From: Alok Chauhan <alokc@xxxxxxxxxx>
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 worst case delay of 1 ms (assuming lowest
clock frequency will be 1 KHZ) before reset the
controller in case of NACK error.
Signed-off-by: Alok Chauhan <alokc@xxxxxxxxxx>
---
drivers/i2c/busses/i2c-tegra.c | 9 +++++++++
1 files changed, 9 insertions(+), 0 deletions(-)
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 6381604..b731499 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -517,6 +517,15 @@ 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 worst case delay of 1 ms (assuming lowest clock
+ * frequency will be 1 KHz) to complete STOP condition.
+ */
+ if (i2c_dev->msg_err == I2C_ERR_NO_ACK)
+ mdelay(1);
+
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
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