platform: msm: add support for external display module

Add support for the external display module, which is a utility
to manage display interface and audio codec interactions
associated with the cable connect/disconnect events of the
display interfaces. The helper class is responsible for
routing operations called by the audio codec to a particular
display, and for creating and updating the audio switch nodes.

This implementation is based on a snapshot of the external
display module as of this commit 3c1b6b9787c7ee06 ("msm: mdss:
remove HDMI connected flags") on kernel-4.4.

CRs-Fixed: 2020938
Change-Id: Ifcfb0ef6e08d979fb3a6dfe8d878e24283a45389
Signed-off-by: Tatenda Chipeperekwa <tatendac@codeaurora.org>
diff --git a/drivers/platform/msm/msm_ext_display.c b/drivers/platform/msm/msm_ext_display.c
new file mode 100644
index 0000000..3be414b
--- /dev/null
+++ b/drivers/platform/msm/msm_ext_display.c
@@ -0,0 +1,525 @@
+/* Copyright (c) 2016-2017, 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.
+ */
+
+#define pr_fmt(fmt)	"%s: " fmt, __func__
+
+#include <linux/slab.h>
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/iopoll.h>
+#include <linux/types.h>
+#include <linux/of_platform.h>
+#include <linux/msm_ext_display.h>
+
+struct msm_ext_disp_list {
+	struct msm_ext_disp_init_data *data;
+	struct list_head list;
+};
+
+struct msm_ext_disp {
+	struct msm_ext_disp_data ext_disp_data;
+	struct platform_device *pdev;
+	enum msm_ext_disp_type current_disp;
+	struct msm_ext_disp_audio_codec_ops *ops;
+	struct extcon_dev audio_sdev;
+	bool audio_session_on;
+	struct list_head display_list;
+	struct mutex lock;
+};
+
+static const unsigned int msm_ext_disp_supported_cable[] = {
+	EXTCON_DISP_DP,
+	EXTCON_DISP_HDMI,
+	EXTCON_NONE,
+};
+
+static int msm_ext_disp_extcon_register(struct msm_ext_disp *ext_disp)
+{
+	int ret = 0;
+
+	if (!ext_disp) {
+		pr_err("invalid params\n");
+		return -EINVAL;
+	}
+
+	memset(&ext_disp->audio_sdev, 0x0, sizeof(ext_disp->audio_sdev));
+	ext_disp->audio_sdev.supported_cable = msm_ext_disp_supported_cable;
+	ext_disp->audio_sdev.dev.parent = &ext_disp->pdev->dev;
+	ret = extcon_dev_register(&ext_disp->audio_sdev);
+	if (ret) {
+		pr_err("audio registration failed");
+		return ret;
+	}
+
+	pr_debug("extcon registration done\n");
+
+	return ret;
+}
+
+static void msm_ext_disp_extcon_unregister(struct msm_ext_disp *ext_disp)
+{
+	if (!ext_disp) {
+		pr_err("Invalid params\n");
+		return;
+	}
+
+	extcon_dev_unregister(&ext_disp->audio_sdev);
+}
+
+static const char *msm_ext_disp_name(enum msm_ext_disp_type type)
+{
+	switch (type) {
+	case EXT_DISPLAY_TYPE_HDMI:	return "EXT_DISPLAY_TYPE_HDMI";
+	case EXT_DISPLAY_TYPE_DP:	return "EXT_DISPLAY_TYPE_DP";
+	default: return "???";
+	}
+}
+
+static int msm_ext_disp_add_intf_data(struct msm_ext_disp *ext_disp,
+		struct msm_ext_disp_init_data *data)
+{
+	struct msm_ext_disp_list *node;
+
+	if (!ext_disp && !data) {
+		pr_err("Invalid params\n");
+		return -EINVAL;
+	}
+
+	node = kzalloc(sizeof(*node), GFP_KERNEL);
+	if (!node)
+		return -ENOMEM;
+
+	node->data = data;
+	list_add(&node->list, &ext_disp->display_list);
+
+	pr_debug("Added new display (%s)\n", msm_ext_disp_name(data->type));
+
+	return 0;
+}
+
+static int msm_ext_disp_get_intf_data(struct msm_ext_disp *ext_disp,
+		enum msm_ext_disp_type type,
+		struct msm_ext_disp_init_data **data)
+{
+	int ret = 0;
+	struct msm_ext_disp_list *node;
+	struct list_head *position = NULL;
+
+	if (!ext_disp || !data || type < EXT_DISPLAY_TYPE_HDMI ||
+			type >=  EXT_DISPLAY_TYPE_MAX) {
+		pr_err("Invalid params\n");
+		ret = -EINVAL;
+		goto end;
+	}
+
+	*data = NULL;
+	list_for_each(position, &ext_disp->display_list) {
+		node = list_entry(position, struct msm_ext_disp_list, list);
+		if (node->data->type == type) {
+			*data = node->data;
+			break;
+		}
+	}
+
+	if (!*data) {
+		pr_err("Display not found (%s)\n", msm_ext_disp_name(type));
+		ret = -ENODEV;
+	}
+end:
+	return ret;
+}
+
+static int msm_ext_disp_process_audio(struct msm_ext_disp *ext_disp,
+		enum msm_ext_disp_type type,
+		enum msm_ext_disp_cable_state new_state)
+{
+	int ret = 0;
+	int state;
+
+	state = ext_disp->audio_sdev.state;
+	ret = extcon_set_state_sync(&ext_disp->audio_sdev,
+			ext_disp->current_disp, !!new_state);
+
+	pr_debug("Audio state %s %d\n",
+			ext_disp->audio_sdev.state == state ?
