[PATCH v3 09/15] drm/bridge: analogix_dp: Add support to get panel from the DP AUX bus

[Damon Ding]

If the panel can not be found in the beginning of rockchip_dp_probe()
using the platform bus, we can still try to find it in analogix_dp_bind()
through the DP AUX bus after the &analogix_dp_device.aux has been
initialized.

Signed-off-by: Damon Ding <damon.ding at rock-chips.com>
---
 .../drm/bridge/analogix/analogix_dp_core.c    | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 9429c50cc1bc..eae02819e3bb 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -19,12 +19,14 @@
 #include <linux/platform_device.h>
 
 #include <drm/bridge/analogix_dp.h>
+#include <drm/display/drm_dp_aux_bus.h>
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_device.h>
 #include <drm/drm_edid.h>
+#include <drm/drm_of.h>
 #include <drm/drm_panel.h>
 #include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>
@@ -1733,6 +1735,23 @@ int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev)
 		goto err_disable_pm_runtime;
 	}
 
+	if (!dp->plat_data->panel) {
+		/*
+		 * If the edp-panel module has not yet been initialized, the
+		 * devm_of_dp_aux_populate_bus() function will return 0 and
+		 * the done_probing() callback will not be called either.
+		 * Consequently, the panel will never be found.
+		 *
+		 * This is the reason why we do not use the done_probing()
+		 * callback and do not check the reture value here.
+		 */
+		devm_of_dp_aux_populate_bus(&dp->aux, NULL);
+		ret = drm_of_find_panel_or_bridge(dp->dev->of_node, 1, 0,
+						  &dp->plat_data->panel, NULL);
+		if (ret)
+			goto err_unregister_aux;
+	}
+
 	ret = analogix_dp_create_bridge(drm_dev, dp);
 	if (ret) {
 		DRM_ERROR("failed to create bridge (%d)\n", ret);
-- 
2.34.1