Re: i2c-mxs woes

[Alexandre Belloni <alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>]

Hi Lucas,

On 19/04/2013 13:53, Lucas Stach wrote:
> Hi Alexandre,
>
> Am Freitag, den 19.04.2013, 13:37 +0200 schrieb Alexandre Belloni:
>> Hi,
>>
>> I'm having some issues with the i2c-mxs driver in 3.9. Marek already
>> pointed me to the patches from Lucas and that greatly improved the
>> situation.
>>
>> For the context, my board has three nau7802 adcs, connected to a gpio
>> i2c-muxer, connected to i2c1.
>>
>> Here is what I observe:
>>
>> On 3.9:
>>
>> # time cat /sys/bus/iio/devices/iio:device1/in_voltage0_raw 
>> 2620
>> real	0m 7.08s
>> user	0m 0.00s
>> sys	0m 0.02s
>> # time cat /sys/bus/iio/devices/iio:device1/in_voltage1_raw 
>> 2623
>> real	0m 6.07s
>> user	0m 0.01s
>> sys	0m 0.01s
>> # 
>>
> Is this with or without my patches? Before introduction of the error
> handling in PIO code there were a lot of situations where the controller
> would signal an error, but the driver would go on as usual, so the next
> transaction wouldn't succeed and stop for a whole second until the
> timeout hits and resets the controller.

This is with v2 of your patches. I applied "i2c-mxs remove races in PIO
code" and "i2c-mxs do error checking and handling in PIO mode"

Regards,

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com