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Date:   Sat, 27 Aug 2022 02:31:16 +0300
From:   Serge Semin <fancer.lancer@gmail.com>
To:     Sudip Mukherjee <sudip.mukherjee@sifive.com>
Cc:     Serge Semin <Sergey.Semin@baikalelectronics.ru>,
        Mark Brown <broonie@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        greentime.hu@sifive.com, jude.onyenegecha@sifive.com,
        william.salmon@sifive.com, adnan.chowdhury@sifive.com,
        ben.dooks@sifive.com, linux-spi@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        jeegar.lakhani@sifive.com
Subject: Re: [PATCH 11/11] spi: dw: initialize dwc-ssi-1.03a controller
Message-ID: <20220826233116.uulisbo663cxiadt@mobilestation>
References: <20220802175755.6530-1-sudip.mukherjee@sifive.com>
 <20220802175755.6530-12-sudip.mukherjee@sifive.com>
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On Tue, Aug 02, 2022 at 06:57:55PM +0100, Sudip Mukherjee wrote:
> Define the initialization of dwc-ssi-1.03a controller and mark it with
> the capability of enhanced SPI supporting dual/quad/octal modes of
> transfer.
> 
> Signed-off-by: Sudip Mukherjee <sudip.mukherjee@sifive.com>
> ---
>  drivers/spi/spi-dw-mmio.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
> index 26c40ea6dd12..db80e0645172 100644
> --- a/drivers/spi/spi-dw-mmio.c
> +++ b/drivers/spi/spi-dw-mmio.c
> @@ -237,6 +237,15 @@ static int dw_spi_canaan_k210_init(struct platform_device *pdev,
>  	return 0;
>  }
>  
> +static int dw_spi_hssi_ext_init(struct platform_device *pdev,
> +				struct dw_spi_mmio *dwsmmio)
> +{
> +	dwsmmio->dws.ip = DW_HSSI_ID;

> +	dwsmmio->dws.caps = DW_SPI_CAP_EXT_SPI;

The eSPI capability shall be auto-detectable by checking whether the
CTRLR0.SPI_FRF field is writable. If it is then you'll need to check
whether the clock stretching is also available by setting to the
SPI_CTRLR0.CLK_STRETCH_EN flag. After that you can set the capability
flag.

Since the auto-detection procedure is available you won't need the
dw_spi_hssi_ext_init() method here. So just drop it and use
dw_spi_hssi_init() for the platform-specific initialization. Note it
will also check the DMA-capability for you.

> +
> +	return 0;
> +}
> +
>  static int dw_spi_mmio_probe(struct platform_device *pdev)
>  {
>  	int (*init_func)(struct platform_device *pdev,
> @@ -352,6 +361,7 @@ static const struct of_device_id dw_spi_mmio_of_match[] = {
>  	{ .compatible = "intel,thunderbay-ssi", .data = dw_spi_intel_init},
>  	{ .compatible = "microchip,sparx5-spi", dw_spi_mscc_sparx5_init},
>  	{ .compatible = "canaan,k210-spi", dw_spi_canaan_k210_init},

> +	{ .compatible = "snps,dwc-ssi-1.03a", dw_spi_hssi_ext_init},

Add "snps,dw-ahb-ssi" with the generic dw_spi_hssi_init() init method.

-Sergey

>  	{ /* end of table */}
>  };
>  MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);
> -- 
> 2.30.2
>