drm/mediatek: dsi: Register DSI host after acquiring clocks and PHY

Registering the dsi host with its ops before getting dsi->regs is
simply wrong: even though there's nothing (for now) asynchronously
calling those ops before the end of the probe function, installing
ops that are using iospace(s) and clocks before even initializing
those is too fragile.

Register the DSI host after getting clocks, iospace and PHY.
This wil also allow to simplify the error paths in a later commit.

Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20240215085316.56835-7-angelogioacchino.delregno@collabora.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

Author: AngeloGioacchino Del Regno

drivers/gpu/drm/mediatek/mtk_dsi.c

@@ -1114,14 +1114,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 	if (!dsi)
 		return -ENOMEM;
 
-	dsi->host.ops = &mtk_dsi_ops;
-	dsi->host.dev = dev;
-	ret = mipi_dsi_host_register(&dsi->host);
-	if (ret < 0) {
-		dev_err(dev, "failed to register DSI host: %d\n", ret);
-		return ret;
-	}
-
 	dsi->driver_data = of_device_get_match_data(dev);
 
 	dsi->engine_clk = devm_clk_get(dev, "engine");
@@ -1130,7 +1122,7 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 
 		if (ret != -EPROBE_DEFER)
 			dev_err(dev, "Failed to get engine clock: %d\n", ret);
-		goto err_unregister_host;
+		return ret;
 	}
 
 	dsi->digital_clk = devm_clk_get(dev, "digital");
@@ -1139,35 +1131,43 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 
 		if (ret != -EPROBE_DEFER)
 			dev_err(dev, "Failed to get digital clock: %d\n", ret);
-		goto err_unregister_host;
+		return ret;
 	}
 
 	dsi->hs_clk = devm_clk_get(dev, "hs");
 	if (IS_ERR(dsi->hs_clk)) {
 		ret = PTR_ERR(dsi->hs_clk);
 		dev_err(dev, "Failed to get hs clock: %d\n", ret);
-		goto err_unregister_host;
+		return ret;
 	}
 
 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	dsi->regs = devm_ioremap_resource(dev, regs);
 	if (IS_ERR(dsi->regs)) {
 		ret = PTR_ERR(dsi->regs);
 		dev_err(dev, "Failed to ioremap memory: %d\n", ret);
-		goto err_unregister_host;
+		return ret;
 	}
 
 	dsi->phy = devm_phy_get(dev, "dphy");
 	if (IS_ERR(dsi->phy)) {
 		ret = PTR_ERR(dsi->phy);
 		dev_err(dev, "Failed to get MIPI-DPHY: %d\n", ret);
-		goto err_unregister_host;
+		return ret;
 	}
 
 	irq_num = platform_get_irq(pdev, 0);
 	if (irq_num < 0) {
 		ret = irq_num;
-		goto err_unregister_host;
+		return ret;
+	}
+
+	dsi->host.ops = &mtk_dsi_ops;
+	dsi->host.dev = dev;
+	ret = mipi_dsi_host_register(&dsi->host);
+	if (ret < 0) {
+		dev_err(dev, "failed to register DSI host: %d\n", ret);
+		return ret;
 	}
 
 	ret = devm_request_irq(&pdev->dev, irq_num, mtk_dsi_irq,