[PATCH v2 0/6] drm/bridge: convert users of of_drm_find_bridge(), part 3

[PATCH v2 0/6] drm/bridge: convert users of of_drm_find_bridge(), part 3

[Luca Ceresoli]

This series converts many DRM drivers from the now deprecated
of_drm_find_bridge() to its replacement of_drm_find_and_get_bridge() which
allows correct bridge refcounting. Where applicable it also converts
per-driver "next_bridge" pointers to the unified drm_bridge::next_bridge
which puts the reference automatically on bridge deallocation.

This is part of the work to support hotplug of DRM bridges. The grand plan
was discussed in [0].

Here's the work breakdown (➜ marks the current series):

 1. ➜ add refcounting to DRM bridges struct drm_bridge,
      based on devm_drm_bridge_alloc()
    A. ✔ add new alloc API and refcounting (v6.16)
    B. ✔ convert all bridge drivers to new API (v6.17)
    C. ✔ kunit tests (v6.17)
    D. ✔ add get/put to drm_bridge_add/remove() + attach/detach()
         and warn on old allocation pattern (v6.17)
    E. ➜ add get/put on drm_bridge accessors
       1. ✔ drm_bridge_chain_get_first_bridge(), add cleanup action (v6.18)
       2. ✔ drm_bridge_get_prev_bridge() (v6.18)
       3. ✔ drm_bridge_get_next_bridge() (v6.19)
       4. ✔ drm_for_each_bridge_in_chain() (v6.19)
       5. ✔ drm_bridge_connector_init (v6.19)
       6. … protect encoder bridge chain with a mutex
       7. ➜ of_drm_find_bridge
          a. ✔… add of_drm_get_bridge(), convert basic direct users
	        (v6.20?, one driver still pending)
	  b. … convert direct of_drm_get_bridge() users, part 2
	  c. ➜ convert direct of_drm_get_bridge() users, part 3
	  d.   convert direct of_drm_get_bridge() users, part 4
	  e.   convert bridge-only drm_of_find_panel_or_bridge() users
       8. drm_of_find_panel_or_bridge, *_of_get_bridge
       9. ✔ enforce drm_bridge_add before drm_bridge_attach (v6.19)
    F. ✔ debugfs improvements
       1. ✔ add top-level 'bridges' file (v6.16)
       2. ✔ show refcount and list lingering bridges (v6.19)
 2. … handle gracefully atomic updates during bridge removal
    A. ✔ Add drm_dev_enter/exit() to protect device resources (v6.20?)
    B. … protect private_obj removal from list
 3. … DSI host-device driver interaction
 4. ✔ removing the need for the "always-disconnected" connector
 5. finish the hotplug bridge work, moving code to the core and potentially
    removing the hotplug-bridge itself (this needs to be clarified as
    points 1-3 are developed)

[0] https://lore.kernel.org/lkml/20250206-hotplug-drm-bridge-v6-0-9d6f2c9c3058@bootlin.com/#t

This work is a continuation of the work to correctly handle bridge
refcounting for existing of_drm_find_bridge(). The ground work is in:

 - commit 293a8fd7721a ("drm/bridge: add of_drm_find_and_get_bridge()")
 - commit 9da0e06abda8 ("drm/bridge: deprecate of_drm_find_bridge()")
 - commit 3fdeae134ba9 ("drm/bridge: add next_bridge pointer to struct drm_bridge")

The whole conversion is split in multiple series to make the review process
a bit smoother:

 - Part 2: mostly drivers in drivers/gpu/drm/bridge [2]
 - Part 3: other drivers, low-medium complexity [this series]
 - Part 4: other drivers, complex (not sent yet)

[2] https://lore.kernel.org/all/20260107-drm-bridge-alloc-getput-drm_of_find_bridge-2-v1-0-283d7bba061a@bootlin.com/

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
Changes in v2:
- Patch 3: fix missing drm_bridge_put()
- Link to v1: https://lore.kernel.org/r/20260107-drm-bridge-alloc-getput-drm_of_find_bridge-3-v1-0-ef48a517828e@bootlin.com

