Re: [PATCH v2] drm/rockchip: rk3066_hdmi: convert to devm_drm_bridge_alloc() API

[Johan Jonker]

Hi,

On 9/3/26 17:12, Heiko Stübner wrote:
> Am Montag, 24. August 2026, 12:21:19 Mitteleuropäische Sommerzeit schrieb Johan Jonker via B4 Relay:
>> From: Hüseyin BIYIK <boogiepop@xxxxxxx>
>>
>> The function devm_drm_bridge_alloc() is the new API for allocating DRM bridges.
>> This conversion was missed during the initial conversion of all bridges to
>> the new API.
>>
>> Signed-off-by: Hüseyin BIYIK <boogiepop@xxxxxxx>
>> Signed-off-by: Johan Jonker <jbx6244@xxxxxxxxx>
>> ---
>>  drivers/gpu/drm/rockchip/rk3066_hdmi.c | 8 ++++----
>>  1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/rockchip/rk3066_hdmi.c b/drivers/gpu/drm/rockchip/rk3066_hdmi.c
>> index f28d6a883e09..39c65ee07caa 100644
>> --- a/drivers/gpu/drm/rockchip/rk3066_hdmi.c
>> +++ b/drivers/gpu/drm/rockchip/rk3066_hdmi.c
>> @@ -703,7 +703,6 @@ rk3066_hdmi_register(struct drm_device *drm, struct rk3066_hdmi *hdmi)
>>  			 DRM_MODE_ENCODER_TMDS, NULL);
>>  

>>  	hdmi->bridge.driver_private = hdmi;

Can this be removed?
See link/comment below.


>> -	hdmi->bridge.funcs = &rk3066_hdmi_bridge_funcs;
>>  	hdmi->bridge.ops = DRM_BRIDGE_OP_DETECT |
>>  			   DRM_BRIDGE_OP_EDID |
>>  			   DRM_BRIDGE_OP_HDMI |
>> @@ -747,9 +746,10 @@ static int rk3066_hdmi_bind(struct device *dev, struct device *master,
>>  	int irq;
>>  	int ret;
>>  
>> -	hdmi = devm_kzalloc(dev, sizeof(*hdmi), GFP_KERNEL);
>> -	if (!hdmi)
>> -		return -ENOMEM;
>> +	hdmi = devm_drm_bridge_alloc(dev, struct rk3066_hdmi, bridge,
>> +				     &rk3066_hdmi_bridge_funcs);
>> +	if (IS_ERR(hdmi))
>> +		return PTR_ERR(hdmi);
> 

> If I'm reading things correctly, the parts in rk3066_hdmi_register setting
> hdmi->bridge.driver_private (should use the container field of struct
> drm_bridge instead) 

The driver_private line was added with this patch:

[PATCH] drm/rockchip: rk3066_hdmi: switch to drm bridge
https://lore.kernel.org/all/20250428102309.1501986-1-andyshrk@xxxxxxx/

and hdmi->bridge.funcs are redundant by this change?

Not redundant, just funcs are attached in a common function __devm_drm_bridge_alloc()

https://elixir.bootlin.com/linux/v7.2.2/source/drivers/gpu/drm/drm_bridge.c#L383

void *__devm_drm_bridge_alloc(struct device *dev, size_t size, size_t offset,
			      const struct drm_bridge_funcs *funcs)
{
	void *container;
	struct drm_bridge *bridge;
	int err;

	if (!funcs) {
		dev_warn(dev, "Missing funcs pointer\n");
		return ERR_PTR(-EINVAL);
	}

	container = kzalloc(size, GFP_KERNEL);
	if (!container)
		return ERR_PTR(-ENOMEM);

	bridge = container + offset;
	INIT_LIST_HEAD(&bridge->list);
	bridge->container = container;
	bridge->funcs = funcs;
	kref_init(&bridge->refcount);

	err = devm_add_action_or_reset(dev, drm_bridge_put_void, bridge);
	if (err)
		return ERR_PTR(err);

	return container;
}
EXPORT_SYMBOL(__devm_drm_bridge_alloc);

===========

Other example from sti:

https://lore.kernel.org/all/ce9c6aa3-5372-468f-a4bf-5a261259e459@xxxxxxxxxxx/

>>>> It looks like you don't set bridge->driver_private anymore. Is it on purpose?
>>> This looks correct to me. In current code, driver_private is used to
>>> hold a pointer to the driver private struct (struct
>>> analogix_dp_device). With devm_drm_bridge_alloc() container_of() is now
>>> enough, no pointer is needed. With the patch applied, driver_private
>>> becomes unused.
>> Then we should remove it from the structure if it's unused.


drm/sti: hdmi: convert to devm_drm_bridge_alloc() API
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ac4531424d907f3983e919a7bda2b90ea0cede4f

============

This serie was missing a few bridges too many.

drm: convert all bridges to devm_drm_bridge_alloc()
https://patchwork.freedesktop.org/series/148229/

====

Please advise what changes are needed?
RK3066_hdmi is broken since somewhere 2025-05.

Johan


> 
> 
> Heiko
> 
> 
> 
>>  
>>  	hdmi->dev = dev;
>>  	hdmi->drm_dev = drm;
>>
>> ---
>> base-commit: 2709dd5ae32f0828f386327c76bba9f39f63a1c6
>> change-id: 20260824-drm-e4689f65ab8c
>>
>> Best regards,
>>
> 
> 
> 
>