[PATCH v5 05/11] spi: imx: Add support for loopback for ECSPI controllers

[Sascha Hauer]

On Sat, Dec 05, 2015 at 05:57:03PM +0100, Anton Bondarenko wrote:
> Support for ECSPI loopback for IMX51, IMX53 and IMX6Q using TEST register.
> 
> Signed-off-by: Mohsin Kazmi <mohsin_kazmi at mentor.com>
> Signed-off-by: Anton Bondarenko <anton.bondarenko.sama at gmail.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 363276d..3525616 100644
> --- a/drivers/spi/spi-imx.c
> +++ b/drivers/spi/spi-imx.c
> @@ -246,6 +246,9 @@ 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)
> @@ -316,6 +319,7 @@ static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx,
>  	u32 ctrl = MX51_ECSPI_CTRL_ENABLE, cfg = 0, dma = 0;
>  	u32 tx_wml_cfg, rx_wml_cfg, rxt_wml_cfg;
>  	u32 clk = config->speed_hz, delay;
> +	u32 lpb = 0;
>  
>  	/*
>  	 * The hardware seems to have a race condition when changing modes. The
> @@ -356,6 +360,12 @@ 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
> @@ -1128,6 +1138,9 @@ 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)
> @@ -1154,10 +1167,10 @@ 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);

Some unrelated lines are moved in these two hunks. Is this necessary or
just some leftover from development?

Sascha

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