diff mbox series

[01/30] drm: Introduce drm_bridge_init()

Message ID 20191126131541.47393-2-mihail.atanassov@arm.com (mailing list archive)
State New, archived
Headers show
Series drm/bridge: Add device links for lifetime control | expand

Commit Message

Mihail Atanassov Nov. 26, 2019, 1:15 p.m. UTC
A simple convenience function to initialize the struct drm_bridge.

Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
---
 drivers/gpu/drm/drm_bridge.c | 29 +++++++++++++++++++++++++++++
 include/drm/drm_bridge.h     |  4 ++++
 2 files changed, 33 insertions(+)

Comments

Daniel Vetter Nov. 26, 2019, 2:26 p.m. UTC | #1
On Tue, Nov 26, 2019 at 01:15:59PM +0000, Mihail Atanassov wrote:
> A simple convenience function to initialize the struct drm_bridge.
> 
> Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>

The commit message here leaves figuring out why we need this to the
reader. Reading ahead the reasons seems to be to roll out bridge->dev
setting for everyone, so that we can set the device_link. Please explain
that in the commit message so the patch is properly motivated.

> ---
>  drivers/gpu/drm/drm_bridge.c | 29 +++++++++++++++++++++++++++++
>  include/drm/drm_bridge.h     |  4 ++++
>  2 files changed, 33 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index cba537c99e43..cbe680aa6eac 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -89,6 +89,35 @@ void drm_bridge_remove(struct drm_bridge *bridge)
>  }
>  EXPORT_SYMBOL(drm_bridge_remove);
>  
> +/**
> + * drm_bridge_init - initialise a drm_bridge structure
> + *
> + * @bridge: bridge control structure
> + * @funcs: control functions
> + * @dev: device
> + * @timings: timing specification for the bridge; optional (may be NULL)
> + * @driver_private: pointer to the bridge driver internal context (may be NULL)

Please also sprinkle some links to this new function to relevant places,
I'd add at least:

"Drivers should call drm_bridge_init() first." to the kerneldoc for
drm_bridge_add. drm_bridge_add should also mention drm_bridge_remove as
the undo function.

And perhaps a longer paragraph to &struct drm_bridge:

"Bridge drivers should call drm_bridge_init() to initialized a bridge
driver, and then register it with drm_bridge_add().

"Users of bridges link a bridge driver into their overall display output
pipeline by calling drm_bridge_attach()."

> + */
> +void drm_bridge_init(struct drm_bridge *bridge, struct device *dev,
> +		     const struct drm_bridge_funcs *funcs,
> +		     const struct drm_bridge_timings *timings,
> +		     void *driver_private)
> +{
> +	WARN_ON(!funcs);
> +
> +	bridge->dev = NULL;

Given that the goal here is to get bridge->dev set up, why not

	WARN_ON(!dev);
	bridge->dev = dev;

That should help us to really move forward with all this.
-Daniel

> +	bridge->encoder = NULL;
> +	bridge->next = NULL;
> +
> +#ifdef CONFIG_OF
> +	bridge->of_node = dev->of_node;
> +#endif
> +	bridge->timings = timings;
> +	bridge->funcs = funcs;
> +	bridge->driver_private = driver_private;
> +}
> +EXPORT_SYMBOL(drm_bridge_init);
> +
>  /**
>   * drm_bridge_attach - attach the bridge to an encoder's chain
>   *
> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> index c0a2286a81e9..d6d9d5301551 100644
> --- a/include/drm/drm_bridge.h
> +++ b/include/drm/drm_bridge.h
> @@ -402,6 +402,10 @@ struct drm_bridge {
>  
>  void drm_bridge_add(struct drm_bridge *bridge);
>  void drm_bridge_remove(struct drm_bridge *bridge);
> +void drm_bridge_init(struct drm_bridge *bridge, struct device *dev,
> +		     const struct drm_bridge_funcs *funcs,
> +		     const struct drm_bridge_timings *timings,
> +		     void *driver_private);
>  struct drm_bridge *of_drm_find_bridge(struct device_node *np);
>  int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
>  		      struct drm_bridge *previous);
> -- 
> 2.23.0
>
Mihail Atanassov Nov. 26, 2019, 3:55 p.m. UTC | #2
Hi Daniel,

Thanks for the quick review.

