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 8591315CD60; Fri, 22 Nov 2024 18:29:12 +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=1732300152; cv=none; b=pvga5JImNUYDpvsc+yE3I811rHCOtJlWFQS12u7I7byeCnvSiqAPmhOTkfQujpthasp6k8fyDV0WybSZJVvxBEIZn1Kes0BgiI0lbMTAR1LmqONWFk9mo8oqnj88I1nwqA4TuNSB20SIXxlvdyPcr72F13yKTuzjLyTCw4RFgWY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732300152; c=relaxed/simple; bh=cpCYLUptjUavyLM1gGDWmsWt7dvqaaPy8JYrWmWGODw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=P/Z1u+SOqU/c54/dT260oXkn5s9DhD7KKuN+pOym+9mxhY93K9pD+5jG1ucpzmDadtKSYastrdnkLMhcCVJ9JKEcsUKIhbaAF7hdHAJswgZR4d9pr6WVcM55WvBIFE4izwNHYhoUSwllf+m3KfqkSeR7VNfG1AzK0ZUo01N1xBY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oiK+1IHj; 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="oiK+1IHj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EE507C4CECE; Fri, 22 Nov 2024 18:29:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732300152; bh=cpCYLUptjUavyLM1gGDWmsWt7dvqaaPy8JYrWmWGODw=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=oiK+1IHjEVmPx3ggwiGLPVPX4CkYYfW0BijKUkvCxeJ2Z8GJV9v190rn2ahBuPBTR phYCLMnAPu2MDGKS/HVHvspsGs3Is60lDksCbPOZI1M4BpUApAboyJ7wa3hcI5riMo KgiD53PxrJzJDKFHb6Vdq2TjEXCpIqJweKS9SCYBG10lw9PcNPHWxikDdGcKjmNIDc MyB9vfeCaW+51v1Naks4tbJoF10yaBGDBFdyL7/YjrFWvd6Y+OtKzhIF1PdodoyjPv 2agjAygAdSSj0TYMbD8iD4WEpJbnkP2Z7r7MJtiFpl0fK7EK148jUhg+DtBO6yyys8 6nADVm7HsNgEw== Message-ID: Date: Fri, 22 Nov 2024 19:29:06 +0100 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/4] dt-bindings: iio: adc: adi,ad4000: Add PulSAR To: Marcelo Schmitt Cc: Marcelo Schmitt , lars@metafoo.de, Michael.Hennerich@analog.com, jic23@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <5kz6ghe56yiprlvhyduv7olcrajvejyvulcpjav6doiyvr6dcl@6qlt4nebp4gb> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 22/11/2024 16:33, Marcelo Schmitt wrote: >> >>> + - items: >>> + - enum: >>> + - adi,ad7942 >>> + - const: adi,ad7946 >>> + >>> + - const: adi,ad7983 >>> + - items: >>> + - enum: >>> + - adi,ad7980 >>> + - adi,ad7988-5 >>> + - adi,ad7686 >>> + - adi,ad7685 >> >> Keep alphabetical order. > > Do the fallbacks declared here have any impact on the match try order or on how > the compatible list should be ordered? I don't understand, we do not talk about fallbacks. I also do not understand at all how this relates to my comment. > The only significant difference between each group of devices is the sample rate. > A faster device can read at slower sample rates so if somebody knows to have > a 16-bit pseudo-differential PulSAR but doesn't know about the exact model they > could have a compatible like > compatible = "adi,ad7980", "adi,ad7988-5", "adi,ad7686", "adi,ad7685", > "adi,ad7988-1", "adi,ad7983"; Can't you autodetect this? > > to try from fastest to slowest device. > The dt doc would indicate that order in the fallback list? > - items: > - enum: > - adi,ad7980 # Fastest 16-bit pseudo-differential ADC > - adi,ad7988-5 # 2nd fastest 16-bit pseudo-differential ADC > - adi,ad7686 # 3rd fastest 16-bit pseudo-differential ADC > - adi,ad7685 # 4th fastest 16-bit pseudo-differential ADC > - adi,ad7988-1 # 5th fastest 16-bit pseudo-differential ADC > - const: adi,ad7983 # Slowest 16-bit pseudo-differential ADC Again, only one fallback here, not sure what are you asking about. BTW, DT spec explains compatibles... > > https://www.analog.com/media/en/technical-documentation/data-sheets/ad7691.pdf > has a nice table with the different devices and sample rates. > > writing-bindings.rst says "DO use fallback compatibles when devices are the same > as or a subset of prior implementations." > But, how can we use fallbacks properly? How DT spec and tutorials like elinux ask... What is exactly the problem or question? > From Documentation/devicetree/bindings/display/bridge/lvds-codec.yaml I'm How LVDS bridge is related to this one here? > inferring only one fallback should be provided per group of devices. > >> >>> + - adi,ad7988-1 >>> + - const: adi,ad7983 >>> + >>> + - const: adi,ad7688 >>> + - items: >>> + - enum: >>> + - adi,ad7693 >>> + - adi,ad7687 >>> + - const: adi,ad7688 >>> + >>> + - const: adi,ad7984 >>> + - items: >>> + - enum: >>> + - adi,ad7982 >>> + - adi,ad7690 >>> + - adi,ad7691 >>> + - const: adi,ad7984 >>> + >>> reg: >>> maxItems: 1 >>> >>> @@ -133,6 +178,32 @@ required: >>> - ref-supply >>> >>> allOf: >>> + # Single-channel PulSAR devices have SDI either tied to VIO, GND, or host CS. >>> + - if: >>> + properties: >>> + compatible: >>> + contains: >>> + enum: >>> + - adi,ad7685 >> >> Why do you need this? It's fallback is already here. > > So dtbs_check can provide an error message if for example compatible = "adi,ad7687"; > and adi,sdi-pin = "sdi"; I mean this compatible, not if clause. Best regards, Krzysztof