disp: msm: dp: add dp aux bridge framework support

Create the framework to support external dp aux bridge device which
can handle DPCD/I2C/HPD from external.

Change-Id: Iabd0998efc8bf7134d186b1751d219c00217385c
Signed-off-by: Xiaowen Wu <wxiaowen@codeaurora.org>
Signed-off-by: Karim Henain <khenain@codeaurora.org>
Signed-off-by: Sudarsan Ramesh <sudarame@codeaurora.org>

msm/dp/dp_aux_bridge.c

@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2019-2021, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+/*
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sub license,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * 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 NON-INFRINGEMENT. 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 "dp_aux_bridge.h"
+
+static DEFINE_MUTEX(dp_aux_bridge_lock);
+static LIST_HEAD(du_aux_bridge_list);
+
+int dp_aux_add_bridge(struct dp_aux_bridge *bridge)
+{
+	mutex_lock(&dp_aux_bridge_lock);
+	list_add_tail(&bridge->head, &du_aux_bridge_list);
+	mutex_unlock(&dp_aux_bridge_lock);
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+struct dp_aux_bridge *of_dp_aux_find_bridge(struct device_node *np)
+{
+	struct dp_aux_bridge *bridge;
+
+	mutex_lock(&dp_aux_bridge_lock);
+
+	list_for_each_entry(bridge, &du_aux_bridge_list, head) {
+		if (bridge->of_node == np) {
+			mutex_unlock(&dp_aux_bridge_lock);
+			return bridge;
+		}
+	}
+
+	mutex_unlock(&dp_aux_bridge_lock);
+	return NULL;
+}
+#endif
+