On Wed, Oct 29, 2025 at 03:14:28PM +0800, Chaoyi Chen wrote: > From: Chaoyi Chen <[email protected]> > > Several USB-C controller drivers have already implemented the DP HPD > bridge function provided by aux-hpd-bridge.c, but there are still > some USB-C controller driver that have not yet implemented it. > > This patch implements a generic DP HPD bridge based on aux-hpd-bridge.c, > so that other USB-C controller drivers don't need to implement it again.
This doesn't describe the problem that you are trying to solve. > > Signed-off-by: Chaoyi Chen <[email protected]> > --- > > Changes in v8: > - Merge generic DP HPD bridge into one module. > > drivers/gpu/drm/bridge/Kconfig | 5 +- > drivers/gpu/drm/bridge/Makefile | 8 +++- > drivers/gpu/drm/bridge/aux-hpd-bridge.c | 23 ++++++++- > drivers/gpu/drm/bridge/aux-hpd-bridge.h | 13 +++++ > .../gpu/drm/bridge/aux-hpd-typec-dp-bridge.c | 47 +++++++++++++++++++ > 5 files changed, 93 insertions(+), 3 deletions(-) > create mode 100644 drivers/gpu/drm/bridge/aux-hpd-bridge.h > 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..17257b223a28 100644 > --- a/drivers/gpu/drm/bridge/Kconfig > +++ b/drivers/gpu/drm/bridge/Kconfig > @@ -23,13 +23,16 @@ config DRM_AUX_BRIDGE > build bridges chain. > > config DRM_AUX_HPD_BRIDGE > - tristate > + tristate "AUX HPD bridge support" Why? No, this is supposed to be selected by other drivers. Users don't know an wouldn't know what is this. > depends on DRM_BRIDGE && OF > select AUXILIARY_BUS > help > Simple bridge that terminates the bridge chain and provides HPD > support. > > + Specifically, if you want a default Type-C DisplayPort HPD bridge for > + each port of the Type-C controller, say Y here. > + > 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..2998937444bc 100644 > --- a/drivers/gpu/drm/bridge/Makefile > +++ b/drivers/gpu/drm/bridge/Makefile > @@ -1,6 +1,12 @@ > # SPDX-License-Identifier: GPL-2.0 > obj-$(CONFIG_DRM_AUX_BRIDGE) += aux-bridge.o > -obj-$(CONFIG_DRM_AUX_HPD_BRIDGE) += aux-hpd-bridge.o > + > +hpd-bridge-y := aux-hpd-bridge.o > +ifneq ($(CONFIG_TYPEC),) > +hpd-bridge-y += aux-hpd-typec-dp-bridge.o > +endif > +obj-$(CONFIG_DRM_AUX_HPD_BRIDGE) += hpd-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-bridge.c > b/drivers/gpu/drm/bridge/aux-hpd-bridge.c > index 2e9c702c7087..11ad6dc776c7 100644 > --- a/drivers/gpu/drm/bridge/aux-hpd-bridge.c > +++ b/drivers/gpu/drm/bridge/aux-hpd-bridge.c > @@ -12,6 +12,8 @@ > #include <drm/drm_bridge.h> > #include <drm/bridge/aux-bridge.h> > > +#include "aux-hpd-bridge.h" > + > static DEFINE_IDA(drm_aux_hpd_bridge_ida); > > struct drm_aux_hpd_bridge_data { > @@ -204,7 +206,26 @@ static struct auxiliary_driver drm_aux_hpd_bridge_drv = { > .id_table = drm_aux_hpd_bridge_table, > .probe = drm_aux_hpd_bridge_probe, > }; > -module_auxiliary_driver(drm_aux_hpd_bridge_drv); > + > +static int drm_aux_hpd_bridge_mod_init(void) > +{ > + int ret; > + > + ret = auxiliary_driver_register(&drm_aux_hpd_bridge_drv); > + if (ret) > + return ret; > + > + return drm_aux_hpd_typec_dp_bridge_init(); > +} > + > +static void drm_aux_hpd_bridge_mod_exit(void) > +{ > + drm_aux_hpd_typec_dp_bridge_exit(); > + auxiliary_driver_unregister(&drm_aux_hpd_bridge_drv); > +} > + > +module_init(drm_aux_hpd_bridge_mod_init); > +module_exit(drm_aux_hpd_bridge_mod_exit); > > MODULE_AUTHOR("Dmitry Baryshkov <[email protected]>"); > MODULE_DESCRIPTION("DRM HPD bridge"); > diff --git a/drivers/gpu/drm/bridge/aux-hpd-bridge.h > b/drivers/gpu/drm/bridge/aux-hpd-bridge.h > new file mode 100644 > index 000000000000..69364731c2f1 > --- /dev/null > +++ b/drivers/gpu/drm/bridge/aux-hpd-bridge.h > @@ -0,0 +1,13 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +#ifndef AUX_HPD_BRIDGE_H > +#define AUX_HPD_BRIDGE_H > + > +#if IS_REACHABLE(CONFIG_TYPEC) > +int drm_aux_hpd_typec_dp_bridge_init(void); > +void drm_aux_hpd_typec_dp_bridge_exit(void); > +#else > +static inline int drm_aux_hpd_typec_dp_bridge_init(void) { return 0; } > +static inline void drm_aux_hpd_typec_dp_bridge_exit(void) { } > +#endif /* IS_REACHABLE(CONFIG_TYPEC) */ > + > +#endif /* AUX_HPD_BRIDGE_H */ > 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..6f2a1fca0fc5 > --- /dev/null > +++ b/drivers/gpu/drm/bridge/aux-hpd-typec-dp-bridge.c > @@ -0,0 +1,47 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +#include <linux/of.h> > +#include <linux/usb/typec_altmode.h> > +#include <linux/usb/typec_dp.h> > +#include <linux/usb/typec_notify.h> > + > +#include <drm/bridge/aux-bridge.h> > + > +#include "aux-hpd-bridge.h" > + > +#if IS_REACHABLE(CONFIG_TYPEC) > +static int drm_typec_bus_event(struct notifier_block *nb, > + unsigned long action, void *data) > +{ This feels like this should be a part of the Type-C subsystem rather than DRM. > + 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, > +}; > + > +int drm_aux_hpd_typec_dp_bridge_init(void) > +{ > + return typec_altmode_register_notify(&drm_typec_event_nb); > +} > + > +void drm_aux_hpd_typec_dp_bridge_exit(void) > +{ > + typec_altmode_unregister_notify(&drm_typec_event_nb); > +} > +#endif > -- > 2.49.0 > -- With best wishes Dmitry
