On Tue, Dec 31, 2024 at 08:28:49PM +0100, Marek Vasut wrote:
> The dw-hdmi output_port is set to 1 in order to look for a connector
> next bridge in order to get DRM_BRIDGE_ATTACH_NO_CONNECTOR working.
> The output_port set to 1 makes the DW HDMI driver core look up the
> next bridge in DT, where the next bridge is often the hdmi-connector .
>
> Similar to 0af5e0b41110 ("drm/meson: encoder_hdmi: switch to bridge DRM_BRIDGE_ATTACH_NO_CONNECTOR")
>
> Note that looking at the upstream arch/arm64/boot/dts/freescale/imx8mp*dts ,
> the oldest commit which adds HDMI support is commit:
>
> 3e67a1ddd56d ("arm64: dts: imx8mp: Enable HDMI on TQMa8MPxL/MBa8MPxL")
>
> That already contains the HDMI connector node. Most follow up additions
> of HDMI support to another devices has been a variation of the same commit,
> including connector node, which is the proper way of eanbling HDMI on the
> i.MX8MP.
>
> The rest should be covered by output_port_optional which should make systems
> with DTs without HDMI connector node work, but such DTs should be updated and
> the HDMI connector node should be added.
>
> Signed-off-by: Marek Vasut <marex@xxxxxxx>
> ---
> Cc: Andrzej Hajda <andrzej.hajda@xxxxxxxxx>
> Cc: David Airlie <airlied@xxxxxxxxx>
> Cc: Fabio Estevam <festevam@xxxxxxxxx>
> Cc: Jernej Skrabec <jernej.skrabec@xxxxxxxxx>
> Cc: Jonas Karlman <jonas@xxxxxxxxx>
> Cc: Laurent Pinchart <Laurent.pinchart@xxxxxxxxxxxxxxxx>
> Cc: Liu Ying <victor.liu@xxxxxxx>
> Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
> Cc: Maxime Ripard <mripard@xxxxxxxxxx>
> Cc: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
> Cc: Pengutronix Kernel Team <kernel@xxxxxxxxxxxxxx>
> Cc: Robert Foss <rfoss@xxxxxxxxxx>
> Cc: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> Cc: Shawn Guo <shawnguo@xxxxxxxxxx>
> Cc: Simona Vetter <simona@xxxxxxxx>
> Cc: Stefan Agner <stefan@xxxxxxxx>
> Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Cc: imx@xxxxxxxxxxxxxxx
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> ---
> V2: No change
> V3: - Update commit message
> - Move select DRM_DISPLAY_CONNECTOR to DRM_IMX8MP_DW_HDMI_BRIDGE
> - Enable output_port_optional
> ---
> drivers/gpu/drm/bridge/imx/Kconfig | 1 +
> drivers/gpu/drm/bridge/imx/imx8mp-hdmi-tx.c | 2 ++
> 2 files changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/imx/Kconfig b/drivers/gpu/drm/bridge/imx/Kconfig
> index 9a480c6abb856..db5c8a76193ac 100644
> --- a/drivers/gpu/drm/bridge/imx/Kconfig
> +++ b/drivers/gpu/drm/bridge/imx/Kconfig
> @@ -17,6 +17,7 @@ config DRM_IMX8MP_DW_HDMI_BRIDGE
> tristate "Freescale i.MX8MP HDMI-TX bridge support"
> depends on OF
> depends on COMMON_CLK
> + select DRM_DISPLAY_CONNECTOR
I was going to write that it is not to be selected by anybody, but then
I stumbled upon meson driver, which also selects the symbol.
I still think that it is not to be selected by your driver as there is
no direct dependency (and there can be other bridges inbetween or the
bridge chain can end up with some other bridge). Such decisions belong
to defconfig or distribution's kernel config file.
> select DRM_DW_HDMI
> imply DRM_IMX8MP_HDMI_PVI
> imply PHY_FSL_SAMSUNG_HDMI_PHY
> diff --git a/drivers/gpu/drm/bridge/imx/imx8mp-hdmi-tx.c b/drivers/gpu/drm/bridge/imx/imx8mp-hdmi-tx.c
> index 1e7a789ec2890..3d63200e468bf 100644
> --- a/drivers/gpu/drm/bridge/imx/imx8mp-hdmi-tx.c
> +++ b/drivers/gpu/drm/bridge/imx/imx8mp-hdmi-tx.c
> @@ -101,6 +101,8 @@ static int imx8mp_dw_hdmi_probe(struct platform_device *pdev)
> plat_data->phy_name = "SAMSUNG HDMI TX PHY";
> plat_data->priv_data = hdmi;
> plat_data->phy_force_vendor = true;
> + plat_data->output_port = 1;
> + plat_data->output_port_optional = true;
>
> hdmi->dw_hdmi = dw_hdmi_probe(pdev, plat_data);
> if (IS_ERR(hdmi->dw_hdmi))
> --
> 2.45.2
>
--
With best wishes
Dmitry
