Hi, On Mon, Oct 20, 2025 at 07:07:46PM +0800, Chaoyi Chen wrote: > Hi Heikki, > > On 10/20/2025 6:02 PM, Heikki Krogerus wrote: > > On Thu, Oct 16, 2025 at 10:27:34AM +0800, Chaoyi Chen wrote: > > > From: Chaoyi Chen <[email protected]> > > > > > > Add default DRM AUX HPD bridge device when register DisplayPort > > > altmode. That makes it redundant for each Type-C driver to implement > > > a similar registration process in embedded scenarios. > > > > > > Signed-off-by: Chaoyi Chen <[email protected]> > > > --- > > > > > > Changes in v6: > > > - Fix depend in Kconfig. > > > > > > Changes in v5: > > > - Remove the calls related to `drm_aux_hpd_bridge_notify()`. > > > - Place the helper functions in the same compilation unit. > > > - Add more comments about parent device. > > > > > > drivers/usb/typec/Kconfig | 2 ++ > > > drivers/usb/typec/class.c | 26 ++++++++++++++++++++++++++ > > > include/linux/usb/typec_altmode.h | 2 ++ > > > 3 files changed, 30 insertions(+) > > > > > > diff --git a/drivers/usb/typec/Kconfig b/drivers/usb/typec/Kconfig > > > index 2f80c2792dbd..a6730fbb576b 100644 > > > --- a/drivers/usb/typec/Kconfig > > > +++ b/drivers/usb/typec/Kconfig > > > @@ -2,6 +2,8 @@ > > > menuconfig TYPEC > > > tristate "USB Type-C Support" > > > + depends on DRM || DRM=n > > > + select DRM_AUX_HPD_BRIDGE if DRM_BRIDGE && OF > > This is wrong. DRM should not dictate how this entire subsystem core > > is configured. The dependency needs to be on the DRM bridge side. > > > > You can for example use the bus notification there to see when a new > > alternate mode is being registered, or use some other notification > > mechanism. > > Is it a good idea to implement notification functions like > drivers/usb/core/notify.c in TCPM, and then let other subsystems (such as DRM) > listen to these notifications?
Don't limit this to tcpm only. I would suggest something similar what we have for usb bus: drivers/usb/core/notify.c So that, but for the typec bus. Then in DRM bridge code you just use typec_register/unregister_notify(). thanks, -- heikki
