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Message-ID: <665202d7-46be-4dc8-a6be-3579e1ec078f@bosc.ac.cn>
Date: Wed, 22 May 2024 20:13:34 +0800
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Subject: Re: [v5,3/3] drm/mediatek: Implement OF graphs support for display
 paths
To: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>,
 chunkuang.hu@kernel.org
Cc: robh@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
 p.zabel@pengutronix.de, airlied@gmail.com, daniel@ffwll.ch,
 maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de,
 matthias.bgg@gmail.com, shawn.sung@mediatek.com, yu-chang.lee@mediatek.com,
 ck.hu@mediatek.com, jitao.shi@mediatek.com, devicetree@vger.kernel.org,
 linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
 linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org,
 wenst@chromium.org, kernel@collabora.com,
 Alexandre Mergnat <amergnat@baylibre.com>
References: <20240521075717.50330-4-angelogioacchino.delregno@collabora.com>
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From: Sui Jingfeng <suijingfeng@bosc.ac.cn>
Organization: bosc
In-Reply-To: <20240521075717.50330-4-angelogioacchino.delregno@collabora.com>
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Hi,


On 5/21/24 15:57, AngeloGioacchino Del Regno wrote:
> +static int mtk_drm_of_get_ddp_comp_type(struct device_node *node, enum mtk_ddp_comp_type *ctype)
> +{
> +	const struct of_device_id *of_id = of_match_node(mtk_ddp_comp_dt_ids, node);
> +
> +	if (!of_id)
> +		return -EINVAL;
> +
> +	*ctype = (enum mtk_ddp_comp_type)((uintptr_t)of_id->data);
> +
> +	return 0;
> +}
> +
> +static int mtk_drm_of_get_ddp_ep_cid(struct device_node *node,
> +				     int output_port, enum mtk_crtc_path crtc_path,
> +				     struct device_node **next, unsigned int *cid)
> +{
> +	struct device_node *ep_dev_node, *ep_out;
> +	enum mtk_ddp_comp_type comp_type;
> +	int ret;
> +
> +	ep_out = of_graph_get_endpoint_by_regs(node, output_port, crtc_path);
> +	if (!ep_out)
> +		return -ENOENT;
> +
> +	ep_dev_node = of_graph_get_remote_port_parent(ep_out);

below here, 'ep_out' will not be used anymore.

of_node_put(ep_out);

Maybe we should call it under a error handling tag?
But this is trivial problem.

> +	if (!ep_dev_node)
> +		return -EINVAL;
> +
> +	/*
> +	 * Pass the next node pointer regardless of failures in the later code
> +	 * so that if this function is called in a loop it will walk through all
> +	 * of the subsequent endpoints anyway.
> +	 */
> +	*next = ep_dev_node;
> +
> +	if (!of_device_is_available(ep_dev_node))
> +		return -ENODEV;
> +
> +	ret = mtk_drm_of_get_ddp_comp_type(ep_dev_node, &comp_type);
> +	if (ret) {
> +		if (mtk_ovl_adaptor_is_comp_present(ep_dev_node)) {
> +			*cid = (unsigned int)DDP_COMPONENT_DRM_OVL_ADAPTOR;
> +			return 0;
> +		}
> +		return ret;
> +	}
> +
> +	ret = mtk_ddp_comp_get_id(ep_dev_node, comp_type);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* All ok! Pass the Component ID to the caller. */
> +	*cid = (unsigned int)ret;
> +
> +	return 0;
> +}
> +

-- 
Best regards
Sui Jingfeng