Commit 9f6aa42b authored by Fabio Estevam's avatar Fabio Estevam Committed by Mark Brown
Browse files

spi: imx: Add loopback mode support 



Loopback mode can be activated by setting bit LBC (LoopBack
Control) of register ECSPI_TESTREG.

Add support for it.

Signed-off-by: default avatarFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 8005c49d

drivers/spi/spi-imx.c

+13 −2
Original line number Diff line number Diff line
@@ -244,6 +244,9 @@ 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_TESTREG	0x20

#define MX51_ECSPI_TESTREG_LBC	BIT(31)



/* MX51 eCSPI */

static unsigned int mx51_ecspi_clkdiv(unsigned int fin, unsigned int fspi,

				      unsigned int *fres)
@@ -313,7 +316,7 @@ 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 clk = config->speed_hz, delay, reg;



	/*

	 * The hardware seems to have a race condition when changing modes. The
@@ -351,6 +354,13 @@ static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx, 
	else

		cfg &= ~MX51_ECSPI_CONFIG_SSBPOL(config->cs);



	reg = readl(spi_imx->base + MX51_ECSPI_TESTREG);

	if (config->mode & SPI_LOOP)

		reg |= MX51_ECSPI_TESTREG_LBC;

	else

		reg &= ~MX51_ECSPI_TESTREG_LBC;

	writel(reg, spi_imx->base + MX51_ECSPI_TESTREG);



	writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL);

	writel(cfg, spi_imx->base + MX51_ECSPI_CONFIG);
@@ -1141,7 +1151,8 @@ 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 |

					     SPI_LOOP;



	init_completion(&spi_imx->xfer_done);