drm/rockchip: dsi: Clean up 'usage_mode' when failing to attach

If we fail to attach the first time (especially: EPROBE_DEFER), we fail
to clean up 'usage_mode', and thus will fail to attach on any subsequent
attempts, with "dsi controller already in use".

Re-set to DW_DSI_USAGE_IDLE on attach failure.

This is especially common to hit when enabling asynchronous probe on a
duel-DSI system (such as RK3399 Gru/Scarlet), such that we're more
likely to fail dw_mipi_dsi_rockchip_find_second() the first time.

Fixes: 71f68fe7 ("drm/rockchip: dsi: add ability to work as a phy instead of full dsi")
Cc: <stable@vger.kernel.org>
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20221019170255.1.Ia68dfb27b835d31d22bfe23812baf366ee1c6eac@changeid

drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c

@@ -1051,23 +1051,31 @@ static int dw_mipi_dsi_rockchip_host_attach(void *priv_data,
 	if (ret) {
 		DRM_DEV_ERROR(dsi->dev, "Failed to register component: %d\n",
 					ret);
-		return ret;
+		goto out;
 	}
 
 	second = dw_mipi_dsi_rockchip_find_second(dsi);
-	if (IS_ERR(second))
-		return PTR_ERR(second);
+	if (IS_ERR(second)) {
+		ret = PTR_ERR(second);
+		goto out;
+	}
 	if (second) {
 		ret = component_add(second, &dw_mipi_dsi_rockchip_ops);
 		if (ret) {
 			DRM_DEV_ERROR(second,
 				      "Failed to register component: %d\n",
 				      ret);
-			return ret;
+			goto out;
 		}
 	}
 
 	return 0;
+
+out:
+	mutex_lock(&dsi->usage_mutex);
+	dsi->usage_mode = DW_DSI_USAGE_IDLE;
+	mutex_unlock(&dsi->usage_mutex);
+	return ret;
 }
 
 static int dw_mipi_dsi_rockchip_host_detach(void *priv_data,