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Message-ID: <20251117-registry-headstand-9c87a7449d28@spud>
Date: Mon, 17 Nov 2025 19:15:07 +0000
From: Conor Dooley <conor@...nel.org>
To: Johan Hovold <johan@...nel.org>
Cc: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>,
Alejandro Enrique <alejandroe1@...tab.com>,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] dt-bindings: gnss: u-blox: use open-drain reset and
safeboot in example
On Fri, Nov 14, 2025 at 04:54:13PM +0100, Johan Hovold wrote:
> The RESET_N and SAFEBOOT_N pins should typically be left open and only
> be connected to ground in rare cases where a device is misbehaving.
>
> Specify GPIO_OPEN_DRAIN in the example as this is what should generally
> be used.
>
> Note that the current Linux driver implementation depends on these pins
> being declared open-drain so that they are not driven while the main
> supply is off.
>
> Signed-off-by: Johan Hovold <johan@...nel.org>
Acked-by: Conor Dooley <conor.dooley@...rochip.com>
pw-bot: not-applicable
> ---
>
> Changes in v2:
> - declare the pins as both active-low and open-drain (as the former is
> no longer implied by the latter)
>
>
> Documentation/devicetree/bindings/gnss/u-blox,neo-6m.yaml | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/gnss/u-blox,neo-6m.yaml b/Documentation/devicetree/bindings/gnss/u-blox,neo-6m.yaml
> index 9f14cfe7efd1..d016808f65cb 100644
> --- a/Documentation/devicetree/bindings/gnss/u-blox,neo-6m.yaml
> +++ b/Documentation/devicetree/bindings/gnss/u-blox,neo-6m.yaml
> @@ -67,7 +67,7 @@ examples:
> compatible = "u-blox,neo-8";
> v-bckp-supply = <&gnss_v_bckp_reg>;
> vcc-supply = <&gnss_vcc_reg>;
> - reset-gpios = <&gpio 1 GPIO_ACTIVE_LOW>;
> - safeboot-gpios = <&gpio 2 GPIO_ACTIVE_LOW>;
> + reset-gpios = <&gpio 1 (GPIO_ACTIVE_LOW | GPIO_OPEN_DRAIN)>;
> + safeboot-gpios = <&gpio 2 (GPIO_ACTIVE_LOW | GPIO_OPEN_DRAIN)>;
> };
> };
> --
> 2.51.0
>
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