From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f171.google.com (mail-pf1-f171.google.com [209.85.210.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 208FA253F11 for ; Fri, 5 Dec 2025 21:11:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764969071; cv=none; b=b7d6kvFUBZi58ICMEmsUrrskYwydTGB603eMEzZGPPyDhav87fTpnUAiFKrWqtdIZEPqv/GME22IHvv1Qs/r0KBWCW0DFyklUwkotaiYDfOgY6eMFcWpDQvdUWCQe1kB7WAX8ryTsgmpf70S2c2zUrTvvr50canmFYdNje1DLYU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764969071; c=relaxed/simple; bh=c7c1J1vIUl2RUCCAw3PryaNjjaYVzuxa0pvkJ9f40DI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=uFUDJzZB349V6pRbNdBZXN82E8pJgzHy7I6XCNPKGUTP34ziWYSqMwJKZGPiZpDmaD9TCmxi7XdKPrvQBXkMvPHOnNpebxRAQhGrF12mLJ9bFtAP1FGTa6Zu7s2C0FbvEIkGG+RkUGHHxXCGqLow9e2ztKWFd556/Vln24nwa6w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=ceybAcf1; arc=none smtp.client-ip=209.85.210.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ceybAcf1" Received: by mail-pf1-f171.google.com with SMTP id d2e1a72fcca58-7aace33b75bso2479603b3a.1 for ; Fri, 05 Dec 2025 13:11:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1764969069; x=1765573869; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=9dp9/mKBjgaa+hOS/JhmxBoz56rQ07ceIHhKFiTPWfA=; b=ceybAcf1xwMEFuJCZDVlTScA7kKEa5jiuiR57JEe8KGzDgCc32QHQ5xWIKXxl5Cagj kkpD+s90WFuP1HKGoV8SK66n6aqhMtmDvUzlydMjRHzIOUpbjjy2KK1IML8Q6sEhtlmm 9BvL1Xs7GTyT3RWnfKtoaHUHsFrNz3SS10SaeNFzJj4kCKdsoYhlwEMED2KYi/PxYgej ZqqqXtCEUSjiY8XBgirtFEL/X/mh0CXx5iQ/kypz9IpUOjRhpL4xoSE1A21rLWdoDXUj Fpn/MjU4JISXEdebcB68AY90/MSvE5K6OYBMxiq7U0JAEL0kg0Eyqb1e02gNT6DsY5OZ XWxg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1764969069; x=1765573869; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=9dp9/mKBjgaa+hOS/JhmxBoz56rQ07ceIHhKFiTPWfA=; b=fc2SBhGwKYHcg49sJKyRAOYOLqyHJggAbaQYVB2ogQR3y3YNjsGfBEVX8jl/lqRavA rRmYhlhU6BrVjj5su9fDMzE1wX8WTVNz0hrM+w20zx7qviNqpCu4U5f2WoHJT9NvpF1I 1AFwbyB/8Eagq0nG2/nzysXEhuxM5lewRv+GFLejeIZ/DIsNNP7IeRzIKPZZtnbQOFs5 qNDMAo3UN7h8oYrzbFczLVwk8r3jCIT943PM3O5Tmkdzno6LCCEvihp3fUHIOr6E+l/V AacIavDW7HOsS4xFS58w8AzxCjyJmGJxroGWtV/FiIu1mIKlRtUK0pYHebx1xhEahRB+ Mr3Q== X-Forwarded-Encrypted: i=1; AJvYcCVtXST+Ip0ZX6zW63PypdAQnqPwOvGM5GTfs5qEc8YrIBOg7I5TKKT6EMSc87wIie5/3swFcH7RQwM=@vger.kernel.org X-Gm-Message-State: AOJu0Ywdl04eDTTsQg442ZutIVAU6UXOM/etAP5zpS3JRFjMz9r7vXdc gQXHSPqnsxiFkX+M5tBORpsCSiP64rPgAN5I8dQURwzRBXPa2ba1ISg9 X-Gm-Gg: ASbGncvFj4q6RWWFxolZMus4nYk7auaV0LJGI1jxkGxplvpJmq0Q48OEw1oMY05TjvF gPRBkrBUbLdoaEWek14cBuauIIabDlP9kZcswQ1LgaE/EEgwGLx/a/4B8F7fFQl2MCSK3Ca9ZYd z1b3avSMM3fPu5/U/XkOkGDrZ4pWn6ldv5wXjVGDSeNxAYA0tYK4cVA+qWJ1Qhe/nAgNhxmznct AM82QYsgP+ksE1mJ4BEWlgtOTrX02lk+dueOnphF0J0eYRlCqBEECvVVkRVYcZ924QpyaGmM2VW q58n9GJzM8T8xU9n48257fW6JBaX8QBnxwzU9mymmGcbaQBouDtGnmv1qfWLilYQvjpoo/TxhyR quw6ih5cm4ThaPdMqwPkB8YGArpgS8A/YGVw0VqIVuB2MIdzi8D9WHSBh5DVQjJtf4HR62iK1X5 o9lyapybPzGaH6TqctDqgN X-Google-Smtp-Source: AGHT+IHcEY0Q1FA1vKURG7RgwRQex46GLvAineu1VoXOdKRh8PgkrSImSe/zY+sC4iAx07qvMIjyjw== X-Received: by 2002:a05:7022:4404:b0:119:e569:f60a with SMTP id a92af1059eb24-11e03162d6amr481897c88.3.1764969069289; Fri, 05 Dec 2025 13:11:09 -0800 (PST) Received: from localhost ([2804:30c:2712:fd00:9579:9ff6:e506:6147]) by smtp.gmail.com with UTF8SMTPSA id a92af1059eb24-11df7552211sm21303509c88.1.2025.12.05.13.11.