drm/ingenic: Implement proper .atomic_get_input_bus_fmts

The .atomic_get_input_bus_fmts() callback of our top bridge should
return the possible input formats for a given output format. If the
requested output format is not supported, then NULL should be returned,
otherwise the bus format negociation will end with a bus format that the
encoder does not support.

Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://patchwork.freedesktop.org/patch/msgid/ab25925723cff2f3e773e7137567ef86fff5fdba.1649330171.git.hns@goldelico.com

diff --git a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
index a4f5a32..8eb0ad5 100644 (file)
--- a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
+++ b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
@@ -833,6 +833,32 @@ static int ingenic_drm_bridge_atomic_check(struct drm_bridge *bridge,
        }
 }
 
+static u32 *
+ingenic_drm_bridge_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)
+{
+       switch (output_fmt) {
+       case MEDIA_BUS_FMT_RGB888_1X24:
+       case MEDIA_BUS_FMT_RGB666_1X18:
+       case MEDIA_BUS_FMT_RGB565_1X16:
+       case MEDIA_BUS_FMT_RGB888_3X8:
+       case MEDIA_BUS_FMT_RGB888_3X8_DELTA:
+               break;
+       default:
+               *num_input_fmts = 0;
+               return NULL;
+       }
+
+       return drm_atomic_helper_bridge_propagate_bus_fmt(bridge, bridge_state,
+                                                         crtc_state, conn_state,
+                                                         output_fmt,
+                                                         num_input_fmts);
+}
+
 static irqreturn_t ingenic_drm_irq_handler(int irq, void *arg)
 {
        struct ingenic_drm *priv = drm_device_get_priv(arg);
@@ -984,7 +1010,7 @@ static const struct drm_bridge_funcs ingenic_drm_bridge_funcs = {
        .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 = drm_atomic_helper_bridge_propagate_bus_fmt,
+       .atomic_get_input_bus_fmts = ingenic_drm_bridge_atomic_get_input_bus_fmts,
 };
 
 static const struct drm_mode_config_funcs ingenic_drm_mode_config_funcs = {