Re: [PATCH v6 2/9] mtk-mdp: add driver to probe mdp components

[Dafna Hirschfeld <dafna.hirschfeld@collabora.com>]

On 02.08.21 14:12, Eizan Miyamoto wrote:
> 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 Miyamoto <eizan@chromium.org>
> ---
> 
> (no changes since v1)
> 
>   drivers/media/platform/mtk-mdp/mtk_mdp_comp.c | 143 ++++++++++++--
>   drivers/media/platform/mtk-mdp/mtk_mdp_comp.h |  25 +--
>   drivers/media/platform/mtk-mdp/mtk_mdp_core.c | 174 +++++++++++++-----
>   drivers/media/platform/mtk-mdp/mtk_mdp_core.h |   1 +
>   4 files changed, 252 insertions(+), 91 deletions(-)
> 
> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> index 76e295c8d9bc..7a0e3acffab9 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> @@ -5,13 +5,50 @@
>    */
>   
>   #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_platform.h>
>   #include <soc/mediatek/smi.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:		Reszer
> + * @MTK_MDP_WDMA:		Write DMA
> + * @MTK_MDP_WROT:		Write DMA with rotation
> + * @MTK_MDP_COMP_TYPE_MAX:	Placeholder for num elems in this enum
> + */
> +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);
>   
>   int mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp)
>   {
> @@ -20,9 +57,7 @@ int 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)
> -			dev_err(dev,
> -				"failed to get larb, err %d. type:%d\n",
> -				err, comp->type);
> +			dev_err(dev, "failed to get larb, err %d.\n", err);
>   	}
>   
>   	for (i = 0; i < ARRAY_SIZE(comp->clk); i++) {
> @@ -62,17 +97,41 @@ 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_comp *comp = dev_get_drvdata(dev);
> +	struct mtk_mdp_dev *mdp = data;
> +
> +	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)

This function can be static

>   {
>   	struct device_node *larb_node;
>   	struct platform_device *larb_pdev;
>   	int ret;
>   	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);

that iteration can be replaced with clk_bulk_get

> @@ -80,19 +139,17 @@ int mtk_mdp_comp_init(struct device *dev, struct device_node *node,
>   			if (PTR_ERR(comp->clk[i]) != -EPROBE_DEFER)
>   				dev_err(dev, "Failed to get clock\n");
>   			ret = PTR_ERR(comp->clk[i]);
> -			goto put_dev;
> +			goto err;
>   		}
>   
>   		/* 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);
> @@ -100,7 +157,7 @@ int mtk_mdp_comp_init(struct device *dev, struct device_node *node,
>   		dev_err(dev,
>   			"Missing mediadek,larb phandle in %pOF node\n", node);
>   		ret = -EINVAL;
> -		goto put_dev;
> +		goto err;
>   	}
>   
>   	larb_pdev = of_find_device_by_node(larb_node);
> @@ -108,7 +165,7 @@ int mtk_mdp_comp_init(struct device *dev, struct device_node *node,
>   		dev_warn(dev, "Waiting for larb device %pOF\n", larb_node);
>   		of_node_put(larb_node);
>   		ret = -EPROBE_DEFER;
> -		goto put_dev;
> +		goto err;
>   	}
>   	of_node_put(larb_node);
>   
> @@ -116,13 +173,59 @@ int mtk_mdp_comp_init(struct device *dev, struct device_node *node,
>   
>   	return 0;
>   
> -put_dev:
> -	of_node_put(comp->dev_node);
> -
> +err:
>   	return ret;
>   }
>   
> -void mtk_mdp_comp_deinit(struct device *dev, struct mtk_mdp_comp *comp)
> +static int mtk_mdp_comp_probe(struct platform_device *pdev)
>   {
> -	of_node_put(comp->dev_node);
> +	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);
> +
> +	return component_add(dev, &mtk_mdp_component_ops);
>   }
> +
> +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 92ab5249bcad..df5fc4c94f90 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
> @@ -7,42 +7,23 @@
>   #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,
> -};
> -
>   /**
>    * 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);
> +
>   int 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 412bbec0f735..b813a822439a 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
>   	},
>   	{ },
>   };
> @@ -106,6 +104,63 @@ 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);
> +		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);
> +
> +	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)
>   {
> @@ -123,8 +178,8 @@ 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)
> @@ -149,36 +204,43 @@ 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 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);
> @@ -203,18 +265,12 @@ 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);
>   	if (ret) {
>   		dev_err(&pdev->dev, "Failed to register reset handler\n");
> -		goto err_m2m_register;
> +		goto err_wdt_reg;
>   	}
>   
>   	platform_set_drvdata(pdev, mdp);
> @@ -222,15 +278,25 @@ static int mtk_mdp_probe(struct platform_device *pdev)
>   	ret = vb2_dma_contig_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(32));
>   	if (ret) {
>   		dev_err(&pdev->dev, "Failed to set vb2 dma mag seg size\n");
> -		goto err_m2m_register;
> +		goto err_set_max_seg_size;
> +	}
> +
> +	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;
>   	}
>   
> -	pm_runtime_enable(dev);
>   	dev_dbg(dev, "mdp-%d registered successfully\n", mdp->id);
>   
>   	return 0;
>   
> -err_m2m_register:
> +err_component_master_add:
> +	vb2_dma_contig_clear_max_seg_size(&pdev->dev);
> +
> +err_set_max_seg_size:
> +
> +err_wdt_reg:
>   	v4l2_device_unregister(&mdp->v4l2_dev);
>   
>   err_dev_register:
> @@ -242,11 +308,6 @@ 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;
>   }
> @@ -254,11 +315,10 @@ 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);
> @@ -267,10 +327,8 @@ 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_warn(&pdev->dev, "not all components removed\n");
>   
>   	dev_dbg(&pdev->dev, "%s driver unloaded\n", pdev->name);
>   	return 0;
> @@ -323,7 +381,25 @@ 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 a6e6dc36307b..8a52539b15d4 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;
>