[PATCH v3 5/7] spi: imx: Add support for loopback for ECSPI controllers

[anton.bondarenko.sama@gmail.com (Anton Bondarenko)]

On 01.11.2015 15:41, Anton Bondarenko wrote:
> From: Anton Bondarenko <anton_bondarenko@mentor.com>
>
> Support for ECSPI loopback for IMX51,IMX53 and IMX6Q using TEST register.
>
> Signed-off-by: Mohsin Kazmi <mohsin_kazmi@mentor.com>
> Signed-off-by: Anton Bondarenko <anton_bondarenko@mentor.com>
> ---
>   drivers/spi/spi-imx.c | 19 ++++++++++++++++---
>   1 file changed, 16 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
> index 48fdfa1..dc492e2 100644
> --- a/drivers/spi/spi-imx.c
> +++ b/drivers/spi/spi-imx.c
> @@ -270,6 +270,9 @@ 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)
> @@ -343,6 +346,7 @@ 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
> @@ -385,6 +389,12 @@ static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx,
>   	writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL);
>   	writel(cfg, spi_imx->base + MX51_ECSPI_CONFIG);
>
> +	if (config->mode & SPI_LOOP)
> +		lpb |= MX51_ECSPI_LOOP;
> +
> +	if ((readl(spi_imx->base + MX51_ECSPI_TEST) & MX51_ECSPI_LOOP) != lpb)
> +		writel(lpb, spi_imx->base + MX51_ECSPI_TEST);
> +
>   	/*
>   	 * Wait until the changes in the configuration register CONFIGREG
>   	 * propagate into the hardware. It takes exactly one tick of the
> @@ -1262,6 +1272,9 @@ 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)
> @@ -1288,10 +1301,10 @@ static int spi_imx_probe(struct platform_device *pdev)
>   	spi_imx->bitbang.master->unprepare_message = spi_imx_unprepare_message;
>   	spi_imx->bitbang.master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
>
> -	init_completion(&spi_imx->xfer_done);
> +	if (is_imx51_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);
>

Does anyone has other comments regarding this commit?

Regards, Anton