---
Luca Ceresoli (6):
      drm/bridge: dw-hdmi: convert to of_drm_find_and_get_bridge()
      drm/meson/dw-hdmi: convert to of_drm_find_and_get_bridge()
      drm/imx/dw-hdmi: convert to of_drm_find_and_get_bridge()
      drm/mediatek: mtk_hdmi*: convert to of_drm_find_and_get_bridge()
      drm/exynos: hdmi: convert to of_drm_find_and_get_bridge()
      drm: rcar-du: lvds: convert to of_drm_find_and_get_bridge()

 drivers/gpu/drm/bridge/synopsys/dw-hdmi.c   |  7 +++----
 drivers/gpu/drm/exynos/exynos_hdmi.c        |  4 +++-
 drivers/gpu/drm/imx/ipuv3/dw_hdmi-imx.c     |  7 +++++--
 drivers/gpu/drm/mediatek/mtk_hdmi.c         |  4 ++--
 drivers/gpu/drm/mediatek/mtk_hdmi_common.c  |  4 ++--
 drivers/gpu/drm/mediatek/mtk_hdmi_common.h  |  1 -
 drivers/gpu/drm/mediatek/mtk_hdmi_v2.c      |  4 ++--
 drivers/gpu/drm/meson/meson_dw_hdmi.c       |  6 +++++-
 drivers/gpu/drm/renesas/rcar-du/rcar_lvds.c | 10 +++++++++-
 9 files changed, 31 insertions(+), 16 deletions(-)
---
base-commit: 13450a1f72fd24c405626c881ae7c9ce5f0d2a28
change-id: 20260107-drm-bridge-alloc-getput-drm_of_find_bridge-3-4f997ea7c79f

Best regards,
-- 
Luca Ceresoli <luca.ceresoli@bootlin.com>

[PATCH v2 1/6] drm/bridge: dw-hdmi: convert to of_drm_find_and_get_bridge()

[Luca Ceresoli]

of_drm_find_bridge() is deprecated. Move to its replacement
of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
is put when done by using the drm_bridge::next_bridge pointer.

Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index 3b77e73ac0ea..ee88c0e793b0 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -132,7 +132,6 @@ struct dw_hdmi_phy_data {
 struct dw_hdmi {
 	struct drm_connector connector;
 	struct drm_bridge bridge;
-	struct drm_bridge *next_bridge;
 
 	unsigned int version;
 
@@ -2912,7 +2911,7 @@ static int dw_hdmi_bridge_attach(struct drm_bridge *bridge,
 	struct dw_hdmi *hdmi = bridge->driver_private;
 
 	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
-		return drm_bridge_attach(encoder, hdmi->next_bridge,
+		return drm_bridge_attach(encoder, hdmi->bridge.next_bridge,
 					 bridge, flags);
 
 	return dw_hdmi_connector_create(hdmi);
@@ -3318,9 +3317,9 @@ static int dw_hdmi_parse_dt(struct dw_hdmi *hdmi)
 	if (!remote)
 		return -ENODEV;
 
-	hdmi->next_bridge = of_drm_find_bridge(remote);
+	hdmi->bridge.next_bridge = of_drm_find_and_get_bridge(remote);
 	of_node_put(remote);
-	if (!hdmi->next_bridge)
+	if (!hdmi->bridge.next_bridge)
 		return -EPROBE_DEFER;
 
 	return 0;

-- 
2.52.0

[PATCH v2 2/6] drm/meson/dw-hdmi: convert to of_drm_find_and_get_bridge()

[Luca Ceresoli]

of_drm_find_bridge() is deprecated. Move to its replacement
of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
is put when done.

dw_hdmi->bridge is used only in dw_hdmi_top_thread_irq(), so in order to
avoid potential use-after-free ensure the irq is freed before putting the
dw_hdmi->bridge reference.

Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 drivers/gpu/drm/meson/meson_dw_hdmi.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
index 0d7c68b29dff..fef1702acb14 100644
--- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
+++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
@@ -778,7 +778,7 @@ static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
 	if (IS_ERR(meson_dw_hdmi->hdmi))
 		return PTR_ERR(meson_dw_hdmi->hdmi);
 
-	meson_dw_hdmi->bridge = of_drm_find_bridge(pdev->dev.of_node);
+	meson_dw_hdmi->bridge = of_drm_find_and_get_bridge(pdev->dev.of_node);
 
 	DRM_DEBUG_DRIVER("HDMI controller initialized\n");
 