+			"is same" : "switched to",
+			ext_disp->audio_sdev.state);
+
+	return ret;
+}
+
+static struct msm_ext_disp *msm_ext_disp_validate_and_get(
+		struct platform_device *pdev,
+		enum msm_ext_disp_type type,
+		enum msm_ext_disp_cable_state state)
+{
+	struct msm_ext_disp_data *ext_disp_data;
+	struct msm_ext_disp *ext_disp;
+
+	if (!pdev) {
+		pr_err("invalid platform device\n");
+		goto err;
+	}
+
+	ext_disp_data = platform_get_drvdata(pdev);
+	if (!ext_disp_data) {
+		pr_err("invalid drvdata\n");
+		goto err;
+	}
+
+	ext_disp = container_of(ext_disp_data,
+			struct msm_ext_disp, ext_disp_data);
+
+	if (state < EXT_DISPLAY_CABLE_DISCONNECT ||
+			state >= EXT_DISPLAY_CABLE_STATE_MAX) {
+		pr_err("invalid HPD state (%d)\n", state);
+		goto err;
+	}
+
+	if (state == EXT_DISPLAY_CABLE_CONNECT) {
+		if (ext_disp->current_disp != EXT_DISPLAY_TYPE_MAX &&
+		    ext_disp->current_disp != type) {
+			pr_err("invalid interface call\n");
+			goto err;
+		}
+	} else {
+		if (ext_disp->current_disp == EXT_DISPLAY_TYPE_MAX ||
+		    ext_disp->current_disp != type) {
+			pr_err("invalid interface call\n");
+			goto err;
+		}
+	}
+	return ext_disp;
+err:
+	return ERR_PTR(-EINVAL);
+}
+
+static int msm_ext_disp_update_audio_ops(struct msm_ext_disp *ext_disp,
+		enum msm_ext_disp_type type,
+		enum msm_ext_disp_cable_state state)
+{
+	int ret = 0;
+	struct msm_ext_disp_init_data *data = NULL;
+
+	ret = msm_ext_disp_get_intf_data(ext_disp, type, &data);
+	if (ret || !data) {
+		pr_err("interface %s not found\n", msm_ext_disp_name(type));
+		goto end;
+	}
+
+	if (state == EXT_DISPLAY_CABLE_CONNECT) {
+		/* connect codec with interface */
+		*ext_disp->ops = data->codec_ops;
+
+		/* update pdev for interface to use */
+		ext_disp->ext_disp_data.intf_pdev = data->pdev;
+		ext_disp->ext_disp_data.intf_data = data->intf_data;
+
+		ext_disp->current_disp = type;
+
+		pr_debug("codec ops set for %s\n", msm_ext_disp_name(type));
+	} else if (state == EXT_DISPLAY_CABLE_DISCONNECT) {
+		*ext_disp->ops = (struct msm_ext_disp_audio_codec_ops){NULL};
+		ext_disp->current_disp = EXT_DISPLAY_TYPE_MAX;
+
+		pr_debug("codec ops cleared for %s\n", msm_ext_disp_name(type));
+	}
+end:
+	return ret;
+}
+
+static int msm_ext_disp_audio_config(struct platform_device *pdev,
+		enum msm_ext_disp_type type,
+		enum msm_ext_disp_cable_state state)
+{
+	int ret = 0;
+	struct msm_ext_disp *ext_disp;
+
+	ext_disp = msm_ext_disp_validate_and_get(pdev, type, state);
+	if (IS_ERR(ext_disp)) {
+		ret = PTR_ERR(ext_disp);
+		goto end;
+	}
+
+	mutex_lock(&ext_disp->lock);
+	ret = msm_ext_disp_update_audio_ops(ext_disp, type, state);
+	mutex_unlock(&ext_disp->lock);
+end:
+	return ret;
+}
+
+static int msm_ext_disp_audio_notify(struct platform_device *pdev,
+		enum msm_ext_disp_type type,
+		enum msm_ext_disp_cable_state state)
+{
+	int ret = 0;
