From mboxrd@z Thu Jan 1 00:00:00 1970 From: Miquel RAYNAL Subject: Re: [PATCH 16/16] arm64: dts: marvell: armada-3720-espressobin: fill UART nodes Date: Mon, 9 Oct 2017 09:30:25 +0200 Message-ID: <20171009093025.78d45a9a@xps13> References: <20171006101344.15590-1-miquel.raynal@free-electrons.com> <20171006101344.15590-17-miquel.raynal@free-electrons.com> <87fuawe8gx.fsf@free-electrons.com> <20171006151521.440418a2@windsurf.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Return-path: Received: from mail.free-electrons.com ([62.4.15.54]:46598 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750930AbdJIHa2 (ORCPT ); Mon, 9 Oct 2017 03:30:28 -0400 In-Reply-To: <20171006151521.440418a2@windsurf.lan> Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Thomas Petazzoni Cc: Gregory CLEMENT , Greg Kroah-Hartman , Linus Walleij , Jason Cooper , Andrew Lunn , Sebastian Hesselbarth , Jiri Slaby , Catalin Marinas , Will Deacon , linux-serial@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-gpio@vger.kernel.org, Antoine Tenart , Nadav Haklai , Wilson Ding Hi Thomas, Gregory, On Fri, 6 Oct 2017 15:15:21 +0200 Thomas Petazzoni wrote: > Hello, > > On Fri, 06 Oct 2017 15:01:18 +0200, Gregory CLEMENT wrote: > > > /* > > * To enable the second UART on J17 (pins 24,26) refer to the uart1 > > * node from armada-3720-db.dts. > > * Note that TX and RX signal are the ones coming directly from > > the SoC: > > * 1.8V TTL. > > */ > > One issue with this comment (and Miquèl's version as well) is that it > does not explain why you don't enable this UART by default. > > The real reason is in the commit log from Miquèl, and should probably > be part of the comment. Perhaps something like: > > /* > > * Connector J17 (pins X, Y, Z) exposes a number of different > * features: > * - UART1 (pins 24 = RX, pins 26 = TX), see armada-3720-db.dts for > an > * example on how to enable UART1. Beware that the signals are 1.8V > * TTL. > * - SPIxyz > * - I2Cxyz > */ Thanks for both your comments, there is my version, inspired from both comments: /* * Connector J17 exposes a number of different features. Some pins are * multiplexed. This is the case for the UART1 feature (pins 24 = RX, * pins 26 = TX). See armada-3720-db.dts for an example of how to enable it. * Beware that the signals are 1.8V TTL. */ Thanks, Miquèl > > Otherwise, it's not clear at all why you don't just enable UART1. Or > perhaps I misunderstood Miquèl's commit log ? > > Best regards, > > Thomas -- Miquel Raynal, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com From mboxrd@z Thu Jan 1 00:00:00 1970 From: miquel.raynal@free-electrons.com (Miquel RAYNAL) Date: Mon, 9 Oct 2017 09:30:25 +0200 Subject: [PATCH 16/16] arm64: dts: marvell: armada-3720-espressobin: fill UART nodes In-Reply-To: <20171006151521.440418a2@windsurf.lan> References: <20171006101344.15590-1-miquel.raynal@free-electrons.com> <20171006101344.15590-17-miquel.raynal@free-electrons.com> <87fuawe8gx.fsf@free-electrons.com> <20171006151521.440418a2@windsurf.lan> Message-ID: <20171009093025.78d45a9a@xps13> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Thomas, Gregory, On Fri, 6 Oct 2017 15:15:21 +0200 Thomas Petazzoni wrote: > Hello, > > On Fri, 06 Oct 2017 15:01:18 +0200, Gregory CLEMENT wrote: > > > /* > > * To enable the second UART on J17 (pins 24,26) refer to the uart1 > > * node from armada-3720-db.dts. > > * Note that TX and RX signal are the ones coming directly from > > the SoC: > > * 1.8V TTL. > > */ > > One issue with this comment (and Miqu?l's version as well) is that it > does not explain why you don't enable this UART by default. > > The real reason is in the commit log from Miqu?l, and should probably > be part of the comment. Perhaps something like: > > /* > > * Connector J17 (pins X, Y, Z) exposes a number of different > * features: > * - UART1 (pins 24 = RX, pins 26 = TX), see armada-3720-db.dts for > an > * example on how to enable UART1. Beware that the signals are 1.8V > * TTL. > * - SPIxyz > * - I2Cxyz > */ Thanks for both your comments, there is my version, inspired from both comments: /* * Connector J17 exposes a number of different features. Some pins are * multiplexed. This is the case for the UART1 feature (pins 24 = RX, * pins 26 = TX). See armada-3720-db.dts for an example of how to enable it. * Beware that the signals are 1.8V TTL. */ Thanks, Miqu?l > > Otherwise, it's not clear at all why you don't just enable UART1. Or > perhaps I misunderstood Miqu?l's commit log ? > > Best regards, > > Thomas -- Miquel Raynal, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com