@@ -789,8 +789,12 @@ static void meson_dw_hdmi_unbind(struct device *dev, struct device *master,
 				   void *data)
 {
 	struct meson_dw_hdmi *meson_dw_hdmi = dev_get_drvdata(dev);
+	struct platform_device *pdev = to_platform_device(dev);
+	int irq = platform_get_irq(pdev, 0);
 
+	devm_free_irq(dev, irq, meson_dw_hdmi);
 	dw_hdmi_unbind(meson_dw_hdmi->hdmi);
+	drm_bridge_put(meson_dw_hdmi->bridge);
 }
 
 static const struct component_ops meson_dw_hdmi_ops = {

-- 
2.52.0

Re: [PATCH v2 2/6] drm/meson/dw-hdmi: convert to of_drm_find_and_get_bridge()

[Neil Armstrong]

On 1/9/26 11:02, Luca Ceresoli wrote:
> of_drm_find_bridge() is deprecated. Move to its replacement
> of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
> is put when done.
> 
> dw_hdmi->bridge is used only in dw_hdmi_top_thread_irq(), so in order to
> avoid potential use-after-free ensure the irq is freed before putting the
> dw_hdmi->bridge reference.
> 
> Acked-by: Maxime Ripard <mripard@kernel.org>
> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
> ---
>   drivers/gpu/drm/meson/meson_dw_hdmi.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
> index 0d7c68b29dff..fef1702acb14 100644
> --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
> +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
> @@ -778,7 +778,7 @@ static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
>   	if (IS_ERR(meson_dw_hdmi->hdmi))
>   		return PTR_ERR(meson_dw_hdmi->hdmi);
>   
> -	meson_dw_hdmi->bridge = of_drm_find_bridge(pdev->dev.of_node);
> +	meson_dw_hdmi->bridge = of_drm_find_and_get_bridge(pdev->dev.of_node);
>   
>   	DRM_DEBUG_DRIVER("HDMI controller initialized\n");
>   
> @@ -789,8 +789,12 @@ static void meson_dw_hdmi_unbind(struct device *dev, struct device *master,
>   				   void *data)
>   {
>   	struct meson_dw_hdmi *meson_dw_hdmi = dev_get_drvdata(dev);
> +	struct platform_device *pdev = to_platform_device(dev);
> +	int irq = platform_get_irq(pdev, 0);
>   
> +	devm_free_irq(dev, irq, meson_dw_hdmi);
>   	dw_hdmi_unbind(meson_dw_hdmi->hdmi);
> +	drm_bridge_put(meson_dw_hdmi->bridge);
>   }
>   
>   static const struct component_ops meson_dw_hdmi_ops = {
> 

Acked-by: Neil Armstrong <neil.armstrong@linaro.org>

Thanks,
Neil

Re: [PATCH v2 2/6] drm/meson/dw-hdmi: convert to of_drm_find_and_get_bridge()

[Martin Blumenstingl]

Hi Luca,

On Fri, Jan 9, 2026 at 11:03 AM Luca Ceresoli <luca.ceresoli@bootlin.com> wrote:
>
> of_drm_find_bridge() is deprecated. Move to its replacement
> of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
> is put when done.
>
> dw_hdmi->bridge is used only in dw_hdmi_top_thread_irq(), so in order to
> avoid potential use-after-free ensure the irq is freed before putting the
> dw_hdmi->bridge reference.
>
> Acked-by: Maxime Ripard <mripard@kernel.org>
> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

[...]
> @@ -789,8 +789,12 @@ static void meson_dw_hdmi_unbind(struct device *dev, struct device *master,
>                                    void *data)
>  {
>         struct meson_dw_hdmi *meson_dw_hdmi = dev_get_drvdata(dev);
> +       struct platform_device *pdev = to_platform_device(dev);
> +       int irq = platform_get_irq(pdev, 0);
>
> +       devm_free_irq(dev, irq, meson_dw_hdmi);
I have one question (so I can understand things better):
is there a particular reason why you went with free'ing the IRQ
instead of "just" masking it (so the hardware won't fire anymore of
those IRQs)?


