diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/zynq_spi.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/spi/zynq_spi.c b/drivers/spi/zynq_spi.c index 5a9b1f0f2e..2b77f1ccdc 100644 --- a/drivers/spi/zynq_spi.c +++ b/drivers/spi/zynq_spi.c @@ -56,6 +56,8 @@ struct zynq_spi_platdata { struct zynq_spi_regs *regs; u32 frequency; /* input frequency */ u32 speed_hz; + uint deactivate_delay_us; /* Delay to wait after deactivate */ + uint activate_delay_us; /* Delay to wait after activate */ }; /* zynq spi priv */ @@ -63,6 +65,7 @@ struct zynq_spi_priv { struct zynq_spi_regs *regs; u8 cs; u8 mode; + ulong last_transaction_us; /* Time of last transaction end */ u8 fifo_depth; u32 freq; /* required frequency */ }; @@ -78,6 +81,10 @@ static int zynq_spi_ofdata_to_platdata(struct udevice *bus) /* FIXME: Use 250MHz as a suitable default */ plat->frequency = fdtdec_get_int(blob, node, "spi-max-frequency", 250000000); + plat->deactivate_delay_us = fdtdec_get_int(blob, node, + "spi-deactivate-delay", 0); + plat->activate_delay_us = fdtdec_get_int(blob, node, + "spi-activate-delay", 0); plat->speed_hz = plat->frequency / 2; debug("%s: regs=%p max-frequency=%d\n", __func__, @@ -133,10 +140,19 @@ static int zynq_spi_probe(struct udevice *bus) static void spi_cs_activate(struct udevice *dev) { struct udevice *bus = dev->parent; + struct zynq_spi_platdata *plat = bus->platdata; struct zynq_spi_priv *priv = dev_get_priv(bus); struct zynq_spi_regs *regs = priv->regs; u32 cr; + /* If it's too soon to do another transaction, wait */ + if (plat->deactivate_delay_us && priv->last_transaction_us) { + ulong delay_us; /* The delay completed so far */ + delay_us = timer_get_us() - priv->last_transaction_us; + if (delay_us < plat->deactivate_delay_us) + udelay(plat->deactivate_delay_us - delay_us); + } + clrbits_le32(®s->cr, ZYNQ_SPI_CR_CS_MASK); cr = readl(®s->cr); /* @@ -147,15 +163,23 @@ static void spi_cs_activate(struct udevice *dev) */ cr |= (~(1 << priv->cs) << ZYNQ_SPI_CR_SS_SHIFT) & ZYNQ_SPI_CR_CS_MASK; writel(cr, ®s->cr); + + if (plat->activate_delay_us) + udelay(plat->activate_delay_us); } static void spi_cs_deactivate(struct udevice *dev) { struct udevice *bus = dev->parent; + struct zynq_spi_platdata *plat = bus->platdata; struct zynq_spi_priv *priv = dev_get_priv(bus); struct zynq_spi_regs *regs = priv->regs; setbits_le32(®s->cr, ZYNQ_SPI_CR_CS_MASK); + + /* Remember time of this transaction so we can honour the bus delay */ + if (plat->deactivate_delay_us) + priv->last_transaction_us = timer_get_us(); } static int zynq_spi_claim_bus(struct udevice *dev) |