Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Eizan Miyamoto <eizan@chromium.org>
To:     LKML <linux-kernel@vger.kernel.org>
Cc:     Eizan Miyamoto <eizan@google.com>, eizan@chromium.org,
        Andrew-CT Chen <andrew-ct.chen@mediatek.com>,
        Houlong Wei <houlong.wei@mediatek.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Minghsiu Tsai <minghsiu.tsai@mediatek.com>,
        linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org,
        linux-mediatek@lists.infradead.org
Subject: [PATCH v1 1/2] [media] mtk-mdp: add driver to probe mdp components
Date:   Tue,  5 May 2020 17:44:30 +1000
Message-Id: <20200505174351.v1.1.I8d2f6e20b8719483cbda30f17548af528527d900@changeid>
In-Reply-To: <20200505074431.242840-1-eizan@google.com>
References: <20200505074431.242840-1-eizan@google.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Broadly, this patch (1) adds a driver for various MTK MDP components to
go alongside the main MTK MDP driver, and (2) hooks them all together
using the component framework.

(1) Up until now, the MTK MDP driver controls 8 devices in the device
tree on its own. When running tests for the hardware video decoder, we
found that the iommus and LARBs were not being properly configured. To
configure them, a driver for each be added to mtk_mdp_comp so that
mtk_iommu_add_device() can (eventually) be called from dma_configure()
inside really_probe().

(2) The integration into the component framework allows us to defer the
registration with the v4l2 subsystem until all the MDP-related devices
have been probed, so that the relevant device node does not become
available until initialization of all the components is complete.

Some notes about how the component framework has been integrated:

- The driver for the rdma0 component serves double duty as the "master"
  (aggregate) driver as well as a component driver. This is a non-ideal
  compromise until a better solution is developed. This device is
  differentiated from the rest by checking for a "mediatek,vpu" property
  in the device node.

- The list of mdp components remains hard-coded as mtk_mdp_comp_dt_ids[]
  in mtk_mdp_core.c, and as mtk_mdp_comp_driver_dt_match[] in
  mtk_mdp_comp.c. This unfortunate duplication of information is
  addressed in a following patch in this series.

- The component driver calls component_add() for each device that is
  probed.

- In mtk_mdp_probe (the "master" device), we scan the device tree for
  any matching nodes against mtk_mdp_comp_dt_ids, and add component
  matches for them. The match criteria is a matching device node
  pointer.

- When the set of components devices that have been probed corresponds
  with the list that is generated by the "master", the callback to
  mtk_mdp_master_bind() is made, which then calls the component bind
  functions.

- Inside mtk_mdp_master_bind(), once all the component bind functions
  have been called, we can then register our device to the v4l2
  subsystem.

- The call to pm_runtime_enable() in the master device is called after
  all the components have been registered by their bind() functions
  called by mtk_mtp_master_bind(). As a result, the list of components
  will not change while power management callbacks mtk_mdp_suspend()/
  resume() are accessing the list of components.

Signed-off-by: eizan@chromium.org
Signed-off-by: Eizan Miyamoto <eizan@google.com>
---

 drivers/media/platform/mtk-mdp/mtk_mdp_comp.c | 164 +++++++++++++++--
 drivers/media/platform/mtk-mdp/mtk_mdp_comp.h |  27 +--
 drivers/media/platform/mtk-mdp/mtk_mdp_core.c | 171 +++++++++++++-----
 drivers/media/platform/mtk-mdp/mtk_mdp_core.h |   1 +
 4 files changed, 274 insertions(+), 89 deletions(-)

diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
index 362fff924aef..4c77a582c79a 100644
--- a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
+++ b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
@@ -5,14 +5,52 @@
  */
 
 #include <linux/clk.h>
+#include <linux/component.h>
 #include <linux/device.h>
-#include <linux/of.h>
+#include <linux/module.h>
 #include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <soc/mediatek/smi.h>
+#include <linux/platform_device.h>
 
