diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-davinci.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-davinci.c | 24 |
1 files changed, 15 insertions, 9 deletions
diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c index b8feac5f2ef4..5795c8398c7c 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, |