drm/mediatek: dsi: Simplify with dev_err_probe and remove gotos

Most of the functions that are called in the probe callback are
devm managed, or all but mipi_dsi_host_register(): simplify the probe
function's error paths with dev_err_probe() and remove the lonely
instance of `goto err_unregister_host` by just directly calling the
mipi_dsi_host_unregister() function in the devm_request_irq() error
path, allowing to also remove the same label.

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/20240215085316.56835-8-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

@@ -1117,64 +1117,44 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 	dsi->driver_data = of_device_get_match_data(dev);
 
 	dsi->engine_clk = devm_clk_get(dev, "engine");
-	if (IS_ERR(dsi->engine_clk)) {
-		ret = PTR_ERR(dsi->engine_clk);
+	if (IS_ERR(dsi->engine_clk))
+		return dev_err_probe(dev, PTR_ERR(dsi->engine_clk),
+				     "Failed to get engine clock\n");
 
-		if (ret != -EPROBE_DEFER)
-			dev_err(dev, "Failed to get engine clock: %d\n", ret);
-		return ret;
-	}
 
 	dsi->digital_clk = devm_clk_get(dev, "digital");
-	if (IS_ERR(dsi->digital_clk)) {
-		ret = PTR_ERR(dsi->digital_clk);
-
-		if (ret != -EPROBE_DEFER)
-			dev_err(dev, "Failed to get digital clock: %d\n", ret);
-		return ret;
-	}
+	if (IS_ERR(dsi->digital_clk))
+		return dev_err_probe(dev, PTR_ERR(dsi->digital_clk),
+				     "Failed to get digital clock\n");
 
 	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);
-		return ret;
-	}
+	if (IS_ERR(dsi->hs_clk))
+		return dev_err_probe(dev, PTR_ERR(dsi->hs_clk), "Failed to get hs clock\n");
 
 	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);
-		return ret;
-	}
+	if (IS_ERR(dsi->regs))
+		return dev_err_probe(dev, PTR_ERR(dsi->regs), "Failed to ioremap memory\n");
 
 	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);
-		return ret;
-	}
+	if (IS_ERR(dsi->phy))
+		return dev_err_probe(dev, PTR_ERR(dsi->phy), "Failed to get MIPI-DPHY\n");
 
 	irq_num = platform_get_irq(pdev, 0);
-	if (irq_num < 0) {
-		ret = irq_num;
-		return ret;
-	}
+	if (irq_num < 0)
+		return irq_num;
 
 	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;
-	}
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "Failed to register DSI host\n");
 
 	ret = devm_request_irq(&pdev->dev, irq_num, mtk_dsi_irq,
 			       IRQF_TRIGGER_NONE, dev_name(&pdev->dev), dsi);
 	if (ret) {
-		dev_err(&pdev->dev, "failed to request mediatek dsi irq\n");
-		goto err_unregister_host;
+		mipi_dsi_host_unregister(&dsi->host);
+		return dev_err_probe(&pdev->dev, ret, "Failed to request DSI irq\n");
 	}
 
 	init_waitqueue_head(&dsi->irq_wait_queue);
@@ -1186,10 +1166,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
 
 	return 0;
-
-err_unregister_host:
-	mipi_dsi_host_unregister(&dsi->host);
-	return ret;
 }
 
 static void mtk_dsi_remove(struct platform_device *pdev)