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rockchip: spi: Implement the delays

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Some devices need delays before and after activiation. Implement these
features in the SPI driver so that we will be able to enable the Chrome
OS EC.

Signed-off-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Simon Glass 2016-01-21 19:44:10 -07:00
parent 486478282e
commit 183a3a0f67
1 changed files with 23 additions and 4 deletions
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27
drivers/spi/rk_spi.c
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@ -32,6 +32,7 @@ struct rockchip_spi_platdata {
s32 frequency; /* Default clock frequency, -1 for none */
fdt_addr_t base;
uint deactivate_delay_us; /* Delay to wait after deactivate */
uint activate_delay_us; /* Delay to wait after activate */
};
struct rockchip_spi_priv {
@ -101,16 +102,32 @@ static int rkspi_wait_till_not_busy(struct rockchip_spi *regs)
return 0;
}
static void spi_cs_activate(struct rockchip_spi *regs, uint cs)
static void spi_cs_activate(struct udevice *dev, uint cs)
{
struct udevice *bus = dev->parent;
struct rockchip_spi_platdata *plat = bus->platdata;
struct rockchip_spi_priv *priv = dev_get_priv(bus);
struct rockchip_spi *regs = priv->regs;
debug("activate cs%u\n", cs);
writel(1 << cs, &regs->ser);
if (plat->activate_delay_us)
udelay(plat->activate_delay_us);
}
static void spi_cs_deactivate(struct rockchip_spi *regs, uint cs)
static void spi_cs_deactivate(struct udevice *dev, uint cs)
{
struct udevice *bus = dev->parent;
struct rockchip_spi_platdata *plat = bus->platdata;
struct rockchip_spi_priv *priv = dev_get_priv(bus);
struct rockchip_spi *regs = priv->regs;
debug("deactivate cs%u\n", cs);
writel(0, &regs->ser);
/* 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 rockchip_spi_ofdata_to_platdata(struct udevice *bus)
@ -145,6 +162,8 @@ static int rockchip_spi_ofdata_to_platdata(struct udevice *bus)
50000000);
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);
debug("%s: base=%x, periph_id=%d, max-frequency=%d, deactivate_delay=%d\n",
__func__, (uint)plat->base, plat->periph_id, plat->frequency,
plat->deactivate_delay_us);
@ -290,7 +309,7 @@ static int rockchip_spi_xfer(struct udevice *dev, unsigned int bitlen,
/* Assert CS before transfer */
if (flags & SPI_XFER_BEGIN)
spi_cs_activate(regs, slave_plat->cs);
spi_cs_activate(dev, slave_plat->cs);
while (len > 0) {
int todo = min(len, 0xffff);
@ -324,7 +343,7 @@ static int rockchip_spi_xfer(struct udevice *dev, unsigned int bitlen,
/* Deassert CS after transfer */
if (flags & SPI_XFER_END)
spi_cs_deactivate(regs, slave_plat->cs);
spi_cs_deactivate(dev, slave_plat->cs);
rkspi_enable_chip(regs, false);