spi: mxc_spi: Fix handling of chip select

In decode_cs() function the polarity of the chip select must be taken into
account.

Also, for the case of low active chip select, the CS was activated too early.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>

diff --git a/drivers/spi/mxc_spi.c b/drivers/spi/mxc_spi.c
index 13bebe8ac1f6b0de80cabb1718af0b0bb1da4d18..b6bad989527b75b6e94d1f1184e929a66203e9e1 100644 (file)
--- a/drivers/spi/mxc_spi.c
+++ b/drivers/spi/mxc_spi.c
@@ -387,7 +387,7 @@ static int decode_cs(struct mxc_spi_slave *mxcs, unsigned int cs)
        if (cs > 3) {
                mxcs->gpio = cs >> 8;
                cs &= 3;
-               ret = gpio_direction_output(mxcs->gpio, 0);
+               ret = gpio_direction_output(mxcs->gpio, !(mxcs->ss_pol));
                if (ret) {
                        printf("mxc_spi: cannot setup gpio %d\n", mxcs->gpio);
                        return -EINVAL;
@@ -414,6 +414,8 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
                return NULL;
        }
 
+       mxcs->ss_pol = (mode & SPI_CS_HIGH) ? 1 : 0;
+
        ret = decode_cs(mxcs, cs);
        if (ret < 0) {
                free(mxcs);
@@ -425,7 +427,6 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
        mxcs->slave.bus = bus;
        mxcs->slave.cs = cs;
        mxcs->base = spi_bases[bus];
-       mxcs->ss_pol = (mode & SPI_CS_HIGH) ? 1 : 0;
 
        ret = spi_cfg_mxc(mxcs, cs, max_hz, mode);
        if (ret) {