[U-Boot] [PATCH 47/50] rockchip: spi: Implement the delays

Simon Glass
2016-01-13T23:25:37Z

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>
---

drivers/spi/rk_spi.c | 27 +++++++++++++++++++++++----
1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/rk_spi.c b/drivers/spi/rk_spi.c
index 2570ca3..91538b4 100644
--- a/drivers/spi/rk_spi.c
+++ b/drivers/spi/rk_spi.c
@@ -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)
@@ -144,6 +161,8 @@ 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);
@@ -289,7 +308,7 @@ 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);
@@ -323,7 +342,7 @@ 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);

--
2.6.0.rc2.230.g3dd15c0