[U-Boot] [PATCH v6 2/5] i2c: fsl_i2c: i2c_read(): dont try to write address w/ alen=0

[dirk.eibach at gdsys.cc]

From: Reinhard Pfau <pfau at gdsys.de>

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

Signed-off-by: Dirk Eibach <dirk.eibach at gdsys.cc>
Signed-off-by: Reinhard Pfau <reinhard.pfau at gdsys.cc>


Signed-off-by: Dirk Eibach <dirk.eibach at gdsys.cc>
---
Changes in v6: None
Changes in v5:
- fix i2c_probe

Changes in v4: None
Changes in v3: None
Changes in v2:
- whitespace fixes

 drivers/i2c/fsl_i2c.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/fsl_i2c.c b/drivers/i2c/fsl_i2c.c
index 1c7265d..5d7e010 100644
--- a/drivers/i2c/fsl_i2c.c
+++ b/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);
-- 
1.8.3