Re: [PATCH v6 04/51] drm/bridge: Add connector-related bridge operations and data

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Hi Daniel,

On Tue, Feb 18, 2020 at 07:44:19AM +0100, Daniel Vetter wrote:
> On Tue, Feb 18, 2020 at 2:21 AM Laurent Pinchart wrote:
> > On Mon, Feb 17, 2020 at 10:53:08AM +0100, Daniel Vetter wrote:
> >> On Sun, Feb 16, 2020 at 11:02:21PM +0200, Laurent Pinchart wrote:
> >>> To support implementation of DRM connectors on top of DRM bridges
> >>> instead of by bridges, the drm_bridge needs to expose new operations and
> >>> data:
> >>>
> >>> - Output detection, hot-plug notification, mode retrieval and EDID
> >>>   retrieval operations
> >>> - Bitmask of supported operations
> >>> - Bridge output type
> >>> - I2C adapter for DDC access
> >>>
> >>> Add and document these.
> >>>
> >>> Three new bridge helper functions are also added to handle hot plug
> >>> notification in a way that is as transparent as possible for the
> >>> bridges.
> >>>
> >>> Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> >>> Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
> >>> Reviewed-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
> >>> ---
> >>> Changes since v3:
> >>>
> >>> - Fix typos
> >>>
> >>> Changes since v2:
> >>>
> >>> - Add wrappers around the .detect(), .get_modes() and .get_edid()
> >>>   operations
> >>> - Warn bridge drivers about valid usage of the connector argument to
> >>>   .get_modes() and .get_edid()
> >>>
> >>> Changes since v1:
> >>>
> >>> - Make .hpd_enable() and .hpd_disable() optional
> >>> - Rename .lost_hotplug() to .hpd_notify()
> >>> - Add ddc field to drm_bridge
> >>> ---
> >>>  drivers/gpu/drm/drm_bridge.c | 162 +++++++++++++++++++++++++++++
> >>>  include/drm/drm_bridge.h     | 192 ++++++++++++++++++++++++++++++++++-
> >>>  2 files changed, 353 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> >>> index 68ab933ee430..78d26a9a3ee6 100644
> >>> --- a/drivers/gpu/drm/drm_bridge.c
> >>> +++ b/drivers/gpu/drm/drm_bridge.c
> >>> @@ -71,6 +71,8 @@ static LIST_HEAD(bridge_list);
> >>>   */
> >>>  void drm_bridge_add(struct drm_bridge *bridge)
> >>>  {
> >>> +   mutex_init(&bridge->hpd_mutex);
> >>> +
> >>>     mutex_lock(&bridge_lock);
> >>>     list_add_tail(&bridge->list, &bridge_list);
> >>>     mutex_unlock(&bridge_lock);
> >>> @@ -87,6 +89,8 @@ void drm_bridge_remove(struct drm_bridge *bridge)
> >>>     mutex_lock(&bridge_lock);
> >>>     list_del_init(&bridge->list);
> >>>     mutex_unlock(&bridge_lock);
> >>> +
> >>> +   mutex_destroy(&bridge->hpd_mutex);
> >>>  }
> >>>  EXPORT_SYMBOL(drm_bridge_remove);
> >>>
> >>> @@ -919,6 +923,164 @@ int drm_atomic_bridge_chain_check(struct drm_bridge *bridge,
> >>>  }
> >>>  EXPORT_SYMBOL(drm_atomic_bridge_chain_check);
> >>>
> >>> +/**
> >>> + * drm_bridge_detect - check if anything is attached to the bridge output
> >>> + * @bridge: bridge control structure
> >>> + *
> >>> + * If the bridge supports output detection, as reported by the
> >>> + * DRM_BRIDGE_OP_DETECT bridge ops flag, call &drm_bridge_funcs.detect for the
> >>> + * bridge and return the connection status. Otherwise return
> >>> + * connector_status_unknown.
> >>> + *
> >>> + * RETURNS:
> >>> + * The detection status on success, or connector_status_unknown if the bridge
> >>> + * doesn't support output detection.
