drm/tegra: dsi: Properly cleanup on probe failure

The driver wasn't even attempting to do any cleanup when probing failed.
Fix this by releasing any resources acquired up to the point of failure
and putting the device back into the original state (reset, clocks off).

Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/dsi.c

@@ -861,64 +861,72 @@ static int tegra_dsi_probe(struct platform_device *pdev)
 	dsi->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(dsi->clk)) {
 		dev_err(&pdev->dev, "cannot get DSI clock\n");
-		return PTR_ERR(dsi->clk);
+		err = PTR_ERR(dsi->clk);
+		goto reset;
 	}
 
 	err = clk_prepare_enable(dsi->clk);
 	if (err < 0) {
 		dev_err(&pdev->dev, "cannot enable DSI clock\n");
-		return err;
+		goto reset;
 	}
 
 	dsi->clk_lp = devm_clk_get(&pdev->dev, "lp");
 	if (IS_ERR(dsi->clk_lp)) {
 		dev_err(&pdev->dev, "cannot get low-power clock\n");
-		return PTR_ERR(dsi->clk_lp);
+		err = PTR_ERR(dsi->clk_lp);
+		goto disable_clk;
 	}
 
 	err = clk_prepare_enable(dsi->clk_lp);
 	if (err < 0) {
 		dev_err(&pdev->dev, "cannot enable low-power clock\n");
-		return err;
+		goto disable_clk;
 	}
 
 	dsi->clk_parent = devm_clk_get(&pdev->dev, "parent");
 	if (IS_ERR(dsi->clk_parent)) {
 		dev_err(&pdev->dev, "cannot get parent clock\n");
-		return PTR_ERR(dsi->clk_parent);
+		err = PTR_ERR(dsi->clk_parent);
+		goto disable_clk_lp;
 	}
 
 	dsi->vdd = devm_regulator_get(&pdev->dev, "avdd-dsi-csi");
 	if (IS_ERR(dsi->vdd)) {
 		dev_err(&pdev->dev, "cannot get VDD supply\n");
-		return PTR_ERR(dsi->vdd);
+		err = PTR_ERR(dsi->vdd);
+		goto disable_clk_lp;
 	}
 
 	err = regulator_enable(dsi->vdd);
 	if (err < 0) {
 		dev_err(&pdev->dev, "cannot enable VDD supply\n");
-		return err;
+		goto disable_clk_lp;
 	}
 
 	err = tegra_dsi_setup_clocks(dsi);
 	if (err < 0) {
 		dev_err(&pdev->dev, "cannot setup clocks\n");
-		return err;
+		goto disable_vdd;
 	}
 
 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	dsi->regs = devm_ioremap_resource(&pdev->dev, regs);
-	if (IS_ERR(dsi->regs))
-		return PTR_ERR(dsi->regs);
+	if (IS_ERR(dsi->regs)) {
+		err = PTR_ERR(dsi->regs);
+		goto disable_vdd;
+	}
 
 	dsi->mipi = tegra_mipi_request(&pdev->dev);
-	if (IS_ERR(dsi->mipi))
-		return PTR_ERR(dsi->mipi);
+	if (IS_ERR(dsi->mipi)) {
+		err = PTR_ERR(dsi->mipi);
+		goto disable_vdd;
+	}
 
 	err = tegra_dsi_pad_calibrate(dsi);
 	if (err < 0) {
 		dev_err(dsi->dev, "MIPI calibration failed: %d\n", err);
-		return err;
+		goto mipi_free;
 	}
 
 	dsi->host.ops = &tegra_dsi_host_ops;
@@ -927,7 +935,7 @@ static int tegra_dsi_probe(struct platform_device *pdev)
 	err = mipi_dsi_host_register(&dsi->host);
 	if (err < 0) {
 		dev_err(&pdev->dev, "failed to register DSI host: %d\n", err);
-		return err;
+		goto mipi_free;
 	}
 
 	INIT_LIST_HEAD(&dsi->client.list);
@@ -938,12 +946,26 @@ static int tegra_dsi_probe(struct platform_device *pdev)
 	if (err < 0) {
 		dev_err(&pdev->dev, "failed to register host1x client: %d\n",
 			err);
-		return err;
+		goto unregister;
 	}
 
 	platform_set_drvdata(pdev, dsi);
 
 	return 0;
+
+unregister:
+	mipi_dsi_host_unregister(&dsi->host);
+mipi_free:
+	tegra_mipi_free(dsi->mipi);
+disable_vdd:
+	regulator_disable(dsi->vdd);
+disable_clk_lp:
+	clk_disable_unprepare(dsi->clk_lp);
+disable_clk:
+	clk_disable_unprepare(dsi->clk);
+reset:
+	reset_control_assert(dsi->rst);
+	return err;
 }
 
 static int tegra_dsi_remove(struct platform_device *pdev)