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 <stephanolbrich@gmx.de>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c
index a6e25c6..496f9ad 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 @@
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 @@
}
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;