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tegra: spi: Drop the claim_bus() method to correct delays

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At present the driver does not properly honour the requested SPI CS
deactivation delay since the SPI bus is changed in the claim_bus() method.

Everything the claim_bus() method does can be done when the device is probed
(setting the speed and mode) and at the start of a new transfer (where the
fifo_status is already cleared). So drop this method.

Also, until the delay is complete, we should not touch the bus, so make sure
that spi_cs_activate() is called before other things are done in the xfer()
method.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
This commit is contained in:
Simon Glass 2015-06-05 14:39:33 -06:00 committed by Tom Warren
parent bbe0d4db53
commit 635c2515c3
1 changed files with 9 additions and 17 deletions

26
drivers/spi/tegra114_spi.c
View File

@ -143,24 +143,18 @@ static int tegra114_spi_probe(struct udevice *bus)
{
struct tegra_spi_platdata *plat = dev_get_platdata(bus);
struct tegra114_spi_priv *priv = dev_get_priv(bus);
struct spi_regs *regs;
priv->regs = (struct spi_regs *)plat->base;
regs = priv->regs;
priv->last_transaction_us = timer_get_us();
priv->freq = plat->frequency;
priv->periph_id = plat->periph_id;
return 0;
}
static int tegra114_spi_claim_bus(struct udevice *dev)
{
struct udevice *bus = dev->parent;
struct tegra114_spi_priv *priv = dev_get_priv(bus);
struct spi_regs *regs = priv->regs;
/* Change SPI clock to correct frequency, PLLP_OUT0 source */
clock_start_periph_pll(priv->periph_id, CLOCK_ID_PERIPH, priv->freq);
clock_start_periph_pll(priv->periph_id, CLOCK_ID_PERIPH,
priv->freq);
/* Clear stale status here */
setbits_le32(&regs->fifo_status,
@ -175,9 +169,8 @@ static int tegra114_spi_claim_bus(struct udevice *dev)
SPI_FIFO_STS_RX_FIFO_EMPTY);
debug("%s: FIFO STATUS = %08x\n", __func__, readl(&regs->fifo_status));
/* Set master mode and sw controlled CS */
setbits_le32(&regs->command1, SPI_CMD1_M_S | SPI_CMD1_CS_SW_HW |
(priv->mode << SPI_CMD1_MODE_SHIFT));
setbits_le32(&priv->regs->command1, SPI_CMD1_M_S | SPI_CMD1_CS_SW_HW |
(priv->mode << SPI_CMD1_MODE_SHIFT) | SPI_CMD1_CS_SW_VAL);
debug("%s: COMMAND1 = %08x\n", __func__, readl(&regs->command1));
return 0;
@ -249,6 +242,9 @@ static int tegra114_spi_xfer(struct udevice *dev, unsigned int bitlen,
ret = 0;
if (flags & SPI_XFER_BEGIN)
spi_cs_activate(dev);
/* clear all error status bits */
reg = readl(&regs->fifo_status);
writel(reg, &regs->fifo_status);
@ -260,9 +256,6 @@ static int tegra114_spi_xfer(struct udevice *dev, unsigned int bitlen,
/* set xfer size to 1 block (32 bits) */
writel(0, &regs->dma_blk);
if (flags & SPI_XFER_BEGIN)
spi_cs_activate(dev);
/* handle data in 32-bit chunks */
while (num_bytes > 0) {
int bytes;
@ -385,7 +378,6 @@ static int tegra114_spi_set_mode(struct udevice *bus, uint mode)
}
static const struct dm_spi_ops tegra114_spi_ops = {
.claim_bus = tegra114_spi_claim_bus,
.xfer = tegra114_spi_xfer,
.set_speed = tegra114_spi_set_speed,
.set_mode = tegra114_spi_set_mode,