[PATCH 5/5] drm/bridge: mhdp8564: Support format negotiation

[Nikhil Devshatwar]

With new connector model, mhdp bridge will not create the connector and
SoC driver will rely on format negotiation to setup the encoder format.

Support format negotiations hooks in the drm_bridge_funcs.
Support a single format for input.

Signed-off-by: Nikhil Devshatwar <nikhil.nd at ti.com>
---
 .../drm/bridge/cadence/cdns-mhdp8546-core.c   | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
index d0c65610ebb5..230f6e28f82f 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
@@ -2078,6 +2078,34 @@ cdns_mhdp_bridge_atomic_reset(struct drm_bridge *bridge)
 	return &cdns_mhdp_state->base;
 }
 
+static u32 *cdns_mhdp_get_input_bus_fmts(struct drm_bridge *bridge,
+				      struct drm_bridge_state *bridge_state,
+				      struct drm_crtc_state *crtc_state,
+				      struct drm_connector_state *conn_state,
+				      u32 output_fmt,
+				      unsigned int *num_input_fmts)
+{
+	u32 *input_fmts;
+	u32 default_bus_format = MEDIA_BUS_FMT_RGB121212_1X36;
+
+	*num_input_fmts = 0;
+
+	/*
+	 * This bridge does not support media_bus_format conversion
+	 * Propagate only if supported
+	 */
+	if (output_fmt != default_bus_format && output_fmt != MEDIA_BUS_FMT_FIXED)
+		return NULL;
+
+	input_fmts = kzalloc(sizeof(*input_fmts), GFP_KERNEL);
+	if (!input_fmts)
+		return NULL;
+
+	*num_input_fmts = 1;
+	input_fmts[0] = default_bus_format;
+	return input_fmts;
+}
+
 static int cdns_mhdp_atomic_check(struct drm_bridge *bridge,
 				  struct drm_bridge_state *bridge_state,
 				  struct drm_crtc_state *crtc_state,
@@ -2142,6 +2170,7 @@ static const struct drm_bridge_funcs cdns_mhdp_bridge_funcs = {
 	.atomic_duplicate_state = cdns_mhdp_bridge_atomic_duplicate_state,
 	.atomic_destroy_state = cdns_mhdp_bridge_atomic_destroy_state,
 	.atomic_reset = cdns_mhdp_bridge_atomic_reset,
+	.atomic_get_input_bus_fmts = cdns_mhdp_get_input_bus_fmts,
 	.detect = cdns_mhdp_bridge_detect,
 	.get_edid = cdns_mhdp_bridge_get_edid,
 	.hpd_enable = cdns_mhdp_bridge_hpd_enable,
-- 
2.17.1