From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7B749350A21; Fri, 23 Jan 2026 09:28:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769160509; cv=none; b=PcWZYRSGYIxTDtFr/BMZedjMKT9SsAkjJBEUgao+cM0oSPYhbyI5UolbSvUwrdXRf1kg2Zg195g7e2xQjfalZMl/6sSGDIWnPXIwGRcs8s4TamFt8xyrk/67gXeAGn0JwAtzZPcai8jkj0qB79qxIjZKV/YWY7haeoElzA1S5IQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769160509; c=relaxed/simple; bh=ke87CicNIBzJitf1GLyB4AYrViCw7+226adczwrhkyk=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=DoW4QVO1L7lTJT+GlWrFg2NhUnt3mPAGqYvEBCdoLf7GBDngQdlwsSXYgEwWDCsi35BZXOA1Emt9RPRQHxeyPd4pgeYsj8I1rFmWr4eqnMbR37VMoznqZJXxfGzUYcvQzNiy8CFCnM7Rwi66D9zEqhb2af4RtFpk0xGvMdYjZmw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=J2uLL95l; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="J2uLL95l" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EA177C4CEF1; Fri, 23 Jan 2026 09:28:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769160509; bh=ke87CicNIBzJitf1GLyB4AYrViCw7+226adczwrhkyk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=J2uLL95ltP1whHjryoLrROiuLH8HtUt6oyF8O1TPoUfIlhSsWJYNFRG2l9OXyGZti mzxGH0CNKlO4GaDEG4FcrevKsvzPk8dNACpXAlmPaWsF8ibDAgdG7Io+hFwsBH9VL1 LKC0AHV58OBpxyY77CsZWeLk122kv1i4s02dxnRt86uK9vGWdKZfLwMnRVhn2CQZou EqhfVAqy//OI5SrF/fHlKTY9101Wb5Hg4ce+EzvHAG1sz58gnyNRzhAPq9pOunokaV Hg+3fmJ3ZizR0rUNvvJ7uyghaWcBj2ACQji8qv0AaeJmH5JjqWSSP/EgQMjG8FVnB7 rQE+FwkvgmVHw== Date: Fri, 23 Jan 2026 09:28:19 +0000 From: Jonathan Cameron To: Conor Dooley Cc: Oleksij Rempel , Rob Herring , Krzysztof Kozlowski , Conor Dooley , kernel@pengutronix.de, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, Andy Shevchenko , David Lechner , Nuno =?UTF-8?B?U8Oh?= , David Jander Subject: Re: [PATCH v1 2/8] dt-bindings: iio: dac: maxim,ds4424: add maxim,rfs-ohms property Message-ID: <20260123092819.6ae81211@jic23-huawei> In-Reply-To: <20260119-turbine-feminize-9dcd5c86feec@spud> References: <20260119182424.1660601-1-o.rempel@pengutronix.de> <20260119182424.1660601-3-o.rempel@pengutronix.de> <20260119-turbine-feminize-9dcd5c86feec@spud> X-Mailer: Claws Mail 4.3.1 (GTK 3.24.51; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@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 Mon, 19 Jan 2026 18:27:52 +0000 Conor Dooley wrote: > On Mon, Jan 19, 2026 at 07:24:18PM +0100, Oleksij Rempel wrote: > > Introduce the 'maxim,rfs-ohms' property. The full-scale output current > > of these DACs is determined by external resistors (Rfs) connected to > > the FS pins. The driver requires the physical resistance values to > > calculate the correct current scale (Amps per step) for the IIO > > subsystem. > > > > Keep it optional to avoid forcing updates of existing DTs; without it > > the driver cannot derive a correct IIO scale. > > I don't really follow the logic here, if the driver doesn't work > properly without it, shouldn't it be a required property even if that > means existing devicetrees get new warnings? Warnings are preferable to > the drivers malfunctioning on those devices, after all! Agreed. The driver can paper over holes or I guess we could provide a default if the datasheet has some reference value or similar? DT binding should require it. > > > > > Signed-off-by: Oleksij Rempel > > --- > > .../devicetree/bindings/iio/dac/maxim,ds4424.yaml | 11 +++++++++++ > > 1 file changed, 11 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/iio/dac/maxim,ds4424.yaml b/Documentation/devicetree/bindings/iio/dac/maxim,ds4424.yaml > > index efe63e6cb55d..b7af8464a4fc 100644 > > --- a/Documentation/devicetree/bindings/iio/dac/maxim,ds4424.yaml > > +++ b/Documentation/devicetree/bindings/iio/dac/maxim,ds4424.yaml > > @@ -27,6 +27,17 @@ properties: > > > > vcc-supply: true > > > > + maxim,rfs-ohms: > > + description: | > > + Array of resistance values in Ohms for the external Rfs resistors > > + connected to the FS pins. > > + - For DS44x2 (2 channels): 2 values required. > > + - For DS44x4 (4 channels): 4 values required. > > + Typical values range from 40000 (40 kOhm) to 160000 (160 kOhm). > > + minItems: 2 > > + maxItems: 4 > > + $ref: /schemas/types.yaml#/definitions/uint32-array > > + > > required: > > - compatible > > - reg > > -- > > 2.47.3 > >