linux-kernel - Re: [PATCH v2] media: i2c: thp7312: use fwnode_for_each_child

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Message-ID: <3d8546b9-92bd-40da-a61a-4534ba7779db@gmail.com>
Date: Tue, 8 Apr 2025 13:26:42 +0300
From: Matti Vaittinen <mazziesaccount@...il.com>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>,
 Sakari Ailus <sakari.ailus@...ux.intel.com>
Cc: Matti Vaittinen <matti.vaittinen@...rohmeurope.com>,
 Paul Elder <paul.elder@...asonboard.com>,
 Mauro Carvalho Chehab <mchehab@...nel.org>, linux-media@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] media: i2c: thp7312: use fwnode_for_each_child_node()

On 08/04/2025 13:12, Laurent Pinchart wrote:
> Hi Sakari,
> 
> On Tue, Apr 08, 2025 at 08:48:45AM +0000, Sakari Ailus wrote:
>> On Fri, Mar 21, 2025 at 12:41:00PM +0200, Laurent Pinchart wrote:
>>> On Fri, Mar 21, 2025 at 10:58:27AM +0200, Matti Vaittinen wrote:
>>>> When fwnode_for_each_available_child_node() is used on the device-tree
>>>> backed systems, it renders to same operation as the
>>>> fwnode_for_each_child_node(), because the fwnode_for_each_child_node()
>>>> does only iterate through those device-tree nodes which are available.
>>>
>>> This makes me wonder why the OF backend implements
>>> fwnode_for_each_child_node() as fwnode_for_each_available_child_node().
>>> Is that on purpose, or is it a bug ?
>>
>> I discussed this with Rafael and he didn't recall why the original
>> implementation was like that. The general direction later on has been not
>> to present unavailable nodes over the fwnode interface.
>>
>> So I'd say:
>>
>> Reviewed-by: Sakari Ailus <sakari.ailus@...ux.intel.com>
>>
>> We should also change the documentation of the fwnode API accordingly.
> 
> Does that also mean that the fwnode_for_each_available_child_node()
> function will be dropped ? It's used by few drivers (5 in addition to
> the thp7312 driver, plus 3 call sites in drivers/base/core.c), so a
> patch series to drop it should be easy.
> 

I assume the fwnode_for_each_available_child_node() still makes sense 
for ACPI backed users, no?

Yours,
	-- Matti