From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Michael Walle <michael@walle.cc>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Rob Herring <robh+dt@kernel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Sakari Ailus <sakari.ailus@linux.intel.com>,
Saravana Kannan <saravanak@google.com>
Subject: Re: fwnode_for_each_child_node() and OF backend discrepancy
Date: Tue, 28 Jun 2022 12:32:12 +0200 [thread overview]
Message-ID: <0b8e357d-1d8b-843f-d8b6-72c760bcd6fb@linaro.org> (raw)
In-Reply-To: <CAJZ5v0jz=ee5TrvYs0_ovWn9sT06bcKDucmmocD8L-d9ZZ5DzQ@mail.gmail.com>
On 27/06/2022 15:33, Rafael J. Wysocki wrote:
> On Mon, Jun 27, 2022 at 3:08 PM Krzysztof Kozlowski
> <krzysztof.kozlowski@linaro.org> wrote:
>>
>> On 27/06/2022 14:49, Michael Walle wrote:
>>> Hi,
>>>
>>> I tired to iterate over all child nodes, regardless if they are
>>> available
>>> or not. Now there is that handy fwnode_for_each_child_node() (and the
>>> fwnode_for_each_available_child_node()). The only thing is the OF
>>> backend
>>> already skips disabled nodes [1], making fwnode_for_each_child_node()
>>> and
>>> fwnode_for_each_available_child_node() behave the same with the OF
>>> backend.
>>>
>>> Doesn't seem to be noticed by anyone for now. I'm not sure how to fix
>>> that
>>> one. fwnode_for_each_child_node() and also fwnode_get_next_child_node()
>>> are
>>> used by a handful of drivers. I've looked at some, but couldn't decide
>>> whether they really want to iterate over all child nodes or just the
>>> enabled
>>> ones.
>>
>> If I get it correctly, this was introduced by 8a0662d9ed29 ("Driver
>> core: Unified interface for firmware node properties")
>> .
>
> Originally it was, but then it has been reworked a few times.
>
> The backend callbacks were introduced by Sakari, in particular.
I see you as an author of 8a0662d9ed29 which adds
device_get_next_child_node() and uses of_get_next_available_child()
instead of of_get_next_child(). Although it was back in 2014, so maybe
it will be tricky to get original intention. :)
Which commit do you mean when you refer to Sakari's work?
>
>> The question to Rafael - what was your intention when you added
>> device_get_next_child_node() looking only for available nodes?
>
> That depends on the backend.
We talk about OF backend. In your commit device_get_next_child_node for
OF uses explicitly available node, not any node.
> fwnode_for_each_available_child_node() is more specific and IIRC it
> was introduced for fw_devlink (CC Saravana).
>
>> My understanding is that this implementation should be consistent with
>> OF implementation, so fwnode_get_next_child_node=get any child.
>
> IIUC, the OF implementation is not consistent with the
> fwnode_get_next_child_node=get any child thing.
>
>> However maybe ACPI treats it somehow differently?
>
> acpi_get_next_subnode() simply returns the next subnode it can find.
Best regards,
Krzysztof
next prev parent reply other threads:[~2022-06-28 10:32 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-27 12:49 fwnode_for_each_child_node() and OF backend discrepancy Michael Walle
2022-06-27 13:08 ` Krzysztof Kozlowski
2022-06-27 13:33 ` Rafael J. Wysocki
2022-06-28 10:32 ` Krzysztof Kozlowski [this message]
2022-06-28 14:41 ` Sakari Ailus
2022-06-29 10:50 ` Rafael J. Wysocki
2022-06-29 13:01 ` Grant Likely
2022-06-28 11:10 ` Andy Shevchenko
2022-06-28 11:36 ` Michael Walle
2022-06-28 13:11 ` Andy Shevchenko
2022-06-28 13:23 ` Michael Walle
2022-06-28 13:29 ` Andy Shevchenko
2022-06-28 13:47 ` Michael Walle
2022-06-28 13:51 ` Krzysztof Kozlowski
2022-06-28 14:22 ` Michael Walle
2022-06-28 14:36 ` Krzysztof Kozlowski
2022-06-28 15:09 ` Michael Walle
2022-06-28 15:17 ` Krzysztof Kozlowski
2022-06-28 20:28 ` Andy Shevchenko
2022-06-28 20:52 ` Horatiu Vultur
2022-06-28 21:07 ` Michael Walle
2022-06-30 20:16 ` Horatiu Vultur
2022-06-30 21:00 ` Michael Walle
2022-06-30 21:21 ` Vladimir Oltean
2022-06-30 21:32 ` Michael Walle
2022-06-28 21:59 ` Vladimir Oltean
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