mpc8xxx_spi: fix SPI support on MPC8308RDB

The MPC8308RDB Reference Manual states that no bits in the SPMODE
register are allowed to change while the enable (EN) bit is set.

This driver changes the character length bits (LEN) while the enable
(EN) bit is set. Clearing the EN bit while changing the LEN bits makes
the driver work correctly on MPC8308RDB.

Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>

diff --git a/drivers/spi/mpc8xxx_spi.c b/drivers/spi/mpc8xxx_spi.c
index 44ab39dd3ff622b5d6d17c81cd1e6b89e4b0f0d4..4e46041dfff5df76c98561d161daa4a13790acd5 100644 (file)
--- a/drivers/spi/mpc8xxx_spi.c
+++ b/drivers/spi/mpc8xxx_spi.c
@@ -124,6 +124,8 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
                 * len > 16               0
                 */
 
+               spi->mode &= ~SPI_MODE_EN;
+
                if (bitlen <= 16) {
                        if (bitlen <= 4)
                                spi->mode = (spi->mode & 0xff0fffff) |
@@ -138,6 +140,8 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
                        dout += 4;
                }
 
+               spi->mode |= SPI_MODE_EN;
+
                spi->tx = tmpdout;      /* Write the data out */
                debug("*** spi_xfer: ... %08x written\n", tmpdout);