From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 802AAECAAA1 for ; Thu, 27 Oct 2022 12:08:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:In-Reply-To:References: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=WvZdgX1fb29NHjTOG8GhQVj1NNeJmgdSRHLrDJFyg/s=; b=UqN3L2hSUAHXrP cgX2E4VZWdbS1QLLQy/XoH6qRpcX6AHLdhNLUQoJ0jQXTtSvYEElBMbs+OuF+m5XZOM6gB/XNTUH0 Zo6cUp9RQgQS8t2eQLe2u1GzYty2DQUXzd3K/vg8Z2f49+gdRD4L7oU/Tcc0irF50aGxTRNOnydKn 3xvqf2t52sI5yCWBA1uI3IRyqFFUEbWdiO9sSgEovFUmZvJ9L4MXVbCYomqFiBGruWqNpvgQPU6Ex lA+4UD56pRzrQYNaXMtRTQT49TCoZskDfQ5InmINZbjUArsTz6D8QO+zch446v6aWBiBMFpGL4g72 suEOwsEsojxNC+L6QjrQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oo1fl-00D7qs-2j; Thu, 27 Oct 2022 12:07:45 +0000 Received: from mx2.securetransport.de ([188.68.39.254]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oo1fh-00D7pj-Va for linux-arm-kernel@lists.infradead.org; Thu, 27 Oct 2022 12:07:44 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dh-electronics.com; s=dhelectronicscom; t=1666872427; bh=0Q4WJMmZYsuUKZ8ySwv4DXKxGRJk55X3Hf7mKSpKNDQ=; h=From:To:CC:Subject:Date:References:In-Reply-To:From; b=B6sUo8Km4GOi1Cb8DX0wdQbr9d9j/oO4cihb4EKeFqhOztCdkXXbKsrodZjSMvHuB m56S6k0LrwTs5esNtNyEneTHJ85SWnLIzOE4g+uYpZLiiWd8/lafnMsDAyjz2aD+Y2 kv4/2iaMY4sY11XiNbiDVRmlu/N4eKFYz/9mkEz1OGToJCm5YjMrThghkkqCemgckZ /AqwKN/HxqhVAdCCuSUaK0UCsBdLgbPCdKnvoyNcVjsDyKRiJnAvEOGdNGG1TWTDEt jzakv2BgzP+FLIqgO5RWv1lU9FegwN5hZfssOMMV4ralfZYuFlIMznIfcFrGwcJo64 bsKrPCqDkIsdA== X-secureTransport-forwarded: yes From: Christoph Niedermaier Complaints-To: abuse@cubewerk.de To: Rob Herring CC: "linux-serial@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "krzysztof.kozlowski+dt@linaro.org" , "marex@denx.de" , "jirislaby@kernel.org" , Greg Kroah-Hartman , "devicetree@vger.kernel.org" Subject: RE: [PATCH 1/4] dt_bindings: rs485: Add binding for GPIO that controls Rx enable during Tx Thread-Topic: [PATCH 1/4] dt_bindings: rs485: Add binding for GPIO that controls Rx enable during Tx Thread-Index: AQHY6VtPL1dpKjxCfE69ES0JgWopKq4hB10AgADJ5GA= Date: Thu, 27 Oct 2022 12:06:56 +0000 Message-ID: References: <20221026165049.9541-1-cniedermaier@dh-electronics.com> <20221026165049.9541-2-cniedermaier@dh-electronics.com> <20221026205914.GA1294440-robh@kernel.org> In-Reply-To: <20221026205914.GA1294440-robh@kernel.org> Accept-Language: de-DE, en-US Content-Language: de-DE X-MS-Has-Attach: X-MS-TNEF-Correlator: MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221027_050742_357256_2A2FD49A X-CRM114-Status: GOOD ( 20.17 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Rob Herring [mailto:robh@kernel.org] Sent: Wednesday, October 26, 2022 10:59 PM > On Wed, Oct 26, 2022 at 06:50:46PM +0200, Christoph Niedermaier wrote: >> Add the binding for a generic definition of a GPIO, that controls whether Rx >> is connected or disconnected by an electrical circuit to have the ability >> to receive the signals on the bus during sending or disable receiving during >> sending. >> >> Signed-off-by: Christoph Niedermaier >> --- >> Cc: Greg Kroah-Hartman >> Cc: Rob Herring >> Cc: Krzysztof Kozlowski >> Cc: Marek Vasut >> Cc: devicetree@vger.kernel.org >> To: linux-serial@vger.kernel.org >> To: linux-arm-kernel@lists.infradead.org >> --- >> Documentation/devicetree/bindings/serial/rs485.yaml | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/serial/rs485.yaml b/Documentation/devicetree/bindings/serial/rs485.yaml >> index 90a1bab40f05..0ebd7690f85d 100644 >> --- a/Documentation/devicetree/bindings/serial/rs485.yaml >> +++ b/Documentation/devicetree/bindings/serial/rs485.yaml >> @@ -51,6 +51,10 @@ properties: >> description: GPIO pin to enable RS485 bus termination. >> maxItems: 1 >> >> + rs485-rx-during-tx-gpios: >> + description: GPIO pin to control RS485 Rx enable during Tx. > > Active state means do what? And inactive? This is an output gating the > RX signal or an input telling the receiver what to do during tx? The > description is not adequate. > > How does this property relate to 'rs485-rx-during-tx' Any combination of > the 2 being present or not is okay? If not, you need some constraints. > > Rob Hi Rob, I have improved the message: The standard RS485 is a half-duplex bus that in most cased is driven by an UART controller. The interface to the bus is controlled by a transceiver, that has a pin called RE (Rx enable) or similar, which connects the bus to Rx signal of the UART controller. This patch adds a binding for a generic definition of a GPIO that can switch between two states to control the RE pin via an electrical circuit: - Active: The RE pin is always active. The UART Rx see everything on the bus and therefore also what happens with the Tx signal on the bus. - Inactive: The RE pin is always active, but during sending on the bus the pin RE is inactive. So basically the receiving during sending is suppressed. Is it now more understandable, or have I still not considered an aspect? Thanks and regards Christoph _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel