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 C283D1D6187; Fri, 26 Sep 2025 22:10:22 +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=1758924622; cv=none; b=qpxzLyShQiL+rOMu0g9VXKkTG5xgESDh6moPGCZImcWc5jJwzdMu5T7o28X7dWV0fRVw9UtnnWLOR2bzF0HL/s1JucAKcehLlan5RpReR8ZM8a/ONH9xKbmVAFvYnZj/UHTgKj7DhyMGCv7Fi9IWkNaSRep8XamDhksKPqM1EcU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758924622; c=relaxed/simple; bh=5k5GZfdKV636YzsUk/ZKQso2EF0o1VhSCWjjXGLdNd8=; h=Date:Content-Type:MIME-Version:From:Cc:To:In-Reply-To:References: Message-Id:Subject; b=om6K9Iil56EbMU13q5pOl55b05syf5UtpnFZO64fDSy+w7bq7tlKBJrqERmb+p6jlhPOD9C+veHgosaUHIFch8dlA4T/qulQhjJ1bXeQMAkFUO/SvI/a3/lVfIogM5+ZmBencVIx5GXlIcwajTX+uwsO3k/GEg+Zvfmb+kUVzek= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=a3WbqDKP; 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="a3WbqDKP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7BA93C4CEF4; Fri, 26 Sep 2025 22:10:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758924622; bh=5k5GZfdKV636YzsUk/ZKQso2EF0o1VhSCWjjXGLdNd8=; h=Date:From:Cc:To:In-Reply-To:References:Subject:From; b=a3WbqDKPdhJf1QoUkTz+56eW3S1Bba9SDnT7JxlSE+Gn6GaaB/T/BubJbSug+kCc9 IZow7S6JkAguxSSxdO6qjwFTKzPcYZ/JzVw09iGGMYpAKriDuTHwT+RW772vbZKUp5 J6ab+VpkbXKFj2+6qffQEq0Cg1i/L/D3Rvq5ap8+rwkHNSZqc5hmcavk6qGhuQ6kUB uDBj5h1wUG0aCEYi0qMV8sGATFDA/yhs0EhIE+nAAj8hWOSHExprMuMGt9F6XLuey5 ZjlObPt13DDN3hPVT4IGJlQuhQ4TKjOONyK27mhbZIvwfnI456H09vWZP1ik/9w4eP 66AgRriMNkNvw== Date: Fri, 26 Sep 2025 17:10:21 -0500 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: "Rob Herring (Arm)" Cc: krzk+dt@kernel.org, jic23@kernel.org, conor+dt@kernel.org, corbet@lwn.net, eblanc@baylibre.com, devicetree@vger.kernel.org, nuno.sa@analog.com, andy@kernel.org, linux-kernel@vger.kernel.org, michael.hennerich@analog.com, linux-iio@vger.kernel.org, marcelo.schmitt1@gmail.com, linux-doc@vger.kernel.org, linux-spi@vger.kernel.org, dlechner@baylibre.com To: Marcelo Schmitt In-Reply-To: <5dc08b622dac1db561f26034c93910ccff75e965.1758916484.git.marcelo.schmitt@analog.com> References: <5dc08b622dac1db561f26034c93910ccff75e965.1758916484.git.marcelo.schmitt@analog.com> Message-Id: <175892462162.1836299.14644550889187111452.robh@kernel.org> Subject: Re: [PATCH v3 7/8] dt-bindings: iio: adc: adi,ad4030: Add ADAQ4216 and ADAQ4224 On Fri, 26 Sep 2025 17:40:47 -0300, Marcelo Schmitt wrote: > ADAQ4216 and ADAQ4224 are similar to AD4030 except that ADAQ devices have a > PGA (programmable gain amplifier) that scales the input signal prior to it > reaching the ADC inputs. The PGA is controlled through a couple of pins (A0 > and A1) that set one of four possible signal gain configurations. > > Signed-off-by: Marcelo Schmitt > --- > Change log v2 -> v3 > - PGA gain now described in decibels. > > The PGA gain is not going to fit well as a channel property because it may > affect more than one channel as in AD7191. > https://www.analog.com/media/en/technical-documentation/data-sheets/AD7191.pdf > > I consulted a very trustworthy source [1, 2] and learned that describing signal > gains in decibels is a common practice. I now think it would be ideal to describe > these PGA and PGA-like gains with properties in decibel units and this patch > is an attempt of doing so. The only problem with this approach is that we end up > with negative values when the gain is lower than 1 (the signal is attenuated) > and device tree specification doesn't support signed integer types. As the > docs being proposed fail dt_binding_check, I guess I have to nack the patch myself. > Any chance of dt specification eventually support signed integers? > Any suggestions appreciated. > > [1] https://en.wikipedia.org/wiki/Decibel > [2] https://en.wikipedia.org/wiki/Gain_(electronics) > > Thanks, > Marcelo > > .../bindings/iio/adc/adi,ad4030.yaml | 84 +++++++++++++++++-- > 1 file changed, 79 insertions(+), 5 deletions(-) > My bot found errors running 'make dt_binding_check' on your patch: yamllint warnings/errors: dtschema/dtc warnings/errors: Error: Documentation/devicetree/bindings/iio/adc/adi,ad4030.example.dts:68.36-37 syntax error FATAL ERROR: Unable to parse input tree make[2]: *** [scripts/Makefile.dtbs:131: Documentation/devicetree/bindings/iio/adc/adi,ad4030.example.dtb] Error 1 make[2]: *** Waiting for unfinished jobs.... make[1]: *** [/builds/robherring/dt-review-ci/linux/Makefile:1527: dt_binding_check] Error 2 make: *** [Makefile:248: __sub-make] Error 2 doc reference errors (make refcheckdocs): See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/5dc08b622dac1db561f26034c93910ccff75e965.1758916484.git.marcelo.schmitt@analog.com The base for the series is generally the latest rc1. A different dependency should be noted in *this* patch. If you already ran 'make dt_binding_check' and didn't see the above error(s), then make sure 'yamllint' is installed and dt-schema is up to date: pip3 install dtschema --upgrade Please check and re-submit after running the above command yourself. Note that DT_SCHEMA_FILES can be set to your schema file to speed up checking your schema. However, it must be unset to test all examples with your schema.