Best regards,
Martin

Re: [PATCH v2 2/6] drm/meson/dw-hdmi: convert to of_drm_find_and_get_bridge()

[Luca Ceresoli]

Hello Martin,

On Mon Jan 12, 2026 at 11:21 PM CET, Martin Blumenstingl wrote:
> Hi Luca,
>
> On Fri, Jan 9, 2026 at 11:03 AM Luca Ceresoli <luca.ceresoli@bootlin.com> wrote:
>>
>> of_drm_find_bridge() is deprecated. Move to its replacement
>> of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
>> is put when done.
>>
>> dw_hdmi->bridge is used only in dw_hdmi_top_thread_irq(), so in order to
>> avoid potential use-after-free ensure the irq is freed before putting the
>> dw_hdmi->bridge reference.
>>
>> Acked-by: Maxime Ripard <mripard@kernel.org>
>> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
> Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
>
> [...]
>> @@ -789,8 +789,12 @@ static void meson_dw_hdmi_unbind(struct device *dev, struct device *master,
>>                                    void *data)
>>  {
>>         struct meson_dw_hdmi *meson_dw_hdmi = dev_get_drvdata(dev);
>> +       struct platform_device *pdev = to_platform_device(dev);
>> +       int irq = platform_get_irq(pdev, 0);
>>
>> +       devm_free_irq(dev, irq, meson_dw_hdmi);
> I have one question (so I can understand things better):
> is there a particular reason why you went with free'ing the IRQ
> instead of "just" masking it (so the hardware won't fire anymore of
> those IRQs)?

One reason is symmetry: _bind requests the irq, so _unbind does the
reverse.

Another is I don't have the hardware, so I wanted my changes to be as small
and clear as possible.

In principle one could request/free the irq in probe/remove and then
enable/disable it in bind/unbind. Whether it would be a good or bad idea I
don't know, but surely it would be more complex and I wouldn't want to do
it without any chance to test it on hardware.

Also, that would only optimize the case of multiple bind/unbind cycles,
which are not quite realistic without bridge hotplug. And brigde hotplug
does not exist yet in mainline, and when it will arrive it will be used
only for a few use cases.

I hope this answers your question.

Best regards,
Luca

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

Re: [PATCH v2 2/6] drm/meson/dw-hdmi: convert to of_drm_find_and_get_bridge()

[Martin Blumenstingl]

Hi Luca,

On Tue, Jan 13, 2026 at 6:31 PM Luca Ceresoli <luca.ceresoli@bootlin.com> wrote:
[...]
> >> @@ -789,8 +789,12 @@ static void meson_dw_hdmi_unbind(struct device *dev, struct device *master,
> >>                                    void *data)
> >>  {
> >>         struct meson_dw_hdmi *meson_dw_hdmi = dev_get_drvdata(dev);
> >> +       struct platform_device *pdev = to_platform_device(dev);
> >> +       int irq = platform_get_irq(pdev, 0);
> >>
> >> +       devm_free_irq(dev, irq, meson_dw_hdmi);
> > I have one question (so I can understand things better):
> > is there a particular reason why you went with free'ing the IRQ
> > instead of "just" masking it (so the hardware won't fire anymore of
> > those IRQs)?
>
> One reason is symmetry: _bind requests the irq, so _unbind does the
> reverse.
>
> Another is I don't have the hardware, so I wanted my changes to be as small
> and clear as possible.
Understood, thanks!

> In principle one could request/free the irq in probe/remove and then
> enable/disable it in bind/unbind. Whether it would be a good or bad idea I
> don't know, but surely it would be more complex and I wouldn't want to do
> it without any chance to test it on hardware.
>
> Also, that would only optimize the case of multiple bind/unbind cycles,
> which are not quite realistic without bridge hotplug. And brigde hotplug
> does not exist yet in mainline, and when it will arrive it will be used
> only for a few use cases.
>
> I hope this answers your question.
Yes, I was curious whether you considered devm_free_irq() as the only
"correct" approach (in this case I would have recommended a comment)
or whether other approaches are fine too.
This is useful knowledge for me in case we ever need to restructure the driver.


Best regards,
Martin

[PATCH v2 3/6] drm/imx/dw-hdmi: convert to of_drm_find_and_get_bridge()

[Luca Ceresoli]

of_drm_find_bridge() is deprecated. Move to its replacement
of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
is put when done.

