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Message-ID: <2a96f734-010d-b42d-8418-715d7c420272@linaro.org>
Date:   Mon, 18 Jul 2022 15:06:18 +0200
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Subject: Re: [PATCH 2/2] dt-bindings: fpga: add binding doc for ecp5-spi fpga
 mgr
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To:     Ivan Bornyakov <i.bornyakov@metrotek.ru>
Cc:     mdf@kernel.org, hao.wu@intel.com, yilun.xu@intel.com,
        trix@redhat.com, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, linux-fpga@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        system@metrotek.ru
References: <20220714122657.17972-1-i.bornyakov@metrotek.ru>
 <20220714122657.17972-3-i.bornyakov@metrotek.ru>
 <044a9736-a4ec-c250-7755-c80a5bcbe38b@linaro.org>
 <20220715100356.fwjomifweifn6zsr@h-e2.ddg>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <20220715100356.fwjomifweifn6zsr@h-e2.ddg>
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Precedence: bulk

On 15/07/2022 12:03, Ivan Bornyakov wrote:
> On Fri, Jul 15, 2022 at 11:33:54AM +0200, Krzysztof Kozlowski wrote:
>> On 14/07/2022 14:26, Ivan Bornyakov wrote:
>>> Add Device Tree Binding doc for Lattice ECP5 FPGA manager using slave
>>> SPI to load .bit formatted uncompressed bitstream image.
>>>
>>> Signed-off-by: Ivan Bornyakov <i.bornyakov@metrotek.ru>
>>> ---
>>>  .../fpga/lattice,ecp5-spi-fpga-mgr.yaml       | 71 +++++++++++++++++++
>>>  1 file changed, 71 insertions(+)
>>>  create mode 100644 Documentation/devicetree/bindings/fpga/lattice,ecp5-spi-fpga-mgr.yaml
>>>
>>> diff --git a/Documentation/devicetree/bindings/fpga/lattice,ecp5-spi-fpga-mgr.yaml b/Documentation/devicetree/bindings/fpga/lattice,ecp5-spi-fpga-mgr.yaml
>>> new file mode 100644
>>> index 000000000000..79868f9c84e2
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/fpga/lattice,ecp5-spi-fpga-mgr.yaml
>>> @@ -0,0 +1,71 @@
>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/fpga/lattice,ecp5-spi-fpga-mgr.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: Lattice ECP5 FPGA manager.
>>> +
>>> +maintainers:
>>> +  - Ivan Bornyakov <i.bornyakov@metrotek.ru>
>>> +
>>> +description:
>>> +  Device Tree Bindings for Lattice ECP5 FPGA Manager using slave SPI to
>>> +  load the uncompressed bitstream in .bit format.
>>
>> s/Device Tree Bindings for//
>>
>> Instead describe the hardware you are adding bindings for. What is a
>> "Manager"? It is so broad and unspecific... It is some dedicated
>> hardware to communicate with FPGA or you just called this regular FPGA
>> interface exposed to the CPU/SoC?
>>
> 
> "FPGA Manager" is a kernel subsystem that exports a set of functions for
> programming an FPGA with a bitstream image.
> See Documentation/driver-api/fpga/fpga-mgr.rst

This is what you want to include in the bindings document? How is it
related to bindings? We do not talk about driver API but we talk about
hardware. Bindings are for the hardware.

> 
>>> +
>>> +properties:
>>> +  compatible:
>>> +    enum:
>>> +      - lattice,ecp5-spi-fpga-mgr
>>
>> Do not encode interface name in compatible so no "spi".
>>
> 
> Recently when I submitted FPGA manager for Microchip PolarFire, I was
> asked the opposite, to add "spi" in compatible. The reason was that FPGA
> can be programmed through other interfaces as well.

I don't see such comment from Rob (DT maintainer):
https://lore.kernel.org/all/?q=%22dt-bindings%3A+fpga%3A+add+binding+doc+for+microchip-spi+fpga+mgr%22

Can you point me to it?

Best regards,
Krzysztof