> >>> + */
> >>> +enum drm_connector_status drm_bridge_detect(struct drm_bridge *bridge)
> >>> +{
> >>> +   if (!(bridge->ops & DRM_BRIDGE_OP_DETECT))
> >>> +           return connector_status_unknown;
> >>> +
> >>> +   return bridge->funcs->detect(bridge);
> >>> +}
> >>> +EXPORT_SYMBOL_GPL(drm_bridge_detect);
> >>> +
> >>> +/**
> >>> + * drm_bridge_get_modes - fill all modes currently valid for the sink into the
> >>> + * @connector
> >>> + * @bridge: bridge control structure
> >>> + * @connector: the connector to fill with modes
> >>> + *
> >>> + * If the bridge supports output modes retrieval, as reported by the
> >>> + * DRM_BRIDGE_OP_MODES bridge ops flag, call &drm_bridge_funcs.get_modes to
> >>> + * fill the connector with all valid modes and return the number of modes
> >>> + * added. Otherwise return 0.
> >>> + *
> >>> + * RETURNS:
> >>> + * The number of modes added to the connector.
> >>> + */
> >>> +int drm_bridge_get_modes(struct drm_bridge *bridge,
> >>> +                    struct drm_connector *connector)
> >>> +{
> >>> +   if (!(bridge->ops & DRM_BRIDGE_OP_MODES))
> >>> +           return 0;
> >>> +
> >>> +   return bridge->funcs->get_modes(bridge, connector);
> >>> +}
> >>> +EXPORT_SYMBOL_GPL(drm_bridge_get_modes);
> >>> +
> >>> +/**
> >>> + * drm_bridge_get_edid - get the EDID data of the connected display
> >>> + * @bridge: bridge control structure
> >>> + * @connector: the connector to read EDID for
> >>> + *
> >>> + * If the bridge supports output EDID retrieval, as reported by the
> >>> + * DRM_BRIDGE_OP_EDID bridge ops flag, call &drm_bridge_funcs.get_edid to
> >>> + * get the EDID and return it. Otherwise return ERR_PTR(-ENOTSUPP).
> >>> + *
> >>> + * RETURNS:
> >>> + * The retrieved EDID on success, or an error pointer otherwise.
> >>> + */
> >>> +struct edid *drm_bridge_get_edid(struct drm_bridge *bridge,
> >>> +                            struct drm_connector *connector)
> >>> +{
> >>> +   if (!(bridge->ops & DRM_BRIDGE_OP_EDID))
> >>> +           return ERR_PTR(-ENOTSUPP);
> >>> +
> >>> +   return bridge->funcs->get_edid(bridge, connector);
> >>> +}
> >>> +EXPORT_SYMBOL_GPL(drm_bridge_get_edid);
> >>> +
> >>> +/**
> >>> + * drm_bridge_hpd_enable - enable hot plug detection for the bridge
> >>> + * @bridge: bridge control structure
> >>> + * @cb: hot-plug detection callback
> >>> + * @data: data to be passed to the hot-plug detection callback
> >>> + *
> >>> + * Call &drm_bridge_funcs.hpd_enable if implemented and register the given @cb
> >>> + * and @data as hot plug notification callback. From now on the @cb will be
> >>> + * called with @data when an output status change is detected by the bridge,
> >>> + * until hot plug notification gets disabled with drm_bridge_hpd_disable().
> >>> + *
> >>> + * Hot plug detection is supported only if the DRM_BRIDGE_OP_HPD flag is set in
> >>> + * bridge->ops. This function shall not be called when the flag is not set.
> >>> + *
> >>> + * Only one hot plug detection callback can be registered at a time, it is an
> >>> + * error to call this function when hot plug detection is already enabled for
> >>> + * the bridge.
> >>> + */
> >>> +void drm_bridge_hpd_enable(struct drm_bridge *bridge,
> >>> +                      void (*cb)(void *data,
> >>> +                                 enum drm_connector_status status),
> >>> +                      void *data)
> >>> +{
> >>> +   if (!bridge || !(bridge->ops & DRM_BRIDGE_OP_HPD))
> >>
> >> Supplying a NULL bridge is a caller bug imo, and you're inconsistent in
> >> handling this. Imo just drop.
> >
> > Sounds good to me, I'll drop it.
> >
> >>> +           return;
> >>> +
> >>> +   mutex_lock(&bridge->hpd_mutex);
> >>> +
> >>> +   if (WARN(bridge->hpd_cb, "Hot plug detection already enabled\n"))
> >>> +           goto unlock;
> >>> +
> >>> +   bridge->hpd_cb = cb;
> >>> +   bridge->hpd_data = data;
> >>> +
> >>> +   if (bridge->funcs->hpd_enable)
> >>> +           bridge->funcs->hpd_enable(bridge);
> >>> +
> >>> +unlock:
> >>> +   mutex_unlock(&bridge->hpd_mutex);
> >>> +}
> >>> +EXPORT_SYMBOL_GPL(drm_bridge_hpd_enable);
> >>> +
> >>> +/**
> >>> + * drm_bridge_hpd_disable - disable hot plug detection for the bridge
> >>> + * @bridge: bridge control structure
> >>> + *
> >>> + * Call &drm_bridge_funcs.hpd_disable if implemented and unregister the hot
> >>> + * plug detection callback previously registered with drm_bridge_hpd_enable().
