From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2132B7EF05; Tue, 30 Jan 2024 23:02:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706655743; cv=none; b=oCBHIXrA6SCJeI1gpauv9zY4kHkEtUpkP5CFwaUvJ7XsepTqyxOTkltiuILsDmrEOLdP9VSHtLoBsudNxpIn6MhbbUFcAv7AGgNRWbvprJaxbA0lVIiH7vWwedFzIk9QgPoPwYarddnanr/xjZKWIjjuV6Nl7EbA4QEGqUidQ6Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706655743; c=relaxed/simple; bh=Q/5sVxq0UBbAMtH5axjn8/3c/o19Bpt/DiCP+LgTKhU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=UCIiijdBtXEfcoI4xV3ubwnd6KL2Jtvv+stRxmN/LOMNHgOXqRFZFgnSc+nSJOrCkwE/hpPdbZM/f9cKRSS8Pq0zm4RdwaF93LtejQ7e/J6KjnfS3tAzKqPUC8AR3lxNZightvzUGG39zWYVy1MTk/Qv0nTxucSb7oK1zw34MNk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bFFzWkI2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bFFzWkI2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D7FAC433F1; Tue, 30 Jan 2024 23:02:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1706655742; bh=Q/5sVxq0UBbAMtH5axjn8/3c/o19Bpt/DiCP+LgTKhU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bFFzWkI23nEDrljXibfFpeh//ZhwiOaUzuVPkBQ2abO2/Y9SHQejdGt/YabotelJQ zi9/4pjDB+6508q+ONxNgxvAlj3y9j54UOIxYBvV6+sdgZIvDTqEqBQbgGBf0ly5zC ZLHiVvyOR2kz+RkZ2Y0XvD37h3WAEkdrxwH0Tgy4pGMD2XmUs4ev4Oje1ZkeMG58yz XL9n6vtKfCoTsoFTpvUdpkS2sA/oASkFLEpiBZvbgFwrLFGraThwDpZ8t/ihP0ZXrZ Guwib0fCCB/9i5WEUXw+doqTL8urbagZHfBMV+dgNE7fRoL5Csn3hprI0zPV39sdDr FRKUgu27RaEoA== Date: Tue, 30 Jan 2024 17:02:20 -0600 From: Rob Herring To: Farouk Bouabid Cc: Greg Kroah-Hartman , Jiri Slaby , Krzysztof Kozlowski , Conor Dooley , Heiko Stuebner , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, quentin.schulz@theobroma-systems.com Subject: Re: [PATCH v5 3/6] dt-bindings: serial: add binding for rs485 rx-enable state when rs485 is disabled Message-ID: <20240130230220.GA2569797-robh@kernel.org> References: <20240126-dev-rx-enable-v5-0-5d934eda05ca@theobroma-systems.com> <20240126-dev-rx-enable-v5-3-5d934eda05ca@theobroma-systems.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240126-dev-rx-enable-v5-3-5d934eda05ca@theobroma-systems.com> On Fri, Jan 26, 2024 at 06:27:44PM +0100, Farouk Bouabid wrote: > RS485 can have a receiver-enable gpio (rx-enable-gpios). When rs485 is s/gpio/GPIO/ > enabled, this gpio, if provided, must be driven active while receiving. > However when RS485 is disabled this gpio should not have an undefined > state. In that case, as DE and RE pins can be connected both to this gpio, > if its state is not properly defined, can cause unexpected transceiver > behavior. > This binding depend on rx-enable-gpios to be implemented. Sounds like a constraint: dependencies: rs485-rx-enable-inactive-when-rs485-disabled: [ rx-enable-gpios ] > > Signed-off-by: Farouk Bouabid > --- > Documentation/devicetree/bindings/serial/rs485.yaml | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/Documentation/devicetree/bindings/serial/rs485.yaml b/Documentation/devicetree/bindings/serial/rs485.yaml > index b64577036b5c..4c79dfaaf460 100644 > --- a/Documentation/devicetree/bindings/serial/rs485.yaml > +++ b/Documentation/devicetree/bindings/serial/rs485.yaml > @@ -55,6 +55,11 @@ properties: > description: GPIO to handle a separate RS485 receive enable signal > maxItems: 1 > > + rs485-rx-enable-inactive-when-rs485-disabled: For something a bit shorter, perhaps: rs485-rx-enable-inactive-on-disable > + description: rx-enable GPIO is not active when RS485 is disabled. If missing, active-state > + is assumed. > + $ref: /schemas/types.yaml#/definitions/flag > + > rs485-term-gpios: > description: GPIO pin to enable RS485 bus termination. > maxItems: 1 > > -- > 2.34.1 >