[PATCH v2 07/12] drm/bridge: analogix_dp: Add support to find panel or bridge

[Damon Ding]

Since the panel/bridge should logically be positioned behind the
Analogix bridge in the display pipeline, it makes sense to handle
the panel/bridge parsing on the Analogix side.

Signed-off-by: Damon Ding <damon.ding at rock-chips.com>
---
 .../drm/bridge/analogix/analogix_dp_core.c    | 48 +++++++++++++++++++
 include/drm/bridge/analogix_dp.h              |  2 +
 2 files changed, 50 insertions(+)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 78d68310e4f6..660f95e90490 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>
@@ -1707,6 +1709,52 @@ struct drm_dp_aux *analogix_dp_get_aux(struct analogix_dp_device *dp)
 }
 EXPORT_SYMBOL_GPL(analogix_dp_get_aux);
 
+static int analogix_dp_aux_done_probing(struct drm_dp_aux *aux)
+{
+	struct analogix_dp_device *dp = to_dp(aux);
+	struct analogix_dp_plat_data *plat_data = dp->plat_data;
+	int port = plat_data->dev_type == EXYNOS_DP ? 0 : 1;
+	int ret;
+
+	/*
+	 * If drm_of_find_panel_or_bridge() returns -ENODEV, there may be no valid panel
+	 * or bridge nodes. The driver should go on for the driver-free bridge or the DP
+	 * mode applications.
+	 */
+	ret = drm_of_find_panel_or_bridge(dp->dev->of_node, port, 0,
+					  &plat_data->panel, &plat_data->bridge);
+	if (ret && ret != -ENODEV)
+		return ret;
+
+	return component_add(dp->dev, plat_data->ops);
+}
+
+int analogix_dp_find_panel_or_bridge(struct analogix_dp_device *dp)
+{
+	int ret;
+
+	ret = devm_of_dp_aux_populate_bus(&dp->aux, analogix_dp_aux_done_probing);
+	if (ret) {
+		/*
+		 * If devm_of_dp_aux_populate_bus() returns -ENODEV, the done_probing() will
+		 * not be called because there are no EP devices. Then the callback function
+		 * analogix_dp_aux_done_probing() will be called directly in order to support
+		 * the other valid DT configurations.
+		 *
+		 * NOTE: The devm_of_dp_aux_populate_bus() is allowed to return -EPROBE_DEFER.
+		 */
+		if (ret != -ENODEV) {
+			dev_err(dp->dev, "failed to populate aux bus\n");
+			return ret;
+		}
+
+		return analogix_dp_aux_done_probing(&dp->aux);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(analogix_dp_find_panel_or_bridge);
+
 MODULE_AUTHOR("Jingoo Han <jg1.han at samsung.com>");
 MODULE_DESCRIPTION("Analogix DP Core Driver");
 MODULE_LICENSE("GPL v2");
diff --git a/include/drm/bridge/analogix_dp.h b/include/drm/bridge/analogix_dp.h
index 202e5eafb2cc..0b6d85f1924e 100644
--- a/include/drm/bridge/analogix_dp.h
+++ b/include/drm/bridge/analogix_dp.h
@@ -30,6 +30,7 @@ struct analogix_dp_plat_data {
 	struct drm_bridge *bridge;
 	struct drm_encoder *encoder;
 	struct drm_connector *connector;
+	const struct component_ops *ops;
 
 	int (*power_on)(struct analogix_dp_plat_data *);
 	int (*power_off)(struct analogix_dp_plat_data *);
@@ -52,5 +53,6 @@ int analogix_dp_stop_crc(struct drm_connector *connector);
 
 struct analogix_dp_plat_data *analogix_dp_aux_to_plat_data(struct drm_dp_aux *aux);
 struct drm_dp_aux *analogix_dp_get_aux(struct analogix_dp_device *dp);
+int analogix_dp_find_panel_or_bridge(struct analogix_dp_device *dp);
 
 #endif /* _ANALOGIX_DP_H_ */
-- 
2.34.1