Merge commit 'v2.6.37-rc1' into for-2.6.37

[~andy/linux] / drivers / i2c / busses / i2c-davinci.c

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 2222c87876b97bc711b6d739fd4a82deef7db330..5795c8398c7c3a25af82319a0ce1d46741def8b2 100644 (file)
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -331,21 +331,16 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
        INIT_COMPLETION(dev->cmd_complete);
        dev->cmd_err = 0;
 
-       /* Take I2C out of reset, configure it as master and set the
-        * start bit */
-       flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST | DAVINCI_I2C_MDR_STT;
+       /* Take I2C out of reset and configure it as master */
+       flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST;
 
        /* if the slave address is ten bit address, enable XA bit */
        if (msg->flags & I2C_M_TEN)
                flag |= DAVINCI_I2C_MDR_XA;
        if (!(msg->flags & I2C_M_RD))
                flag |= DAVINCI_I2C_MDR_TRX;
-       if (stop)
-               flag |= DAVINCI_I2C_MDR_STP;
-       if (msg->len == 0) {
+       if (msg->len == 0)
                flag |= DAVINCI_I2C_MDR_RM;
-               flag &= ~DAVINCI_I2C_MDR_STP;
-       }
 
        /* Enable receive or transmit interrupts */
        w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
@@ -357,7 +352,11 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
 
        dev->terminate = 0;
 
-       /* write the data into mode register */
+       /*
+        * Write mode register first as needed for correct behaviour
+        * on OMAP-L138, but don't set STT yet to avoid a race with XRDY
+        * occuring before we have loaded DXR
+        */
        davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
 
        /*
@@ -365,12 +364,19 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
         * because transmit-data-ready interrupt can come before
         * NACK-interrupt during sending of previous message and
         * ICDXR may have wrong data
+        * It also saves us one interrupt, slightly faster
         */
        if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) {
                davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++);
                dev->buf_len--;
        }
 
+       /* Set STT to begin transmit now DXR is loaded */
+       flag |= DAVINCI_I2C_MDR_STT;
+       if (stop && msg->len != 0)
+               flag |= DAVINCI_I2C_MDR_STP;
+       davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
+
        r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
                                                      dev->adapter.timeout);
        if (r == 0) {