On Tuesday, 26 November 2019 14:26:10 GMT Daniel Vetter wrote:
> On Tue, Nov 26, 2019 at 01:15:59PM +0000, Mihail Atanassov wrote:
> > A simple convenience function to initialize the struct drm_bridge.
> > 
> > Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
> 
> The commit message here leaves figuring out why we need this to the
> reader. Reading ahead the reasons seems to be to roll out bridge->dev
> setting for everyone, so that we can set the device_link. Please explain
> that in the commit message so the patch is properly motivated.

Ack, but with one caveat: bridge->dev is the struct drm_device that is
the bridge client, we need to add a bridge->device (patch 29 in this
series) which is the struct device that will manage the bridge lifetime.

> 
> > ---
> >  drivers/gpu/drm/drm_bridge.c | 29 +++++++++++++++++++++++++++++
> >  include/drm/drm_bridge.h     |  4 ++++
> >  2 files changed, 33 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> > index cba537c99e43..cbe680aa6eac 100644
> > --- a/drivers/gpu/drm/drm_bridge.c
> > +++ b/drivers/gpu/drm/drm_bridge.c
> > @@ -89,6 +89,35 @@ void drm_bridge_remove(struct drm_bridge *bridge)
> >  }
> >  EXPORT_SYMBOL(drm_bridge_remove);
> >  
> > +/**
> > + * drm_bridge_init - initialise a drm_bridge structure
> > + *
> > + * @bridge: bridge control structure
> > + * @funcs: control functions
> > + * @dev: device
> > + * @timings: timing specification for the bridge; optional (may be NULL)
> > + * @driver_private: pointer to the bridge driver internal context (may be NULL)
> 
> Please also sprinkle some links to this new function to relevant places,
> I'd add at least:
> 
> "Drivers should call drm_bridge_init() first." to the kerneldoc for
> drm_bridge_add. drm_bridge_add should also mention drm_bridge_remove as
> the undo function.
> 
> And perhaps a longer paragraph to &struct drm_bridge:
> 
> "Bridge drivers should call drm_bridge_init() to initialized a bridge
> driver, and then register it with drm_bridge_add().
> 
> "Users of bridges link a bridge driver into their overall display output
> pipeline by calling drm_bridge_attach()."

Will do.

> 
> > + */
> > +void drm_bridge_init(struct drm_bridge *bridge, struct device *dev,
> > +		     const struct drm_bridge_funcs *funcs,
> > +		     const struct drm_bridge_timings *timings,
> > +		     void *driver_private)
> > +{
> > +	WARN_ON(!funcs);
> > +
> > +	bridge->dev = NULL;
> 
> Given that the goal here is to get bridge->dev set up, why not
> 
> 	WARN_ON(!dev);
> 	bridge->dev = dev;

See above struct device vs struct drm_device. I add a

	bridge->device = dev;

in patch 29, which takes care of that. I skipped the warn since
there's a dereference of dev, but I now realized it's behind CONFIG_OF,
so I'll add it in for v2.

Yes, 'device' isn't the best of names, but I took Russell's patch
almost as-is, I didn't have any better ideas for bikeshedding.