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

---

Changes  in v2:
- add missing drm_bridge_put() on component_add() failure
- reorder lines in dw_hdmi_imx_remove()
---
 drivers/gpu/drm/imx/ipuv3/dw_hdmi-imx.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/imx/ipuv3/dw_hdmi-imx.c b/drivers/gpu/drm/imx/ipuv3/dw_hdmi-imx.c
index 07e5f96202d4..398f3cce5532 100644
--- a/drivers/gpu/drm/imx/ipuv3/dw_hdmi-imx.c
+++ b/drivers/gpu/drm/imx/ipuv3/dw_hdmi-imx.c
@@ -241,7 +241,7 @@ static int dw_hdmi_imx_probe(struct platform_device *pdev)
 	if (IS_ERR(hdmi->hdmi))
 		return PTR_ERR(hdmi->hdmi);
 
-	hdmi->bridge = of_drm_find_bridge(np);
+	hdmi->bridge = of_drm_find_and_get_bridge(np);
 	if (!hdmi->bridge) {
 		dev_err(hdmi->dev, "Unable to find bridge\n");
 		dw_hdmi_remove(hdmi->hdmi);
@@ -249,8 +249,10 @@ static int dw_hdmi_imx_probe(struct platform_device *pdev)
 	}
 
 	ret = component_add(&pdev->dev, &dw_hdmi_imx_ops);
-	if (ret)
+	if (ret) {
+		drm_bridge_put(hdmi->bridge);
 		dw_hdmi_remove(hdmi->hdmi);
+	}
 
 	return ret;
 }
@@ -260,6 +262,7 @@ static void dw_hdmi_imx_remove(struct platform_device *pdev)
 	struct imx_hdmi *hdmi = platform_get_drvdata(pdev);
 
 	component_del(&pdev->dev, &dw_hdmi_imx_ops);
+	drm_bridge_put(hdmi->bridge);
 	dw_hdmi_remove(hdmi->hdmi);
 }
 

-- 
2.52.0

Re: [PATCH v2 3/6] drm/imx/dw-hdmi: convert to of_drm_find_and_get_bridge()

[Philipp Zabel]

On Fr, 2026-01-09 at 11:02 +0100, Luca Ceresoli wrote:
> of_drm_find_bridge() is deprecated. Move to its replacement
> of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
> is put when done.
> 
> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>

regards
Philipp

Re: [PATCH v2 3/6] drm/imx/dw-hdmi: convert to of_drm_find_and_get_bridge()

[Maxime Ripard]

On Fri, 9 Jan 2026 11:02:52 +0100, Luca Ceresoli wrote:
> of_drm_find_bridge() is deprecated. Move to its replacement
> of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
> is put when done.
> 
> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
> 
> [ ... ]

Acked-by: Maxime Ripard <mripard@kernel.org>

Thanks!
Maxime

[PATCH v2 4/6] drm/mediatek: mtk_hdmi*: convert to of_drm_find_and_get_bridge()

[Luca Ceresoli]

of_drm_find_bridge() is deprecated. Move to its replacement
of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
is put when done by using the drm_bridge::next_bridge pointer.

Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 drivers/gpu/drm/mediatek/mtk_hdmi.c        | 4 ++--
 drivers/gpu/drm/mediatek/mtk_hdmi_common.c | 4 ++--
 drivers/gpu/drm/mediatek/mtk_hdmi_common.h | 1 -
 drivers/gpu/drm/mediatek/mtk_hdmi_v2.c     | 4 ++--
 4 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi.c b/drivers/gpu/drm/mediatek/mtk_hdmi.c
index 0face4dcaa36..1ea259854780 100644
--- a/drivers/gpu/drm/mediatek/mtk_hdmi.c
+++ b/drivers/gpu/drm/mediatek/mtk_hdmi.c
@@ -986,8 +986,8 @@ static int mtk_hdmi_bridge_attach(struct drm_bridge *bridge,
 		return -EINVAL;
 	}
 
