drm: bridge: icn6211: Implement atomic_get_input_bus_fmts

Implement .atomic_get_input_bus_fmts callback, which sets up the
input (DSI-end) format, and that format can then be used in pipeline
format negotiation between the DSI-end of this bridge and the other
component closer to the scanout engine.
Acked-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Jagan Teki <jagan@amarulasolutions.com>
Cc: Maxime Ripard <maxime@cerno.tech>
Cc: Robert Foss <robert.foss@linaro.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
To: dri-devel@lists.freedesktop.org
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220331150509.9838-9-marex@denx.de

drivers/gpu/drm/bridge/chipone-icn6211.c

@@ -383,6 +383,32 @@ static int chipone_attach(struct drm_bridge *bridge, enum drm_bridge_attach_flag
 	return drm_bridge_attach(bridge->encoder, icn->panel_bridge, bridge, flags);
 }
 
+#define MAX_INPUT_SEL_FORMATS	1
+
+static u32 *
+chipone_atomic_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;
+
+	*num_input_fmts = 0;
+
+	input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts),
+			     GFP_KERNEL);
+	if (!input_fmts)
+		return NULL;
+
+	/* This is the DSI-end bus format */
+	input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
+	*num_input_fmts = 1;
+
+	return input_fmts;
+}
+
 static const struct drm_bridge_funcs chipone_bridge_funcs = {
 	.atomic_duplicate_state	= drm_atomic_helper_bridge_duplicate_state,
 	.atomic_destroy_state	= drm_atomic_helper_bridge_destroy_state,
@@ -392,6 +418,7 @@ static const struct drm_bridge_funcs chipone_bridge_funcs = {
 	.atomic_post_disable	= chipone_atomic_post_disable,
 	.mode_set		= chipone_mode_set,
 	.attach			= chipone_attach,
+	.atomic_get_input_bus_fmts = chipone_atomic_get_input_bus_fmts,
 };
 
 static int chipone_parse_dt(struct chipone *icn)