> 
> That should help us to really move forward with all this.
> -Daniel
> 
> > +	bridge->encoder = NULL;
> > +	bridge->next = NULL;
> > +
> > +#ifdef CONFIG_OF
> > +	bridge->of_node = dev->of_node;
> > +#endif
> > +	bridge->timings = timings;
> > +	bridge->funcs = funcs;
> > +	bridge->driver_private = driver_private;
> > +}
> > +EXPORT_SYMBOL(drm_bridge_init);
> > +
> >  /**
> >   * drm_bridge_attach - attach the bridge to an encoder's chain
> >   *
> > diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> > index c0a2286a81e9..d6d9d5301551 100644
> > --- a/include/drm/drm_bridge.h
> > +++ b/include/drm/drm_bridge.h
> > @@ -402,6 +402,10 @@ struct drm_bridge {
> >  
> >  void drm_bridge_add(struct drm_bridge *bridge);
> >  void drm_bridge_remove(struct drm_bridge *bridge);
> > +void drm_bridge_init(struct drm_bridge *bridge, struct device *dev,
> > +		     const struct drm_bridge_funcs *funcs,
> > +		     const struct drm_bridge_timings *timings,
> > +		     void *driver_private);
> >  struct drm_bridge *of_drm_find_bridge(struct device_node *np);
> >  int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
> >  		      struct drm_bridge *previous);
> 
>
Daniel Vetter Nov. 26, 2019, 5:04 p.m. UTC | #3
On Tue, Nov 26, 2019 at 4:55 PM Mihail Atanassov
<Mihail.Atanassov@arm.com> wrote:
>
> Hi Daniel,
>
> Thanks for the quick review.
>
> On Tuesday, 26 November 2019 14:26:10 GMT Daniel Vetter wrote:
> > On Tue, Nov 26, 2019 at 01:15:59PM +0000, Mihail Atanassov wrote:
> > > A simple convenience function to initialize the struct drm_bridge.
> > >
> > > Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
> >
> > The commit message here leaves figuring out why we need this to the
> > reader. Reading ahead the reasons seems to be to roll out bridge->dev
> > setting for everyone, so that we can set the device_link. Please explain
> > that in the commit message so the patch is properly motivated.
>
> Ack, but with one caveat: bridge->dev is the struct drm_device that is
> the bridge client, we need to add a bridge->device (patch 29 in this
> series) which is the struct device that will manage the bridge lifetime.

Ah yes, ->dev is for drm_bridge_attach.

> >
> > > ---
> > >  drivers/gpu/drm/drm_bridge.c | 29 +++++++++++++++++++++++++++++
> > >  include/drm/drm_bridge.h     |  4 ++++
> > >  2 files changed, 33 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> > > index cba537c99e43..cbe680aa6eac 100644
> > > --- a/drivers/gpu/drm/drm_bridge.c
> > > +++ b/drivers/gpu/drm/drm_bridge.c
> > > @@ -89,6 +89,35 @@ void drm_bridge_remove(struct drm_bridge *bridge)
> > >  }
> > >  EXPORT_SYMBOL(drm_bridge_remove);
> > >
> > > +/**
> > > + * drm_bridge_init - initialise a drm_bridge structure
> > > + *
> > > + * @bridge: bridge control structure
> > > + * @funcs: control functions
> > > + * @dev: device
> > > + * @timings: timing specification for the bridge; optional (may be NULL)
> > > + * @driver_private: pointer to the bridge driver internal context (may be NULL)
> >
> > Please also sprinkle some links to this new function to relevant places,
> > I'd add at least:
> >
> > "Drivers should call drm_bridge_init() first." to the kerneldoc for
> > drm_bridge_add. drm_bridge_add should also mention drm_bridge_remove as
> > the undo function.
> >
> > And perhaps a longer paragraph to &struct drm_bridge:
> >
> > "Bridge drivers should call drm_bridge_init() to initialized a bridge
> > driver, and then register it with drm_bridge_add().
> >
> > "Users of bridges link a bridge driver into their overall display output
> > pipeline by calling drm_bridge_attach()."
>
> Will do.
>
> >
> > > + */
> > > +void drm_bridge_init(struct drm_bridge *bridge, struct device *dev,
> > > +                const struct drm_bridge_funcs *funcs,
> > > +                const struct drm_bridge_timings *timings,
> > > +                void *driver_private)
> > > +{
> > > +   WARN_ON(!funcs);
> > > +
> > > +   bridge->dev = NULL;
> >
> > Given that the goal here is to get bridge->dev set up, why not
> >
> >       WARN_ON(!dev);
> >       bridge->dev = dev;
>
> See above struct device vs struct drm_device. I add a
>
>         bridge->device = dev;
>
> in patch 29, which takes care of that. I skipped the warn since
> there's a dereference of dev, but I now realized it's behind CONFIG_OF,
> so I'll add it in for v2.

