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 BB38F26ACD; Tue, 24 Sep 2024 08:02:44 +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=1727164964; cv=none; b=oWnIA+Q/++TBiJ6r5uE9k9BzvE+T8t8Um8EMG5PW78tVTW4Gchijabqd09FDOrGkm6qhWMJvnS218RXKZrNduwAo+t1LQ6r+PKGmOEbFV8zxY57yefEy1VZCQUY7WTIGB0Xkmm1H4NpbuftZcfRMN7MjVn52hrjJ+ZzZqPInfGY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727164964; c=relaxed/simple; bh=GwIj96U0zgt0NA9cPDbtRvwRw9+4p1LybTpIOFcn+yY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=NaizhAVegAiLzDF+1YLZ7TfeVXo9OzUfclG3nz576MNI3IOGP1KTFoe00kL6fdr7NH648halMzeGJZxmY+248Uv2Za/B5TkX88DZXw/tVHjdUAb6mmOmhVLvaXdDLen7YfK1IoixoIveVzoQJ1ZipgXazKJYOFYy+bNDMi57UhI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lNpqkS8G; 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="lNpqkS8G" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE837C4CEC4; Tue, 24 Sep 2024 08:02:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727164964; bh=GwIj96U0zgt0NA9cPDbtRvwRw9+4p1LybTpIOFcn+yY=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=lNpqkS8Gxtwy24wUEf8d5qRmy/zorF2N+KTvAahjIXx4j2U5UFK3Z0rfkFo9Xdx+U Wdo04oGYf08qZy7p2T46iQeBYH9xrlJb8NaGe8xbXQCQaEnr2o5QNJ1EtlliIe2DkR McbvStXOUcvYp+I5d3v9Bon625b1aIGVyT/Qblh7kIJXkXG/vf1Etlu8CCUW2PPCpQ i6dT1sgUNfGAOrfjWIb/T6b97w36yOx/g+Vkf1Psb7Ex8RhKV3tPeTY0R+rayddhdx Pw8XEoW7sebiM0y0GNPyRlEoXfwDoqEeyTFDcToQMBW7BPTzN5CBa8LQN5OnsixtNL V9QH4Gj28UdJA== Message-ID: Date: Tue, 24 Sep 2024 10:02:37 +0200 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 04/10] dt-bindings: iio: dac: ad3552r: add io-backend support To: Angelo Dureghello Cc: Lars-Peter Clausen , Michael Hennerich , Nuno Sa , Jonathan Cameron , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Olivier Moysan , linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, dlechner@baylibre.com References: <20240919-wip-bl-ad3552r-axi-v0-iio-testing-v3-0-a17b9b3d05d9@baylibre.com> <20240919-wip-bl-ad3552r-axi-v0-iio-testing-v3-4-a17b9b3d05d9@baylibre.com> <418a8a9b-3bcf-4b8f-92a0-619a3bf26ab5@baylibre.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 23/09/2024 17:50, Angelo Dureghello wrote: > Hi Krzysztof, > > On 22/09/24 23:02, Krzysztof Kozlowski wrote: >> On Thu, Sep 19, 2024 at 11:20:00AM +0200, Angelo Dureghello wrote: >>> From: Angelo Dureghello >>> >>> There is a version AXI DAC IP block (for FPGAs) that provides >>> a physical bus for AD3552R and similar chips, and acts as >>> an SPI controller. >>> >>> For this case, the binding is modified to include some >>> additional properties. >>> >>> Signed-off-by: Angelo Dureghello >>> --- >>> .../devicetree/bindings/iio/dac/adi,ad3552r.yaml | 42 ++++++++++++++++++++++ >>> 1 file changed, 42 insertions(+) >>> >>> diff --git a/Documentation/devicetree/bindings/iio/dac/adi,ad3552r.yaml b/Documentation/devicetree/bindings/iio/dac/adi,ad3552r.yaml >>> index 41fe00034742..aca4a41c2633 100644 >>> --- a/Documentation/devicetree/bindings/iio/dac/adi,ad3552r.yaml >>> +++ b/Documentation/devicetree/bindings/iio/dac/adi,ad3552r.yaml >>> @@ -60,6 +60,18 @@ properties: >>> $ref: /schemas/types.yaml#/definitions/uint32 >>> enum: [0, 1, 2, 3] >>> >>> + io-backends: >>> + description: The iio backend reference. >>> + An example backend can be found at >>> + https://analogdevicesinc.github.io/hdl/library/axi_ad3552r/index.html >>> + maxItems: 1 >>> + >>> + adi,synchronous-mode: >>> + description: Enable waiting for external synchronization signal. >>> + Some AXI IP configuration can implement a dual-IP layout, with internal >>> + wirings for streaming synchronization. >>> + type: boolean >>> + >>> '#address-cells': >>> const: 1 >>> >>> @@ -128,6 +140,7 @@ patternProperties: >>> - custom-output-range-config >>> >>> allOf: >>> + - $ref: /schemas/spi/spi-peripheral-props.yaml# >>> - if: >>> properties: >>> compatible: >>> @@ -238,4 +251,33 @@ examples: >>> }; >>> }; >>> }; >>> + >>> + - | >>> + axi_dac: spi@44a70000 { >>> + compatible = "adi,axi-ad3552r"; >> That is either redundant or entire example should go to the parent node, >> if this device is fixed child of complex device (IOW, adi,ad3552r cannot >> be used outside of adi,axi-ad3552r). > > ad3552r can still be used by a generic "classic" spi > controller (SCLK/CS/MISO) but at a slower samplerate, fpga > controller only (axi-ad3552r) can reach 33MUPS. OK, then this is just redundant. Drop the node. Parent example should contain the children, though. > >> >>> + reg = <0x44a70000 0x1000>; >>> + dmas = <&dac_tx_dma 0>; >>> + dma-names = "tx"; >>> + #io-backend-cells = <0>; >>> + clocks = <&ref_clk>; >>> + >>> + #address-cells = <1>; >>> + #size-cells = <0>; >>> + >>> + dac@0 { >>> + compatible = "adi,ad3552r"; >>> + reg = <0>; >>> + reset-gpios = <&gpio0 92 0>; >> Use standard defines for GPIO flags. > > fixed, thanks > >>> + io-backends = <&axi_dac>; >> Why do you need to point to the parent? How much coupled are these >> devices? Child pointing to parent is not usually expected, because >> that's obvious. > > > "io-backends" is actually the way to refer to the backend module, > (used already for i.e. ad9739a), > it is needed because the backend is not only acting as spi-controller, > but is also providing some APIs for synchronization and bus setup support. But if backend is the parent, then this is redundant. You can take it from the child-parent relationship. Is this pointing to other devices (non-parent) in other ad3552r configurations? Best regards, Krzysztof