> >>> + * Once this function returns the callback will not be called by the bridge
> >>> + * when an output status change occurs.
> >>> + *
> >>> + * Hot plug detection is supported only if the DRM_BRIDGE_OP_HPD flag is set in
> >>> + * bridge->ops. This function shall not be called when the flag is not set.
> >>> + */
> >>> +void drm_bridge_hpd_disable(struct drm_bridge *bridge)
> >>> +{
> >>> +   if (!bridge || !(bridge->ops & DRM_BRIDGE_OP_HPD))
> >>> +           return;
> >>> +
> >>> +   mutex_lock(&bridge->hpd_mutex);
> >>> +   if (bridge->funcs->hpd_disable)
> >>> +           bridge->funcs->hpd_disable(bridge);
> >>> +
> >>> +   bridge->hpd_cb = NULL;
> >>> +   bridge->hpd_data = NULL;
> >>> +   mutex_unlock(&bridge->hpd_mutex);
> >>> +}
> >>> +EXPORT_SYMBOL_GPL(drm_bridge_hpd_disable);
> >>> +
> >>> +/**
> >>> + * drm_bridge_hpd_notify - notify hot plug detection events
> >>> + * @bridge: bridge control structure
> >>> + * @status: output connection status
> >>> + *
> >>> + * Bridge drivers shall call this function to report hot plug events when they
> >>> + * detect a change in the output status, when hot plug detection has been
> >>> + * enabled by drm_bridge_hpd_enable().
> >>> + *
> >>> + * This function shall be called in a context that can sleep.
> >>> + */
> >>> +void drm_bridge_hpd_notify(struct drm_bridge *bridge,
> >>> +                      enum drm_connector_status status)
> >>> +{
> >>> +   mutex_lock(&bridge->hpd_mutex);
> >>> +   if (bridge->hpd_cb)
> >>> +           bridge->hpd_cb(bridge->hpd_data, status);
> >>> +   mutex_unlock(&bridge->hpd_mutex);
> >>> +}
> >>> +EXPORT_SYMBOL_GPL(drm_bridge_hpd_notify);
> >>> +
> >>>  #ifdef CONFIG_OF
> >>>  /**
> >>>   * of_drm_find_bridge - find the bridge corresponding to the device node in
> >>> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> >>> index 45626ecf20f8..ba9b7c84f11e 100644
> >>> --- a/include/drm/drm_bridge.h
> >>> +++ b/include/drm/drm_bridge.h
> >>> @@ -23,8 +23,9 @@
> >>>  #ifndef __DRM_BRIDGE_H__
> >>>  #define __DRM_BRIDGE_H__
> >>>
> >>> -#include <linux/list.h>
> >>>  #include <linux/ctype.h>
> >>> +#include <linux/list.h>
> >>> +#include <linux/mutex.h>
> >>>
> >>>  #include <drm/drm_atomic.h>
> >>>  #include <drm/drm_encoder.h>
> >>> @@ -33,7 +34,10 @@
> >>>
> >>>  struct drm_bridge;
> >>>  struct drm_bridge_timings;
> >>> +struct drm_connector;
> >>>  struct drm_panel;
> >>> +struct edid;
> >>> +struct i2c_adapter;
> >>>
> >>>  /**
> >>>   * struct drm_bridge_funcs - drm_bridge control functions
> >>> @@ -488,6 +492,119 @@ struct drm_bridge_funcs {
> >>>      * giving the reason of the failure otherwise.
> >>>      */
> >>>     struct drm_bridge_state *(*atomic_reset)(struct drm_bridge *bridge);
> >>> +
> >>> +   /**
> >>> +    * @detect:
> >>> +    *
> >>> +    * Check if anything is attached to the bridge output.
> >>> +    *
> >>> +    * This callback is optional, if not implemented the bridge will be
> >>> +    * considered as always having a component attached to its output.
> >>> +    * Bridges that implement this callback shall set the
> >>> +    * DRM_BRIDGE_OP_DETECT flag in their &drm_bridge->ops.
