Subject: [PATCH v2 5/8] spi: imx: Add support for loopback for ECSPI controllers

From: [email-masked] (Robin Gong)
Date: Wed, 30 Sep 2015 16:42:20 +0800

On Fri, Sep 25, 2015 at 07:57:12PM +0200, Anton Bondarenko wrote:
> Support for ECSPI loopback for IMX51,IMX53 and IMX6Q using TEST register.
> 
> Signed-off-by: Mohsin Kazmi <[email-masked]>
> Signed-off-by: Anton Bondarenko <[email-masked]>
> ---
>  drivers/spi/spi-imx.c | 20 ++++++++++++++++----
>  1 file changed, 16 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
> index 41c9cef..4b3c16e 100644
> --- a/drivers/spi/spi-imx.c
> +++ b/drivers/spi/spi-imx.c
> @@ -265,6 +265,9 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
>  #define MX51_ECSPI_STAT		0x18
>  #define MX51_ECSPI_STAT_RR		(1 <<  3)
>  
> +#define MX51_ECSPI_TEST			0x20
> +#define MX51_ECSPI_LOOP			BIT(31)
> +
>  /* MX51 eCSPI */
>  static unsigned int mx51_ecspi_clkdiv(unsigned int fin, unsigned int fspi,
>  				      unsigned int *fres)
> @@ -338,6 +341,7 @@ static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx,
>  	u32 ctrl = MX51_ECSPI_CTRL_ENABLE, dma = 0;
>  	u32 cfg = readl(spi_imx->base + MX51_ECSPI_CONFIG);
>  	u32 delay;
> +	u32 lpb = 0;
>  
>  	/*
>  	 * The hardware seems to have a race condition when changing modes. The
> @@ -370,8 +374,12 @@ static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx,
>  	if (config->mode & SPI_CS_HIGH)
>  		cfg |= MX51_ECSPI_CONFIG_SSBPOL(config->cs);
>  
> +	if (config->mode & SPI_LOOP)
> +		lpb |= MX51_ECSPI_LOOP;
> +
>  	writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL);
>  	writel(cfg, spi_imx->base + MX51_ECSPI_CONFIG);
> +	writel(lpb, spi_imx->base + MX51_ECSPI_TEST);
It's better write this MX51_ECSPI_TEST only in LOOP mode.
>  
>  	/*
>  	 * Wait until the changes in the configuration register CONFIGREG
> @@ -1252,6 +1260,9 @@ static int spi_imx_probe(struct platform_device *pdev)
>  	spi_imx = spi_master_get_devdata(master);
>  	spi_imx->bitbang.master = master;
>  
> +	spi_imx->devtype_data = of_id ? of_id->data :
> +		(struct spi_imx_devtype_data *)pdev->id_entry->driver_data;
> +
>  	for (i = 0; i < master->num_chipselect; i++) {
>  		int cs_gpio = of_get_named_gpio(np, "cs-gpios", i);
>  		if (!gpio_is_valid(cs_gpio) && mxc_platform_info)
> @@ -1276,12 +1287,13 @@ static int spi_imx_probe(struct platform_device *pdev)
>  	spi_imx->bitbang.master->cleanup = spi_imx_cleanup;
>  	spi_imx->bitbang.master->prepare_message = spi_imx_prepare_message;
>  	spi_imx->bitbang.master->unprepare_message = spi_imx_unprepare_message;
> -	spi_imx->bitbang.master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
> +	spi_imx->bitbang.master->mode_bits = SPI_CPOL | SPI_CPHA |
> +				SPI_CS_HIGH;
Any change?
>  
> -	init_completion(&spi_imx->xfer_done);
> +	if (is_imx5x_ecspi(spi_imx))
> +		spi_imx->bitbang.master->mode_bits |= SPI_LOOP;
>  
> -	spi_imx->devtype_data = of_id ? of_id->data :
> -		(struct spi_imx_devtype_data *) pdev->id_entry->driver_data;
> +	init_completion(&spi_imx->xfer_done);
>  
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	spi_imx->base = devm_ioremap_resource(&pdev->dev, res);
> -- 
> 2.5.2
>