From: Linus Walleij <linusw@kernel.org>
To: Petar Stepanovic <pstepanovic@axiado.com>
Cc: Tzu-Hao Wei <twei@axiado.com>, Swark Yang <syang@axiado.com>,
Prasad Bolisetty <pbolisetty@axiado.com>,
Bartosz Golaszewski <brgl@kernel.org>,
Rob Herring <robh@kernel.org>,
Krzysztof Kozlowski <krzk+dt@kernel.org>,
Conor Dooley <conor+dt@kernel.org>,
Harshit Shah <hshah@axiado.com>,
SriNavmani A <srinavmani@axiado.com>,
linux-gpio@vger.kernel.org, devicetree@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] dt-bindings: gpio: add Axiado SGPIO controller
Date: Sat, 23 May 2026 11:13:45 +0200 [thread overview]
Message-ID: <CAD++jLkos3kC_ALAaoevaF29_Jf_WY5Z_2mZ1_Ldi+hCDbzt9w@mail.gmail.com> (raw)
In-Reply-To: <c20dc0cb-252b-4637-bb22-6078be62b21d@axiado.com>
On Wed, May 13, 2026 at 10:59 AM Petar Stepanovic
<pstepanovic@axiado.com> wrote:
> Some SGPIO outputs may control host-critical signals. For example, if the
> BMC reboots while the host/server remains powered on, changing SGPIO output
> values during driver initialization could potentially reset or shut down the
> running host.
>
> The purpose of `dout-init` is to provide a deterministic safe output state
> during SGPIO initialization, before any GPIO consumer has requested the line.
>
> That said, if the preferred approach is to preserve the existing hardware
> DOUT state during probe and only change the value when a GPIO consumer
> requests the line, I can rework the driver in that direction.
That is usually the best. The gpio framework scans the direction
of each line at probe(). While it does not know about the initial *value*
of each line, consumers can take this into account
when requesting a GPIO line like this:
gpio_vbus = devm_gpiod_get(dev, "vbus", GPIOD_ASIS);
This means the kernel does not put any initial value on the line.
Yours,
Linus Walleij
next prev parent reply other threads:[~2026-05-23 9:13 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-14 13:48 [PATCH 0/3] Subject: [PATCH 0/3] gpio: add support for Axiado SGPIO controller Petar Stepanovic
2026-04-14 13:48 ` [PATCH 1/3] dt-bindings: gpio: add " Petar Stepanovic
2026-04-14 14:06 ` Krzysztof Kozlowski
2026-04-24 7:26 ` Linus Walleij
2026-05-07 8:05 ` Petar Stepanovic
2026-05-07 9:44 ` Linus Walleij
2026-05-08 7:57 ` Petar Stepanovic
2026-05-11 8:36 ` Linus Walleij
2026-05-13 8:59 ` Petar Stepanovic
2026-05-23 9:13 ` Linus Walleij [this message]
2026-04-14 13:48 ` [PATCH 2/3] gpio: axiado: add SGPIO controller support Petar Stepanovic
2026-04-14 14:04 ` Krzysztof Kozlowski
2026-04-20 9:25 ` Bartosz Golaszewski
2026-04-24 7:44 ` Linus Walleij
2026-04-14 13:48 ` [PATCH 3/3] MAINTAINERS: add Axiado SGPIO controller Petar Stepanovic
2026-04-14 14:12 ` Krzysztof Kozlowski
2026-04-22 1:48 ` Prasad Bolisetty
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