From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (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 C57051C693; Tue, 26 Mar 2024 17:13:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711473208; cv=none; b=OlLdGGH87ipYWGDR0u6GtOf48YF8azH2X3Aagxo5ZxFPRXALWmSwN3NjGqF6O+K9o+a89610h1c/a4VSDAiQPXb+x8WGxq16hU+USZjUf/1Bspeb6vsO/OZuxyWtMSYbX9JNKCpRLmdkyaOBgf7PGXkn7K1lTt7FUewhENQRyP0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711473208; c=relaxed/simple; bh=MnzMXAzZV1h7sUIdg5Aeq4kt19V4kaa+bzh/Anm4CGE=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=lQVM3FBPbhLfitugcH1VRsvXuvn14cOaOZ0AuKUwzY5OJZyzd78yMKmMFiK3UWR2SeyNJMvSaVkTLx74uTZ11p/6nD4dOzteqsSojVAUnfeHCOwin4Z+6PRWqFMapoQNP+zjPzG0VmeLiBWilaHQr9bi+9LjttwUgDSVwTdy+hc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=Huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=Huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.186.31]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4V3x8z72w7z6K9KK; Wed, 27 Mar 2024 01:08:51 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (unknown [7.191.163.240]) by mail.maildlp.com (Postfix) with ESMTPS id EC4C6140594; Wed, 27 Mar 2024 01:13:17 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.35; Tue, 26 Mar 2024 17:13:17 +0000 Date: Tue, 26 Mar 2024 17:13:16 +0000 From: Jonathan Cameron To: Laurent Pinchart CC: Jonathan Cameron , , , , "Trevor Zaharichuk" , Greg Lytle , "Lars-Peter Clausen" , Rob Herring , "Krzysztof Kozlowski" , Conor Dooley , Sean Nyekjaer , Subject: Re: [PATCH 1/5] dt-bindings: iio: dac: ti,dac5571: Add DAC081C081 support Message-ID: <20240326171316.000018f5@Huawei.com> In-Reply-To: <20240326165043.GB28895@pendragon.ideasonboard.com> References: <20240325203245.31660-1-laurent.pinchart@ideasonboard.com> <20240325203245.31660-2-laurent.pinchart@ideasonboard.com> <20240325204857.4f2fd468@jic23-huawei> <20240325205641.GD23988@pendragon.ideasonboard.com> <20240326152927.00006229@Huawei.com> <20240326165043.GB28895@pendragon.ideasonboard.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: lhrpeml100006.china.huawei.com (7.191.160.224) To lhrpeml500005.china.huawei.com (7.191.163.240) On Tue, 26 Mar 2024 18:50:43 +0200 Laurent Pinchart wrote: > On Tue, Mar 26, 2024 at 03:29:27PM +0000, Jonathan Cameron wrote: > > On Mon, 25 Mar 2024 22:56:41 +0200 Laurent Pinchart wrote: =20 > > > On Mon, Mar 25, 2024 at 08:48:57PM +0000, Jonathan Cameron wrote: =20 > > > > On Mon, 25 Mar 2024 22:32:41 +0200 Laurent Pinchart wrote: > > > > =20 > > > > > The DAC081C081 is a TI DAC whose software interface is compatible= with > > > > > the DAC5571. It is the 8-bit version of the DAC121C081, already > > > > > supported by the DAC5571 bindings. Extends the bindings to suppor= t this > > > > > chip. > > > > >=20 > > > > > Signed-off-by: Laurent Pinchart =20 > > > >=20 > > > > Hi Laurent, > > > >=20 > > > > Given it's a part number where no one is going to guess it is compa= tible > > > > with the DAC5571 and that we don't have a history of fallback compa= tibles > > > > I'm fine with this change, but just wanted to ask is a fallback com= patible > > > > useful to you to run with older kernels? > > > >=20 > > > > I should have noticed when Peter added the dac121c081. If we add a = fallback > > > > should do that one as well. =20 > > >=20 > > > I've indeed noticed that there should have been a fallback for > > > dac121c081, but didn't stop to ponder why that wasn't the case, and j= ust > > > went along with the flow :-) I agree a fallback could be useful, which > > > would then allow dropping patch 2/5 from this series (*). I can do so= if > > > you prefer. > > >=20 > > > * This is not entirely true. While the DAC1081C081 is largely compati= ble > > > with the DAC5573, they have different values for one of the power-down > > > resistors (2.5k=CE=A9 instead of 1k=CE=A9 if I recall correctly). To = be completely > > > accurate, the driver should report that. We could still use the fallb= ack > > > compatible, reporting the wrong power-down resistor value. =20 > >=20 > > Hmm - Would anyone really care about that value being wrong? =20 >=20 > I don't have enough expertise with IIO to be sure, but my guess is that > nobody would. >=20 > > I think perhaps that's just about significant enough that maybe a fallb= ack > > compatible doesn't make sense here. =20 >=20 > Then let's keep it simple and just merge this patch as-is ? :-) Makes sense. I'm on wrong computer at the moment but will pick it up at weekend if not before. Jonathan >=20 > > > > > --- > > > > > Documentation/devicetree/bindings/iio/dac/ti,dac5571.yaml | 1 + > > > > > 1 file changed, 1 insertion(+) > > > > >=20 > > > > > diff --git a/Documentation/devicetree/bindings/iio/dac/ti,dac5571= .yaml b/Documentation/devicetree/bindings/iio/dac/ti,dac5571.yaml > > > > > index 79da0323c327..e59db861e2eb 100644 > > > > > --- a/Documentation/devicetree/bindings/iio/dac/ti,dac5571.yaml > > > > > +++ b/Documentation/devicetree/bindings/iio/dac/ti,dac5571.yaml > > > > > @@ -21,6 +21,7 @@ properties: > > > > > - ti,dac5573 > > > > > - ti,dac6573 > > > > > - ti,dac7573 > > > > > + - ti,dac081c081 > > > > > - ti,dac121c081 > > > > > =20 > > > > > reg: =20 >=20