> >>> +    *
> >>> +    * RETURNS:
> >>> +    *
> >>> +    * drm_connector_status indicating the bridge output status.
> >>> +    */
> >>> +   enum drm_connector_status (*detect)(struct drm_bridge *bridge);
> >>> +
> >>> +   /**
> >>> +    * @get_modes:
> >>> +    *
> >>> +    * Fill all modes currently valid for the sink into the &drm_connector
> >>> +    * with drm_mode_probed_add().
> >>> +    *
> >>> +    * The @get_modes callback is mostly intended to support non-probeable
> >>> +    * displays such as many fixed panels. Bridges that support reading
> >>> +    * EDID shall leave @get_modes unimplemented and implement the
> >>> +    * &drm_bridge_funcs->get_edid callback instead.
> >>> +    *
> >>> +    * This callback is optional. Bridges that implement it shall set the
> >>> +    * DRM_BRIDGE_OP_MODES flag in their &drm_bridge->ops.
> >>> +    *
> >>> +    * The connector parameter shall be used for the sole purpose of
> >>> +    * filling modes, and shall not be stored internally by bridge drivers
> >>> +    * for future usage.
> >>> +    *
> >>> +    * RETURNS:
> >>> +    *
> >>> +    * The number of modes added by calling drm_mode_probed_add().
> >>> +    */
> >>> +   int (*get_modes)(struct drm_bridge *bridge,
> >>> +                    struct drm_connector *connector);
> >>> +
> >>> +   /**
> >>> +    * @get_edid:
> >>> +    *
> >>> +    * Read and parse the EDID data of the connected display.
> >>> +    *
> >>> +    * The @get_edid callback is the preferred way of reporting mode
> >>> +    * information for a display connected to the bridge output. Bridges
> >>> +    * that support reading EDID shall implement this callback and leave
> >>> +    * the @get_modes callback unimplemented.
> >>> +    *
> >>> +    * The caller of this operation shall first verify the output
> >>> +    * connection status and refrain from reading EDID from a disconnected
> >>> +    * output.
> >>> +    *
> >>> +    * This callback is optional. Bridges that implement it shall set the
> >>> +    * DRM_BRIDGE_OP_EDID flag in their &drm_bridge->ops.
> >>> +    *
> >>> +    * The connector parameter shall be used for the sole purpose of EDID
> >>> +    * retrieval and parsing, and shall not be stored internally by bridge
> >>> +    * drivers for future usage.
> >>> +    *
> >>> +    * RETURNS:
> >>> +    *
> >>> +    * An edid structure newly allocated with kmalloc() (or similar) on
> >>> +    * success, or NULL otherwise. The caller is responsible for freeing
> >>> +    * the returned edid structure with kfree().
> >>> +    */
> >>> +   struct edid *(*get_edid)(struct drm_bridge *bridge,
> >>> +                            struct drm_connector *connector);
> >>> +
> >>> +   /**
> >>> +    * @hpd_notify:
> >>> +    *
> >>> +    * Notify the bridge of hot plug detection.
> >>> +    *
> >>> +    * This callback is optional, it may be implemented by bridges that
> >>> +    * need to be notified of display connection or disconnection for
> >>> +    * internal reasons. One use case is to reset the internal state of CEC
> >>> +    * controllers for HDMI bridges.
> >>> +    */
> >>> +   void (*hpd_notify)(struct drm_bridge *bridge,
> >>> +                      enum drm_connector_status status);
> >>> +
> >>> +   /**
> >>> +    * @hpd_enable:
> >>> +    *
> >>> +    * Enable hot plug detection. From now on the bridge shall call
> >>> +    * drm_bridge_hpd_notify() each time a change is detected in the output
> >>> +    * connection status, until hot plug detection gets disabled with
> >>> +    * @hpd_disable.
> >>> +    *
> >>> +    * This callback is optional and shall only be implemented by bridges
> >>> +    * that support hot-plug notification without polling. Bridges that
> >>> +    * implement it shall also implement the @hpd_disable callback and set
> >>> +    * the DRM_BRIDGE_OP_HPD flag in their &drm_bridge->ops.
> >>> +    */
> >>> +   void (*hpd_enable)(struct drm_bridge *bridge);
> >>> +
> >>> +   /**
> >>> +    * @hpd_disable:
> >>> +    *
> >>> +    * Disable hot plug detection. Once this function returns the bridge
> >>> +    * shall not call drm_bridge_hpd_notify() when a change in the output
> >>> +    * connection status occurs.
