From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephan Olbrich Subject: [PATCH v2 2/2] spi: bcm2835aux: fix CPOL/CPHA setting Date: Sun, 14 Feb 2016 11:04:29 +0100 Message-ID: <1455444269-4797-3-git-send-email-stephanolbrich@gmx.de> References: <1455444269-4797-1-git-send-email-stephanolbrich@gmx.de> Cc: Stephan Olbrich To: Mark Brown , Stephen Warren , Lee Jones , Eric Anholt , linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rpi-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Martin Sperl Return-path: In-Reply-To: <1455444269-4797-1-git-send-email-stephanolbrich-Mmb7MZpHnFY@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: 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 --- 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 103335e..7428091 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; -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html