From 9f6aa42bbbb23d2115704c5044da951a7e685cc5 Mon Sep 17 00:00:00 2001 From: Fabio Estevam Date: Thu, 3 Dec 2015 23:23:24 -0200 Subject: [PATCH] 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: Fabio Estevam Signed-off-by: Mark Brown --- drivers/spi/spi-imx.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c index 0e5723ab47f0..e7e4f0c0f14d 100644 --- a/drivers/spi/spi-imx.c +++ b/drivers/spi/spi-imx.c @@ -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); -- 2.20.1