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Message-ID: <1c58deef-bc0f-4889-bf40-54168ce9ff7c@linaro.org>
Date: Thu, 25 Jan 2024 16:38:07 +0000
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Subject: Re: [PATCH v2 05/28] spi: dt-bindings: samsung: add
 samsung,spi-fifosize property
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To: Mark Brown <broonie@kernel.org>
Cc: andi.shyti@kernel.org, arnd@arndb.de, robh+dt@kernel.org,
 krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
 alim.akhtar@samsung.com, linux-spi@vger.kernel.org,
 linux-samsung-soc@vger.kernel.org, devicetree@vger.kernel.org,
 linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
 linux-arch@vger.kernel.org, andre.draszik@linaro.org,
 peter.griffin@linaro.org, semen.protsenko@linaro.org,
 kernel-team@android.com, willmcvicker@google.com
References: <20240125145007.748295-1-tudor.ambarus@linaro.org>
 <20240125145007.748295-6-tudor.ambarus@linaro.org>
 <7ef86704-3e40-4d39-a69d-a30719c96660@sirena.org.uk>
From: Tudor Ambarus <tudor.ambarus@linaro.org>
In-Reply-To: <7ef86704-3e40-4d39-a69d-a30719c96660@sirena.org.uk>
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On 1/25/24 16:16, Mark Brown wrote:
> On Thu, Jan 25, 2024 at 02:49:43PM +0000, Tudor Ambarus wrote:
>> Up to now the SPI alias was used as an index into an array defined in
>> the SPI driver to determine the SPI FIFO size. Drop the dependency on
>> the SPI alias and allow the SPI nodes to specify their SPI FIFO size.
> 
> ...
> 
>> +  samsung,spi-fifosize:
>> +    description: The fifo size supported by the SPI instance.
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +    enum: [64, 256]
> 
> Do we have any cases where we'd ever want to vary this independently of
> the SoC - this isn't a configurable IP shipped to random integrators?

The IP supports FIFO depths from 8 to 256 bytes (in powers of 2 I
guess). The integrator is the one dictating the IP configuration. In
gs101's case all USIxx_USI (which includes SPI, I2C, and UART) are
configured with 64 bytes FIFO depths.