On Tue, Dec 31, 2024 at 08:28:50PM +0100, Marek Vasut wrote:
> 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 Plus.
>
> Reviewed-by: Dmitry Baryshkov <dmitry.barysh...@linaro.org>
> Signed-off-by: Marek Vasut <ma...@denx.de>
> ---
> Cc: Andrzej Hajda <andrzej.ha...@intel.com>
> Cc: David Airlie <airl...@gmail.com>
> Cc: Fabio Estevam <feste...@gmail.com>
> Cc: Jernej Skrabec <jernej.skra...@gmail.com>
> Cc: Jonas Karlman <jo...@kwiboo.se>
> Cc: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
> Cc: Liu Ying <victor....@nxp.com>
> Cc: Maarten Lankhorst <maarten.lankho...@linux.intel.com>
> Cc: Maxime Ripard <mrip...@kernel.org>
> Cc: Neil Armstrong <neil.armstr...@linaro.org>
> Cc: Pengutronix Kernel Team <ker...@pengutronix.de>
> Cc: Robert Foss <rf...@kernel.org>
> Cc: Sascha Hauer <s.ha...@pengutronix.de>
> Cc: Shawn Guo <shawn...@kernel.org>
> Cc: Simona Vetter <sim...@ffwll.ch>
> Cc: Stefan Agner <ste...@agner.ch>
> Cc: Thomas Zimmermann <tzimmerm...@suse.de>
> Cc: dri-devel@lists.freedesktop.org
> Cc: i...@lists.linux.dev
> Cc: linux-arm-ker...@lists.infradead.org
> ---
> V2: Add RB from Dmitry
> V3: - Select DRM_DISPLAY_HELPER
> - Use return dev_err_probe() directly
> - Add missing of_node_put(ep)
> - Add test using drm_bridge_get_next_bridge() to try and determine
> if the HDMI connector was missing in DT or not, and if it was
> missing, if it was created by the HDMI bridge driver.
> ---
> drivers/gpu/drm/mxsfb/Kconfig | 2 ++
> drivers/gpu/drm/mxsfb/lcdif_drv.c | 30 ++++++++++++++++++++++++++++--
> 2 files changed, 30 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/mxsfb/Kconfig b/drivers/gpu/drm/mxsfb/Kconfig
> index 264e74f455547..fe98674d5a298 100644
> --- a/drivers/gpu/drm/mxsfb/Kconfig
> +++ b/drivers/gpu/drm/mxsfb/Kconfig
> @@ -12,6 +12,7 @@ config DRM_MXSFB
> select DRM_CLIENT_SELECTION
> select DRM_MXS
> select DRM_KMS_HELPER
> + select DRM_BRIDGE_CONNECTOR
Shouldn't this chunk go to another patch?
> select DRM_GEM_DMA_HELPER
> select DRM_PANEL
> select DRM_PANEL_BRIDGE
> @@ -28,6 +29,7 @@ config DRM_IMX_LCDIF
> depends on COMMON_CLK
> depends on ARCH_MXC || COMPILE_TEST
> select DRM_CLIENT_SELECTION
> + select DRM_DISPLAY_HELPER
> select DRM_MXS
> select DRM_KMS_HELPER
> select DRM_GEM_DMA_HELPER
> diff --git a/drivers/gpu/drm/mxsfb/lcdif_drv.c
> b/drivers/gpu/drm/mxsfb/lcdif_drv.c
> index 8ee00f59ca821..dc39adabb3cd9 100644
> --- a/drivers/gpu/drm/mxsfb/lcdif_drv.c
> +++ b/drivers/gpu/drm/mxsfb/lcdif_drv.c
> @@ -17,6 +17,7 @@
> #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_drv.h>
> #include <drm/drm_encoder.h>
> #include <drm/drm_fbdev_dma.h>
> @@ -48,8 +49,10 @@ static const struct drm_encoder_funcs lcdif_encoder_funcs
> = {
> static int lcdif_attach_bridge(struct lcdif_drm_private *lcdif)
> {
> struct device *dev = lcdif->drm->dev;
> + struct drm_device *drm = lcdif->drm;
> + struct drm_connector *connector;
> struct device_node *ep;
> - struct drm_bridge *bridge;
> + struct drm_bridge *bridge, *nextbridge;
> int ret;
>
> for_each_endpoint_of_node(dev->of_node, ep) {
> @@ -97,13 +100,36 @@ static int lcdif_attach_bridge(struct lcdif_drm_private
> *lcdif)
> return ret;
> }
>
> - ret = drm_bridge_attach(encoder, bridge, NULL, 0);
> + ret = drm_bridge_attach(encoder, bridge, NULL,
> + DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> if (ret) {
> of_node_put(ep);
> return dev_err_probe(dev, ret,
> "Failed to attach bridge for
> endpoint%u\n",
> of_ep.id);
> }
> +
> + nextbridge = drm_bridge_get_next_bridge(bridge);
> + nextbridge = drm_bridge_get_next_bridge(nextbridge);
> + /* Test if connector node in DT, if not, it was created already
> */
By whom? And why? There is no display-connector bridge, but there is a
normal bridge chain, you have passed DRM_BRIDGE_ATTACH_NO_CONNECTOR, so
now it's a proper time to create drm_bridge_connector. You have added
the next_bridge_optional flag, but it should just prevent the dw driver
from returning the error if there is no next_bridge.
> + if (!nextbridge)
> + continue;
> +
> + connector = drm_bridge_connector_init(drm, encoder);
> + if (IS_ERR(connector)) {
> + of_node_put(ep);
> + return dev_err_probe(drm->dev, PTR_ERR(connector),
> + "Failed to initialize bridge
> connector: %pe\n",
> + connector);
> + }
> +
> + ret = drm_connector_attach_encoder(connector, encoder);
> + if (ret < 0) {
> + of_node_put(ep);
> + drm_connector_cleanup(connector);
> + return dev_err_probe(drm->dev, ret,
> + "Failed to attach encoder.\n");
> + }
> }
>
> return 0;
> --
> 2.45.2
>
--
With best wishes
Dmitry
