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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AADD2C61DA4 for ; Fri, 3 Feb 2023 14:13:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233656AbjBCONn (ORCPT ); Fri, 3 Feb 2023 09:13:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58332 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233074AbjBCON0 (ORCPT ); Fri, 3 Feb 2023 09:13:26 -0500 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4E3141DB9E for ; Fri, 3 Feb 2023 06:12:32 -0800 (PST) Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1pNwnb-0005rJ-S7; Fri, 03 Feb 2023 15:12:19 +0100 Received: from mfe by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1pNwnZ-0003oW-PY; Fri, 03 Feb 2023 15:12:17 +0100 Date: Fri, 3 Feb 2023 15:12:17 +0100 From: Marco Felsch To: Alexander Stein Cc: Jonathan Cameron , Cai Huoqing , Haibo Chen , Lars-Peter Clausen , Rob Herring , Krzysztof Kozlowski , Shawn Guo , Sascha Hauer , Fabio Estevam , devicetree@vger.kernel.org, linux-iio@vger.kernel.org, NXP Linux Team , Pengutronix Kernel Team , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 1/1] dt-bindings: iio: adc: add missing vref-supply Message-ID: <20230203141217.et55oxbtxcilg3ig@pengutronix.de> References: <20230131101323.606931-1-alexander.stein@ew.tq-group.com> <20230201121343.vk2t2dfpbvhflols@pengutronix.de> <20230202171052.502ec666@jic23-huawei> <1922814.PYKUYFuaPT@steina-w> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1922814.PYKUYFuaPT@steina-w> User-Agent: NeoMutt/20180716 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: mfe@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: devicetree@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi, On 23-02-03, Alexander Stein wrote: ... > > > > > > + vref-supply: > > > > > > + description: External ADC reference voltage supply on VREFH > > > > > > pad. > > > > > > > > > > Please add it to the list of required properties, we can remove it as > > > > > soon as the driver has support for the internal reference voltages. > > > > > > > > I was thinking in doing so before as well. But DT describes the > > > > hardware, and this ADC apparently would be functioning without a > > > > reference voltage on that pad, using a different one. What the driver > > > > actual does is a different matter.> > > > I have also thought about it first but than I checked the RM which says > > > that "multi-reference selection" is chip dependent. > > Nice for pointing this out. I wasn't aware that there are differences. > > > Oh goody. So is it detectable? > > That's my problem. I didn't find any source of information which chips do > support multiple references and which don't. > Marco, do you have some information on this? You can download the RM from the NXP website but you need an account for it: https://www.nxp.com/products/processors-and-microcontrollers/arm-processors/i-mx-applications-processors/i-mx-8-applications-processors/i-mx-8-family-arm-cortex-a53-cortex-a72-virtualization-vision-3d-graphics-4k-video:i.MX8 Or is this the wrong model? The naming scheme is quite confusing to me. > > If we are going to stick to a single compatible rather than adding them for > > the variants with and without this feature, should probably add a note at > > least to say it is required for some parts. > > That's a good idea. I'm okay with that, until there is more information > available. According the RM there is a bit which can be read: Multi Vref Implemented (MVI). Regards, Marco 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 0EBA9C61DA4 for ; Fri, 3 Feb 2023 14:27:26 +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:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=TTnKpXr1gLcyN8vkAAWUM2GpR49gZ8no1MipL4TFoFA=; b=es96kJugzeffit 9RiG0WQUXQBvIr75Xll1RE/TCLprQTJqq/NqUVc+DWxjIRvhhsGJlAreWrgq2/6QiZh50MLfJr4cT xO+eQj1yxNl4Mp44TlHXOqwB/WiOzG+Iiworhgcc5uq5EhWNUhdXcbsgHywhjpGoSDd8Qjpcmnq0M ShmJNrSIf5lhmV3imS/BXhqwhjRL8xcJu3Mvu/Ynr10gBNaXVdAr/O3lsXTAhZ85vbETz4HPrVdl3 ZKiE2XoWaOZ/4i7bVE5y+MmGVm2iGZjRzf0Y+GjKgHHJnLBaKff5JRCDsX/Fe9Ih5ianl0QlQGxzK 6YmlaU6bVSRjiaYDCJSw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pNx1A-002PXY-Nm; Fri, 03 Feb 2023 14:26:21 +0000 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pNwnw-002Inw-A8 for linux-arm-kernel@lists.infradead.org; Fri, 03 Feb 2023 14:12:46 +0000 Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1pNwnb-0005rJ-S7; Fri, 03 Feb 2023 15:12:19 +0100 Received: from mfe by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1pNwnZ-0003oW-PY; Fri, 03 Feb 2023 15:12:17 +0100 Date: Fri, 3 Feb 2023 15:12:17 +0100 From: Marco Felsch To: Alexander Stein Cc: Jonathan Cameron , Cai Huoqing , Haibo Chen , Lars-Peter Clausen , Rob Herring , Krzysztof Kozlowski , Shawn Guo , Sascha Hauer , Fabio Estevam , devicetree@vger.kernel.org, linux-iio@vger.kernel.org, NXP Linux Team , Pengutronix Kernel Team , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 1/1] dt-bindings: iio: adc: add missing vref-supply Message-ID: <20230203141217.et55oxbtxcilg3ig@pengutronix.de> References: <20230131101323.606931-1-alexander.stein@ew.tq-group.com> <20230201121343.vk2t2dfpbvhflols@pengutronix.de> <20230202171052.502ec666@jic23-huawei> <1922814.PYKUYFuaPT@steina-w> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1922814.PYKUYFuaPT@steina-w> User-Agent: NeoMutt/20180716 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: mfe@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-arm-kernel@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230203_061240_400407_933AF130 X-CRM114-Status: GOOD ( 29.96 ) 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 Hi, On 23-02-03, Alexander Stein wrote: ... > > > > > > + vref-supply: > > > > > > + description: External ADC reference voltage supply on VREFH > > > > > > pad. > > > > > > > > > > Please add it to the list of required properties, we can remove it as > > > > > soon as the driver has support for the internal reference voltages. > > > > > > > > I was thinking in doing so before as well. But DT describes the > > > > hardware, and this ADC apparently would be functioning without a > > > > reference voltage on that pad, using a different one. What the driver > > > > actual does is a different matter.> > > > I have also thought about it first but than I checked the RM which says > > > that "multi-reference selection" is chip dependent. > > Nice for pointing this out. I wasn't aware that there are differences. > > > Oh goody. So is it detectable? > > That's my problem. I didn't find any source of information which chips do > support multiple references and which don't. > Marco, do you have some information on this? You can download the RM from the NXP website but you need an account for it: https://www.nxp.com/products/processors-and-microcontrollers/arm-processors/i-mx-applications-processors/i-mx-8-applications-processors/i-mx-8-family-arm-cortex-a53-cortex-a72-virtualization-vision-3d-graphics-4k-video:i.MX8 Or is this the wrong model? The naming scheme is quite confusing to me. > > If we are going to stick to a single compatible rather than adding them for > > the variants with and without this feature, should probably add a note at > > least to say it is required for some parts. > > That's a good idea. I'm okay with that, until there is more information > available. According the RM there is a bit which can be read: Multi Vref Implemented (MVI). Regards, Marco _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel