notifier.c - notify CEC drivers of physical address changes
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*
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* Copyright 2016 Russell King <rmk+kernel@arm.linux.org.uk>
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* Copyright 2016-2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
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*/
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#include <linux/export.h>
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <linux/list.h>
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#include <linux/kref.h>
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#include <linux/of_platform.h>
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#include <media/cec.h>
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#include <media/cec-notifier.h>
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#include <drm/drm_edid.h>
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struct cec_notifier {
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struct mutex lock;
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struct list_head head;
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struct kref kref;
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struct device *dev;
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const char *conn;
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struct cec_adapter *cec_adap;
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void (*callback)(struct cec_adapter *adap, u16 pa);
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u16 phys_addr;
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};
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static LIST_HEAD(cec_notifiers);
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static DEFINE_MUTEX(cec_notifiers_lock);
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struct cec_notifier *cec_notifier_get_conn(struct device *dev, const char *conn)
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{
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struct cec_notifier *n;
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mutex_lock(&cec_notifiers_lock);
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list_for_each_entry(n, &cec_notifiers, head) {
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if (n->dev == dev &&
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(!conn || !strcmp(n->conn, conn))) {
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kref_get(&n->kref);
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mutex_unlock(&cec_notifiers_lock);
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return n;
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}
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}
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n = kzalloc(sizeof(*n), GFP_KERNEL);
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if (!n)
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goto unlock;
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n->dev = dev;
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if (conn)
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n->conn = kstrdup(conn, GFP_KERNEL);
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n->phys_addr = CEC_PHYS_ADDR_INVALID;
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mutex_init(&n->lock);
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kref_init(&n->kref);
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list_add_tail(&n->head, &cec_notifiers);
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unlock:
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mutex_unlock(&cec_notifiers_lock);
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return n;
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}
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EXPORT_SYMBOL_GPL(cec_notifier_get_conn);
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static void cec_notifier_release(struct kref *kref)
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{
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struct cec_notifier *n =
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container_of(kref, struct cec_notifier, kref);
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list_del(&n->head);
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kfree(n->conn);
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kfree(n);
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}
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void cec_notifier_put(struct cec_notifier *n)
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{
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mutex_lock(&cec_notifiers_lock);
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kref_put(&n->kref, cec_notifier_release);
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mutex_unlock(&cec_notifiers_lock);
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}
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EXPORT_SYMBOL_GPL(cec_notifier_put);
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void cec_notifier_set_phys_addr(struct cec_notifier *n, u16 pa)
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{
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if (n == NULL)
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return;
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mutex_lock(&n->lock);
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n->phys_addr = pa;
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if (n->callback)
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n->callback(n->cec_adap, n->phys_addr);
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mutex_unlock(&n->lock);
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}
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EXPORT_SYMBOL_GPL(cec_notifier_set_phys_addr);
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void cec_notifier_set_phys_addr_from_edid(struct cec_notifier *n,
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const struct edid *edid)
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{
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u16 pa = CEC_PHYS_ADDR_INVALID;
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if (n == NULL)
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return;
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if (edid && edid->extensions)
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pa = cec_get_edid_phys_addr((const u8 *)edid,
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EDID_LENGTH * (edid->extensions + 1), NULL);
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cec_notifier_set_phys_addr(n, pa);
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}
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EXPORT_SYMBOL_GPL(cec_notifier_set_phys_addr_from_edid);
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void cec_notifier_register(struct cec_notifier *n,
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struct cec_adapter *adap,
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void (*callback)(struct cec_adapter *adap, u16 pa))
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{
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kref_get(&n->kref);
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mutex_lock(&n->lock);
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n->cec_adap = adap;
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n->callback = callback;
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n->callback(adap, n->phys_addr);
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mutex_unlock(&n->lock);
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}
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EXPORT_SYMBOL_GPL(cec_notifier_register);
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void cec_notifier_unregister(struct cec_notifier *n)
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{
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mutex_lock(&n->lock);
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n->callback = NULL;
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mutex_unlock(&n->lock);
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cec_notifier_put(n);
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}
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EXPORT_SYMBOL_GPL(cec_notifier_unregister);
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struct device *cec_notifier_parse_hdmi_phandle(struct device *dev)
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{
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struct platform_device *hdmi_pdev;
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struct device *hdmi_dev = NULL;
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struct device_node *np;
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np = of_parse_phandle(dev->of_node, "hdmi-phandle", 0);
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if (!np) {
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dev_err(dev, "Failed to find HDMI node in device tree\n");
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return ERR_PTR(-ENODEV);
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}
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hdmi_pdev = of_find_device_by_node(np);
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of_node_put(np);
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if (hdmi_pdev) {
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hdmi_dev = &hdmi_pdev->dev;
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/*
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* Note that the device struct is only used as a key into the
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* cec_notifiers list, it is never actually accessed.
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* So we decrement the reference here so we don't leak
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* memory.
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*/
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put_device(hdmi_dev);
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return hdmi_dev;
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}
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return ERR_PTR(-EPROBE_DEFER);
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}
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EXPORT_SYMBOL_GPL(cec_notifier_parse_hdmi_phandle);
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