 #include "mtk_mdp_comp.h"
-
+#include "mtk_mdp_core.h"
+
+/**
+ * enum mtk_mdp_comp_type - the MDP component
+ * @MTK_MDP_RDMA:	Read DMA
+ * @MTK_MDP_RSZ:	Riszer
+ * @MTK_MDP_WDMA:	Write DMA
+ * @MTK_MDP_WROT:	Write DMA with rotation
+ */
+enum mtk_mdp_comp_type {
+	MTK_MDP_RDMA,
+	MTK_MDP_RSZ,
+	MTK_MDP_WDMA,
+	MTK_MDP_WROT,
+	MTK_MDP_COMP_TYPE_MAX,
+};
+
+static const struct of_device_id mtk_mdp_comp_driver_dt_match[] = {
+	{
+		.compatible = "mediatek,mt8173-mdp-rdma",
+		.data = (void *)MTK_MDP_RDMA
+	}, {
+		.compatible = "mediatek,mt8173-mdp-rsz",
+		.data = (void *)MTK_MDP_RSZ
+	}, {
+		.compatible = "mediatek,mt8173-mdp-wdma",
+		.data = (void *)MTK_MDP_WDMA
+	}, {
+		.compatible = "mediatek,mt8173-mdp-wrot",
+		.data = (void *)MTK_MDP_WROT
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(of, mtk_mdp_comp_driver_dt_match);
 
 void mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp)
 {
@@ -20,10 +58,14 @@ void mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp)
 
 	if (comp->larb_dev) {
 		err = mtk_smi_larb_get(comp->larb_dev);
-		if (err)
+		if (err) {
+			enum mtk_mdp_comp_type comp_type =
+				(enum mtk_mdp_comp_type)
+				of_device_get_match_data(dev);
 			dev_err(dev,
 				"failed to get larb, err %d. type:%d\n",
-				err, comp->type);
+				err, comp_type);
+		}
 	}
 
 	for (i = 0; i < ARRAY_SIZE(comp->clk); i++) {
@@ -32,8 +74,8 @@ void mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp)
 		err = clk_prepare_enable(comp->clk[i]);
 		if (err)
 			dev_err(dev,
-			"failed to enable clock, err %d. type:%d i:%d\n",
-				err, comp->type, i);
+				"failed to enable clock, err %d. i:%d\n",
+				err, i);
 	}
 }
 
@@ -51,16 +93,41 @@ void mtk_mdp_comp_clock_off(struct device *dev, struct mtk_mdp_comp *comp)
 		mtk_smi_larb_put(comp->larb_dev);
 }
 
-int mtk_mdp_comp_init(struct device *dev, struct device_node *node,
-		      struct mtk_mdp_comp *comp,
-		      enum mtk_mdp_comp_type comp_type)
+static int mtk_mdp_comp_bind(struct device *dev, struct device *master,
+			void *data)
+{
+	struct mtk_mdp_comp *comp = dev_get_drvdata(dev);
+	struct mtk_mdp_dev *mdp = data;
+
+	mtk_mdp_register_component(mdp, comp);
+
+	return 0;
+}
+
+static void mtk_mdp_comp_unbind(struct device *dev, struct device *master,
+			   void *data)
+{
+	struct mtk_mdp_dev *mdp = data;
+	struct mtk_mdp_comp *comp = dev_get_drvdata(dev);
+
+	mtk_mdp_unregister_component(mdp, comp);
+}
+
+static const struct component_ops mtk_mdp_component_ops = {
+	.bind   = mtk_mdp_comp_bind,
+	.unbind = mtk_mdp_comp_unbind,
+};
+
+int mtk_mdp_comp_init(struct mtk_mdp_comp *comp, struct device *dev)
 {
 	struct device_node *larb_node;
 	struct platform_device *larb_pdev;
 	int i;
+	struct device_node *node = dev->of_node;
+	enum mtk_mdp_comp_type comp_type =
+		 (enum mtk_mdp_comp_type)of_device_get_match_data(dev);
 
-	comp->dev_node = of_node_get(node);
-	comp->type = comp_type;
+	INIT_LIST_HEAD(&comp->node);
 
 	for (i = 0; i < ARRAY_SIZE(comp->clk); i++) {
 		comp->clk[i] = of_clk_get(node, i);
@@ -72,15 +139,15 @@ int mtk_mdp_comp_init(struct device *dev, struct device_node *node,
 		}
 
