[PATCH 1/3] dt-bindings: gpio: add Axiado SGPIO controller
Linus Walleij
linusw at kernel.org
Sat May 23 02:13:45 PDT 2026
On Wed, May 13, 2026 at 10:59 AM Petar Stepanovic
<pstepanovic at 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
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