linux-kernel - Re: [PATCH v5 4/7] spi: spi-axi-spi-engine: Add support for MOSI idle configuration

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Date: Wed, 26 Jun 2024 10:06:28 -0500
From: David Lechner <dlechner@...libre.com>
To: Marcelo Schmitt <marcelo.schmitt@...log.com>, broonie@...nel.org,
 lars@...afoo.de, Michael.Hennerich@...log.com, jic23@...nel.org,
 robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
 nuno.sa@...log.com, corbet@....net, marcelo.schmitt1@...il.com
Cc: linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
 linux-spi@...r.kernel.org, linux-doc@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 4/7] spi: spi-axi-spi-engine: Add support for MOSI idle
 configuration

On 6/25/24 4:54 PM, Marcelo Schmitt wrote:
> Implement MOSI idle low and MOSI idle high to better support peripherals
> that request specific MOSI behavior.
> 
> Signed-off-by: Marcelo Schmitt <marcelo.schmitt@...log.com>
> ---
>  drivers/spi/spi-axi-spi-engine.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/spi/spi-axi-spi-engine.c b/drivers/spi/spi-axi-spi-engine.c
> index 0aa31d745734..5a88d31ca758 100644
> --- a/drivers/spi/spi-axi-spi-engine.c
> +++ b/drivers/spi/spi-axi-spi-engine.c
> @@ -41,6 +41,7 @@
>  #define SPI_ENGINE_CONFIG_CPHA			BIT(0)
>  #define SPI_ENGINE_CONFIG_CPOL			BIT(1)
>  #define SPI_ENGINE_CONFIG_3WIRE			BIT(2)
> +#define SPI_ENGINE_CONFIG_SDO_IDLE_HIGH		BIT(3)
>  
>  #define SPI_ENGINE_INST_TRANSFER		0x0
>  #define SPI_ENGINE_INST_ASSERT			0x1
> @@ -132,6 +133,10 @@ static unsigned int spi_engine_get_config(struct spi_device *spi)
>  		config |= SPI_ENGINE_CONFIG_CPHA;
>  	if (spi->mode & SPI_3WIRE)
>  		config |= SPI_ENGINE_CONFIG_3WIRE;
> +	if (spi->mode & SPI_MOSI_IDLE_HIGH)
> +		config |= SPI_ENGINE_CONFIG_SDO_IDLE_HIGH;
> +	if (spi->mode & SPI_MOSI_IDLE_LOW)
> +		config &= ~SPI_ENGINE_CONFIG_SDO_IDLE_HIGH;
>  
>  	return config;
>  }
> @@ -646,6 +651,9 @@ static int spi_engine_probe(struct platform_device *pdev)
>  
>  	host->dev.of_node = pdev->dev.of_node;
>  	host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_3WIRE;
> +	if (ADI_AXI_PCORE_VER_MAJOR(version) >= 1 &&
> +	    ADI_AXI_PCORE_VER_MINOR(version) >= 3)
> +		host->mode_bits |=  SPI_MOSI_IDLE_LOW | SPI_MOSI_IDLE_HIGH;
>  	host->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
>  	host->max_speed_hz = clk_get_rate(spi_engine->ref_clk) / 2;
>  	host->transfer_one_message = spi_engine_transfer_one_message;

The driver already has a section:

	/* Some features depend of the IP core version. */
	if (ADI_AXI_PCORE_VER_MINOR(version) >= 2) {
		host->mode_bits |= SPI_CS_HIGH;
		host->setup = spi_engine_setup;
	}

So I would prefer to add the version check there instead.

With that change:

Reviewed-by: David Lechner <dlechner@...libre.com>