drm/bridge: parade-ps8622: add drm_panel_bridge support

Prepare the bridge driver for use in a chained setup by
replacing direct use of drm_panel with drm_panel_bridge support.

The connecter is now either created by the panel bridge or the display
driver. So all code for connector creation in this driver is no longer
relevant and thus dropped.

The connector code had some special polling handling:
    connector.polled = DRM_CONNECTOR_POLL_HPD;
    drm_helper_hpd_irq_event(ps8622->bridge.dev);

This code was most likely added to speed up detection of the connector.
If really needed then this functionality belongs somewhere else.

Note: the bridge panel will use the connector type from the panel.

v2:
  - Fix to avoid creating connector twice (Laurent)
  - Drop all connector code - defer to bridge panel
  - Use panel_bridge for local variable to align with other drivers
  - Set bridge.type to DRM_MODE_CONNECTOR_LVDS;

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
Cc: Jonas Karlman <jonas@kwiboo.se>
Cc: Jernej Skrabec <jernej.skrabec@siol.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200726203324.3722593-9-sam@ravnborg.org

drivers/gpu/drm/bridge/parade-ps8622.c

@@ -42,10 +42,9 @@
 #endif
 
 struct ps8622_bridge {
-	struct drm_connector connector;
 	struct i2c_client *client;
 	struct drm_bridge bridge;
-	struct drm_panel *panel;
+	struct drm_bridge *panel_bridge;
 	struct regulator *v12;
 	struct backlight_device *bl;
 
@@ -64,12 +63,6 @@ static inline struct ps8622_bridge *
 	return container_of(bridge, struct ps8622_bridge, bridge);
 }
 
-static inline struct ps8622_bridge *
-		connector_to_ps8622(struct drm_connector *connector)
-{
-	return container_of(connector, struct ps8622_bridge, connector);
-}
-
 static int ps8622_set(struct i2c_client *client, u8 page, u8 reg, u8 val)
 {
 	int ret;
@@ -365,11 +358,6 @@ static void ps8622_pre_enable(struct drm_bridge *bridge)
 			DRM_ERROR("fails to enable ps8622->v12");
 	}
 
-	if (drm_panel_prepare(ps8622->panel)) {
-		DRM_ERROR("failed to prepare panel\n");
-		return;
-	}
-
 	gpiod_set_value(ps8622->gpio_slp, 1);
 
 	/*
@@ -399,24 +387,9 @@ static void ps8622_pre_enable(struct drm_bridge *bridge)
 	ps8622->enabled = true;
 }
 
-static void ps8622_enable(struct drm_bridge *bridge)
-{
-	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
-
-	if (drm_panel_enable(ps8622->panel)) {
-		DRM_ERROR("failed to enable panel\n");
-		return;
-	}
-}
-
 static void ps8622_disable(struct drm_bridge *bridge)
 {
-	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
-
-	if (drm_panel_disable(ps8622->panel)) {
-		DRM_ERROR("failed to disable panel\n");
-		return;
-	}
+	/* Delay after panel is disabled */
 	msleep(PS8622_PWMO_END_T12_MS);
 }
 
@@ -436,11 +409,6 @@ static void ps8622_post_disable(struct drm_bridge *bridge)
 	 */
 	gpiod_set_value(ps8622->gpio_slp, 0);
 
-	if (drm_panel_unprepare(ps8622->panel)) {
-		DRM_ERROR("failed to unprepare panel\n");
-		return;
-	}
-
 	if (ps8622->v12)
 		regulator_disable(ps8622->v12);
 
@@ -455,67 +423,17 @@ static void ps8622_post_disable(struct drm_bridge *bridge)
 	msleep(PS8622_POWER_OFF_T17_MS);
 }
 
-static int ps8622_get_modes(struct drm_connector *connector)
-{
-	struct ps8622_bridge *ps8622;
-
-	ps8622 = connector_to_ps8622(connector);
-
-	return drm_panel_get_modes(ps8622->panel, connector);
-}
-
-static const struct drm_connector_helper_funcs ps8622_connector_helper_funcs = {
-	.get_modes = ps8622_get_modes,
-};
-
-static const struct drm_connector_funcs ps8622_connector_funcs = {
-	.fill_modes = drm_helper_probe_single_connector_modes,
-	.destroy = drm_connector_cleanup,
-	.reset = drm_atomic_helper_connector_reset,
-	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
-	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
-};
-
 static int ps8622_attach(struct drm_bridge *bridge,
 			 enum drm_bridge_attach_flags flags)
 {
 	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
-	int ret;
-
-	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
-		DRM_ERROR("Fix bridge driver to make connector optional!");
-		return -EINVAL;
-	}
 
-	if (!bridge->encoder) {
-		DRM_ERROR("Parent encoder object not found");
-		return -ENODEV;
-	}
-
-	ps8622->connector.polled = DRM_CONNECTOR_POLL_HPD;
-	ret = drm_connector_init(bridge->dev, &ps8622->connector,
-			&ps8622_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
-	if (ret) {
-		DRM_ERROR("Failed to initialize connector with drm\n");
-		return ret;
-	}
-	drm_connector_helper_add(&ps8622->connector,
-					&ps8622_connector_helper_funcs);
-	drm_connector_register(&ps8622->connector);
-	drm_connector_attach_encoder(&ps8622->connector,
-							bridge->encoder);
-
-	if (ps8622->panel)
-		drm_panel_attach(ps8622->panel, &ps8622->connector);
-
-	drm_helper_hpd_irq_event(ps8622->connector.dev);
-
-	return ret;
+	return drm_bridge_attach(ps8622->bridge.encoder, ps8622->panel_bridge,
+				 &ps8622->bridge, flags);
 }
 
 static const struct drm_bridge_funcs ps8622_bridge_funcs = {
 	.pre_enable = ps8622_pre_enable,
-	.enable = ps8622_enable,
 	.disable = ps8622_disable,
 	.post_disable = ps8622_post_disable,
 	.attach = ps8622_attach,
@@ -533,16 +451,23 @@ static int ps8622_probe(struct i2c_client *client,
 {
 	struct device *dev = &client->dev;
 	struct ps8622_bridge *ps8622;
+	struct drm_bridge *panel_bridge;
+	struct drm_panel *panel;
 	int ret;
 
 	ps8622 = devm_kzalloc(dev, sizeof(*ps8622), GFP_KERNEL);
 	if (!ps8622)
 		return -ENOMEM;
 
-	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0, &ps8622->panel, NULL);
+	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0, &panel, NULL);
 	if (ret)
 		return ret;
 
+	panel_bridge = devm_drm_panel_bridge_add(dev, panel);
+	if (IS_ERR(panel_bridge))
+		return PTR_ERR(panel_bridge);
+
+	ps8622->panel_bridge = panel_bridge;
 	ps8622->client = client;
 
 	ps8622->v12 = devm_regulator_get(dev, "vdd12");
@@ -595,6 +520,7 @@ static int ps8622_probe(struct i2c_client *client,
 	}
 
 	ps8622->bridge.funcs = &ps8622_bridge_funcs;
+	ps8622->bridge.type = DRM_MODE_CONNECTOR_LVDS;
 	ps8622->bridge.of_node = dev->of_node;
 	drm_bridge_add(&ps8622->bridge);