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spi: fsl-espi: add support for dual output read mode 

This patch adds support for dual output read mode.

It was successfully tested on a P1014-based device with S25FL128S
SPINOR flash. With 50MHz SPI clock the read rate is 11MByte/s.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Heiner Kallweit 2016-11-09 22:58:34 +01:00 committed by Mark Brown
parent aca75157d9
commit 8263cb33c8
1 changed files with 12 additions and 1 deletions
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13
drivers/spi/spi-fsl-espi.c
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@ -334,6 +334,8 @@ static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t)
mpc8xxx_spi->tx_len = mpc8xxx_spi->rxskip;
mpc8xxx_spi->rx_len = t->len - mpc8xxx_spi->rxskip;
mpc8xxx_spi->rx = t->rx_buf + mpc8xxx_spi->rxskip;
if (t->rx_nbits == SPI_NBITS_DUAL)
spcom |= SPCOM_DO;
}
fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPCOM, spcom);
@ -369,6 +371,11 @@ static int fsl_espi_trans(struct spi_message *m, struct spi_transfer *trans)
int ret;
mspi->rxskip = fsl_espi_check_rxskip_mode(m);
if (trans->rx_nbits == SPI_NBITS_DUAL && !mspi->rxskip) {
dev_err(mspi->dev, "Dual output mode requires RXSKIP mode!\n");
return -EINVAL;
}
fsl_espi_copy_to_buf(m, mspi);
fsl_espi_setup_transfer(spi, trans);
@ -387,7 +394,7 @@ static int fsl_espi_do_one_msg(struct spi_master *master,
struct spi_message *m)
{
struct mpc8xxx_spi *mspi = spi_master_get_devdata(m->spi->master);
unsigned int delay_usecs = 0;
unsigned int delay_usecs = 0, rx_nbits = 0;
struct spi_transfer *t, trans = {};
int ret;
@ -398,6 +405,8 @@ static int fsl_espi_do_one_msg(struct spi_master *master,
list_for_each_entry(t, &m->transfers, transfer_list) {
if (t->delay_usecs > delay_usecs)
delay_usecs = t->delay_usecs;
if (t->rx_nbits > rx_nbits)
rx_nbits = t->rx_nbits;
}
t = list_first_entry(&m->transfers, struct spi_transfer,
@ -409,6 +418,7 @@ static int fsl_espi_do_one_msg(struct spi_master *master,
trans.delay_usecs = delay_usecs;
trans.tx_buf = mspi->local_buf;
trans.rx_buf = mspi->local_buf;
trans.rx_nbits = rx_nbits;
if (trans.len)
ret = fsl_espi_trans(m, &trans);
@ -580,6 +590,7 @@ static int fsl_espi_probe(struct device *dev, struct resource *mem,
mpc8xxx_spi_probe(dev, mem, irq);
master->mode_bits |= SPI_RX_DUAL;
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
master->setup = fsl_espi_setup;
master->cleanup = fsl_espi_cleanup;