Ok, sounds good. Having the WARN_ON in patch 1 should also help making
sure all the conversion patches dtrt (and any future users).
-Daniel

> Yes, 'device' isn't the best of names, but I took Russell's patch
> almost as-is, I didn't have any better ideas for bikeshedding.
>
> >
> > That should help us to really move forward with all this.
> > -Daniel
> >
> > > +   bridge->encoder = NULL;
> > > +   bridge->next = NULL;
> > > +
> > > +#ifdef CONFIG_OF
> > > +   bridge->of_node = dev->of_node;
> > > +#endif
> > > +   bridge->timings = timings;
> > > +   bridge->funcs = funcs;
> > > +   bridge->driver_private = driver_private;
> > > +}
> > > +EXPORT_SYMBOL(drm_bridge_init);
> > > +
> > >  /**
> > >   * drm_bridge_attach - attach the bridge to an encoder's chain
> > >   *
> > > diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> > > index c0a2286a81e9..d6d9d5301551 100644
> > > --- a/include/drm/drm_bridge.h
> > > +++ b/include/drm/drm_bridge.h
> > > @@ -402,6 +402,10 @@ struct drm_bridge {
> > >
> > >  void drm_bridge_add(struct drm_bridge *bridge);
> > >  void drm_bridge_remove(struct drm_bridge *bridge);
> > > +void drm_bridge_init(struct drm_bridge *bridge, struct device *dev,
> > > +                const struct drm_bridge_funcs *funcs,
> > > +                const struct drm_bridge_timings *timings,
> > > +                void *driver_private);
> > >  struct drm_bridge *of_drm_find_bridge(struct device_node *np);
> > >  int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
> > >                   struct drm_bridge *previous);
> >
> >
>
>
> --
> Mihail
>
>
>


--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
Sam Ravnborg Nov. 26, 2019, 7:24 p.m. UTC | #4
Hi Mihail.

> Ack, but with one caveat: bridge->dev is the struct drm_device that is
> the bridge client, we need to add a bridge->device (patch 29 in this
> series) which is the struct device that will manage the bridge lifetime.
Other places uses the variable name "drm" for a drm_device.
This is less confusion than the "dev" name.

It seems a recent trend to use the variable name "drm" so you can find a
lot of places using "dev".

bike-shedding - but also about readability.

	Sam
Mihail Atanassov Nov. 27, 2019, 11:05 a.m. UTC | #5
On Tuesday, 26 November 2019 19:24:45 GMT Sam Ravnborg wrote:
> Hi Mihail.

Hi Sam,

> 
> > Ack, but with one caveat: bridge->dev is the struct drm_device that is
> > the bridge client, we need to add a bridge->device (patch 29 in this
> > series) which is the struct device that will manage the bridge lifetime.
> Other places uses the variable name "drm" for a drm_device.
> This is less confusion than the "dev" name.
> 
> It seems a recent trend to use the variable name "drm" so you can find a
> lot of places using "dev".
> 
> bike-shedding - but also about readability.
> 
> 	Sam
> 

I'm okay with the idea, I can do a follow-up patch or series for the
rename; I expect it would be a bit hefty to do it prior to this.

@Daniel, thoughts on s/bridge.dev/bridge.drm/ and
s/bridge.device/bridge.dev/ after this series?
Daniel Vetter Nov. 27, 2019, 11:31 a.m. UTC | #6
On Wed, Nov 27, 2019 at 11:05:56AM +0000, Mihail Atanassov wrote:
> On Tuesday, 26 November 2019 19:24:45 GMT Sam Ravnborg wrote:
> > Hi Mihail.
> 
> Hi Sam,
> 
> > 
> > > Ack, but with one caveat: bridge->dev is the struct drm_device that is
> > > the bridge client, we need to add a bridge->device (patch 29 in this
> > > series) which is the struct device that will manage the bridge lifetime.
> > Other places uses the variable name "drm" for a drm_device.
> > This is less confusion than the "dev" name.
> > 
> > It seems a recent trend to use the variable name "drm" so you can find a
> > lot of places using "dev".
> > 
> > bike-shedding - but also about readability.
> > 
> > 	Sam
> > 
> 
> I'm okay with the idea, I can do a follow-up patch or series for the
> rename; I expect it would be a bit hefty to do it prior to this.
> 
> @Daniel, thoughts on s/bridge.dev/bridge.drm/ and
> s/bridge.device/bridge.dev/ after this series?

