spi: fix mxc_spi_slave structure allocation to clear memory

Use calloc() instead of malloc() to allocate the mxc_spi_slave structure.
Clearing the memory is necessary since most of the time this gets done
super early in boot, but on warm reboots, and when SPI probing is done
long after the init stages it could actually pick up previously used memory,
and things like the chipselect polarity and other data end up being filled
with trash data if not explicitly set by the board files.

This solves a semi-random, almost unreproducable error whereby SPI devices
act very, very strangly on boot. Tested on Efika MX over several years..

Signed-off-by: Matt Sealey <matt@genesi-usa.com>
Acked-by: Stefano Babic <sbabic@denx.de>

diff --git a/drivers/spi/mxc_spi.c b/drivers/spi/mxc_spi.c
index cf1462f94f8714e030d507a1117597eafd219841..13bebe8ac1f6b0de80cabb1718af0b0bb1da4d18 100644 (file)
--- a/drivers/spi/mxc_spi.c
+++ b/drivers/spi/mxc_spi.c
@@ -408,7 +408,7 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
        if (bus >= ARRAY_SIZE(spi_bases))
                return NULL;
 
-       mxcs = malloc(sizeof(struct mxc_spi_slave));
+       mxcs = calloc(sizeof(struct mxc_spi_slave), 1);
        if (!mxcs) {
                puts("mxc_spi: SPI Slave not allocated !\n");
                return NULL;