-	if (hdmi->next_bridge) {
-		ret = drm_bridge_attach(encoder, hdmi->next_bridge,
+	if (hdmi->bridge.next_bridge) {
+		ret = drm_bridge_attach(encoder, hdmi->bridge.next_bridge,
 					bridge, flags);
 		if (ret)
 			return ret;
diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi_common.c b/drivers/gpu/drm/mediatek/mtk_hdmi_common.c
index e78eb0876f16..40ded86dbea3 100644
--- a/drivers/gpu/drm/mediatek/mtk_hdmi_common.c
+++ b/drivers/gpu/drm/mediatek/mtk_hdmi_common.c
@@ -315,8 +315,8 @@ static int mtk_hdmi_dt_parse_pdata(struct mtk_hdmi *hdmi, struct platform_device
 		return -EINVAL;
 
 	if (!of_device_is_compatible(remote, "hdmi-connector")) {
-		hdmi->next_bridge = of_drm_find_bridge(remote);
-		if (!hdmi->next_bridge) {
+		hdmi->bridge.next_bridge = of_drm_find_and_get_bridge(remote);
+		if (!hdmi->bridge.next_bridge) {
 			dev_err(dev, "Waiting for external bridge\n");
 			of_node_put(remote);
 			return -EPROBE_DEFER;
diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi_common.h b/drivers/gpu/drm/mediatek/mtk_hdmi_common.h
index de5e064585f8..cace3c5dc067 100644
--- a/drivers/gpu/drm/mediatek/mtk_hdmi_common.h
+++ b/drivers/gpu/drm/mediatek/mtk_hdmi_common.h
@@ -150,7 +150,6 @@ struct mtk_hdmi_conf {
 
 struct mtk_hdmi {
 	struct drm_bridge bridge;
-	struct drm_bridge *next_bridge;
 	struct drm_connector *curr_conn;/* current connector (only valid when 'enabled') */
 	struct device *dev;
 	const struct mtk_hdmi_conf *conf;
diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi_v2.c b/drivers/gpu/drm/mediatek/mtk_hdmi_v2.c
index c272e1e74b7d..2adeece499b6 100644
--- a/drivers/gpu/drm/mediatek/mtk_hdmi_v2.c
+++ b/drivers/gpu/drm/mediatek/mtk_hdmi_v2.c
@@ -940,8 +940,8 @@ static int mtk_hdmi_v2_bridge_attach(struct drm_bridge *bridge,
 		DRM_ERROR("The flag DRM_BRIDGE_ATTACH_NO_CONNECTOR must be supplied\n");
 		return -EINVAL;
 	}
-	if (hdmi->next_bridge) {
-		ret = drm_bridge_attach(encoder, hdmi->next_bridge, bridge, flags);
+	if (hdmi->bridge.next_bridge) {
+		ret = drm_bridge_attach(encoder, hdmi->bridge.next_bridge, bridge, flags);
 		if (ret)
 			return ret;
 	}

-- 
2.52.0

[PATCH v2 5/6] drm/exynos: hdmi: convert to of_drm_find_and_get_bridge()

[Luca Ceresoli]

of_drm_find_bridge() is deprecated. Move to its replacement
of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
is put when done.

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 drivers/gpu/drm/exynos/exynos_hdmi.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/exynos/exynos_hdmi.c b/drivers/gpu/drm/exynos/exynos_hdmi.c
index 01813e11e6c6..bfcf2fa62fe1 100644
--- a/drivers/gpu/drm/exynos/exynos_hdmi.c
+++ b/drivers/gpu/drm/exynos/exynos_hdmi.c
@@ -1779,7 +1779,7 @@ static int hdmi_bridge_init(struct hdmi_context *hdata)
 		return -EINVAL;
 	}
 
-	hdata->bridge = of_drm_find_bridge(np);
+	hdata->bridge = of_drm_find_and_get_bridge(np);
 	of_node_put(np);
 
 	if (!hdata->bridge)
@@ -2096,6 +2096,8 @@ static void hdmi_remove(struct platform_device *pdev)
 
 	put_device(&hdata->ddc_adpt->dev);
 
+	drm_bridge_put(hdata->bridge);
+
 	mutex_destroy(&hdata->mutex);
 }
 

-- 
2.52.0

Re: [PATCH v2 5/6] drm/exynos: hdmi: convert to of_drm_find_and_get_bridge()

[Maxime Ripard]

On Fri, 9 Jan 2026 11:02:54 +0100, Luca Ceresoli wrote:
> of_drm_find_bridge() is deprecated. Move to its replacement
> of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
> is put when done.
> 
> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
> 
> [ ... ]

Acked-by: Maxime Ripard <mripard@kernel.org>

Thanks!
Maxime

[PATCH v2 6/6] drm: rcar-du: lvds: convert to of_drm_find_and_get_bridge()

[Luca Ceresoli]

of_drm_find_bridge() is deprecated. Move to its replacement
of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
is put when done.

