From: "Arnd Bergmann" <arnd@arndb.de>
To: "Khristine Andreea Barbulescu"
<khristineandreea.barbulescu@oss.nxp.com>,
"Krzysztof Kozlowski" <krzk@kernel.org>,
"Ghennadi Procopciuc" <ghennadi.procopciuc@oss.nxp.com>
Cc: "Linus Walleij" <linus.walleij@linaro.org>,
"Bartosz Golaszewski" <brgl@bgdev.pl>,
"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
"Conor Dooley" <conor+dt@kernel.org>,
"Chester Lin" <chester62515@gmail.com>,
"Matthias Brugger" <mbrugger@suse.com>,
"Ghennadi Procopciuc" <ghennadi.procopciuc@nxp.com>,
"Larisa Grigore" <larisa.grigore@nxp.com>,
"Lee Jones" <lee@kernel.org>, "Shawn Guo" <shawnguo@kernel.org>,
"Sascha Hauer" <s.hauer@pengutronix.de>,
"Fabio Estevam" <festevam@gmail.com>,
"Aisheng Dong" <aisheng.dong@nxp.com>,
"Jacky Bai" <ping.bai@nxp.com>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
"Alberto Ruiz" <aruizrui@redhat.com>,
"Christophe Lizzi" <clizzi@redhat.com>,
devicetree@vger.kernel.org,
"Enric Balletbo" <eballetb@redhat.com>,
"Eric Chanudet" <echanude@redhat.com>,
imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
linux-kernel@vger.kernel.org, "NXP S32 Linux Team" <s32@nxp.com>,
"Pengutronix Kernel Team" <kernel@pengutronix.de>,
"Vincent Guittot" <vincent.guittot@linaro.org>,
"Rob Herring" <robh@kernel.org>
Subject: Re: [PATCH v8 01/10] dt-bindings: mfd: add support for the NXP SIUL2 module
Date: Mon, 23 Mar 2026 16:33:57 +0100 [thread overview]
Message-ID: <bd3df7c9-af55-4454-b120-a008b6362972@app.fastmail.com> (raw)
In-Reply-To: <5f1b651b-1064-4280-a7e0-b7d66c396cde@oss.nxp.com>
On Mon, Mar 23, 2026, at 08:57, Khristine Andreea Barbulescu wrote:
> On 3/14/2026 9:31 AM, Arnd Bergmann wrote:
>> On Fri, Mar 13, 2026, at 18:10, Krzysztof Kozlowski wrote:
>>
>> That said, there is probably room for improvement, since some of
>> the register contents are read-only and could just be accessed
>> by the boot firmware in order to move the information into more
>> regular DT properties instead of defining bindings for drivers
>> to access the information in raw form.
>
> Assuming we drop the syscon approach entirely, for the SerDes
> presence information we could follow Arnd’s suggestion and have
> it provided by the boot firmware instead of exposing it through SIUL2.
I didn't say you would necessarily drop the syscon interface
entirely, but for each user of it, you can see if the data
in it is static at runtime, and if so, you turn it into
devicetree properties.
> However, SerDes presence is not the only information involved.
> As mentioned in the earlier replies, we also have the PCIe device ID,
> which will be needed once PCIe endpoint support is added.
>
> Would it be acceptable to describe this information in DT, as in
> other existing approaches [1], [2], [3], by adding a device-id
> property to the PCIe node?
I don't know how endpoint devices normally get the vendor/device
ID pair, but as far as I can tell, these are not normally assigned
by the boot firmware but are picked by whatever function driver is
running on the endpoint device: the idea for the device ID is
to identify the protocol that a driver on the host side needs to
use, rather than identify what hardware it is running on.
In that case, neither DT nor syscon are an appropriate way to
pass the PCI device ID.
From looking at the links you provided, all of those appear
to refer to host mode vendor/device ID pairs that get written
into the device at probe time, either because the boot firmware
fails to initialize the devices properly, or because the ID data
is not persistent across a device reset. In endpoint mode,
this would not apply.