+	struct msm_ext_disp *ext_disp;
+
+	ext_disp = msm_ext_disp_validate_and_get(pdev, type, state);
+	if (IS_ERR(ext_disp)) {
+		ret = PTR_ERR(ext_disp);
+		goto end;
+	}
+
+	mutex_lock(&ext_disp->lock);
+	ret = msm_ext_disp_process_audio(ext_disp, type, state);
+	mutex_unlock(&ext_disp->lock);
+end:
+	return ret;
+}
+
+int msm_hdmi_register_audio_codec(struct platform_device *pdev,
+		struct msm_ext_disp_audio_codec_ops *ops)
+{
+	return msm_ext_disp_register_audio_codec(pdev, ops);
+}
+
+int msm_ext_disp_register_audio_codec(struct platform_device *pdev,
+		struct msm_ext_disp_audio_codec_ops *ops)
+{
+	int ret = 0;
+	struct msm_ext_disp *ext_disp = NULL;
+	struct msm_ext_disp_data *ext_disp_data = NULL;
+
+	if (!pdev || !ops) {
+		pr_err("Invalid params\n");
+		return -EINVAL;
+	}
+
+	ext_disp_data = platform_get_drvdata(pdev);
+	if (!ext_disp_data) {
+		pr_err("Invalid drvdata\n");
+		return -EINVAL;
+	}
+
+	ext_disp = container_of(ext_disp_data, struct msm_ext_disp,
+				ext_disp_data);
+
+	mutex_lock(&ext_disp->lock);
+
+	if ((ext_disp->current_disp != EXT_DISPLAY_TYPE_MAX)
+			&& ext_disp->ops) {
+		pr_err("Codec already registered\n");
+		ret = -EINVAL;
+		goto end;
+	}
+
+	ext_disp->ops = ops;
+
+	pr_debug("audio codec registered\n");
+
+end:
+	mutex_unlock(&ext_disp->lock);
+
+	return ret;
+}
+
+static int msm_ext_disp_validate_intf(struct msm_ext_disp_init_data *init_data)
+{
+	if (!init_data) {
+		pr_err("Invalid init_data\n");
+		return -EINVAL;
+	}
+
+	if (!init_data->pdev) {
+		pr_err("Invalid display intf pdev\n");
+		return -EINVAL;
+	}
+
+	if (!init_data->codec_ops.get_audio_edid_blk ||
+			!init_data->codec_ops.cable_status ||
+			!init_data->codec_ops.audio_info_setup) {
+		pr_err("Invalid codec operation pointers\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int msm_ext_disp_register_intf(struct platform_device *pdev,
+		struct msm_ext_disp_init_data *init_data)
+{
+	int ret = 0;
+	struct msm_ext_disp_init_data *data = NULL;
+	struct msm_ext_disp *ext_disp = NULL;
+	struct msm_ext_disp_data *ext_disp_data = NULL;
+
+	if (!pdev || !init_data) {
+		pr_err("Invalid params\n");
+		return -EINVAL;
+	}
+
+	ext_disp_data = platform_get_drvdata(pdev);
+	if (!ext_disp_data) {
+		pr_err("Invalid drvdata\n");
+		return -EINVAL;
+	}
+
+	ext_disp = container_of(ext_disp_data, struct msm_ext_disp,
+				ext_disp_data);
+
+	mutex_lock(&ext_disp->lock);
+
+	ret = msm_ext_disp_validate_intf(init_data);
+	if (ret)
+		goto end;
+
+	ret = msm_ext_disp_get_intf_data(ext_disp, init_data->type, &data);
+	if (!ret) {
+		pr_err("%s already registered\n",
+			msm_ext_disp_name(init_data->type));
+		goto end;
+	}
+
+	ret = msm_ext_disp_add_intf_data(ext_disp, init_data);
+	if (ret)
+		goto end;
+
+	init_data->intf_ops.audio_config = msm_ext_disp_audio_config;
+	init_data->intf_ops.audio_notify = msm_ext_disp_audio_notify;
