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Message-ID: <79fd7e19-ceef-14fb-5a83-603740735f8f@foss.st.com>
Date:   Mon, 8 Aug 2022 18:08:59 +0200
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Subject: Re: [PATCH 1/3] dt-bindings: spi: stm32: Add st,dual-flash property
 in st,stm32-qspi.yaml
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To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Mark Brown <broonie@kernel.org>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        <robh+dt@kernel.org>, <krzysztof.kozlowski+dt@linaro.org>
CC:     <linux-spi@vger.kernel.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, <christophe.kerello@foss.st.com>,
        <devicetree@vger.kernel.org>
References: <20220808074051.44736-1-patrice.chotard@foss.st.com>
 <20220808074051.44736-2-patrice.chotard@foss.st.com>
 <9ad4b4a8-988e-f185-f80c-6f15f341ce8c@linaro.org>
From:   Patrice CHOTARD <patrice.chotard@foss.st.com>
In-Reply-To: <9ad4b4a8-988e-f185-f80c-6f15f341ce8c@linaro.org>
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Hi Krzystof

On 8/8/22 11:01, Krzysztof Kozlowski wrote:
> On 08/08/2022 10:40, patrice.chotard@foss.st.com wrote:
>> From: Patrice Chotard <patrice.chotard@foss.st.com>
>>
>> Add new property st,dual-flash which allows to use the QSPI interface as a
>> communication channel using up to 8 qspi line.
>> This mode can only be used if cs-gpios property is defined.
>>
>> Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
>> ---
>>  Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml | 8 ++++++++
>>  1 file changed, 8 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml
>> index 6ec6f556182f..5e4f9109799e 100644
>> --- a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml
>> +++ b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml
>> @@ -46,6 +46,14 @@ properties:
>>        - const: tx
>>        - const: rx
>>  
>> +  st,dual-flash:
>> +    type: boolean
>> +    description:
>> +      Allows to use 8 data lines in case cs-gpios property is defined.
> 
> It's named dual-flash, but what if you want to use QSPI to connect for
> example to FPGA?
> 
> Also how is this related to parallel-memories property?

I called it "dual-flash" simply because it enable the dual flash feature of the QSPI block (bit CR_DFM : Dual Flash Mode)
which allows to use the 8 lines simultaneously of our dual QSPI block.

Best regards
Patrice


> 
> Best regards,
> Krzysztof