[PATCH v3 4/4] drm/mxsfb: add DRM_BRIDGE_ATTACH_NO_CONNECTOR flag to drm_bridge_attach

[Marek Vasut]

Commit a25b988ff83f ("drm/bridge: Extend bridge API to disable connector creation")
added DRM_BRIDGE_ATTACH_NO_CONNECTOR bridge flag and all bridges handle
this flag in some way since then.
Newly added bridge drivers must no longer contain the connector creation and
will fail probing if this flag isn't set.

In order to be able to connect to those newly added bridges as well,
make use of drm_bridge_connector API and have the connector initialized
by the display controller.

Based on 2e87bf389e13 ("drm/rockchip: add DRM_BRIDGE_ATTACH_NO_CONNECTOR flag to drm_bridge_attach")

This makes LT9611 work with i.MX8M Mini.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
Signed-off-by: Marek Vasut <marex at denx.de>
---
Cc: Andrzej Hajda <andrzej.hajda at intel.com>
Cc: David Airlie <airlied at gmail.com>
Cc: Fabio Estevam <festevam at gmail.com>
Cc: Jernej Skrabec <jernej.skrabec at gmail.com>
Cc: Jonas Karlman <jonas at kwiboo.se>
Cc: Laurent Pinchart <Laurent.pinchart at ideasonboard.com>
Cc: Liu Ying <victor.liu at nxp.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Maxime Ripard <mripard at kernel.org>
Cc: Neil Armstrong <neil.armstrong at linaro.org>
Cc: Pengutronix Kernel Team <kernel at pengutronix.de>
Cc: Robert Foss <rfoss at kernel.org>
Cc: Sascha Hauer <s.hauer at pengutronix.de>
Cc: Shawn Guo <shawnguo at kernel.org>
Cc: Simona Vetter <simona at ffwll.ch>
Cc: Stefan Agner <stefan at agner.ch>
Cc: Thomas Zimmermann <tzimmermann at suse.de>
Cc: dri-devel at lists.freedesktop.org
Cc: imx at lists.linux.dev
Cc: linux-arm-kernel at lists.infradead.org
---
V2: Cache connector from drm_bridge_connector_init()
V3: - Add RB from Dmitry
    - Select DRM_DISPLAY_HELPER
    - Use return dev_err_probe() directly
    - Drop the single use fail path
---
 drivers/gpu/drm/mxsfb/Kconfig     |  2 ++
 drivers/gpu/drm/mxsfb/mxsfb_drv.c | 31 ++++++++++++++++++++-----------
 2 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/mxsfb/Kconfig b/drivers/gpu/drm/mxsfb/Kconfig
index fe98674d5a298..eb51d38455a6c 100644
--- a/drivers/gpu/drm/mxsfb/Kconfig
+++ b/drivers/gpu/drm/mxsfb/Kconfig
@@ -10,6 +10,7 @@ config DRM_MXSFB
 	depends on COMMON_CLK
 	depends on ARCH_MXS || ARCH_MXC || COMPILE_TEST
 	select DRM_CLIENT_SELECTION
+	select DRM_DISPLAY_HELPER
 	select DRM_MXS
 	select DRM_KMS_HELPER
 	select DRM_BRIDGE_CONNECTOR
@@ -32,6 +33,7 @@ config DRM_IMX_LCDIF
 	select DRM_DISPLAY_HELPER
 	select DRM_MXS
 	select DRM_KMS_HELPER
+	select DRM_BRIDGE_CONNECTOR
 	select DRM_GEM_DMA_HELPER
 	select DRM_PANEL
 	select DRM_PANEL_BRIDGE
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
index 59020862cf65e..07784c4f5be48 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
@@ -20,6 +20,7 @@
 #include <drm/clients/drm_client_setup.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
+#include <drm/drm_bridge_connector.h>
 #include <drm/drm_connector.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_fbdev_dma.h>
@@ -119,9 +120,9 @@ static const struct drm_mode_config_helper_funcs mxsfb_mode_config_helpers = {
 static int mxsfb_attach_bridge(struct mxsfb_drm_private *mxsfb)
 {
 	struct drm_device *drm = mxsfb->drm;
-	struct drm_connector_list_iter iter;
-	struct drm_panel *panel;
+	struct drm_connector *connector;
 	struct drm_bridge *bridge;
+	struct drm_panel *panel;
 	int ret;
 
 	ret = drm_of_find_panel_or_bridge(drm->dev->of_node, 0, 0, &panel,
@@ -139,19 +140,27 @@ static int mxsfb_attach_bridge(struct mxsfb_drm_private *mxsfb)
 	if (!bridge)
 		return -ENODEV;
 
-	ret = drm_bridge_attach(&mxsfb->encoder, bridge, NULL, 0);
+	ret = drm_bridge_attach(&mxsfb->encoder, bridge, NULL,
+				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
 	if (ret)
 		return dev_err_probe(drm->dev, ret, "Failed to attach bridge\n");
 
-	mxsfb->bridge = bridge;
+	connector = drm_bridge_connector_init(drm, &mxsfb->encoder);
+	if (IS_ERR(connector)) {
+		return dev_err_probe(drm->dev, PTR_ERR(connector),
+				     "Failed to initialize bridge connector: %pe\n",
+				     connector);
+	}
 
-	/*
-	 * Get hold of the connector. This is a bit of a hack, until the bridge
-	 * API gives us bus flags and formats.
-	 */
-	drm_connector_list_iter_begin(drm, &iter);
-	mxsfb->connector = drm_connector_list_iter_next(&iter);
-	drm_connector_list_iter_end(&iter);
+	ret = drm_connector_attach_encoder(connector, &mxsfb->encoder);
+	if (ret < 0) {
+		drm_connector_cleanup(connector);
+		return dev_err_probe(drm->dev, ret,
+				     "Failed to attach encoder.\n");
+	}
+
+	mxsfb->bridge = bridge;
+	mxsfb->connector = connector;
 
 	return 0;
 }
-- 
2.45.2