 		/* Only RDMA needs two clocks */
-		if (comp->type != MTK_MDP_RDMA)
+		if (comp_type != MTK_MDP_RDMA)
 			break;
 	}
 
 	/* Only DMA capable components need the LARB property */
 	comp->larb_dev = NULL;
-	if (comp->type != MTK_MDP_RDMA &&
-	    comp->type != MTK_MDP_WDMA &&
-	    comp->type != MTK_MDP_WROT)
+	if (comp_type != MTK_MDP_RDMA &&
+	    comp_type != MTK_MDP_WDMA &&
+	    comp_type != MTK_MDP_WROT)
 		return 0;
 
 	larb_node = of_parse_phandle(node, "mediatek,larb", 0);
@@ -103,7 +170,70 @@ int mtk_mdp_comp_init(struct device *dev, struct device_node *node,
 	return 0;
 }
 
-void mtk_mdp_comp_deinit(struct device *dev, struct mtk_mdp_comp *comp)
+void mtk_mdp_comp_deinit(struct mtk_mdp_comp *comp)
 {
-	of_node_put(comp->dev_node);
 }
+
+static int mtk_mdp_comp_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *vpu_node;
+	int status;
+	struct mtk_mdp_comp *comp;
+
+	vpu_node = of_parse_phandle(dev->of_node, "mediatek,vpu", 0);
+	if (vpu_node) {
+		of_node_put(vpu_node);
+		/*
+		 * The device tree node with a mediatek,vpu property is deemed
+		 * the MDP "master" device, we don't want to add a component
+		 * for it in this function because the initialization for the
+		 * master is done elsewhere.
+		 */
+		dev_info(dev, "vpu node found, not probing\n");
+		return -ENODEV;
+	}
+
+	comp = devm_kzalloc(dev, sizeof(*comp), GFP_KERNEL);
+	if (!comp)
+		return -ENOMEM;
+
+	status = mtk_mdp_comp_init(comp, dev);
+	if (status) {
+		dev_err(dev, "Failed to initialize component: %d\n", status);
+		return status;
+	}
+
+	dev_set_drvdata(dev, comp);
+
+	status = component_add(dev, &mtk_mdp_component_ops);
+	if (status) {
+		dev_err(dev, "Failed to add component: %d\n", status);
+		goto err_component_add;
+	}
+
+	return 0;
+
+err_component_add:
+	mtk_mdp_comp_deinit(comp);
+
+	return status;
+}
+
+static int mtk_mdp_comp_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+
+	component_del(dev, &mtk_mdp_component_ops);
+	return 0;
+}
+
+struct platform_driver mtk_mdp_component_driver = {
+	.probe          = mtk_mdp_comp_probe,
+	.remove         = mtk_mdp_comp_remove,
+	.driver         = {
+		.name   = "mediatek-mdp-comp",
+		.owner  = THIS_MODULE,
+		.of_match_table = mtk_mdp_comp_driver_dt_match,
+	},
+};
diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
index 1bf0242cce46..edc2ece717b5 100644
--- a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
+++ b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
@@ -7,43 +7,24 @@
 #ifndef __MTK_MDP_COMP_H__
 #define __MTK_MDP_COMP_H__
 
-/**
- * enum mtk_mdp_comp_type - the MDP component
- * @MTK_MDP_RDMA:	Read DMA
- * @MTK_MDP_RSZ:	Riszer
- * @MTK_MDP_WDMA:	Write DMA
- * @MTK_MDP_WROT:	Write DMA with rotation
- */
-enum mtk_mdp_comp_type {
-	MTK_MDP_RDMA,
-	MTK_MDP_RSZ,
-	MTK_MDP_WDMA,
-	MTK_MDP_WROT,
-	MTK_MDP_COMP_TYPE_MAX,
-};
-
 /**
  * struct mtk_mdp_comp - the MDP's function component data
  * @node:	list node to track sibing MDP components
- * @dev_node:	component device node
  * @clk:	clocks required for component
  * @larb_dev:	SMI device required for component
- * @type:	component type
  */
 struct mtk_mdp_comp {
 	struct list_head	node;
-	struct device_node	*dev_node;
 	struct clk		*clk[2];
 	struct device		*larb_dev;
-	enum mtk_mdp_comp_type	type;
 };
 
