[PATCH] drm/rcar-du: Convert to of_drm_find_and_get_bridge()

[PATCH] drm/rcar-du: Convert to of_drm_find_and_get_bridge()

[Amin GATTOUT]

of_drm_find_bridge() is deprecated.
Replace it with of_drm_find_and_get_bridge() which increments
the bridge refcount as required.

Signed-off-by: Amin GATTOUT <amin.gattout@gmail.com>
---
 drivers/gpu/drm/renesas/rcar-du/rcar_du_encoder.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_du_encoder.c b/drivers/gpu/drm/renesas/rcar-du/rcar_du_encoder.c
index 7ecec7b04a8d..42253c1251b5 100644
--- a/drivers/gpu/drm/renesas/rcar-du/rcar_du_encoder.c
+++ b/drivers/gpu/drm/renesas/rcar-du/rcar_du_encoder.c
@@ -72,7 +72,7 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
 		if (IS_ERR(bridge))
 			return PTR_ERR(bridge);
 	} else {
-		bridge = of_drm_find_bridge(enc_node);
+		bridge = of_drm_find_and_get_bridge(enc_node);
 		if (!bridge)
 			return -EPROBE_DEFER;
 

---
base-commit: d813f421930c5b01b9f61043932de02602dd6ae3
change-id: 20260326-bridge-43ecbef9d39f

Best regards,
-- 
Amin GATTOUT <amin.gattout@gmail.com>

Re: [PATCH] drm/rcar-du: Convert to of_drm_find_and_get_bridge()

[Laurent Pinchart]

Hello Amin,

On Thu, Mar 26, 2026 at 09:10:15PM +0100, Amin GATTOUT wrote:
> of_drm_find_bridge() is deprecated.
> Replace it with of_drm_find_and_get_bridge() which increments
> the bridge refcount as required.
> 
> Signed-off-by: Amin GATTOUT <amin.gattout@gmail.com>
> ---
>  drivers/gpu/drm/renesas/rcar-du/rcar_du_encoder.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_du_encoder.c b/drivers/gpu/drm/renesas/rcar-du/rcar_du_encoder.c
> index 7ecec7b04a8d..42253c1251b5 100644
> --- a/drivers/gpu/drm/renesas/rcar-du/rcar_du_encoder.c
> +++ b/drivers/gpu/drm/renesas/rcar-du/rcar_du_encoder.c
> @@ -72,7 +72,7 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
>  		if (IS_ERR(bridge))
>  			return PTR_ERR(bridge);
>  	} else {
> -		bridge = of_drm_find_bridge(enc_node);
> +		bridge = of_drm_find_and_get_bridge(enc_node);

How did you test this ?

>  		if (!bridge)
>  			return -EPROBE_DEFER;
>  
> 
> ---
> base-commit: d813f421930c5b01b9f61043932de02602dd6ae3
> change-id: 20260326-bridge-43ecbef9d39f

-- 
Regards,

Laurent Pinchart

Re: [PATCH] drm/rcar-du: Convert to of_drm_find_and_get_bridge()

[Luca Ceresoli]

Hello Amin,

On Thu Mar 26, 2026 at 9:10 PM CET, Amin GATTOUT wrote:
> of_drm_find_bridge() is deprecated.
> Replace it with of_drm_find_and_get_bridge() which increments
> the bridge refcount as required.

Thanks for taking care of the conversion to the new API!

> --- a/drivers/gpu/drm/renesas/rcar-du/rcar_du_encoder.c
> +++ b/drivers/gpu/drm/renesas/rcar-du/rcar_du_encoder.c
> @@ -72,7 +72,7 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
>  		if (IS_ERR(bridge))
>  			return PTR_ERR(bridge);
>  	} else {
> -		bridge = of_drm_find_bridge(enc_node);
> +		bridge = of_drm_find_and_get_bridge(enc_node);

This change alone is not correct I'm afraid. The difference between
of_drm_find_bridge() and of_drm_find_and_get_bridge() is the latter get a
reference to the bridge, so you have to put that reference when the bridge
pointer is no more accessible.

Have a look at previous commits doing the same API replacement, you can
find examples similar to this one, where:

 * the bridge pointer is stored in a local variable (not saved in a struct)
 * the bridge pointer could be set wither by of_drm_find_bridge() or
   a function adding a panel bridge

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH] drm/rcar-du: Convert to of_drm_find_and_get_bridge()

[Laurent Pinchart]

Hi Luca,

On Fri, Mar 27, 2026 at 08:57:45AM +0100, Luca Ceresoli wrote:
> On Thu Mar 26, 2026 at 9:10 PM CET, Amin GATTOUT wrote:
> > of_drm_find_bridge() is deprecated.
> > Replace it with of_drm_find_and_get_bridge() which increments
> > the bridge refcount as required.
> 
> Thanks for taking care of the conversion to the new API!

I suspect you may be talking to a machine (possibly through a human
proxy).

> > --- a/drivers/gpu/drm/renesas/rcar-du/rcar_du_encoder.c
> > +++ b/drivers/gpu/drm/renesas/rcar-du/rcar_du_encoder.c
> > @@ -72,7 +72,7 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
> >  		if (IS_ERR(bridge))
> >  			return PTR_ERR(bridge);
> >  	} else {
> > -		bridge = of_drm_find_bridge(enc_node);
> > +		bridge = of_drm_find_and_get_bridge(enc_node);
> 
> This change alone is not correct I'm afraid. The difference between
> of_drm_find_bridge() and of_drm_find_and_get_bridge() is the latter get a
> reference to the bridge, so you have to put that reference when the bridge
> pointer is no more accessible.
> 
> Have a look at previous commits doing the same API replacement, you can
> find examples similar to this one, where:
> 
>  * the bridge pointer is stored in a local variable (not saved in a struct)
>  * the bridge pointer could be set wither by of_drm_find_bridge() or
>    a function adding a panel bridge
> 
> Luca

-- 
Regards,

Laurent Pinchart

Re: [PATCH] drm/rcar-du: Convert to of_drm_find_and_get_bridge()

[Amin]

Hi

Thanks for the feedback. I did reference commit 7282066e55347 (Luca's
earlier conversion) but I should have been more cautious since the
patch I submitted was a bit too simple/"dummy".

To answer Laurent's question: I did not test this on hardware.
I was working through the deprecated API TODO  list and made the
mistake of treating this as a simple find-and-replace.

I'll send a v2.
Thanks for the patience...

 Regards,
 Amin

Re: [PATCH] drm/rcar-du: Convert to of_drm_find_and_get_bridge()

[Laurent Pinchart]

On Fri, Mar 27, 2026 at 09:54:42AM +0100, Amin wrote:
> Hi
> 
> Thanks for the feedback. I did reference commit 7282066e55347 (Luca's
> earlier conversion) but I should have been more cautious since the
> patch I submitted was a bit too simple/"dummy".
> 
> To answer Laurent's question: I did not test this on hardware.
> I was working through the deprecated API TODO  list and made the
> mistake of treating this as a simple find-and-replace.
> 
> I'll send a v2.

Luca has already submitted a patch, see
https://lore.kernel.org/dri-devel/20260318-drm-bridge-alloc-getput-drm_of_find_bridge-4-v3-3-10f502520357@bootlin.com/

-- 
Regards,

Laurent Pinchart