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MX28: SPI: Pull out the PIO transfer function

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Pull out all the PIO transfer logic into separate function,
so DMA can be added.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Otavio Salvador <otavio@ossystems.com.br>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
This commit is contained in:
Marek Vasut 2012-07-09 00:48:32 +00:00 • committed by Albert ARIBAUD
parent c7065fa824
commit ccd4d5a0d4
1 changed files with 41 additions and 33 deletions
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74
drivers/spi/mxs_spi.c
View file

@ -140,47 +140,19 @@ static void mxs_spi_end_xfer(struct mx28_ssp_regs *ssp_regs)
writel(SSP_CTRL0_IGNORE_CRC, &ssp_regs->hw_ssp_ctrl0_set); writel(SSP_CTRL0_IGNORE_CRC, &ssp_regs->hw_ssp_ctrl0_set);
} }
int spi_xfer(struct spi_slave *slave, unsigned int bitlen, static int mxs_spi_xfer_pio(struct mxs_spi_slave *slave,
const void *dout, void *din, unsigned long flags) char *data, int length, int write, unsigned long flags)
{ {
struct mxs_spi_slave *mxs_slave = to_mxs_slave(slave); struct mx28_ssp_regs *ssp_regs = slave->regs;
struct mx28_ssp_regs *ssp_regs = mxs_slave->regs;
int len = bitlen / 8;
char dummy;
int write = 0;
char *data = NULL;
if (bitlen == 0) {
if (flags & SPI_XFER_END) {
din = (void *)&dummy;
len = 1;
} else
return 0;
}
/* Half-duplex only */
if (din && dout)
return -EINVAL;
/* No data */
if (!din && !dout)
return 0;
if (dout) {
data = (char *)dout;
write = 1;
} else if (din) {
data = (char *)din;
write = 0;
}
if (flags & SPI_XFER_BEGIN) if (flags & SPI_XFER_BEGIN)
mxs_spi_start_xfer(ssp_regs); mxs_spi_start_xfer(ssp_regs);
while (len--) { while (length--) {
/* We transfer 1 byte */ /* We transfer 1 byte */
writel(1, &ssp_regs->hw_ssp_xfer_size); writel(1, &ssp_regs->hw_ssp_xfer_size);
if ((flags & SPI_XFER_END) && !len) if ((flags & SPI_XFER_END) && !length)
mxs_spi_end_xfer(ssp_regs); mxs_spi_end_xfer(ssp_regs);
if (write) if (write)
@ -220,4 +192,40 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
} }
return 0; return 0;
}
int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
const void *dout, void *din, unsigned long flags)
{
struct mxs_spi_slave *mxs_slave = to_mxs_slave(slave);
int len = bitlen / 8;
char dummy;
int write = 0;
char *data = NULL;
if (bitlen == 0) {
if (flags & SPI_XFER_END) {
din = (void *)&dummy;
len = 1;
} else
return 0;
}
/* Half-duplex only */
if (din && dout)
return -EINVAL;
/* No data */
if (!din && !dout)
return 0;
if (dout) {
data = (char *)dout;
write = 1;
} else if (din) {
data = (char *)din;
write = 0;
}
return mxs_spi_xfer_pio(mxs_slave, data, len, write, flags);
} }