Hi, On Tue, Aug 04, 2026 at 03:07:24PM +0800, Chaoyi Chen wrote: > From: Chaoyi Chen <[email protected]> > > Add a new API to check whether a DisplayPort HPD bridge has already > been registered. This helps avoid duplicate registration of the same > HPD bridge, although the current framework allows doing so. > > Suggested-by: Sebastian Reichel <[email protected]> > Signed-off-by: Chaoyi Chen <[email protected]> > ---
Reviewed-by: Sebastian Reichel <[email protected]> Tested-by: Sebastian Reichel <[email protected]> I still see the bridge registered twice for fusb302. Apparently the the new notifier is faster than the explicit registration in the driver. The code added here works though; reloading aux_hpd_typec_dp_bridge does not register more and more bridges :) Greetings, -- Sebastian > drivers/gpu/drm/bridge/aux-hpd-bridge.c | 42 ++++++++++++++++++++++++- > include/drm/bridge/aux-bridge.h | 6 ++++ > 2 files changed, 47 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/bridge/aux-hpd-bridge.c > b/drivers/gpu/drm/bridge/aux-hpd-bridge.c > index f02a38a2638a..a56c88eba005 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> > > +#define DRM_AUX_HPD_BRIDGE_NAME "dp_hpd_bridge" > + > static DEFINE_IDA(drm_aux_hpd_bridge_ida); > > struct drm_aux_hpd_bridge_data { > @@ -36,6 +38,44 @@ static void drm_aux_hpd_bridge_free_adev(void *_adev) > auxiliary_device_uninit(_adev); > } > > +static int hpd_bridge_match(struct device *dev, const void *data) > +{ > + const struct device_node *np = data; > + struct auxiliary_device *adev; > + > + if (!dev_is_auxiliary(dev)) > + return 0; > + > + adev = to_auxiliary_dev(dev); > + if (strcmp(adev->name, DRM_AUX_HPD_BRIDGE_NAME)) > + return 0; > + > + return adev->dev.platform_data == np; > +} > + > +/** > + * drm_dev_has_dp_hpd_bridge - check whether a HPD DisplayPort bridge is > registered > + * @parent: device instance providing this bridge > + * @np: device node pointer corresponding to this bridge instance > + * > + * Walk the children of @parent and check whether a HPD DisplayPort bridge > for > + * the given @np has already been registered via > devm_drm_dp_hpd_bridge_add(). > + * > + * Return: true if a HPD bridge for @parent / @np already exists, false > otherwise > + */ > +bool drm_dev_has_dp_hpd_bridge(struct device *parent, struct device_node *np) > +{ > + struct device *child; > + > + child = device_find_child(parent, np, hpd_bridge_match); > + if (child) { > + put_device(child); > + return true; > + } > + return false; > +} > +EXPORT_SYMBOL_GPL(drm_dev_has_dp_hpd_bridge); > + > /** > * devm_drm_dp_hpd_bridge_alloc - allocate a HPD DisplayPort bridge > * @parent: device instance providing this bridge > @@ -63,7 +103,7 @@ struct auxiliary_device > *devm_drm_dp_hpd_bridge_alloc(struct device *parent, str > } > > adev->id = ret; > - adev->name = "dp_hpd_bridge"; > + adev->name = DRM_AUX_HPD_BRIDGE_NAME; > adev->dev.parent = parent; > adev->dev.release = drm_aux_hpd_bridge_release; > adev->dev.platform_data = of_node_get(np); > diff --git a/include/drm/bridge/aux-bridge.h b/include/drm/bridge/aux-bridge.h > index c2f5a855512f..cca07a8e2d45 100644 > --- a/include/drm/bridge/aux-bridge.h > +++ b/include/drm/bridge/aux-bridge.h > @@ -25,6 +25,7 @@ struct auxiliary_device > *devm_drm_dp_hpd_bridge_alloc(struct device *parent, str > int devm_drm_dp_hpd_bridge_add(struct device *dev, struct auxiliary_device > *adev); > struct device *drm_dp_hpd_bridge_register(struct device *parent, > struct device_node *np); > +bool drm_dev_has_dp_hpd_bridge(struct device *parent, struct device_node > *np); > void drm_aux_hpd_bridge_notify(struct device *dev, enum drm_connector_status > status); > #else > static inline struct auxiliary_device *devm_drm_dp_hpd_bridge_alloc(struct > device *parent, > @@ -44,6 +45,11 @@ static inline struct device > *drm_dp_hpd_bridge_register(struct device *parent, > return NULL; > } > > +static inline bool drm_dev_has_dp_hpd_bridge(struct device *parent, struct > device_node *np) > +{ > + return false; > +} > + > static inline void drm_aux_hpd_bridge_notify(struct device *dev, enum > drm_connector_status status) > { > } > -- > 2.53.0 >
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