+
+	pr_debug("%s registered\n", msm_ext_disp_name(init_data->type));
+
+	mutex_unlock(&ext_disp->lock);
+
+	return ret;
+
+end:
+	mutex_unlock(&ext_disp->lock);
+
+	return ret;
+}
+
+static int msm_ext_disp_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+	struct device_node *of_node = NULL;
+	struct msm_ext_disp *ext_disp = NULL;
+
+	if (!pdev) {
+		pr_err("No platform device found\n");
+		ret = -ENODEV;
+		goto end;
+	}
+
+	of_node = pdev->dev.of_node;
+	if (!of_node) {
+		pr_err("No device node found\n");
+		ret = -ENODEV;
+		goto end;
+	}
+
+	ext_disp = devm_kzalloc(&pdev->dev, sizeof(*ext_disp), GFP_KERNEL);
+	if (!ext_disp) {
+		ret = -ENOMEM;
+		goto end;
+	}
+
+	platform_set_drvdata(pdev, &ext_disp->ext_disp_data);
+	ext_disp->pdev = pdev;
+
+	ret = msm_ext_disp_extcon_register(ext_disp);
+	if (ret)
+		goto extcon_dev_failure;
+
+	ret = of_platform_populate(of_node, NULL, NULL, &pdev->dev);
+	if (ret) {
+		pr_err("Failed to add child devices. Error = %d\n", ret);
+		goto child_node_failure;
+	} else {
+		pr_debug("%s: Added child devices.\n", __func__);
+	}
+
+	mutex_init(&ext_disp->lock);
+
+	INIT_LIST_HEAD(&ext_disp->display_list);
+	ext_disp->current_disp = EXT_DISPLAY_TYPE_MAX;
+
+	return ret;
+
+child_node_failure:
+	msm_ext_disp_extcon_unregister(ext_disp);
+extcon_dev_failure:
+	devm_kfree(&ext_disp->pdev->dev, ext_disp);
+end:
+	return ret;
+}
+
+static int msm_ext_disp_remove(struct platform_device *pdev)
+{
+	int ret = 0;
+	struct msm_ext_disp *ext_disp = NULL;
+	struct msm_ext_disp_data *ext_disp_data = NULL;
+
+	if (!pdev) {
+		pr_err("No platform device\n");
+		ret = -ENODEV;
+		goto end;
+	}
+
+	ext_disp_data = platform_get_drvdata(pdev);
+	if (!ext_disp_data) {
+		pr_err("No drvdata found\n");
+		ret = -ENODEV;
+		goto end;
+	}
+
+	ext_disp = container_of(ext_disp_data, struct msm_ext_disp,
+				ext_disp_data);
+
+	msm_ext_disp_extcon_unregister(ext_disp);
+
+	mutex_destroy(&ext_disp->lock);
+	devm_kfree(&ext_disp->pdev->dev, ext_disp);
+
+end:
+	return ret;
+}
+
+static const struct of_device_id msm_ext_dt_match[] = {
+	{.compatible = "qcom,msm-ext-disp",},
+	{ /* Sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, msm_ext_dt_match);
+
+static struct platform_driver this_driver = {
+	.probe = msm_ext_disp_probe,
+	.remove = msm_ext_disp_remove,
+	.driver = {
+		.name = "msm-ext-disp",
+		.of_match_table = msm_ext_dt_match,
+	},
+};
+
+static int __init msm_ext_disp_init(void)
+{
+	int ret = 0;
+
+	ret = platform_driver_register(&this_driver);
+	if (ret)
+		pr_err("failed, ret = %d\n", ret);
+
+	return ret;
+}
+
+static void __exit msm_ext_disp_exit(void)
+{
+	platform_driver_unregister(&this_driver);
+}
+
+subsys_initcall(msm_ext_disp_init);
+module_exit(msm_ext_disp_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("MSM External Display");