[PATCH v9 4/4] drm/tegra: output: rgb: Wrap directly-connected panel into DRM bridge

[Dmitry Osipenko]

Currently Tegra DRM driver manually manages display panel, but this
management could be moved out into DRM core if we'll wrap panel into
DRM bridge. This patch wraps RGB panel into a DRM bridge and removes
manual handling of the panel from the RGB output code.

Suggested-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Acked-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
 drivers/gpu/drm/tegra/rgb.c | 70 ++++++++++---------------------------
 1 file changed, 18 insertions(+), 52 deletions(-)

diff --git a/drivers/gpu/drm/tegra/rgb.c b/drivers/gpu/drm/tegra/rgb.c
index 9a7024ec96bc..4142a56ca764 100644
--- a/drivers/gpu/drm/tegra/rgb.c
+++ b/drivers/gpu/drm/tegra/rgb.c
@@ -8,7 +8,6 @@
 
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge_connector.h>
-#include <drm/drm_panel.h>
 #include <drm/drm_simple_kms_helper.h>
 
 #include "drm.h"
@@ -86,45 +85,13 @@ static void tegra_dc_write_regs(struct tegra_dc *dc,
 		tegra_dc_writel(dc, table[i].value, table[i].offset);
 }
 
-static const struct drm_connector_funcs tegra_rgb_connector_funcs = {
-	.reset = drm_atomic_helper_connector_reset,
-	.detect = tegra_output_connector_detect,
-	.fill_modes = drm_helper_probe_single_connector_modes,
-	.destroy = tegra_output_connector_destroy,
-	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
-	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
-};
-
-static enum drm_mode_status
-tegra_rgb_connector_mode_valid(struct drm_connector *connector,
-			       struct drm_display_mode *mode)
-{
-	/*
-	 * FIXME: For now, always assume that the mode is okay. There are
-	 * unresolved issues with clk_round_rate(), which doesn't always
-	 * reliably report whether a frequency can be set or not.
-	 */
-	return MODE_OK;
-}
-
-static const struct drm_connector_helper_funcs tegra_rgb_connector_helper_funcs = {
-	.get_modes = tegra_output_connector_get_modes,
-	.mode_valid = tegra_rgb_connector_mode_valid,
-};
-
 static void tegra_rgb_encoder_disable(struct drm_encoder *encoder)
 {
 	struct tegra_output *output = encoder_to_output(encoder);
 	struct tegra_rgb *rgb = to_rgb(output);
 
-	if (output->panel)
-		drm_panel_disable(output->panel);
-
 	tegra_dc_write_regs(rgb->dc, rgb_disable, ARRAY_SIZE(rgb_disable));
 	tegra_dc_commit(rgb->dc);
-
-	if (output->panel)
-		drm_panel_unprepare(output->panel);
 }
 
 static void tegra_rgb_encoder_enable(struct drm_encoder *encoder)
@@ -133,9 +100,6 @@ static void tegra_rgb_encoder_enable(struct drm_encoder *encoder)
 	struct tegra_rgb *rgb = to_rgb(output);
 	u32 value;
 
-	if (output->panel)
-		drm_panel_prepare(output->panel);
-
 	tegra_dc_write_regs(rgb->dc, rgb_enable, ARRAY_SIZE(rgb_enable));
 
 	value = DE_SELECT_ACTIVE | DE_CONTROL_NORMAL;
@@ -157,9 +121,6 @@ static void tegra_rgb_encoder_enable(struct drm_encoder *encoder)
 	tegra_dc_writel(rgb->dc, value, DC_DISP_SHIFT_CLOCK_OPTIONS);
 
 	tegra_dc_commit(rgb->dc);
-
-	if (output->panel)
-		drm_panel_enable(output->panel);
 }
 
 static int
@@ -278,6 +239,23 @@ int tegra_dc_rgb_init(struct drm_device *drm, struct tegra_dc *dc)
 	drm_encoder_helper_add(&output->encoder,
 			       &tegra_rgb_encoder_helper_funcs);
 
+	/*
+	 * Wrap directly-connected panel into DRM bridge in order to let
+	 * DRM core to handle panel for us.
+	 */
+	if (output->panel) {
+		output->bridge = devm_drm_panel_bridge_add(output->dev,
+							   output->panel);
+		if (IS_ERR(output->bridge)) {
+			dev_err(output->dev,
+				"failed to wrap panel into bridge: %pe\n",
+				output->bridge);
+			return PTR_ERR(output->bridge);
+		}
+
+		output->panel = NULL;
+	}
+
 	/*
 	 * Tegra devices that have LVDS panel utilize LVDS encoder bridge
 	 * for converting up to 28 LCD LVTTL lanes into 5/4 LVDS lanes that
@@ -292,8 +270,7 @@ int tegra_dc_rgb_init(struct drm_device *drm, struct tegra_dc *dc)
 	 * Newer device-trees utilize LVDS encoder bridge, which provides
 	 * us with a connector and handles the display panel.
 	 *
-	 * For older device-trees we fall back to our own connector and use
-	 * nvidia,panel phandle.
+	 * For older device-trees we wrapped panel into the panel-bridge.
 	 */
 	if (output->bridge) {
 		err = drm_bridge_attach(&output->encoder, output->bridge,
@@ -313,17 +290,6 @@ int tegra_dc_rgb_init(struct drm_device *drm, struct tegra_dc *dc)
 		}
 
 		drm_connector_attach_encoder(connector, &output->encoder);
-	} else {
-		drm_connector_init(drm, &output->connector,
-				   &tegra_rgb_connector_funcs,
-				   DRM_MODE_CONNECTOR_LVDS);
-		drm_connector_helper_add(&output->connector,
-					 &tegra_rgb_connector_helper_funcs);
-		output->connector.dpms = DRM_MODE_DPMS_OFF;
-
-		drm_connector_attach_encoder(&output->connector,
-					     &output->encoder);
-		drm_connector_register(&output->connector);
 	}
 
 	err = tegra_output_init(drm, output);
-- 
2.26.0