drivers: video: Remove emc clock management

EMC clock is not intended to be managed by the kernel/ccplex. It is
completely managed by the BPMP BWMGR driver.

Remove outdated code that touches emc clock directly, and fix the NULL
pointer dereference issue.

Bug 5622903

Change-Id: Ied1b6aaceaa026f954917b4b46f47dece1521d62
Signed-off-by: Johnny Liu <johnliu@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nv-oot/+/3487187
Reviewed-by: Chinniah Poosapadi <cpoosapadi@nvidia.com>
Reviewed-by: Narendra Kondapalli <nkondapalli@nvidia.com>
Reviewed-by: Shubham Chandra <shubhamc@nvidia.com>
Reviewed-by: Akihiro Mizusawa <amizusawa@nvidia.com>
GVS: buildbot_gerritrpt <buildbot_gerritrpt@nvidia.com>
Reviewed-by: svcacv <svcacv@nvidia.com>

drivers/media/platform/tegra/camera/vi/vi5_fops.c

@@ -1107,22 +1107,12 @@ static int vi5_channel_stop_streaming(struct vb2_queue *vq)
 
 int tegra_vi5_enable(struct tegra_mc_vi *vi)
 {
-	int ret;
-
-	ret = tegra_camera_emc_clk_enable();
-	if (ret)
-		goto err_emc_enable;
-
 	return 0;
-
-err_emc_enable:
-	return ret;
 }
 
 void tegra_vi5_disable(struct tegra_mc_vi *vi)
 {
 	tegra_channel_ec_close(vi);
-	tegra_camera_emc_clk_disable();
 }
 
 static int vi5_power_on(struct tegra_channel *chan)

drivers/video/tegra/camera/tegra_camera_platform.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * SPDX-FileCopyrightText: Copyright (c) 2015-2024 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+ * SPDX-FileCopyrightText: Copyright (c) 2015-2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
  */
 
 #include <nvidia/conftest.h>
@@ -91,46 +91,6 @@ static int tegra_camera_isomgr_request(
 	return 0;
 }
 
-int tegra_camera_emc_clk_enable(void)
-{
-	struct tegra_camera_info *info;
-	int ret = 0;
-
-	info = dev_get_drvdata(tegra_camera_misc.parent);
-	if (!info)
-		return -EINVAL;
-	ret = clk_prepare_enable(info->emc);
-	if (ret) {
-		dev_err(info->dev, "Cannot enable camera.emc\n");
-		return ret;
-	}
-
-	ret = clk_prepare_enable(info->iso_emc);
-	if (ret) {
-		dev_err(info->dev, "Cannot enable camera_iso.emc\n");
-		goto err_iso_emc;
-	}
-
-	return 0;
-err_iso_emc:
-	clk_disable_unprepare(info->emc);
-	return ret;
-}
-EXPORT_SYMBOL(tegra_camera_emc_clk_enable);
-
-int tegra_camera_emc_clk_disable(void)
-{
-	struct tegra_camera_info *info;
-
-	info = dev_get_drvdata(tegra_camera_misc.parent);
-	if (!info)
-		return -EINVAL;
-	clk_disable_unprepare(info->emc);
-	clk_disable_unprepare(info->iso_emc);
-	return 0;
-}
-EXPORT_SYMBOL(tegra_camera_emc_clk_disable);
-
 static int tegra_camera_open(struct inode *inode, struct file *file)
 {
 	struct tegra_camera_info *info;
@@ -140,7 +100,7 @@ static int tegra_camera_open(struct inode *inode, struct file *file)
 	info = dev_get_drvdata(mdev->parent);
 	file->private_data = info;
 
-	return tegra_camera_emc_clk_enable();
+	return 0;
 }
 
 static int tegra_camera_release(struct inode *inode, struct file *file)
@@ -148,7 +108,7 @@ static int tegra_camera_release(struct inode *inode, struct file *file)
 	struct tegra_camera_info *info;
 
 	info = file->private_data;
-	tegra_camera_emc_clk_disable();
+
 	return 0;
 }
 

include/media/tegra_camera_platform.h

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 /*
- * SPDX-FileCopyrightText: Copyright (C) 2015-2023 NVIDIA CORPORATION.  All rights reserved.
+ * SPDX-FileCopyrightText: Copyright (C) 2015-2025 NVIDIA CORPORATION.  All rights reserved.
  */
 
 #ifndef _TEGRA_CAMERA_PLATFORM_H_
@@ -90,8 +90,6 @@ struct tegra_camera_dev_info {
 };
 
 int tegra_camera_update_isobw(void);
-int tegra_camera_emc_clk_enable(void);
-int tegra_camera_emc_clk_disable(void);
 int tegra_camera_device_register(struct tegra_camera_dev_info *cdev_info,
 					void *priv);
 int tegra_camera_device_unregister(void *priv);