spi: sun4i: Add rx_buf NULL pointer check

Current driver doesn't check if the destination pointer is NULL.
This cause the data from the FIFO to be stored inside the internal
SDRAM ( address 0 ).

The patch add simple check if the destination pointer is NULL.

Signed-off-by: Stefan Mavrodiev <stefan@olimex.com>
Acked-by: Jagan Teki <jagan@openedev.com>
[jagan: fix commit message]
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>

diff --git a/drivers/spi/sun4i_spi.c b/drivers/spi/sun4i_spi.c
index b86b5a00adb9032672daaa02b640b2199002986d..38cc743c6144d9819d8f4c0fba7e932ef9d5ddf0 100644 (file)
--- a/drivers/spi/sun4i_spi.c
+++ b/drivers/spi/sun4i_spi.c
@@ -129,7 +129,8 @@ static inline void sun4i_spi_drain_fifo(struct sun4i_spi_priv *priv, int len)
 
        while (len--) {
                byte = readb(&priv->regs->rxdata);
-               *priv->rx_buf++ = byte;
+               if (priv->rx_buf)
+                       *priv->rx_buf++ = byte;
        }
 }