drm/bridge: ti-sn65dsi86: Wrap panel with panel-bridge

To simplify interfacing with the panel, wrap it in a panel-bridge and
let the DRM bridge helpers handle chaining of operations.

This also prepares for support of DRM_BRIDGE_ATTACH_NO_CONNECTOR, which
requires all components in the display pipeline to be represented by
bridges.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210624000304.16281-5-laurent.pinchart+renesas@ideasonboard.com

drivers/gpu/drm/bridge/ti-sn65dsi86.c

@@ -127,7 +127,7 @@
  * @host_node:    Remote DSI node.
  * @dsi:          Our MIPI DSI source.
  * @refclk:       Our reference clock.
- * @panel:        Our panel.
+ * @next_bridge:  The bridge on the eDP side.
  * @enable_gpio:  The GPIO we toggle to enable the bridge.
  * @supplies:     Data for bulk enabling/disabling our regulators.
  * @dp_lanes:     Count of dp_lanes we're using.
@@ -159,7 +159,7 @@ struct ti_sn65dsi86 {
 	struct device_node		*host_node;
 	struct mipi_dsi_device		*dsi;
 	struct clk			*refclk;
-	struct drm_panel		*panel;
+	struct drm_bridge		*next_bridge;
 	struct gpio_desc		*enable_gpio;
 	struct regulator_bulk_data	supplies[SN_REGULATOR_SUPPLY_NUM];
 	int				dp_lanes;
@@ -404,7 +404,8 @@ connector_to_ti_sn65dsi86(struct drm_connector *connector)
 static int ti_sn_bridge_connector_get_modes(struct drm_connector *connector)
 {
 	struct ti_sn65dsi86 *pdata = connector_to_ti_sn65dsi86(connector);
-	return drm_panel_get_modes(pdata->panel, connector);
+
+	return drm_bridge_get_modes(pdata->next_bridge, connector);
 }
 
 static enum drm_mode_status
@@ -530,8 +531,16 @@ static int ti_sn_bridge_attach(struct drm_bridge *bridge,
 	}
 	pdata->dsi = dsi;
 
+	/* Attach the next bridge */
+	ret = drm_bridge_attach(bridge->encoder, pdata->next_bridge,
+				&pdata->bridge, flags);
+	if (ret < 0)
+		goto err_dsi_detach;
+
 	return 0;
 
+err_dsi_detach:
+	mipi_dsi_detach(dsi);
 err_dsi_attach:
 	mipi_dsi_device_unregister(dsi);
 err_dsi_host:
@@ -550,8 +559,6 @@ static void ti_sn_bridge_disable(struct drm_bridge *bridge)
 {
 	struct ti_sn65dsi86 *pdata = bridge_to_ti_sn65dsi86(bridge);
 
-	drm_panel_disable(pdata->panel);
-
 	/* disable video stream */
 	regmap_update_bits(pdata->regmap, SN_ENH_FRAME_REG, VSTREAM_ENABLE, 0);
 	/* semi auto link training mode OFF */
@@ -878,8 +885,6 @@ static void ti_sn_bridge_enable(struct drm_bridge *bridge)
 	/* enable video stream */
 	regmap_update_bits(pdata->regmap, SN_ENH_FRAME_REG, VSTREAM_ENABLE,
 			   VSTREAM_ENABLE);
-
-	drm_panel_enable(pdata->panel);
 }
 
 static void ti_sn_bridge_pre_enable(struct drm_bridge *bridge)
@@ -890,16 +895,12 @@ static void ti_sn_bridge_pre_enable(struct drm_bridge *bridge)
 
 	if (!pdata->refclk)
 		ti_sn65dsi86_enable_comms(pdata);
-
-	drm_panel_prepare(pdata->panel);
 }
 
 static void ti_sn_bridge_post_disable(struct drm_bridge *bridge)
 {
 	struct ti_sn65dsi86 *pdata = bridge_to_ti_sn65dsi86(bridge);
 
-	drm_panel_unprepare(pdata->panel);
-
 	if (!pdata->refclk)
 		ti_sn65dsi86_disable_comms(pdata);
 
@@ -1304,13 +1305,20 @@ static int ti_sn_bridge_probe(struct auxiliary_device *adev,
 {
 	struct ti_sn65dsi86 *pdata = dev_get_drvdata(adev->dev.parent);
 	struct device_node *np = pdata->dev->of_node;
+	struct drm_panel *panel;
 	int ret;
 
-	ret = drm_of_find_panel_or_bridge(np, 1, 0, &pdata->panel, NULL);
+	ret = drm_of_find_panel_or_bridge(np, 1, 0, &panel, NULL);
 	if (ret)
 		return dev_err_probe(&adev->dev, ret,
 				     "could not find any panel node\n");
 
+	pdata->next_bridge = devm_drm_panel_bridge_add(pdata->dev, panel);
+	if (IS_ERR(pdata->next_bridge)) {
+		DRM_ERROR("failed to create panel bridge\n");
+		return PTR_ERR(pdata->next_bridge);
+	}
+
 	ti_sn_bridge_parse_lanes(pdata, np);
 
 	ret = ti_sn_bridge_parse_dsi_host(pdata);