[bug report] drm/mediatek: Add drm ovl_adaptor sub driver for MT8195

[Dan Carpenter]

Hello Nancy.Lin,

The patch 0d9eee9118b7: "drm/mediatek: Add drm ovl_adaptor sub driver
for MT8195" from Mar 21, 2023, leads to the following Smatch static
checker warning:

	drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c:606 mtk_ddp_comp_init()
	error: uninitialized symbol 'comp_pdev'.

drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
    546 int mtk_ddp_comp_init(struct device_node *node, struct mtk_ddp_comp *comp,
    547                       unsigned int comp_id)
    548 {
    549         struct platform_device *comp_pdev;
    550         enum mtk_ddp_comp_type type;
    551         struct mtk_ddp_comp_dev *priv;
    552 #if IS_REACHABLE(CONFIG_MTK_CMDQ)
    553         int ret;
    554 #endif
    555 
    556         if (comp_id < 0 || comp_id >= DDP_COMPONENT_DRM_ID_MAX)
    557                 return -EINVAL;
    558 
    559         type = mtk_ddp_matches[comp_id].type;
    560 
    561         comp->id = comp_id;
    562         comp->funcs = mtk_ddp_matches[comp_id].funcs;
    563         /* Not all drm components have a DTS device node, such as ovl_adaptor,
    564          * which is the drm bring up sub driver
    565          */
    566         if (node) {
    567                 comp_pdev = of_find_device_by_node(node);
    568                 if (!comp_pdev) {
    569                         DRM_INFO("Waiting for device %s\n", node->full_name);
    570                         return -EPROBE_DEFER;
    571                 }
    572                 comp->dev = &comp_pdev->dev;
    573         }

comp_pdev not initialized on else path.

    574 
    575         if (type == MTK_DISP_AAL ||
    576             type == MTK_DISP_BLS ||
    577             type == MTK_DISP_CCORR ||
    578             type == MTK_DISP_COLOR ||
    579             type == MTK_DISP_GAMMA ||
    580             type == MTK_DISP_MERGE ||
    581             type == MTK_DISP_OVL ||
    582             type == MTK_DISP_OVL_2L ||
    583             type == MTK_DISP_OVL_ADAPTOR ||
    584             type == MTK_DISP_PWM ||
    585             type == MTK_DISP_RDMA ||
    586             type == MTK_DPI ||
    587             type == MTK_DP_INTF ||
    588             type == MTK_DSI)
    589                 return 0;
    590 
    591         priv = devm_kzalloc(comp->dev, sizeof(*priv), GFP_KERNEL);
    592         if (!priv)
    593                 return -ENOMEM;
    594 
    595         priv->regs = of_iomap(node, 0);
    596         priv->clk = of_clk_get(node, 0);
    597         if (IS_ERR(priv->clk))
    598                 return PTR_ERR(priv->clk);
    599 
    600 #if IS_REACHABLE(CONFIG_MTK_CMDQ)
    601         ret = cmdq_dev_get_client_reg(comp->dev, &priv->cmdq_reg, 0);
    602         if (ret)
    603                 dev_dbg(comp->dev, "get mediatek,gce-client-reg fail!\n");
    604 #endif
    605 
--> 606         platform_set_drvdata(comp_pdev, priv);
                                     ^^^^^^^^^
Warning msg triggered here.

    607 
    608         return 0;
    609 }

regards,
dan carpenter