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Date: Thu, 1 Feb 2024 13:24:52 -0500 (EST)
From: Charles Perry <charles.perry@savoirfairelinux.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: mdf <mdf@kernel.org>, Allen VANDIVER <avandiver@markem-imaje.com>, 
	Brian CODY <bcody@markem-imaje.com>, hao wu <hao.wu@intel.com>, 
	yilun xu <yilun.xu@intel.com>, Tom Rix <trix@redhat.com>, 
	Rob Herring <robh+dt@kernel.org>, 
	krzysztof kozlowski+dt <krzysztof.kozlowski+dt@linaro.org>, 
	Conor Dooley <conor+dt@kernel.org>, 
	Michal Simek <michal.simek@amd.com>, 
	linux-fpga <linux-fpga@vger.kernel.org>, 
	devicetree <devicetree@vger.kernel.org>, 
	linux-kernel <linux-kernel@vger.kernel.org>, 
	linux-arm-kernel@lists.infradead.org
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References: <20240129225602.3832449-1-charles.perry@savoirfairelinux.com> <20240131230542.3993409-1-charles.perry@savoirfairelinux.com> <20240131230542.3993409-3-charles.perry@savoirfairelinux.com> <d5fe1ec2-b647-4902-a599-fb866e96e9cf@linaro.org>
Subject: Re: [PATCH 2/3] dt-bindings: fpga: xlnx,fpga-slave-selectmap: add
 DT schema
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Thread-Topic: dt-bindings: fpga: xlnx,fpga-slave-selectmap: add DT schema
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----- On Feb 1, 2024, at 3:07 AM, Krzysztof Kozlowski krzysztof.kozlowski@linaro.org wrote:

> On 01/02/2024 00:05, Charles Perry wrote:
>> Document the slave SelectMAP interface of Xilinx 7 series FPGA.
>> 
>> Signed-off-by: Charles Perry <charles.perry@savoirfairelinux.com>
>> ---
>>  .../bindings/fpga/xlnx,fpga-selectmap.yaml    | 83 +++++++++++++++++++
>>  1 file changed, 83 insertions(+)
>>  create mode 100644
>>  Documentation/devicetree/bindings/fpga/xlnx,fpga-selectmap.yaml
>> 
>> diff --git a/Documentation/devicetree/bindings/fpga/xlnx,fpga-selectmap.yaml
>> b/Documentation/devicetree/bindings/fpga/xlnx,fpga-selectmap.yaml
>> new file mode 100644
>> index 0000000000000..c9a446b43cdd9
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/fpga/xlnx,fpga-selectmap.yaml
>> @@ -0,0 +1,83 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/fpga/xlnx,fpga-selectmap.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Xilinx SelectMAP FPGA interface
>> +
>> +maintainers:
>> +  - Charles Perry <charles.perry@savoirfairelinux.com>
>> +
>> +description: |
>> +  Xilinx 7 Series FPGAs support a method of loading the bitstream over a
>> +  parallel port named the SelectMAP interface in the documentation. Only
>> +  the x8 mode is supported where data is loaded at one byte per rising edge of
>> +  the clock, with the MSB of each byte presented to the D0 pin.
>> +
>> +  Datasheets:
>> +
>> https://www.xilinx.com/support/documentation/user_guides/ug470_7Series_Config.pdf
>> +
>> +allOf:
>> +  - $ref: /schemas/memory-controllers/mc-peripheral-props.yaml#
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - xlnx,fpga-selectmap
> 
> Your description mentions "7 Series" which is not present in compatible
> and title. What is exactly the product here? Interface usually is not
> the final binding, so is this specific to some particular FPGA or SoC?
> 
> 
> Best regards,
> Krzysztof

This is specific to the FPGA, the 7 series encompass the following part
family:
 * Spartan-7 (XC7S6, XC7S15, ... XC7S100)
 * Artix-7 (XC7A12T, XC7A15T, ... XC7A200T)
 * Kintex-7 (XC7K70T, XC7K160T, ... XC7K480T)
 * Virtex-7 (XC7V585T, XC7V2000T, 
             XC7VX330T, XC7VX415T, ... XC7VX1140T,
             XC7VH580T, XC7VH870T)


The configuration guide of Xilinx [1] tells us that all those devices
share a common programming scheme.

I do agree that having a mention of "7 series" in the compatible name
would be beneficial as Xilinx has more FPGA than just the 7 series.
The name was inspired from "xlnx,fpga-slave-serial" which is the compatible
for the serial interface.

What about "xlnx,fpga-xc7-selectmap" ?

I'm also seeing that I missed some mention of the "slave" word in the
commit message, will fix.

Regards,
Charles

[1] https://www.xilinx.com/support/documentation/user_guides/ug470_7Series_Config.pdf