On Fri, Feb 11, 2011 at 4:20 PM, Jarkko Nikula <jhnikula@xxxxxxxxx> wrote:
> On Fri, 11 Feb 2011 12:15:18 +0530
> Keerthy <j-keerthy@xxxxxx> wrote:
>
>> From: Richard woodruff <r-woodruff2@xxxxxx>
>>
>> ProDB00017052 - ARDY interrupt reasserted after being cleared.
>> This errata caused intermittent i2c instabilty(1 error per 3 hours) on several
>> customer platforms. After applying the workaround the intermittent errors were
>> not seen. This is not captured in the usual errata documents.
>>
>> The workaround is to have a double clear of ARDY status in
>> irq handler.
>>
>> Signed-off-by: Richard woodruff <r-woodruff2@xxxxxx>
>> Signed-off-by: Keerthy <j-keerthy@xxxxxx>
>> ---
>> drivers/i2c/busses/i2c-omap.c | 3 ++-
>> 1 files changed, 2 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
>> index 445de08..9bcefae 100644
>> --- a/drivers/i2c/busses/i2c-omap.c
>> +++ b/drivers/i2c/busses/i2c-omap.c
>> @@ -851,7 +851,8 @@ complete:
>> OMAP_I2C_STAT_AL)) {
>> omap_i2c_ack_stat(dev, stat &
>> (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR |
>> - OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
>> + OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR |
>> + OMAP_I2C_STAT_ARDY));
>
> Most probably this is correct but I was just wondering are there any use
> for ARDY interrupt (register access ready) anyway and is the ARDY here
> caused by omap_i2c_write_reg for STAT_NACK in a few lines above.
>
Hello Jarkko,
ARDY interrupt indicates that the previous access has been performed
and the registers are ready to be accessed again. Coming to the second
part i checked even when the STAT_NACK bit is set and after
omap_i2c_write_reg the ARDY bit is not set. So that does not seem to
be the cause of ARDY getting set.
> Just my 2 cents about possible further patches (while this having the
> priority as fixes the issue).
>
> --
> Jarkko
>
--
Regards and Thanks,
Keerthy
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