Since the companion bridge pointer is used by .atomic_enable, putting its
reference in the remove function would be dangerous. Use .destroy to put it
on final deallocation.

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 drivers/gpu/drm/renesas/rcar-du/rcar_lvds.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_lvds.c b/drivers/gpu/drm/renesas/rcar-du/rcar_lvds.c
index 001b3543924a..227818e37390 100644
--- a/drivers/gpu/drm/renesas/rcar-du/rcar_lvds.c
+++ b/drivers/gpu/drm/renesas/rcar-du/rcar_lvds.c
@@ -633,6 +633,13 @@ static bool rcar_lvds_mode_fixup(struct drm_bridge *bridge,
 	return true;
 }
 
+static void rcar_lvds_destroy(struct drm_bridge *bridge)
+{
+	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
+
+	drm_bridge_put(lvds->companion);
+}
+
 static int rcar_lvds_attach(struct drm_bridge *bridge,
 			    struct drm_encoder *encoder,
 			    enum drm_bridge_attach_flags flags)
@@ -648,6 +655,7 @@ static int rcar_lvds_attach(struct drm_bridge *bridge,
 
 static const struct drm_bridge_funcs rcar_lvds_bridge_ops = {
 	.attach = rcar_lvds_attach,
+	.destroy = rcar_lvds_destroy,
 	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
 	.atomic_reset = drm_atomic_helper_bridge_reset,
@@ -740,7 +748,7 @@ static int rcar_lvds_parse_dt_companion(struct rcar_lvds *lvds)
 		goto done;
 	}
 
-	lvds->companion = of_drm_find_bridge(companion);
+	lvds->companion = of_drm_find_and_get_bridge(companion);
 	if (!lvds->companion) {
 		ret = -EPROBE_DEFER;
 		goto done;

-- 
2.52.0

Re: [PATCH v2 6/6] drm: rcar-du: lvds: convert to of_drm_find_and_get_bridge()

[Maxime Ripard]

On Fri, 9 Jan 2026 11:02:55 +0100, Luca Ceresoli wrote:
> of_drm_find_bridge() is deprecated. Move to its replacement
> of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
> is put when done.
> 
> Since the companion bridge pointer is used by .atomic_enable, putting its
> 
> [ ... ]

Acked-by: Maxime Ripard <mripard@kernel.org>

Thanks!
Maxime

Re: [PATCH v2 0/6] drm/bridge: convert users of of_drm_find_bridge(), part 3

[Luca Ceresoli]

On Fri, 09 Jan 2026 11:02:49 +0100, Luca Ceresoli wrote:
> This series converts many DRM drivers from the now deprecated
> of_drm_find_bridge() to its replacement of_drm_find_and_get_bridge() which
> allows correct bridge refcounting. Where applicable it also converts
> per-driver "next_bridge" pointers to the unified drm_bridge::next_bridge
> which puts the reference automatically on bridge deallocation.
> 
> This is part of the work to support hotplug of DRM bridges. The grand plan
> was discussed in [0].
> 
> [...]

Applied, thanks!

[1/6] drm/bridge: dw-hdmi: convert to of_drm_find_and_get_bridge()
      commit: 4e7fd5aa3f3939dfcd8b0578de57f1cc00d6c31c
[2/6] drm/meson/dw-hdmi: convert to of_drm_find_and_get_bridge()
      commit: 9afbf7a9cce584e3ce7b709ea5654f2721b00694
[3/6] drm/imx/dw-hdmi: convert to of_drm_find_and_get_bridge()
      commit: 6dfebeee296cbb3296f06c28f3b2d053ec8374e7
[4/6] drm/mediatek: mtk_hdmi*: convert to of_drm_find_and_get_bridge()
      commit: 4ace6fbcd25f5ef275c91b93424e715f96197e50
[5/6] drm/exynos: hdmi: convert to of_drm_find_and_get_bridge()
      commit: 2db0d298f22d685e0c9f7f66ab6470f12a0255b6
[6/6] drm: rcar-du: lvds: convert to of_drm_find_and_get_bridge()
      commit: 95d628c9e4738c070ba780488efbab894e583646

Best regards,
-- 
Luca Ceresoli <luca.ceresoli@bootlin.com>