linux-kernel - Re: [PATCH v4 4/6] spi: spi-axi-spi-engine: Add support for MOSI idle configuration

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <6f945701-cac0-4a56-9ca7-1daceccc5efd@baylibre.com>
Date: Wed, 19 Jun 2024 08:56:54 -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, marcelo.schmitt1@...il.com
Cc: linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
 linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 4/6] spi: spi-axi-spi-engine: Add support for MOSI idle
 configuration

On 6/18/24 6:11 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..787e22ae80c0 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		BIT(3)

Calling this SPI_ENGINE_CONFIG_SDO_IDLE_HIGH would make it more
clear what happens when the bit is enabled.

>  
>  #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;
> +	if (spi->mode & SPI_MOSI_IDLE_LOW)
> +		config &= ~SPI_ENGINE_CONFIG_SDO_IDLE;
>  
>  	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 &&

Currently, the major version is required to be 1, so this check is not
strictly needed.

> +	    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;