From: Alok Chauhan <[email protected]> In NACK error condition, I2C controller violates clock-to-data setup time before stop. In Software, because of this reset of controller is happening before I2C controller could complete STOP condition.
Added delay of 2 clock period before reset the controller in case of NACK error. Signed-off-by: Alok Chauhan <[email protected]> --- Instead of setting constant value for delay as was in previous patch, now in the current modification delay will be calculated based on clock frequency of the bus. drivers/i2c/busses/i2c-tegra.c | 8 ++++++++ 1 files changed, 8 insertions(+), 0 deletions(-) diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index 6381604..62e197c 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -517,6 +517,14 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev, if (likely(i2c_dev->msg_err == I2C_ERR_NONE)) return 0; + /* + * In NACK error condition resetting of I2C controller happens + * before STOP condition is properly completed by I2C controller, + * so wait for 2 clock cycle to complete STOP condition. + */ + if (i2c_dev->msg_err == I2C_ERR_NO_ACK) + udelay(DIV_ROUND_UP(2 * 1000000, i2c_dev->bus_clk_rate)); + tegra_i2c_init(i2c_dev); if (i2c_dev->msg_err == I2C_ERR_NO_ACK) { if (msg->flags & I2C_M_IGNORE_NAK) -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
