From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (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 98DCB2F2D; Mon, 25 Mar 2024 20:56:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711400212; cv=none; b=baBtFtWQT9m7dpDPYaR+48lc0JKJrAzA4KQ45wWx3fZFAthzBkUjvWkXkejvTHFZa/efGspNL3xU3sbhWSZXeIQDJIz+YpTdKD/Fu8HozRqpxfsqiBrFblO71EMOrCTT2eL2tMSFxSLn7K5q2d9UJePRMuGkq7MHORKjRHc8Klk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711400212; c=relaxed/simple; bh=jZAaZSV8+oeKiKviZ1HtHAmT0OJ5cJAbq/XwTAhv4Z4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AM2dmk7gYY6fMUqDwUTRXv6hG3w3yP+ohiG14E5d6qrxn7uCFBpTvB7UmgoI5fPm4TQQhCyX7ArH2Gli7qqcn+fUyDL5Gv67cr0CYMvofgAgmlvssiI3ZutdiXrBJGVRltTWBgg9EvXG+maGHlr/HCwNmgyBB0i+HZFgAobqjes= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=WkH5Ay4Y; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="WkH5Ay4Y" Received: from pendragon.ideasonboard.com (81-175-209-231.bb.dnainternet.fi [81.175.209.231]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id E4DBC7E4; Mon, 25 Mar 2024 21:56:17 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1711400178; bh=jZAaZSV8+oeKiKviZ1HtHAmT0OJ5cJAbq/XwTAhv4Z4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WkH5Ay4YO65Efcg8u+F3/kraIMLvPDeJo/fzZf51YWL3VgPRDsc+cFPhDTiD6eBZT m4Gl67UD6OVYRs5tS+4GWkTR3FReLcNPdrV29i8Okyz6jJcy3aHj6YGNj1R0buhf0z qnqQBXINhnHz5v2pojkw/D4bAG6n1prJr9TrCiYs= Date: Mon, 25 Mar 2024 22:56:41 +0200 From: Laurent Pinchart To: Jonathan Cameron Cc: devicetree@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Trevor Zaharichuk , Greg Lytle , Lars-Peter Clausen , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Sean Nyekjaer , linux-iio@vger.kernel.org Subject: Re: [PATCH 1/5] dt-bindings: iio: dac: ti,dac5571: Add DAC081C081 support Message-ID: <20240325205641.GD23988@pendragon.ideasonboard.com> References: <20240325203245.31660-1-laurent.pinchart@ideasonboard.com> <20240325203245.31660-2-laurent.pinchart@ideasonboard.com> <20240325204857.4f2fd468@jic23-huawei> 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-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240325204857.4f2fd468@jic23-huawei> Hi Jonathan, On Mon, Mar 25, 2024 at 08:48:57PM +0000, Jonathan Cameron wrote: > On Mon, 25 Mar 2024 22:32:41 +0200 Laurent Pinchart wrote: > > > 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 support this > > chip. > > > > Signed-off-by: Laurent Pinchart > > Hi Laurent, > > Given it's a part number where no one is going to guess it is compatible > with the DAC5571 and that we don't have a history of fallback compatibles > I'm fine with this change, but just wanted to ask is a fallback compatible > useful to you to run with older kernels? > > I should have noticed when Peter added the dac121c081. If we add a fallback > should do that one as well. 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 just 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. * This is not entirely true. While the DAC1081C081 is largely compatible with the DAC5573, they have different values for one of the power-down resistors (2.5kΩ instead of 1kΩ if I recall correctly). To be completely accurate, the driver should report that. We could still use the fallback compatible, reporting the wrong power-down resistor value. > > --- > > Documentation/devicetree/bindings/iio/dac/ti,dac5571.yaml | 1 + > > 1 file changed, 1 insertion(+) > > > > 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 > > > > reg: -- Regards, Laurent Pinchart