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-rw-r--r--drivers/i2c/busses/i2c-davinci.c24
1 files changed, 15 insertions, 9 deletions
diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index b8feac5f2ef..5795c8398c7 100644
--- 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);
@@ -358,17 +353,28 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
dev->terminate = 0;
/*
+ * 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);
+
+ /*
* First byte should be set here, not after interrupt,
* 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--;
}
- /* write the data into mode register; start transmitting */
+ /* 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,