[PATCH v3 2/6] drm/bridge: tfp410: Support format negotiation hooks

[Nikhil Devshatwar]

With new connector model, tfp410 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.
Use helper functions for state management.

Output format is expected to be MEDIA_BUS_FMT_FIXED
Input format is the one selected by the bridge from DT properties.

Signed-off-by: Nikhil Devshatwar <nikhil.nd at ti.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
---

Notes:
    changes from v1:
    * Use only MEDIA_BUS_FMT_FIXED for output

 drivers/gpu/drm/bridge/ti-tfp410.c | 33 ++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/drivers/gpu/drm/bridge/ti-tfp410.c b/drivers/gpu/drm/bridge/ti-tfp410.c
index ba3fa2a9b8a4..3def9acba86b 100644
--- a/drivers/gpu/drm/bridge/ti-tfp410.c
+++ b/drivers/gpu/drm/bridge/ti-tfp410.c
@@ -204,12 +204,45 @@ static enum drm_mode_status tfp410_mode_valid(struct drm_bridge *bridge,
 	return MODE_OK;
 }
 
+static u32 *tfp410_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)
+{
+	struct tfp410 *dvi = drm_bridge_to_tfp410(bridge);
+	u32 *input_fmts;
+
+	*num_input_fmts = 0;
+
+	/*
+	 * Output of tfp410 is DVI, which is TMDS.
+	 * There is no media format defined for this.
+	 * Using MEDIA_BUS_FMT_FIXED for now.
+	 */
+	if (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] = dvi->bus_format;
+	return input_fmts;
+}
+
 static const struct drm_bridge_funcs tfp410_bridge_funcs = {
 	.attach		= tfp410_attach,
 	.detach		= tfp410_detach,
 	.enable		= tfp410_enable,
 	.disable	= tfp410_disable,
 	.mode_valid	= tfp410_mode_valid,
+	.atomic_reset = drm_atomic_helper_bridge_reset,
+	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
+	.atomic_get_input_bus_fmts = tfp410_get_input_bus_fmts,
 };
 
 static const struct drm_bridge_timings tfp410_default_timings = {
-- 
2.17.1