I'm firmly in the "no opionon" on this.
-Daniel
James Qian Wang Dec. 2, 2019, 5:55 a.m. UTC | #7
On Tue, Nov 26, 2019 at 01:15:59PM +0000, Mihail Atanassov wrote:
> A simple convenience function to initialize the struct drm_bridge.
> 
> Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
> ---
>  drivers/gpu/drm/drm_bridge.c | 29 +++++++++++++++++++++++++++++
>  include/drm/drm_bridge.h     |  4 ++++
>  2 files changed, 33 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index cba537c99e43..cbe680aa6eac 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -89,6 +89,35 @@ void drm_bridge_remove(struct drm_bridge *bridge)
>  }
>  EXPORT_SYMBOL(drm_bridge_remove);
>  
> +/**
> + * drm_bridge_init - initialise a drm_bridge structure
> + *
> + * @bridge: bridge control structure
> + * @funcs: control functions
> + * @dev: device
> + * @timings: timing specification for the bridge; optional (may be NULL)
> + * @driver_private: pointer to the bridge driver internal context (may be NULL)
> + */
> +void drm_bridge_init(struct drm_bridge *bridge, struct device *dev,
> +		     const struct drm_bridge_funcs *funcs,
> +		     const struct drm_bridge_timings *timings,
> +		     void *driver_private)
> +{
> +	WARN_ON(!funcs);
> +
> +	bridge->dev = NULL;
> +	bridge->encoder = NULL;
> +	bridge->next = NULL;
> +
> +#ifdef CONFIG_OF
> +	bridge->of_node = dev->of_node;
> +#endif
> +	bridge->timings = timings;
> +	bridge->funcs = funcs;
> +	bridge->driver_private = driver_private;

Can we directly put drm_bridge_add() here. then
- User always need to call bridge_init and add together.
- Consistent with others like drm_plane/crtc_init which directly has
  drm_mode_object_add() in it.

James.
> +}
> +EXPORT_SYMBOL(drm_bridge_init);
> +
>  /**
>   * drm_bridge_attach - attach the bridge to an encoder's chain
>   *
> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> index c0a2286a81e9..d6d9d5301551 100644
> --- a/include/drm/drm_bridge.h
> +++ b/include/drm/drm_bridge.h
> @@ -402,6 +402,10 @@ struct drm_bridge {
>  
>  void drm_bridge_add(struct drm_bridge *bridge);
>  void drm_bridge_remove(struct drm_bridge *bridge);
> +void drm_bridge_init(struct drm_bridge *bridge, struct device *dev,
> +		     const struct drm_bridge_funcs *funcs,
> +		     const struct drm_bridge_timings *timings,
> +		     void *driver_private);
>  struct drm_bridge *of_drm_find_bridge(struct device_node *np);
>  int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
>  		      struct drm_bridge *previous);
Daniel Vetter Dec. 2, 2019, 8:49 a.m. UTC | #8
On Mon, Dec 02, 2019 at 05:55:06AM +0000, james qian wang (Arm Technology China) wrote:
> On Tue, Nov 26, 2019 at 01:15:59PM +0000, Mihail Atanassov wrote:
> > A simple convenience function to initialize the struct drm_bridge.
> > 
> > Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
> > ---
> >  drivers/gpu/drm/drm_bridge.c | 29 +++++++++++++++++++++++++++++
> >  include/drm/drm_bridge.h     |  4 ++++
> >  2 files changed, 33 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> > index cba537c99e43..cbe680aa6eac 100644
> > --- a/drivers/gpu/drm/drm_bridge.c
> > +++ b/drivers/gpu/drm/drm_bridge.c
> > @@ -89,6 +89,35 @@ void drm_bridge_remove(struct drm_bridge *bridge)
> >  }
> >  EXPORT_SYMBOL(drm_bridge_remove);
> >  
> > +/**
> > + * drm_bridge_init - initialise a drm_bridge structure
> > + *
> > + * @bridge: bridge control structure
> > + * @funcs: control functions
> > + * @dev: device
> > + * @timings: timing specification for the bridge; optional (may be NULL)
> > + * @driver_private: pointer to the bridge driver internal context (may be NULL)
> > + */
> > +void drm_bridge_init(struct drm_bridge *bridge, struct device *dev,
> > +		     const struct drm_bridge_funcs *funcs,
> > +		     const struct drm_bridge_timings *timings,
> > +		     void *driver_private)
> > +{
> > +	WARN_ON(!funcs);
> > +
> > +	bridge->dev = NULL;
> > +	bridge->encoder = NULL;
> > +	bridge->next = NULL;
> > +
> > +#ifdef CONFIG_OF
> > +	bridge->of_node = dev->of_node;
> > +#endif
> > +	bridge->timings = timings;
> > +	bridge->funcs = funcs;
> > +	bridge->driver_private = driver_private;
> 
> Can we directly put drm_bridge_add() here. then
> - User always need to call bridge_init and add together.
> - Consistent with others like drm_plane/crtc_init which directly has
>   drm_mode_object_add() in it.

