[PATCH v2 03/14] drm/bridge: analogix_dp: register AUX bus after enabling runtime PM

[Lucas Stach]

AUX transactions require the controller to be in working state and
take a runtime PM reference. To avoid potential races beween the
first transactions on the bus and runtime PM being set up, move the
AUX registration behind the runtime PM setup.

Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
Reviewed-by: Robert Foss <rfoss at kernel.org>
Tested-by: Heiko Stuebner <heiko at sntech.de> (rk3288-veyron and rk3399-gru)
---
 .../drm/bridge/analogix/analogix_dp_core.c    | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 31fa67d966c7..ae79802b62bb 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -1721,31 +1721,34 @@ int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev)
 	dp->drm_dev = drm_dev;
 	dp->encoder = dp->plat_data->encoder;
 
+	pm_runtime_use_autosuspend(dp->dev);
+	pm_runtime_set_autosuspend_delay(dp->dev, 100);
+	pm_runtime_enable(dp->dev);
+
 	dp->aux.name = "DP-AUX";
 	dp->aux.transfer = analogix_dpaux_transfer;
 	dp->aux.dev = dp->dev;
 	dp->aux.drm_dev = drm_dev;
 
 	ret = drm_dp_aux_register(&dp->aux);
-	if (ret)
-		return ret;
-
-	pm_runtime_use_autosuspend(dp->dev);
-	pm_runtime_set_autosuspend_delay(dp->dev, 100);
-	pm_runtime_enable(dp->dev);
+	if (ret) {
+		DRM_ERROR("failed to register AUX (%d)\n", ret);
+		goto err_disable_pm_runtime;
+	}
 
 	ret = analogix_dp_create_bridge(drm_dev, dp);
 	if (ret) {
 		DRM_ERROR("failed to create bridge (%d)\n", ret);
-		goto err_disable_pm_runtime;
+		goto err_unregister_aux;
 	}
 
 	return 0;
 
+err_unregister_aux:
+	drm_dp_aux_unregister(&dp->aux);
 err_disable_pm_runtime:
 	pm_runtime_dont_use_autosuspend(dp->dev);
 	pm_runtime_disable(dp->dev);
-	drm_dp_aux_unregister(&dp->aux);
 
 	return ret;
 }
-- 
2.39.2