Re: [PATCH 1/3] i2c: Revert "i2c: xiic: Do not reset controller before every transfer"

[Lars-Peter Clausen <lars@metafoo.de>]

On 11/17/2015 03:28 PM, Shubhrajyoti Datta wrote:
> On Tue, Nov 17, 2015 at 1:04 PM, Lars-Peter Clausen <lars@metafoo.de> wrote:
>> On 11/17/2015 06:17 AM, Shubhrajyoti Datta wrote:
>>> On Mon, Nov 16, 2015 at 7:12 PM, Lars-Peter Clausen <lars@metafoo.de> wrote:
>>>> Commit d701667bb331 ("i2c: xiic: Do not reset controller before every
>>>> transfer") removed the reinitialization of the controller before the start
>>>> of each transfer. Apparently this change is not safe to make and the commit
>>>> results in random I2C bus failures.
>>>
>>> Which is the platform and the ip version that you  saw the issue.
>>> Did you see the issue with read and write as  well?
>>
>> The IP version is the axi-iic v2.0 Revision 8. I've tested this on a few
>> platforms, custom ones and standard ones and I could reproduce it on most.
>> One of them was on the ZED board. The one where I couldn't reproduce it was
>> the ZC706. But that doesn't necessarily mean it doesn't happen there, just
>> that it is not triggered by the testcase.
> All the boards having the same version of the ip is what I have understood.
> 
> Thanks for the info I will try to  reproduce the issue.
> 
>>
>> The problem is that it is random corruption,
> Of registers?

To be honest I don't know if there is corruption during I2C write transfers,
but there is definitely corruption during read transactions.

- Lars