"Sudhakar Rajashekhara" <sudhakar.raj@xxxxxx> writes:
> Hi,
>
> On Wed, Jan 27, 2010 at 05:11:28, Kevin Hilman wrote:
>> From: Dirk Behme <dirk.behme@xxxxxxxxxxxxxx>
>>
>> This fixes Oops at kernel startup while "scanning" for TLV320AIC23IDx
>> addresses.
>>
>> Signed-off-by: Alexander Vasiliev <alexvasiljev@xxxxxxxxx>
>> Signed-off-by: Brad Griffis <bgriffis@xxxxxx>
>> Signed-off-by: Dirk Behme <dirk.behme@xxxxxxxxx>
>> Acked-by: Kevin Hilman <khilman@xxxxxxxxxx>
>> ---
>> drivers/i2c/busses/i2c-davinci.c | 29 +++++++++++++++++++++++++----
>> 1 files changed, 25 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
>> index c89687a..444a9f2 100644
>> --- a/drivers/i2c/busses/i2c-davinci.c
>> +++ b/drivers/i2c/busses/i2c-davinci.c
>
> [...]
>
>> @@ -290,6 +293,16 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
>> davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
>>
>> dev->terminate = 0;
>> +
>> + /* 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 */
>> + if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) {
>> + davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++);
>> + dev->buf_len--;
>> + }
>> +
>
> I found an issue on DA850 while using this patch.
ok, I'll drop this one for 2.6.34 until we figure this out.
> I think the above code should come after the
> below lines because an I2C transaction is being carried out before configuring the I2C mode
> register (which has bits to configure Master, Start condition etc), which causes undefined
> behavior.
hmm, are you seeing this behavior on davinci git too? This is the same
patch that has been in davinci git for some time?
Kevin
>
>> /* write the data into mode register */
>> davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
>>
>
> Regards,
> Sudhakar
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