Uh no, the trouble here is that drm_bridge_add should actually be called
_register, because it publishes the bridge to the world. I think we even
have a todo item to rename _add to _register ... Once that's done the
bridge can't be changed anymore, all init code must have completed. So
often you need a bit of code between _init() and _register().

drm_mode_object_add is different since for mode objects it doesn't publish
it to the world, that's done with drm_dev_register and
drm_connector_register. drm_mode_object_add just does a bit of internal
house keeping.
-Daniel

> 
> James.
> > +}
> > +EXPORT_SYMBOL(drm_bridge_init);
> > +
> >  /**
> >   * drm_bridge_attach - attach the bridge to an encoder's chain
> >   *
> > diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> > index c0a2286a81e9..d6d9d5301551 100644
> > --- a/include/drm/drm_bridge.h
> > +++ b/include/drm/drm_bridge.h
> > @@ -402,6 +402,10 @@ struct drm_bridge {
> >  
> >  void drm_bridge_add(struct drm_bridge *bridge);
> >  void drm_bridge_remove(struct drm_bridge *bridge);
> > +void drm_bridge_init(struct drm_bridge *bridge, struct device *dev,
> > +		     const struct drm_bridge_funcs *funcs,
> > +		     const struct drm_bridge_timings *timings,
> > +		     void *driver_private);
> >  struct drm_bridge *of_drm_find_bridge(struct device_node *np);
> >  int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
> >  		      struct drm_bridge *previous);
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
James Qian Wang Dec. 3, 2019, 6:12 a.m. UTC | #9
On Mon, Dec 02, 2019 at 09:49:35AM +0100, Daniel Vetter wrote:
> On Mon, Dec 02, 2019 at 05:55:06AM +0000, james qian wang (Arm Technology China) wrote:
> > On Tue, Nov 26, 2019 at 01:15:59PM +0000, Mihail Atanassov wrote:
> > > A simple convenience function to initialize the struct drm_bridge.
> > >
> > > Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
> > > ---
> > >  drivers/gpu/drm/drm_bridge.c | 29 +++++++++++++++++++++++++++++
> > >  include/drm/drm_bridge.h     |  4 ++++
> > >  2 files changed, 33 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> > > index cba537c99e43..cbe680aa6eac 100644
> > > --- a/drivers/gpu/drm/drm_bridge.c
> > > +++ b/drivers/gpu/drm/drm_bridge.c
> > > @@ -89,6 +89,35 @@ void drm_bridge_remove(struct drm_bridge *bridge)
> > >  }
> > >  EXPORT_SYMBOL(drm_bridge_remove);
> > >
> > > +/**
> > > + * drm_bridge_init - initialise a drm_bridge structure
> > > + *
> > > + * @bridge: bridge control structure
> > > + * @funcs: control functions
> > > + * @dev: device
> > > + * @timings: timing specification for the bridge; optional (may be NULL)
> > > + * @driver_private: pointer to the bridge driver internal context (may be NULL)
> > > + */
> > > +void drm_bridge_init(struct drm_bridge *bridge, struct device *dev,
> > > +              const struct drm_bridge_funcs *funcs,
> > > +              const struct drm_bridge_timings *timings,
> > > +              void *driver_private)
> > > +{
> > > + WARN_ON(!funcs);
> > > +
> > > + bridge->dev = NULL;
> > > + bridge->encoder = NULL;
> > > + bridge->next = NULL;
> > > +
> > > +#ifdef CONFIG_OF
> > > + bridge->of_node = dev->of_node;
> > > +#endif
> > > + bridge->timings = timings;
> > > + bridge->funcs = funcs;
> > > + bridge->driver_private = driver_private;
> >
> > Can we directly put drm_bridge_add() here. then
> > - User always need to call bridge_init and add together.
> > - Consistent with others like drm_plane/crtc_init which directly has
> >   drm_mode_object_add() in it.
>
> Uh no, the trouble here is that drm_bridge_add should actually be called
> _register, because it publishes the bridge to the world. I think we even
> have a todo item to rename _add to _register ... Once that's done the
> bridge can't be changed anymore, all init code must have completed. So
> often you need a bit of code between _init() and _register().
>
> drm_mode_object_add is different since for mode objects it doesn't publish
> it to the world, that's done with drm_dev_register and
> drm_connector_register. drm_mode_object_add just does a bit of internal
> house keeping.
> -Daniel
>