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 05 Dec 2025 13:11:08 -0800 (PST) Date: Fri, 5 Dec 2025 18:12:41 -0300 From: Marcelo Schmitt To: Rob Herring Cc: David Lechner , Mark Brown , Krzysztof Kozlowski , Conor Dooley , Marcelo Schmitt , Michael Hennerich , Nuno =?iso-8859-1?Q?S=E1?= , Jonathan Cameron , Andy Shevchenko , Sean Anderson , linux-spi@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org Subject: Re: [PATCH v3 7/7] dt-bindings: iio: adc: adi,ad4030: add data-lanes property Message-ID: References: <20251201-spi-add-multi-bus-support-v3-0-34e05791de83@baylibre.com> <20251201-spi-add-multi-bus-support-v3-7-34e05791de83@baylibre.com> <20251204213348.GA2198382-robh@kernel.org> Precedence: bulk X-Mailing-List: linux-iio@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: <20251204213348.GA2198382-robh@kernel.org> On 12/04, Rob Herring wrote: > On Mon, Dec 01, 2025 at 08:20:45PM -0600, David Lechner wrote: > > Add data-lanes property to specify the number of data lanes used on the > > ad463x chips that support reading two samples at the same time using > > two data lanes with a capable SPI controller. > > > > Signed-off-by: David Lechner > > --- > > v3 changes: new patch > > > > I added this one to give a real-world use case where spi-rx-bus-width > > was not sufficient to fully describe the hardware configuration. > > > > spi-rx-bus-width = <4>; alone could be be interpreted as either: > > > > +--------------+ +----------+ > > | SPI | | AD4630 | > > | Controller | | ADC | > > | | | | > > | SDIA0 |<---| SDOA0 | > > | SDIA1 |<---| SDOA1 | > > | SDIA2 |<---| SDOA2 | > > | SDIA3 |<---| SDOA3 | > > | | | | > > | SDIB0 |x | SDOB0 | > > | SDIB1 |x | SDOB1 | > > | SDIB2 |x | SDOB2 | > > | SDIB3 |x | SDOB3 | > > | | | | > > +--------------+ +---------+ > > > > or > > > > +--------------+ +----------+ > > | SPI | | AD4630 | > > | Controller | | ADC | > > | | | | > > | SDIA0 |<---| SDOA0 | > > | SDIA1 |<---| SDOA1 | > > | SDIA2 |x | SDOA2 | > > | SDIA3 |x | SDOA3 | > > | | | | > > | SDIB0 |<---| SDOB0 | > > | SDIB1 |<---| SDOB1 | > > | SDIB2 |x | SDOB2 | > > | SDIB3 |x | SDOB3 | > > | | | | > > +--------------+ +---------+ > > > > Now, with data-lanes having a default value of [0] (inherited from > > spi-peripheral-props.yaml), specifying: > > > > spi-rx-bus-width = <4>; > > > > is unambiguously the first case and the example given in the binding > > documentation is the second case: > > > > spi-rx-bus-width = <2>; > > data-lanes = <0>, <1>; > > I just reviewed this and all, but what if you just did: > > spi-rx-bus-width = <2>, <2>; > > So *-bus-width becomes equal to the number of serializers/channels. Unless I'm missing something, I think that would also describe the currently possible use cases as well. To me, it actually seems even more accurate than data-lanes. The data-lanes property only describes the SPI controller input lines/lanes, no info is given about the output lanes. Well yeah, that would only be a problem for a device with multiple input serializers and multiple output serializers. Still, the *-bus-width = , , ... ; notation looks clearer, IMHO. > > Rob >