Re: [PATCH v9 4/4] drm/mediatek: Fix mediatek-drm device probing

[CK Hu <ck.hu@mediatek.com>]

Hi, Enric:

On Wed, 2020-02-26 at 11:54 +0100, Enric Balletbo i Serra wrote:
> In the actual implementation the same compatible string
> "mediatek,<chip>-mmsys" is used to bind the clock drivers
> (drivers/soc/mediatek) as well as to the gpu driver
> (drivers/gpu/drm/mediatek/mtk_drm_drv.c). This ends with the problem
> that the only probed driver is the clock driver and there is no display
> at all.
> 
> In any case having the same compatible string for two drivers is not
> correct and should be fixed. To fix this, and maintain backward
> compatibility, we can consider that the mmsys driver is the top-level
> entry point for the multimedia subsystem, so is not a pure clock
> controller but a system controller, and the drm driver is instantiated
> by that MMSYS driver.
> 

Reviewed-by: CK Hu <ck.hu@mediatek.com>

> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> ---
> 
> Changes in v9:
> - Do not move the display routing from the drm driver (CK)
> 
> Changes in v8:
> - New patch introduced in this series.
> 
> Changes in v7: None
> 
>  drivers/gpu/drm/mediatek/mtk_drm_drv.c | 34 ++++++++++++++------------
>  drivers/soc/mediatek/mt8173-mmsys.c    |  6 +++++
>  2 files changed, 25 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> index b68837ea02b3..17f118ee0e57 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> @@ -422,9 +422,21 @@ static const struct of_device_id mtk_ddp_comp_dt_ids[] = {
>  	{ }
>  };
>  
> +static const struct of_device_id mtk_drm_of_ids[] = {
> +	{ .compatible = "mediatek,mt2701-mmsys",
> +	  .data = &mt2701_mmsys_driver_data},
> +	{ .compatible = "mediatek,mt2712-mmsys",
> +	  .data = &mt2712_mmsys_driver_data},
> +	{ .compatible = "mediatek,mt8173-mmsys",
> +	  .data = &mt8173_mmsys_driver_data},
> +	{ }
> +};
> +
>  static int mtk_drm_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> +	struct device_node *phandle = dev->parent->of_node;
> +	const struct of_device_id *of_id;
>  	struct mtk_drm_private *private;
>  	struct device_node *node;
>  	struct component_match *match = NULL;
> @@ -435,15 +447,18 @@ static int mtk_drm_probe(struct platform_device *pdev)
>  	if (!private)
>  		return -ENOMEM;
>  
> -	private->data = of_device_get_match_data(dev);
> +	of_id = of_match_node(mtk_drm_of_ids, phandle);
> +	if (!of_id)
> +		return -ENODEV;
> +
> +	private->data = of_id->data;
>  
> -	private->config_regs = syscon_node_to_regmap(dev->of_node);
> +	private->config_regs = syscon_node_to_regmap(phandle);
>  	if (IS_ERR(private->config_regs))
>  		return PTR_ERR(private->config_regs);
>  
>  	/* Iterate over sibling DISP function blocks */
> -	for_each_child_of_node(dev->of_node->parent, node) {
> -		const struct of_device_id *of_id;
> +	for_each_child_of_node(phandle->parent, node) {
>  		enum mtk_ddp_comp_type comp_type;
>  		int comp_id;
>  
> @@ -576,22 +591,11 @@ static int mtk_drm_sys_resume(struct device *dev)
>  static SIMPLE_DEV_PM_OPS(mtk_drm_pm_ops, mtk_drm_sys_suspend,
>  			 mtk_drm_sys_resume);
>  
> -static const struct of_device_id mtk_drm_of_ids[] = {
> -	{ .compatible = "mediatek,mt2701-mmsys",
> -	  .data = &mt2701_mmsys_driver_data},
> -	{ .compatible = "mediatek,mt2712-mmsys",
> -	  .data = &mt2712_mmsys_driver_data},
> -	{ .compatible = "mediatek,mt8173-mmsys",
> -	  .data = &mt8173_mmsys_driver_data},
> -	{ }
> -};
> -
>  static struct platform_driver mtk_drm_platform_driver = {
>  	.probe	= mtk_drm_probe,
>  	.remove	= mtk_drm_remove,
>  	.driver	= {
>  		.name	= "mediatek-drm",
> -		.of_match_table = mtk_drm_of_ids,
>  		.pm     = &mtk_drm_pm_ops,
>  	},
>  };
> diff --git a/drivers/soc/mediatek/mt8173-mmsys.c b/drivers/soc/mediatek/mt8173-mmsys.c
> index 48e6c157d28e..c894db5b6ca9 100644
> --- a/drivers/soc/mediatek/mt8173-mmsys.c
> +++ b/drivers/soc/mediatek/mt8173-mmsys.c
> @@ -103,6 +103,7 @@ static int mt8173_mmsys_probe(struct platform_device *pdev)
>  {
>  	struct device_node *node = pdev->dev.of_node;
>  	struct clk_onecell_data *clk_data;
> +	struct platform_device *drm;
>  	int ret;
>  
>  	clk_data = mtk_alloc_clk_data(CLK_MM_NR_CLK);
> @@ -118,6 +119,11 @@ static int mt8173_mmsys_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> +	drm = platform_device_register_data(&pdev->dev, "mediatek-drm",
> +					    PLATFORM_DEVID_NONE, NULL, 0);
> +	if (IS_ERR(drm))
> +		return PTR_ERR(drm);
> +
>  	return 0;
>  }
>