From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 9824D20E334; Wed, 1 Jul 2026 00:28:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782865727; cv=none; b=GMqnECuRdLoCpFSp7BCPuv1rEzOSYCXgQZEMq/VnhmtldkE47/tUUVZpsLxHZYk3oKqZsHpfzATGy+yzxmUso4ijCq8IQLqP4V2Cms9CU4kX0zXpDijcnmaCXhXQM2MN3Jkt361p+n/3QQnTsEzswigQm87CBiDeHD3F2heMqNo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782865727; c=relaxed/simple; bh=zWxjksPIfxoI6uHdScDSIU4oTXVlyl8ziOx0gjJqN+c=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=NLTK+aJ2/Bqv9Uh1KGearNeynO0MZIHORhdi0gvCegWF26l4uP/jLujqgK7hXQo1npTOu2ALiw7sYnJgF4R3QomYP3r+bnHBiOUkNsz8v0upwMXnoWpHsLB03AffT3dnA486dIbriezWlnvFaSjBWmLvffaueIoqSKeWHmU+gY8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OhD0ATVJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OhD0ATVJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D2C31F000E9; Wed, 1 Jul 2026 00:28:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782865726; bh=5vTPIgjR+M1/x2HvzngY6H3y5OMxpG+8Ki8k0FRaUHQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=OhD0ATVJnBZCxf+wKTX9dVdgks5geXSblUQHQxcgwWg13sf+IhLCebyn5FAluaEqT Vz95yuu2Dl9ts5YcjRCSpbKG6iSzMKZP0rpsOGJjReHUbGG9XT0vQXOecfZC/iC2YQ JN3CgwzAQIynxghnmeNoTWzR9e4LrfZb4T+1lPP3M3sCZd9xVTKOxfrulofHPLH7rN UR97Q5ynoDswAxeqbOMLFEScGzrR3zCNRBYFvNF0Trw/mpv7/NpypVBFjI9W9NaC8V q61rMN5Gpbwlz7KHYfaoacdzD2Sls5UiGjJoE3joDyWm56oN6+8ActlGH4Tss+C6V7 y228S945NN9Jw== Date: Wed, 1 Jul 2026 01:28:42 +0100 From: Jonathan Cameron To: David Lechner Cc: Kurt Borja , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Nuno =?UTF-8?B?U8Oh?= , Andy Shevchenko , linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/7] dt-bindings: iio: adc: Add TI ADS126x ADC family Message-ID: <20260701012842.16272045@jic23-huawei> In-Reply-To: <2a0a9fe9-b3b5-49a0-bf58-5035655fc16d@baylibre.com> References: <20260628-ads126x-v2-0-4b1b231325ba@gmail.com> <20260628-ads126x-v2-1-4b1b231325ba@gmail.com> <946a30c9-01e9-42f1-bd2b-b7934fda85cf@baylibre.com> <22e1e1c2-659c-4991-857c-b38d66769c7e@baylibre.com> <2a0a9fe9-b3b5-49a0-bf58-5035655fc16d@baylibre.com> X-Mailer: Claws Mail 4.4.0 (GTK 3.24.52; x86_64-pc-linux-gnu) 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-Transfer-Encoding: 7bit On Tue, 30 Jun 2026 13:38:30 -0500 David Lechner wrote: > On 6/30/26 12:14 PM, Kurt Borja wrote: > > On Mon Jun 29, 2026 at 11:43 AM -05, David Lechner wrote: > >> On 6/29/26 11:27 AM, Kurt Borja wrote: > >>> On Mon Jun 29, 2026 at 9:21 AM -05, David Lechner wrote: > >>>> On 6/28/26 2:12 PM, Kurt Borja wrote: > >>>>> On Sun Jun 28, 2026 at 10:45 AM -05, David Lechner wrote: > >>>>>> On 6/28/26 12:36 AM, Kurt Borja wrote: > >>>>>>> The ADS1262 and ADS1263 are 32-bit, 38.4-kSPS delta-sigma ADCs with an > >>>>>>> integrated PGA, internal reference, excitation and burn-out current > >>>>>>> sources for sensor biasing and diagnostics. The ADS1263 adds a second, > >>>>>>> 24-bit delta-sigma ADC (ADC2) for background measurements. > >>>>>>> > >>>> > >>>> ... > >>>> > >>>>>>> + > >>>>>>> +patternProperties: > >>>>>>> + "^channel@[0-9]+$": > >>>>>>> + $ref: /schemas/iio/adc/adc.yaml# > >>>>>>> + unevaluatedProperties: false > >>>>>>> + > >>>>>>> + properties: > >>>>>>> + reg: > >>>>>>> + maxItems: 1 > >>>>>>> + > >>>>>> > >>>>>> If we want to allow single-ended/pseudo-differential inputs, then we should > >>>>>> also allow single-channel (positive pin) and common-mode-channel (negative > >>>>>> pin) properties. > >>>>>> > >>>>>> This will also require additional common-mode--supply properties to allow > >>>>>> for the negative pin connected to something other than GND. > >>>>> > >>>>> Ah interesting. Why the N though? wouldn't a single supply connected to > >>>>> AINCOM be enough here? > >>>> > >>>> In theory, any AINx could be a common mode input by connecting it to > >>>> a constant voltage supply. > >>> > >>> Technically yes, but there is a pin named AINCOM intended for this > >>> purpose. Can we do a simplification here? I propose having > >>> > >>> common-mode-channel: > >>> /* AINCOM pin */ > >>> const: 10 > >>> > >>> That way we would only need one common-mode-supply. Would that be okay? > >>> > >> > >> Ideally, we shouldn't limit how the chip can be wired up in the devicetree > >> bindings. It doesn't mean that we have to implement everything in the driver > >> though. I'm a bit confused on this. Arguably you could wire up any side of a differential pair to a common mode signal, but we haven't had this binding applied more generally than cases where their is a setup where the intent is a shared common (shielding on cable in some cases IIRC). So why is this case special? I see AIN_COM can be wired up to an internal vbias but other than that it looks like any other AINX input. Jonathan > > > > Makes sense. > > > > I just have a doubt: In the ADS112c14 bindings, is there a specific > > reason why you didn't describe common-mode--supply? > > > > For singled-ended inputs on ADS112c14, there is an internal > connection to GND, so it isn't possible to have a pseudo- > differential input like that. I guess technically, it could > still be possible, but wasn't a typical wiring described in > the datasheet like it is on ADS1263. >