Implement SPI modes for CPOL/CPHA in the soft-spi driver. Previously, CPOL=1 was hard-coded and CPHA was implemented inversely (defaulting to CPHA=1).
Signed-off-by: Johannes Holland joh.ho@gmx.de --- drivers/spi/soft_spi.c | 56 ++++++++++++++++++++++++++++++++---------- 1 file changed, 43 insertions(+), 13 deletions(-)
diff --git a/drivers/spi/soft_spi.c b/drivers/spi/soft_spi.c index b80f810bd1..5932ce8c5c 100644 --- a/drivers/spi/soft_spi.c +++ b/drivers/spi/soft_spi.c @@ -58,10 +58,12 @@ static int soft_spi_sda(struct udevice *dev, int bit) static int soft_spi_cs_activate(struct udevice *dev) { struct udevice *bus = dev_get_parent(dev); + struct soft_spi_priv *priv = dev_get_priv(bus); struct soft_spi_platdata *plat = dev_get_platdata(bus); + int cidle = !!(priv->mode & SPI_CPOL);
dm_gpio_set_value(&plat->cs, 0); - dm_gpio_set_value(&plat->sclk, 0); + dm_gpio_set_value(&plat->sclk, cidle); /* to idle */ dm_gpio_set_value(&plat->cs, 1);
return 0; @@ -79,11 +81,14 @@ static int soft_spi_cs_deactivate(struct udevice *dev)
static int soft_spi_claim_bus(struct udevice *dev) { + struct udevice *bus = dev_get_parent(dev); + struct soft_spi_priv *priv = dev_get_priv(bus); + int cidle = !!(priv->mode & SPI_CPOL); /* * Make sure the SPI clock is in idle state as defined for * this slave. */ - return soft_spi_scl(dev, 0); + return soft_spi_scl(dev, cidle); }
static int soft_spi_release_bus(struct udevice *dev) @@ -114,15 +119,18 @@ static int soft_spi_xfer(struct udevice *dev, unsigned int bitlen, uchar tmpdout = 0; const u8 *txd = dout; u8 *rxd = din; - int cpha = priv->mode & SPI_CPHA; + int cpha = !!(priv->mode & SPI_CPHA); + int cidle = !!(priv->mode & SPI_CPOL); unsigned int j;
debug("spi_xfer: slave %s:%s dout %08X din %08X bitlen %u\n", dev->parent->name, dev->name, *(uint *)txd, *(uint *)rxd, bitlen);
- if (flags & SPI_XFER_BEGIN) + if (flags & SPI_XFER_BEGIN) { soft_spi_cs_activate(dev); + udelay(plat->spi_delay_us); + }
for (j = 0; j < bitlen; j++) { /* @@ -140,22 +148,42 @@ static int soft_spi_xfer(struct udevice *dev, unsigned int bitlen, tmpdin = 0; }
- if (!cpha) - soft_spi_scl(dev, 0); + /* + * CPOL 0: idle is low (0), active is high (1) + * CPOL 1: idle is high (1), active is low (0) + */ + + /* + * drive bit + * CPHA 1: CLK from idle to active + */ + if (cpha) + soft_spi_scl(dev, !cidle); if ((plat->flags & SPI_MASTER_NO_TX) == 0) soft_spi_sda(dev, !!(tmpdout & 0x80)); udelay(plat->spi_delay_us); - if (cpha) - soft_spi_scl(dev, 0); + + /* + * sample bit + * CPHA 0: CLK from idle to active + * CPHA 1: CLK from active to idle + */ + if (!cpha) + soft_spi_scl(dev, !cidle); else - soft_spi_scl(dev, 1); + soft_spi_scl(dev, cidle); tmpdin <<= 1; if ((plat->flags & SPI_MASTER_NO_RX) == 0) tmpdin |= dm_gpio_get_value(&plat->miso); tmpdout <<= 1; udelay(plat->spi_delay_us); - if (cpha) - soft_spi_scl(dev, 1); + + /* + * drive bit + * CPHA 0: CLK from active to idle + */ + if (!cpha) + soft_spi_scl(dev, cidle); } /* * If the number of bits isn't a multiple of 8, shift the last @@ -168,15 +196,17 @@ static int soft_spi_xfer(struct udevice *dev, unsigned int bitlen, *rxd++ = tmpdin; }
- if (flags & SPI_XFER_END) + if (flags & SPI_XFER_END) { + udelay(plat->spi_delay_us); soft_spi_cs_deactivate(dev); + }
return 0; }
static int soft_spi_set_speed(struct udevice *dev, unsigned int speed) { - /* Accept any speed */ + /* Ignore any speed settings. Speed is implemented via "spi-delay-us" */ return 0; }
-- 2.26.0