> >>> +    *
> >>> +    * This callback is optional and shall only be implemented by bridges
> >>> +    * that support hot-plug notification without polling. Bridges that
> >>> +    * implement it shall also implement the @hpd_enable callback and set
> >>> +    * the DRM_BRIDGE_OP_HPD flag in their &drm_bridge->ops.
> >>> +    */
> >>> +   void (*hpd_disable)(struct drm_bridge *bridge);
> >>>  };
> >>>
> >>>  /**
> >>> @@ -526,6 +643,39 @@ struct drm_bridge_timings {
> >>>     bool dual_link;
> >>>  };
> >>>
> >>> +/**
> >>> + * enum drm_bridge_ops - Bitmask of operations supported by the bridge
> >>> + */
> >>> +enum drm_bridge_ops {
> >>> +   /**
> >>> +    * @DRM_BRIDGE_OP_DETECT: The bridge can detect displays connected to
> >>> +    * its output. Bridges that set this flag shall implement the
> >>> +    * &drm_bridge_funcs->detect callback.
> >>> +    */
> >>> +   DRM_BRIDGE_OP_DETECT = BIT(0),
> >>> +   /**
> >>> +    * @DRM_BRIDGE_OP_EDID: The bridge can retrieve the EDID of the display
> >>> +    * connected to its output. Bridges that set this flag shall implement
> >>> +    * the &drm_bridge_funcs->get_edid callback.
> >>> +    */
> >>> +   DRM_BRIDGE_OP_EDID = BIT(1),
> >>> +   /**
> >>> +    * @DRM_BRIDGE_OP_HPD: The bridge can detect hot-plug and hot-unplug
> >>> +    * without requiring polling. Bridges that set this flag shall
> >>> +    * implement the &drm_bridge_funcs->hpd_enable and
> >>> +    * &drm_bridge_funcs->hpd_disable callbacks if they support enabling
> >>> +    * and disabling hot-plug detection dynamically.
> >>> +    */
> >>> +   DRM_BRIDGE_OP_HPD = BIT(2),
> >>> +   /**
> >>> +    * @DRM_BRIDGE_OP_MODES: The bridge can retrieve the modes supported
> >>> +    * by the display at its output. This does not include reading EDID
> >>> +    * which is separately covered by @DRM_BRIDGE_OP_EDID. Bridges that set
> >>> +    * this flag shall implement the &drm_bridge_funcs->get_modes callback.
> >>> +    */
> >>> +   DRM_BRIDGE_OP_MODES = BIT(3),
> >>> +};
> >>
> >> I still don't like this one here, since most of them are tracking
> >> redundant information. If you don't like just checking for the hook
> >> directly wrap it in a helper, e.g.
> >>
> >> bool drm_bridge_supports_detect(bridge)
> >> {
> >>       return bridge->ops->detect;
> >> }
> >
> > It seems I've done a really bad job explaining why the flags are
> > required, so let me try again :-)
> >
> > There's a difference between supporting an operation in a driver, and
> > supporting it in a given system. When a bridge hardware supports reading
> > EDID, or detecting hotplug, the driver will implement this and expose
> > the corresponding operation in drm_bridge_funcs by setting the function
> > pointers appropriately.
> >
> > However, this doesn't mean that the DDC lines are wired to the bridge on
> > a particular board, they could be connected to an I2C controller of the
> > SoC. Same for the HPD line, it could be connected to a GPIO instead of a
> > dedicated pin of the bridge. This board-specific information is reported
> > by the firmware (ACPI or DT), parsed by the bridge driver, and reflected
> > in the drm_bridge_ops flags.
> >
> > drm_bridge_funcs and drm_bridge_ops are thus different, the latter
> > supplements the former. We could merge the two by setting the
> > corresponding function pointer in drm_bridge_funcs to NULL when the
> > drm_bridge_ops flag isn't set. This would however require allocating
> > drm_bridge_funcs dynamically (either by embedding it into a
> > driver-specific structure, or allocating it dynamically directly)
> > instead of using a global static const struct, and this is considered to
> > be a security issue as it allows a potential attacker to overwrite
> > function pointers (there have been quite a lot of security patches
> > merged that move function pointers to .rodata or otherwise const
> > memory).
> 
> Hm so I'm pretty sure you've explained this to me already (at least!)
