From: Chaoyi Chen <[email protected]> The HPD function of Type-C DP is implemented through drm_connector_oob_hotplug_event(). For embedded DP, it is required that the DRM connector fwnode corresponds to the Type-C port fwnode.
To describe the relationship between the DP controller and the Type-C port device, we usually using drm_bridge to build a bridge chain. Now several USB-C controller drivers have already implemented the DP HPD bridge function provided by aux-hpd-bridge.c, it will build a DP HPD bridge on USB-C connector port device. But this requires the USB-C controller driver to manually register the HPD bridge. If the driver does not implement this feature, the bridge will not be create. So this patch implements a generic DP HPD bridge based on aux-hpd-bridge.c. It will monitor Type-C bus events, and when a Type-C port device containing the DP svid is registered, it will create an HPD bridge for it without the need for the USB-C controller driver to implement it. Signed-off-by: Chaoyi Chen <[email protected]> Reviewed-by: Heikki Krogerus <[email protected]> --- (no changes since v10) Changes in v9: - Remove the exposed DRM_AUX_HPD_BRIDGE option, and select DRM_AUX_HPD_TYPEC_BRIDGE when it is available. - Add more commit comment about problem background. Changes in v8: - Merge generic DP HPD bridge into one module. drivers/gpu/drm/bridge/Kconfig | 10 ++++ drivers/gpu/drm/bridge/Makefile | 1 + .../gpu/drm/bridge/aux-hpd-typec-dp-bridge.c | 50 +++++++++++++++++++ 3 files changed, 61 insertions(+) create mode 100644 drivers/gpu/drm/bridge/aux-hpd-typec-dp-bridge.c diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig index a250afd8d662..559487aa09a9 100644 --- a/drivers/gpu/drm/bridge/Kconfig +++ b/drivers/gpu/drm/bridge/Kconfig @@ -30,6 +30,16 @@ config DRM_AUX_HPD_BRIDGE Simple bridge that terminates the bridge chain and provides HPD support. +if DRM_AUX_HPD_BRIDGE +config DRM_AUX_HPD_TYPEC_BRIDGE + tristate + depends on TYPEC || !TYPEC + default TYPEC + help + Simple bridge that terminates the bridge chain and provides HPD + support. It build bridge on each USB-C connector device node. +endif + menu "Display Interface Bridges" depends on DRM && DRM_BRIDGE diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile index c7dc03182e59..a3a0393d2e72 100644 --- a/drivers/gpu/drm/bridge/Makefile +++ b/drivers/gpu/drm/bridge/Makefile @@ -1,6 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_DRM_AUX_BRIDGE) += aux-bridge.o obj-$(CONFIG_DRM_AUX_HPD_BRIDGE) += aux-hpd-bridge.o +obj-$(CONFIG_DRM_AUX_HPD_TYPEC_BRIDGE) += aux-hpd-typec-dp-bridge.o obj-$(CONFIG_DRM_CHIPONE_ICN6211) += chipone-icn6211.o obj-$(CONFIG_DRM_CHRONTEL_CH7033) += chrontel-ch7033.o obj-$(CONFIG_DRM_CROS_EC_ANX7688) += cros-ec-anx7688.o diff --git a/drivers/gpu/drm/bridge/aux-hpd-typec-dp-bridge.c b/drivers/gpu/drm/bridge/aux-hpd-typec-dp-bridge.c new file mode 100644 index 000000000000..9cb6a0cb0f0a --- /dev/null +++ b/drivers/gpu/drm/bridge/aux-hpd-typec-dp-bridge.c @@ -0,0 +1,50 @@ +// SPDX-License-Identifier: GPL-2.0+ +#include <linux/of.h> +#include <linux/usb/typec_altmode.h> +#include <linux/usb/typec_dp.h> + +#include <drm/bridge/aux-bridge.h> + +static int drm_typec_bus_event(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct typec_altmode *alt = (struct typec_altmode *)data; + + if (action != TYPEC_ALTMODE_REGISTERED) + goto done; + + if (is_typec_partner(&alt->dev) || alt->svid != USB_TYPEC_DP_SID) + goto done; + + /* + * alt->dev.parent->parent : USB-C controller device + * alt->dev.parent : USB-C connector device + */ + drm_dp_hpd_bridge_register(alt->dev.parent->parent, + to_of_node(alt->dev.parent->fwnode)); + +done: + return NOTIFY_OK; +} + +static struct notifier_block drm_typec_event_nb = { + .notifier_call = drm_typec_bus_event, +}; + +static void drm_aux_hpd_typec_dp_bridge_module_exit(void) +{ + typec_altmode_unregister_notify(&drm_typec_event_nb); +} + +static int __init drm_aux_hpd_typec_dp_bridge_module_init(void) +{ + typec_altmode_register_notify(&drm_typec_event_nb); + + return 0; +} + +module_init(drm_aux_hpd_typec_dp_bridge_module_init); +module_exit(drm_aux_hpd_typec_dp_bridge_module_exit); + +MODULE_DESCRIPTION("DRM TYPEC DP HPD BRIDGE"); +MODULE_LICENSE("GPL"); -- 2.51.1