-int mtk_mdp_comp_init(struct device *dev, struct device_node *node,
-		      struct mtk_mdp_comp *comp,
-		      enum mtk_mdp_comp_type comp_type);
-void mtk_mdp_comp_deinit(struct device *dev, struct mtk_mdp_comp *comp);
+int mtk_mdp_comp_init(struct mtk_mdp_comp *comp, struct device *dev);
+void mtk_mdp_comp_deinit(struct mtk_mdp_comp *comp);
+
 void mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp);
 void mtk_mdp_comp_clock_off(struct device *dev, struct mtk_mdp_comp *comp);
 
+extern struct platform_driver mtk_mdp_component_driver;
 
 #endif /* __MTK_MDP_COMP_H__ */
diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_core.c b/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
index b1227c99569a..fe8ae4ad0d3e 100644
--- a/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
+++ b/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
@@ -6,6 +6,7 @@
  */
 
 #include <linux/clk.h>
+#include <linux/component.h>
 #include <linux/device.h>
 #include <linux/errno.h>
 #include <linux/interrupt.h>
@@ -19,6 +20,7 @@
 #include <linux/workqueue.h>
 #include <soc/mediatek/smi.h>
 
+#include "mtk_mdp_comp.h"
 #include "mtk_mdp_core.h"
 #include "mtk_mdp_m2m.h"
 #include "mtk_vpu.h"
@@ -32,16 +34,12 @@ module_param(mtk_mdp_dbg_level, int, 0644);
 static const struct of_device_id mtk_mdp_comp_dt_ids[] = {
 	{
 		.compatible = "mediatek,mt8173-mdp-rdma",
-		.data = (void *)MTK_MDP_RDMA
 	}, {
 		.compatible = "mediatek,mt8173-mdp-rsz",
-		.data = (void *)MTK_MDP_RSZ
 	}, {
 		.compatible = "mediatek,mt8173-mdp-wdma",
-		.data = (void *)MTK_MDP_WDMA
 	}, {
 		.compatible = "mediatek,mt8173-mdp-wrot",
-		.data = (void *)MTK_MDP_WROT
 	},
 	{ },
 };
@@ -91,6 +89,65 @@ static void mtk_mdp_reset_handler(void *priv)
 	queue_work(mdp->wdt_wq, &mdp->wdt_work);
 }
 
+static int compare_of(struct device *dev, void *data)
+{
+	return dev->of_node == data;
+}
+
+static void release_of(struct device *dev, void *data)
+{
+	of_node_put(data);
+}
+
+static int mtk_mdp_master_bind(struct device *dev)
+{
+	int status;
+	struct mtk_mdp_dev *mdp = dev_get_drvdata(dev);
+
+	mtk_mdp_register_component(mdp, &mdp->comp_self);
+
+	status = component_bind_all(dev, mdp);
+	if (status) {
+		dev_err(dev, "Failed to bind all components: %d\n", status);
+		goto err_component_bind_all;
+	}
+
+	status = mtk_mdp_register_m2m_device(mdp);
+	if (status) {
+		dev_err(dev, "Failed to register m2m device: %d\n", status);
+		v4l2_err(&mdp->v4l2_dev, "Failed to init mem2mem device\n");
+		goto err_mtk_mdp_register_m2m_device;
+	}
+
+	pm_runtime_enable(dev);
+
+	return 0;
+
+err_mtk_mdp_register_m2m_device:
+	component_unbind_all(dev, mdp);
+
+err_component_bind_all:
+	mtk_mdp_unregister_component(mdp, &mdp->comp_self);
+	mtk_mdp_comp_deinit(&mdp->comp_self);
+
+	return status;
+}
+
+static void mtk_mdp_master_unbind(struct device *dev)
+{
+	struct mtk_mdp_dev *mdp = dev_get_drvdata(dev);
+
+	pm_runtime_disable(dev);
+	mtk_mdp_unregister_m2m_device(mdp);
+	component_unbind_all(dev, mdp);
+	mtk_mdp_unregister_component(mdp, &mdp->comp_self);
+}
+
+static const struct component_master_ops mtk_mdp_com_ops = {
+	.bind		= mtk_mdp_master_bind,
+	.unbind		= mtk_mdp_master_unbind,
+};
+
 void mtk_mdp_register_component(struct mtk_mdp_dev *mdp,
 				struct mtk_mdp_comp *comp)
 {
@@ -108,8 +165,8 @@ static int mtk_mdp_probe(struct platform_device *pdev)
 	struct mtk_mdp_dev *mdp;
 	struct device *dev = &pdev->dev;
 	struct device_node *node, *parent;
-	struct mtk_mdp_comp *comp, *comp_temp;
-	int ret = 0;
+	int i, ret = 0;
+	struct component_match *match = NULL;
 
