[v2,PATCH 3/3] drm/mediatek: dpi: add bus format negotiation

[Rex-BC Chen <rex-bc.chen@xxxxxxxxxxxx>]

Add the atomic_get_output_bus_fmts, atomic_get_input_bus_fmts to negotiate
the possible output and input formats for the current mode and monitor,
and use the negotiated formats in a basic atomic_check callback.

Signed-off-by: Jitao Shi <jitao.shi@xxxxxxxxxxxx>
Signed-off-by: Rex-BC Chen <rex-bc.chen@xxxxxxxxxxxx>
---
 drivers/gpu/drm/mediatek/mtk_dpi.c | 89 ++++++++++++++++++++++++++++--
 1 file changed, 84 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
index 76431fe849b8..b4e9c6c8d706 100644
--- a/drivers/gpu/drm/mediatek/mtk_dpi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
@@ -536,6 +536,87 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi,
 	return 0;
 }
 
+#define MAX_OUTPUT_SEL_FORMATS	2
+
+static u32 *mtk_dpi_bridge_atomic_get_output_bus_fmts(struct drm_bridge *bridge,
+					struct drm_bridge_state *bridge_state,
+					struct drm_crtc_state *crtc_state,
+					struct drm_connector_state *conn_state,
+					unsigned int *num_output_fmts)
+{
+	struct drm_display_mode *mode = &crtc_state->mode;
+	u32 *output_fmts;
+	struct mtk_dpi *dpi = bridge_to_dpi(bridge);
+
+	*num_output_fmts = 0;
+
+	output_fmts = kcalloc(MAX_OUTPUT_SEL_FORMATS, sizeof(*output_fmts),
+			      GFP_KERNEL);
+	if (!output_fmts)
+		return NULL;
+
+	/* Default 8bit RGB fallback */
+	if (dpi->conf->dual_edge) {
+		output_fmts[0] =  MEDIA_BUS_FMT_RGB888_2X12_LE;
+		output_fmts[1] =  MEDIA_BUS_FMT_RGB888_2X12_BE;
+		*num_output_fmts = 2;
+	} else {
+		output_fmts[0] =  MEDIA_BUS_FMT_RGB888_1X24;
+		*num_output_fmts = 1;
+	}
+
+	return output_fmts;
+}
+
+#define MAX_INPUT_SEL_FORMATS	1
+
+static u32 *mtk_dpi_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)
+{
+	u32 *input_fmts;
+
+	*num_input_fmts = 0;
+
+	input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts),
+			     GFP_KERNEL);
+	if (!input_fmts)
+		return NULL;
+
+	*num_input_fmts = 1;
+	input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
+
+	return input_fmts;
+}
+
+static int mtk_dpi_bridge_atomic_check(struct drm_bridge *bridge,
+				       struct drm_bridge_state *bridge_state,
+				       struct drm_crtc_state *crtc_state,
+				       struct drm_connector_state *conn_state)
+{
+	struct mtk_dpi *dpi = bridge->driver_private;
+	unsigned int out_bus_format;
+
+	out_bus_format = bridge_state->output_bus_cfg.format;
+
+	dev_dbg(dpi->dev, "input format 0x%04x, output format 0x%04x\n",
+		bridge_state->input_bus_cfg.format,
+		bridge_state->output_bus_cfg.format);
+
+	dpi->ddr_edge_sel = (out_bus_format == MEDIA_BUS_FMT_RGB888_2X12_LE) ?
+		 		true : false;
+
+	dpi->bit_num = MTK_DPI_OUT_BIT_NUM_8BITS;
+	dpi->channel_swap = MTK_DPI_OUT_CHANNEL_SWAP_RGB;
+	dpi->yc_map = MTK_DPI_OUT_YC_MAP_RGB;
+	dpi->color_format = MTK_DPI_COLOR_FORMAT_RGB;
+
+	return 0;
+}
+
 static int mtk_dpi_bridge_attach(struct drm_bridge *bridge,
 				 enum drm_bridge_attach_flags flags)
 {
@@ -574,6 +655,9 @@ static const struct drm_bridge_funcs mtk_dpi_bridge_funcs = {
 	.mode_set = mtk_dpi_bridge_mode_set,
 	.disable = mtk_dpi_bridge_disable,
 	.enable = mtk_dpi_bridge_enable,
+	.atomic_check = mtk_dpi_bridge_atomic_check,
+	.atomic_get_output_bus_fmts = mtk_dpi_bridge_atomic_get_output_bus_fmts,
+	.atomic_get_input_bus_fmts = mtk_dpi_bridge_atomic_get_input_bus_fmts,
 };
 
 void mtk_dpi_start(struct device *dev)
@@ -620,11 +704,6 @@ static int mtk_dpi_bind(struct device *dev, struct device *master, void *data)
 	}
 	drm_connector_attach_encoder(dpi->connector, &dpi->encoder);
 
-	dpi->bit_num = MTK_DPI_OUT_BIT_NUM_8BITS;
-	dpi->channel_swap = MTK_DPI_OUT_CHANNEL_SWAP_RGB;
-	dpi->yc_map = MTK_DPI_OUT_YC_MAP_RGB;
-	dpi->color_format = MTK_DPI_COLOR_FORMAT_RGB;
-
 	return 0;
 
 err_cleanup:
-- 
2.18.0