From e9dd4edcc98593bbcdffc0c4f37545b8fd0ad3ea Mon Sep 17 00:00:00 2001 From: Stephan Olbrich Date: Sun, 14 Feb 2016 11:04:29 +0100 Subject: [PATCH] spi: bcm2835aux: fix CPOL/CPHA setting The auxiliary spi supports only CPHA=0 modes as the first bit is always output to the pin before the first clock cycle. In CPHA=1 modes the first clock edge outputs the second bit hence the slave can never read the first bit. Also the CPHA registers switch between clocking data in/out on rising/falling edge hence depend on the CPOL setting. Signed-off-by: Stephan Olbrich Reviewed-by: Eric Anholt Signed-off-by: Mark Brown --- drivers/spi/spi-bcm2835aux.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c index a6e25c6c66ca..496f9adb9fc1 100644 --- a/drivers/spi/spi-bcm2835aux.c +++ b/drivers/spi/spi-bcm2835aux.c @@ -64,9 +64,9 @@ #define BCM2835_AUX_SPI_CNTL0_VAR_WIDTH 0x00004000 #define BCM2835_AUX_SPI_CNTL0_DOUTHOLD 0x00003000 #define BCM2835_AUX_SPI_CNTL0_ENABLE 0x00000800 -#define BCM2835_AUX_SPI_CNTL0_CPHA_IN 0x00000400 +#define BCM2835_AUX_SPI_CNTL0_IN_RISING 0x00000400 #define BCM2835_AUX_SPI_CNTL0_CLEARFIFO 0x00000200 -#define BCM2835_AUX_SPI_CNTL0_CPHA_OUT 0x00000100 +#define BCM2835_AUX_SPI_CNTL0_OUT_RISING 0x00000100 #define BCM2835_AUX_SPI_CNTL0_CPOL 0x00000080 #define BCM2835_AUX_SPI_CNTL0_MSBF_OUT 0x00000040 #define BCM2835_AUX_SPI_CNTL0_SHIFTLEN 0x0000003F @@ -92,9 +92,6 @@ #define BCM2835_AUX_SPI_POLLING_LIMIT_US 30 #define BCM2835_AUX_SPI_POLLING_JIFFIES 2 -#define BCM2835_AUX_SPI_MODE_BITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH \ - | SPI_NO_CS) - struct bcm2835aux_spi { void __iomem *regs; struct clk *clk; @@ -389,12 +386,12 @@ static int bcm2835aux_spi_prepare_message(struct spi_master *master, bs->cntl[1] = BCM2835_AUX_SPI_CNTL1_MSBF_IN; /* handle all the modes */ - if (spi->mode & SPI_CPOL) + if (spi->mode & SPI_CPOL) { bs->cntl[0] |= BCM2835_AUX_SPI_CNTL0_CPOL; - if (spi->mode & SPI_CPHA) - bs->cntl[0] |= BCM2835_AUX_SPI_CNTL0_CPHA_OUT | - BCM2835_AUX_SPI_CNTL0_CPHA_IN; - + bs->cntl[0] |= BCM2835_AUX_SPI_CNTL0_OUT_RISING; + } else { + bs->cntl[0] |= BCM2835_AUX_SPI_CNTL0_IN_RISING; + } bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]); bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL0, bs->cntl[0]); @@ -434,7 +431,7 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev) } platform_set_drvdata(pdev, master); - master->mode_bits = BCM2835_AUX_SPI_MODE_BITS; + master->mode_bits = (SPI_CPOL | SPI_CS_HIGH | SPI_NO_CS); master->bits_per_word_mask = SPI_BPW_MASK(8); master->num_chipselect = -1; master->transfer_one = bcm2835aux_spi_transfer_one; -- 2.45.2