i2c: xlp9xx: Handle NACK on DATA properly

BugLink: https://bugs.launchpad.net/bugs/1762812
In case we receive NACK on DATA we shouldn't be resetting the controller,
rather we should issue STOP command. This will terminate the current
transaction and -EIO is returned.

While at that handle the SMBus Quick Command properly.
We shouldn't be setting the XLP9XX_I2C_CMD_READ/WRITE for such
transactions.

Signed-off-by: George Cherian <george.cherian@cavium.com>
Reviewed-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
(cherry picked from commit e349d7d08e7044caf37a36409305edbd5af013c7)
Signed-off-by: dann frazier <dann.frazier@canonical.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>

diff --git a/drivers/i2c/busses/i2c-xlp9xx.c b/drivers/i2c/busses/i2c-xlp9xx.c
index 42dd1fa0b6442550577fbeca13c4c0ea220896ba..eb8913eba0c5c144c7d1b0986f51862bac1887f7 100644 (file)
--- a/drivers/i2c/busses/i2c-xlp9xx.c
+++ b/drivers/i2c/busses/i2c-xlp9xx.c
@@ -352,7 +352,9 @@ static int xlp9xx_i2c_xfer_msg(struct xlp9xx_i2c_dev *priv, struct i2c_msg *msg,
 
        /* set cmd reg */
        cmd = XLP9XX_I2C_CMD_START;
-       cmd |= (priv->msg_read ? XLP9XX_I2C_CMD_READ : XLP9XX_I2C_CMD_WRITE);
+       if (msg->len)
+               cmd |= (priv->msg_read ?
+                       XLP9XX_I2C_CMD_READ : XLP9XX_I2C_CMD_WRITE);
        if (last_msg)
                cmd |= XLP9XX_I2C_CMD_STOP;
 
@@ -361,12 +363,12 @@ static int xlp9xx_i2c_xfer_msg(struct xlp9xx_i2c_dev *priv, struct i2c_msg *msg,
        timeleft = msecs_to_jiffies(XLP9XX_I2C_TIMEOUT_MS);
        timeleft = wait_for_completion_timeout(&priv->msg_complete, timeleft);
 
-       if (priv->msg_err) {
+       if (priv->msg_err & XLP9XX_I2C_INTEN_BUSERR) {
                dev_dbg(priv->dev, "transfer error %x!\n", priv->msg_err);
-               if (priv->msg_err & XLP9XX_I2C_INTEN_BUSERR)
-                       xlp9xx_i2c_init(priv);
-               return (priv->msg_err & XLP9XX_I2C_INTEN_NACKADDR) ?
-                       -ENXIO : -EIO;
+               xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CMD, XLP9XX_I2C_CMD_STOP);
+               return -EIO;
+       } else if (priv->msg_err & XLP9XX_I2C_INTEN_NACKADDR) {
+               return -ENXIO;
        }
 
        if (timeleft == 0) {