 	mdp = devm_kzalloc(dev, sizeof(*mdp), GFP_KERNEL);
 	if (!mdp)
@@ -134,37 +191,43 @@ static int mtk_mdp_probe(struct platform_device *pdev)
 	}
 
 	/* Iterate over sibling MDP function blocks */
+	i = 0;
 	for_each_child_of_node(parent, node) {
-		const struct of_device_id *of_id;
-		enum mtk_mdp_comp_type comp_type;
+		struct platform_device *pdev;
 
-		of_id = of_match_node(mtk_mdp_comp_dt_ids, node);
-		if (!of_id)
+		if (!of_match_node(mtk_mdp_comp_dt_ids, node))
 			continue;
 
-		if (!of_device_is_available(node)) {
-			dev_err(dev, "Skipping disabled component %pOF\n",
-				node);
+		if (!of_device_is_available(node))
 			continue;
-		}
-
-		comp_type = (enum mtk_mdp_comp_type)of_id->data;
 
-
-		comp = devm_kzalloc(dev, sizeof(*comp), GFP_KERNEL);
-		if (!comp) {
-			ret = -ENOMEM;
-			of_node_put(node);
-			goto err_comp;
+		pdev = of_find_device_by_node(node);
+		if (!pdev) {
+			dev_warn(dev, "Unable to find comp device %s\n",
+				 node->full_name);
+			continue;
 		}
 
-		ret = mtk_mdp_comp_init(dev, node, comp, comp_type);
-		if (ret) {
-			of_node_put(node);
-			goto err_comp;
+		/*
+		 * Do not add add a match for my own (rdma0) device node.
+		 * I will be managing it directly instead using comp_self.
+		 */
+		if (&pdev->dev != dev) {
+			dev_dbg(dev, "adding match %d for: %pOF\n", i++, node);
+			component_match_add_release(dev, &match, release_of,
+						    compare_of,
+						    of_node_get(node));
 		}
+	}
 
-		mtk_mdp_register_component(mdp, comp);
+	/*
+	 * Create a component for myself so that clocks can be toggled in
+	 * clock_on().
+	 */
+	ret = mtk_mdp_comp_init(&mdp->comp_self, dev);
+	if (ret) {
+		dev_err(dev, "Failed to initialize component\n");
+		goto err_comp;
 	}
 
 	mdp->job_wq = create_singlethread_workqueue(MTK_MDP_MODULE_NAME);
@@ -189,12 +252,6 @@ static int mtk_mdp_probe(struct platform_device *pdev)
 		goto err_dev_register;
 	}
 
-	ret = mtk_mdp_register_m2m_device(mdp);
-	if (ret) {
-		v4l2_err(&mdp->v4l2_dev, "Failed to init mem2mem device\n");
-		goto err_m2m_register;
-	}
-
 	mdp->vpu_dev = vpu_get_plat_device(pdev);
 	ret = vpu_wdt_reg_handler(mdp->vpu_dev, mtk_mdp_reset_handler, mdp,
 				  VPU_RST_MDP);
@@ -211,16 +268,22 @@ static int mtk_mdp_probe(struct platform_device *pdev)
 		goto err_set_max_seg_size;
 	}
 
