drm/tegra: dsi: Reset across ->exit()/->init()

This allows a DRM driver unload/reload cycle to completely reset the DSI
controller and may help in situations where it's broken.

Signed-off-by: Thierry Reding <[e-mail]>

drivers/gpu/drm/tegra/dsi.c

···
 	struct tegra_dsi *dsi = host1x_client_to_dsi(client);
 	int err;
 
+	reset_control_deassert(dsi->rst);
+
+	err = tegra_dsi_pad_calibrate(dsi);
+	if (err < 0) {
+		dev_err(dsi->dev, "MIPI calibration failed: %d\n", err);
+		goto reset;
+	}
+
 	/* Gangsters must not register their own outputs. */
 	if (!dsi->master) {
 		dsi->output.type = TEGRA_OUTPUT_DSI;
···
 	}
 
 	return 0;
+
+reset:
+	reset_control_assert(dsi->rst);
+	return err;
 }
 
 static int tegra_dsi_exit(struct host1x_client *client)
···
 			return err;
 		}
 	}
+
+	reset_control_assert(dsi->rst);
 
 	return 0;
 }
···
 	if (IS_ERR(dsi->rst))
 		return PTR_ERR(dsi->rst);
 
-	err = reset_control_deassert(dsi->rst);
-	if (err < 0) {
-		dev_err(&pdev->dev, "failed to bring DSI out of reset: %d\n",
-			err);
-		return err;
-	}
-
 	dsi->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(dsi->clk)) {
 		dev_err(&pdev->dev, "cannot get DSI clock\n");
···
 	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);
-		goto mipi_free;
 	}
 
 	dsi->host.ops = &tegra_dsi_host_ops;