i2c: fsl_i2c: i2c_read(): dont try to write address w/ alen=0

if alen is 0: no longer start a write cycle before reading data.

Signed-off-by: Dirk Eibach <dirk.eibach@gdsys.cc>
Signed-off-by: Reinhard Pfau <reinhard.pfau@gdsys.cc>
Acked-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Andy Fleming <afleming@freescale.com>

drivers/i2c/fsl_i2c.c

@@ -383,13 +383,16 @@ i2c_read(u8 dev, uint addr, int alen, u8 *data, int length)
 	int i = -1; /* signal error */
 	u8 *a = (u8*)&addr;
 
-	if (i2c_wait4bus() >= 0
+	if (i2c_wait4bus() < 0)
+		return -1;
+
+	if ((!length || alen > 0)
 	    && i2c_write_addr(dev, I2C_WRITE_BIT, 0) != 0
 	    && __i2c_write(&a[4 - alen], alen) == alen)
 		i = 0; /* No error so far */
 
-	if (length
-	    && i2c_write_addr(dev, I2C_READ_BIT, 1) != 0)
+	if (length &&
+	    i2c_write_addr(dev, I2C_READ_BIT, alen ? 1 : 0) != 0)
 		i = __i2c_read(data, length);
 
 	writeb(I2C_CR_MEN, &i2c_dev[i2c_bus_num]->cr);