Arnd
next prev parent reply other threads:[~2026-03-23 15:34 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-20 11:59 [PATCH v8 00/10] gpio: siul2-s32g2: add initial GPIO driver Khristine Andreea Barbulescu
2026-01-20 11:59 ` [PATCH v8 01/10] dt-bindings: mfd: add support for the NXP SIUL2 module Khristine Andreea Barbulescu
2026-01-21 2:19 ` Rob Herring
2026-02-19 11:36 ` Khristine Andreea Barbulescu
2026-02-20 10:16 ` Krzysztof Kozlowski
2026-02-20 14:36 ` Khristine Andreea Barbulescu
2026-02-20 14:41 ` Krzysztof Kozlowski
2026-02-23 11:51 ` Khristine Andreea Barbulescu
2026-02-23 13:14 ` Krzysztof Kozlowski
2026-02-25 9:40 ` Ghennadi Procopciuc
2026-03-03 13:28 ` Ghennadi Procopciuc
2026-03-13 17:10 ` Krzysztof Kozlowski
2026-03-14 7:31 ` Arnd Bergmann
2026-03-23 7:57 ` Khristine Andreea Barbulescu
2026-03-23 8:07 ` Krzysztof Kozlowski
2026-03-31 7:48 ` Khristine Andreea Barbulescu
2026-03-31 10:11 ` Arnd Bergmann
2026-03-31 13:43 ` Khristine Andreea Barbulescu
2026-03-31 14:08 ` Arnd Bergmann
2026-03-23 15:33 ` Arnd Bergmann [this message]
2026-02-20 10:18 ` Krzysztof Kozlowski
2026-02-20 14:14 ` Khristine Andreea Barbulescu
2026-01-20 11:59 ` [PATCH v8 02/10] mfd: nxp-siul2: add support for NXP SIUL2 Khristine Andreea Barbulescu
2026-01-22 18:52 ` Sander Vanheule
2026-01-20 11:59 ` [PATCH v8 03/10] arm64: dts: s32g: change pinctrl node into the new mfd node Khristine Andreea Barbulescu
2026-01-27 9:13 ` Linus Walleij
2026-01-20 11:59 ` [PATCH v8 04/10] pinctrl: s32cc: use dev_err_probe() and improve error messages Khristine Andreea Barbulescu
2026-01-20 12:04 ` Bartosz Golaszewski
2026-01-20 11:59 ` [PATCH v8 05/10] pinctrl: s32cc: change to "devm_pinctrl_register_and_init" Khristine Andreea Barbulescu
2026-01-20 12:04 ` Bartosz Golaszewski
2026-01-20 11:59 ` [PATCH v8 06/10] pinctrl: s32g2: change the driver to also be probed as an MFD cell Khristine Andreea Barbulescu
2026-01-20 12:08 ` Bartosz Golaszewski
2026-01-23 13:57 ` Vincent Guittot
2026-01-20 11:59 ` [PATCH v8 07/10] pinctrl: s32cc: skip syscon child nodes when parsing funcs and groups Khristine Andreea Barbulescu
2026-01-20 12:16 ` Bartosz Golaszewski
2026-01-27 9:14 ` Linus Walleij
2026-01-20 11:59 ` [PATCH v8 08/10] pinctrl: s32cc: implement GPIO functionality Khristine Andreea Barbulescu
2026-01-23 13:56 ` Vincent Guittot
2026-01-20 11:59 ` [PATCH v8 09/10] MAINTAINERS: add MAINTAINER for NXP SIUL2 MFD driver Khristine Andreea Barbulescu
2026-01-27 9:17 ` Linus Walleij
2026-01-20 11:59 ` [PATCH v8 10/10] pinctrl: s32cc: set num_custom_params to 0 Khristine Andreea Barbulescu
2026-01-20 12:16 ` Bartosz Golaszewski
2026-01-20 13:45 ` Daniel Baluta
2026-01-20 19:49 ` [PATCH v8 00/10] gpio: siul2-s32g2: add initial GPIO driver Rob Herring
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