> once in the past, and your favorite context-free & stateless reviewer
> didn't bother to remember :-)
> 
> I think it's time to improve the intro DOC: section with a few special
> notes on chaining bridges. That didn't happen ever since the original
> bridge stuff landed, and that non-working idea from years ago evolved
> a lot with all this work now. I think adding an entire sub-section or
> separate DOC comment for this, which maybe also links to the
> connector-bridge helper and kinda ties the entire story you guys
> developed together would be really good. Otherwise I'm pretty sure
> this is not going to be the last time you have to explain this to
> someone ...

Why ô why did I have to start the DRM/KMS documentation effort years
ago, to see it biting me back now ? :-)

I'll give it a go. It may not cover the whole bridge API though,
depending on how much time I can spend, but will definitely cover this
and put it in context.

> >> hpd seems to be special, since a bridge can support hotplug but not have
> >> the enable_hpd/disable_hpd hooks. Which smells somewhat fishy, since if
> >> you have multiple bridges with hpd, how do you make sure you get hpd
> >> events only from the right one?
> >
> > On a given board HPD should only be generated by one bridge in practice.
> > If we ever encounter systems where multiple bridges can generate HPD for
> > the same external HPD event, I think we can deal with them at that time.
> >
> >> Aside from that just having a
> >>
> >>       bool supports_hpd;
> >>
> >> seems a lot simpler.
> >
> > If we only needed DRM_BRIDGE_OP_HPD, I agree that a bool would be
> > simpler, but as explained above we need the other ones too :-)
> >
> >> Yes I know that the drm DRIVER_FOO flags don't work like that, and I'm
> >> kinda unhappy about them since forever. Managed to delete most of them
> >> even :-)
> >>
> >>> +
> >>>  /**
> >>>   * struct drm_bridge - central DRM bridge control structure
> >>>   */
> >>> @@ -554,6 +704,33 @@ struct drm_bridge {
> >>>     const struct drm_bridge_funcs *funcs;
> >>>     /** @driver_private: pointer to the bridge driver's internal context */
> >>>     void *driver_private;
> >>> +   /** @ops: bitmask of operations supported by the bridge */
> >>> +   enum drm_bridge_ops ops;
> >>> +   /**
> >>> +    * @type: Type of the connection at the bridge output
> >>> +    * (DRM_MODE_CONNECTOR_*). For bridges at the end of this chain this
> >>> +    * identifies the type of connected display.
> >>> +    */
> >>> +   int type;
> >>> +   /**
> >>> +    * @ddc: Associated I2C adapter for DDC access, if any.
> >>> +    */
> >>> +   struct i2c_adapter *ddc;
> >>> +   /** private: */
> >>> +   /**
> >>> +    * @hpd_mutex: Protects the @hpd_cb and @hpd_data fields.
> >>> +    */
> >>> +   struct mutex hpd_mutex;
> >>> +   /**
> >>> +    * @hpd_cb: Hot plug detection callback, registered with
> >>> +    * drm_bridge_hpd_enable().
> >>> +    */
> >>> +   void (*hpd_cb)(void *data, enum drm_connector_status status);
> >>> +   /**
> >>> +    * @hpd_data: Private data passed to the Hot plug detection callback
> >>> +    * @hpd_cb.
> >>> +    */
> >>> +   void *hpd_data;
> >>>  };
> >>>
> >>>  static inline struct drm_bridge *
> >>> @@ -660,6 +837,19 @@ drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge,
> >>>                                     u32 output_fmt,
> >>>                                     unsigned int *num_input_fmts);
> >>>
> >>> +enum drm_connector_status drm_bridge_detect(struct drm_bridge *bridge);
> >>> +int drm_bridge_get_modes(struct drm_bridge *bridge,
> >>> +                    struct drm_connector *connector);
> >>> +struct edid *drm_bridge_get_edid(struct drm_bridge *bridge,
> >>> +                            struct drm_connector *connector);
> >>> +void drm_bridge_hpd_enable(struct drm_bridge *bridge,
> >>> +                      void (*cb)(void *data,
> >>> +                                 enum drm_connector_status status),
> >>> +                      void *data);
> >>> +void drm_bridge_hpd_disable(struct drm_bridge *bridge);
> >>> +void drm_bridge_hpd_notify(struct drm_bridge *bridge,
> >>> +                      enum drm_connector_status status);
> >>> +
> >>>  #ifdef CONFIG_DRM_PANEL_BRIDGE
> >>>  struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel);
> >>>  struct drm_bridge *drm_panel_bridge_add_typed(struct drm_panel *panel,

-- 
Regards,

Laurent Pinchart
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