-	pm_runtime_enable(dev);
+	ret = component_master_add_with_match(dev, &mtk_mdp_com_ops, match);
+	if (ret) {
+		dev_err(dev, "Component master add failed\n");
+		goto err_component_master_add;
+	}
+
 	dev_dbg(dev, "mdp-%d registered successfully\n", mdp->id);
 
 	return 0;
 
+err_component_master_add:
+	vb2_dma_contig_clear_max_seg_size(&pdev->dev);
+
 err_set_max_seg_size:
 
 err_wdt_reg:
-
-err_m2m_register:
 	v4l2_device_unregister(&mdp->v4l2_dev);
 
 err_dev_register:
@@ -232,11 +295,6 @@ static int mtk_mdp_probe(struct platform_device *pdev)
 err_alloc_job_wq:
 
 err_comp:
-	list_for_each_entry_safe(comp, comp_temp, &mdp->comp_list, node) {
-		mtk_mdp_unregister_component(mdp, comp);
-		mtk_mdp_comp_deinit(dev, comp);
-	}
-
 	dev_dbg(dev, "err %d\n", ret);
 	return ret;
 }
@@ -244,11 +302,10 @@ static int mtk_mdp_probe(struct platform_device *pdev)
 static int mtk_mdp_remove(struct platform_device *pdev)
 {
 	struct mtk_mdp_dev *mdp = platform_get_drvdata(pdev);
-	struct mtk_mdp_comp *comp, *comp_temp;
 
-	pm_runtime_disable(&pdev->dev);
+	component_master_del(&pdev->dev, &mtk_mdp_com_ops);
+
 	vb2_dma_contig_clear_max_seg_size(&pdev->dev);
-	mtk_mdp_unregister_m2m_device(mdp);
 	v4l2_device_unregister(&mdp->v4l2_dev);
 
 	flush_workqueue(mdp->wdt_wq);
@@ -257,10 +314,8 @@ static int mtk_mdp_remove(struct platform_device *pdev)
 	flush_workqueue(mdp->job_wq);
 	destroy_workqueue(mdp->job_wq);
 
-	list_for_each_entry_safe(comp, comp_temp, &mdp->comp_list, node) {
-		mtk_mdp_unregister_component(mdp, comp);
-		mtk_mdp_comp_deinit(&pdev->dev, comp);
-	}
+	if (!list_empty(&mdp->comp_list))
+		dev_err(&pdev->dev, "not all components removed\n");
 
 	dev_dbg(&pdev->dev, "%s driver unloaded\n", pdev->name);
 	return 0;
@@ -315,7 +370,25 @@ static struct platform_driver mtk_mdp_driver = {
 	}
 };
 
-module_platform_driver(mtk_mdp_driver);
+static struct platform_driver * const mtk_mdp_drivers[] = {
+	&mtk_mdp_driver,
+	&mtk_mdp_component_driver,
+};
+
+static int __init mtk_mdp_init(void)
+{
+	return platform_register_drivers(mtk_mdp_drivers,
+					 ARRAY_SIZE(mtk_mdp_drivers));
+}
+
+static void __exit mtk_mdp_exit(void)
+{
+	platform_unregister_drivers(mtk_mdp_drivers,
+				    ARRAY_SIZE(mtk_mdp_drivers));
+}
+
+module_init(mtk_mdp_init);
+module_exit(mtk_mdp_exit);
 
 MODULE_AUTHOR("Houlong Wei <houlong.wei@mediatek.com>");
 MODULE_DESCRIPTION("Mediatek image processor driver");
diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_core.h b/drivers/media/platform/mtk-mdp/mtk_mdp_core.h
index a7da14b97077..230f531400ca 100644
--- a/drivers/media/platform/mtk-mdp/mtk_mdp_core.h
+++ b/drivers/media/platform/mtk-mdp/mtk_mdp_core.h
@@ -155,6 +155,7 @@ struct mtk_mdp_dev {
 	struct mtk_mdp_variant		*variant;
 	u16				id;
 	struct list_head		comp_list;
+	struct mtk_mdp_comp		comp_self;
 	struct v4l2_m2m_dev		*m2m_dev;
 	struct list_head		ctx_list;
 	struct video_device		*vdev;
-- 
2.26.2.526.g744177e7f7-goog