Re: [lm-sensors] Alix 2D2

[Guenter Roeck <guenter.roeck@ericsson.com>]

On Wed, Aug 17, 2011 at 01:25:55AM -0400, Jean-Denis Girard wrote:
> Hi,
> 
> Le 16/08/2011 06:47, Guenter Roeck a écrit :
> > First question is what you mean with "for some time now". days ? weeks ?
> > months ? years ? since 3.0 ? 2.6.39 ? 2.4.16 ?
> 
> Unfortunately I don't know, but it is more than one year. It did work in
> 2.6.32.2, I'm sure it didn't work in 2.6.38, 2.6.39.
> 
> > Would be great if you can point to the most recent working kernel.
> 
> Sorry, I didn't notice when it stopped to work.
> 
> > 
> > Second, please provide output of "i2cdetect 0" (i2c-dev needs to be
> > loaded for this to work). That should show us if the sensor is still
> > detected on the i2c bus.
> 
> [admin@ix100 ~]$ sudo i2cdetect 0
> Error: Could not open file `/dev/i2c-0': No such device
> 
> > 
> > If it is, please also provide output of "i2cdump 0 0x4c".
> > 
> > For the lm90 module, please make sure that it is really loaded. You can
> > verify this with the "lsmod" command.
> 
> lsmod gives:
> Module                  Size  Used by
> lm90                    7852  0
> i2c_dev                 3324  0
> scx200_acb              3388  0
> ...
> 
> This is what I see in my logs
> i2c /dev entries driver
> i2c-core: driver [lm90] registered
> 

Looks like the i2c adapter is not recognized. Do you see anything in /sys/class/i2c-adapter ?

Looking into the i2c bus driver code, it was recently converted into a platform driver.
The supporting mfd driver would be cs5535-mfd. That might be one possible reason
for your problem, though it happened less than a year ago.

There have been other changes over time; since you don't know when the problem started,
it will be quite difficult if not impossible to track down the problem. You may have to
do some trials with different kernel versions to identify when the problem was introduced,
and then do some development work and use bisect to track down the actual commit.

Anyway, this is quite obviously a i2c bus driver problem, meaning you are on the wrong
mailing list. i2c issues should be discussed on linux-i2c@vger.kernel.org.

Thanks,
Guenter

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