[i2c] i2c-pport with kernel 2.6.X

Jean Delvare khali at linux-fr.org
Wed Apr 25 16:19:35 CEST 2007

Hi Pierre,

On Wed, 25 Apr 2007 11:29:36 +0200, pierre demanax wrote:
> Hi jean,
> Many thanks for those explanation, now i understand why some of those files 
> didn't match those of my kernel source.
> I did further investigation about i2c over parallel port as it doesn't work 
> yet on my system. I managed to get a scope and I tried to monitor signal on 
> my port.
> Actually I get NO HW activity on the port ( i tried i2cpport, as well as 
> i2c-parport with different pining, with the i2cdetect or sensors-detect 
> function..)
> Then I installed a parallel printer with appropriate drivers to check if the 
> port is well working :-). That part work.
> I guess i am doing something wrong.
> Next I summarize what I do in order to use the i2c over // port, maybe 
> someone could correct me:
> I self compiled my kernel which is a 2.6.20 ( I included all the i2c package 
> in the make menuconfig)
> Then I did an apt-get install lm-sensors. ( my system is a debian sarge with 
> a new kernel)
> Next I added the i2c_pport from rudolf marek, That i compiled with the help 
> of the i2c-community.
> In order to use the i2c , i modprobe manually the following ones:
> modprobe i2c-algo-bit
> modprobe i2c-dev
> insmod i2c-pport.ko ( modprobe doesn't work for that one) OR
> modprobe i2c-parport type=1 ....
> then I do i2cdetect 0  and also sensors-detect
> In the latter there is a message to detect sensors on the primitive parallel 
> port or the parallel port that give me the impression the driver is well 
> loaded.
> During the detection i used the scope on the pining refered in the 
> documentation. But on my system there are no activities ?
> Did i forget something ?

I seem to remember that i2c-pport only works when the parallel port is
in standard mode, not when it is in EPP/ECP mode. Check the mode in
your BIOS.

I also noticed that I wasn't able to use i2c-parport-light once the
"parport_pc" module has been loaded. parport_pc seems to somehow
reconfigure the parallel port in such a way that i2c-parport-light
can't do anything with it afterwards. So I suggest that you blacklist
the other drivers related to parallel port (such as lp) to make sure
they don't get automatically loaded.

Other than that, I don't know, sorry.

> regards,
> vincent

Il faudrait savoir, c'est Pierre ou Vincent ? :p

Jean Delvare

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