[PATCH v2 3/4] spi: spi-imx: add support for SPI_MOSI_IDLE_LOW mode bit

[Boerge Struempfel]

By default, the spi-imx controller pulls the mosi line high, whenever it
is idle. This behaviour can be inverted per CS by setting the
corresponding DATA_CTL bit in the config register of the controller.

Also, since the controller mode-bits have to be touched anyways, the
SPI_CPOL and SPI_CPHA are replaced by the combined SPI_MODE_X_MASK flag.

Signed-off-by: Boerge Struempfel <bstruempfel at ultratronik.de>
---
 drivers/spi/spi-imx.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 34e5f81ec431e..cb6c088706b21 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -281,6 +281,7 @@ static bool spi_imx_can_dma(struct spi_controller *controller, struct spi_device
 #define MX51_ECSPI_CONFIG_SCLKPOL(cs)	(1 << ((cs & 3) +  4))
 #define MX51_ECSPI_CONFIG_SBBCTRL(cs)	(1 << ((cs & 3) +  8))
 #define MX51_ECSPI_CONFIG_SSBPOL(cs)	(1 << ((cs & 3) + 12))
+#define MX51_ECSPI_CONFIG_DATACTL(cs)	(1 << ((cs & 3) + 16))
 #define MX51_ECSPI_CONFIG_SCLKCTL(cs)	(1 << ((cs & 3) + 20))
 
 #define MX51_ECSPI_INT		0x10
@@ -573,6 +574,11 @@ static int mx51_ecspi_prepare_message(struct spi_imx_data *spi_imx,
 		cfg &= ~MX51_ECSPI_CONFIG_SCLKCTL(spi_get_chipselect(spi, 0));
 	}
 
+	if (spi->mode & SPI_MOSI_IDLE_LOW)
+		cfg |= MX51_ECSPI_CONFIG_DATACTL(spi->chip_select);
+	else
+		cfg &= ~MX51_ECSPI_CONFIG_DATACTL(spi->chip_select);
+
 	if (spi->mode & SPI_CS_HIGH)
 		cfg |= MX51_ECSPI_CONFIG_SSBPOL(spi_get_chipselect(spi, 0));
 	else
@@ -1743,7 +1749,8 @@ static int spi_imx_probe(struct platform_device *pdev)
 	spi_imx->controller->prepare_message = spi_imx_prepare_message;
 	spi_imx->controller->unprepare_message = spi_imx_unprepare_message;
 	spi_imx->controller->slave_abort = spi_imx_slave_abort;
-	spi_imx->controller->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_NO_CS;
+	spi_imx->controller->mode_bits = SPI_MODE_X_MASK | SPI_CS_HIGH | SPI_NO_CS |
+					 SPI_MOSI_IDLE_LOW;
 
 	if (is_imx35_cspi(spi_imx) || is_imx51_ecspi(spi_imx) ||
 	    is_imx53_ecspi(spi_imx))
-- 
2.25.1