[PATCH v2 2/3] drm/msm/disp/dpu1: add helper to know if display is pluggable

[Kalyan Thota <quic_kalyant@quicinc.com>]

Since DRM encoder type for few encoders can be similar
(like eDP and DP) find out if the interface supports HPD
from encoder bridge to differentiate between builtin
and pluggable displays.

Changes in v1:
- add connector type in the disp_info (Dmitry)
- add helper functions to know encoder type
- update commit text reflecting the change

Changes in v2:
- avoid hardcode of connector type for DSI as it may not be true (Dmitry)
- get the HPD information from encoder bridge

Signed-off-by: Kalyan Thota <quic_kalyant@quicinc.com>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 16 ++++++++++++++++
 drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h |  6 ++++++
 2 files changed, 22 insertions(+)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
index 9c6817b..be93269 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
@@ -15,6 +15,7 @@
 #include <drm/drm_crtc.h>
 #include <drm/drm_file.h>
 #include <drm/drm_probe_helper.h>
+#include <drm/drm_bridge.h>
 
 #include "msm_drv.h"
 #include "dpu_kms.h"
@@ -217,6 +218,21 @@ static u32 dither_matrix[DITHER_MATRIX_SZ] = {
 	15, 7, 13, 5, 3, 11, 1, 9, 12, 4, 14, 6, 0, 8, 2, 10
 };
 
+bool dpu_encoder_is_pluggable(struct drm_encoder *encoder)
+{
+	struct drm_bridge *bridge;
+	int ops = 0;
+
+	if (!encoder)
+		return false;
+
+	/* Get last bridge in the chain to determine pluggable state */
+	drm_for_each_bridge_in_chain(encoder, bridge)
+		if (!drm_bridge_get_next_bridge(bridge))
+			ops = bridge->ops;
+
+	return ops & DRM_BRIDGE_OP_HPD;
+}
 
 bool dpu_encoder_is_widebus_enabled(const struct drm_encoder *drm_enc)
 {
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
index 9e7236e..691ab57 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
@@ -224,4 +224,10 @@ void dpu_encoder_cleanup_wb_job(struct drm_encoder *drm_enc,
  */
 bool dpu_encoder_is_valid_for_commit(struct drm_encoder *drm_enc);
 
+/**
+ * dpu_encoder_is_pluggable - find if the encoder is of type pluggable
+ * @drm_enc:    Pointer to previously created drm encoder structure
+ */
+bool dpu_encoder_is_pluggable(struct drm_encoder *drm_enc);
+
 #endif /* __DPU_ENCODER_H__ */
-- 
2.7.4