Yes, the name _register() is more better.

And thank you for such detailed explanation.

Thanks
James

> >
> > James.
> > > +}
> > > +EXPORT_SYMBOL(drm_bridge_init);
> > > +
> > >  /**
> > >   * drm_bridge_attach - attach the bridge to an encoder's chain
> > >   *
> > > diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> > > index c0a2286a81e9..d6d9d5301551 100644
> > > --- a/include/drm/drm_bridge.h
> > > +++ b/include/drm/drm_bridge.h
> > > @@ -402,6 +402,10 @@ struct drm_bridge {
> > >
> > >  void drm_bridge_add(struct drm_bridge *bridge);
> > >  void drm_bridge_remove(struct drm_bridge *bridge);
> > > +void drm_bridge_init(struct drm_bridge *bridge, struct device *dev,
> > > +              const struct drm_bridge_funcs *funcs,
> > > +              const struct drm_bridge_timings *timings,
> > > +              void *driver_private);
> > >  struct drm_bridge *of_drm_find_bridge(struct device_node *np);
> > >  int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
> > >                 struct drm_bridge *previous);
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
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diff mbox series

Patch

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index cba537c99e43..cbe680aa6eac 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -89,6 +89,35 @@  void drm_bridge_remove(struct drm_bridge *bridge)
 }
 EXPORT_SYMBOL(drm_bridge_remove);
 
+/**
+ * drm_bridge_init - initialise a drm_bridge structure
+ *
+ * @bridge: bridge control structure
+ * @funcs: control functions
+ * @dev: device
+ * @timings: timing specification for the bridge; optional (may be NULL)
+ * @driver_private: pointer to the bridge driver internal context (may be NULL)
+ */
+void drm_bridge_init(struct drm_bridge *bridge, struct device *dev,
+		     const struct drm_bridge_funcs *funcs,
+		     const struct drm_bridge_timings *timings,
+		     void *driver_private)
+{
+	WARN_ON(!funcs);
+
+	bridge->dev = NULL;
+	bridge->encoder = NULL;
+	bridge->next = NULL;
+
+#ifdef CONFIG_OF
+	bridge->of_node = dev->of_node;
+#endif
+	bridge->timings = timings;
+	bridge->funcs = funcs;
+	bridge->driver_private = driver_private;
+}
+EXPORT_SYMBOL(drm_bridge_init);
+
 /**
  * drm_bridge_attach - attach the bridge to an encoder's chain
  *
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index c0a2286a81e9..d6d9d5301551 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -402,6 +402,10 @@  struct drm_bridge {
 
 void drm_bridge_add(struct drm_bridge *bridge);
 void drm_bridge_remove(struct drm_bridge *bridge);
+void drm_bridge_init(struct drm_bridge *bridge, struct device *dev,
+		     const struct drm_bridge_funcs *funcs,
+		     const struct drm_bridge_timings *timings,
+		     void *driver_private);
 struct drm_bridge *of_drm_find_bridge(struct device_node *np);
 int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
 		      struct drm_bridge *previous);