you may wish to put an oscilloscope on the parallel port lines to see if it is working.
Also try modprobe i2c-algo-bit debug=1 to get some debugging printks.
Oliver Joa wrote:
> hi,
>
> i want to use the i2c-pport driver to control some pcf8574. i have wired
> the pcf8574 to the parallel-port and connected 8 leds to the pcf8574 to
> show the status of the 8 bit outports. i have loaded the following
> modules:
>
> debian:/home/olli# lsmod
> Module Size Used by Not tainted
> rtc 5916 0 (unused)
> i2c-proc 6016 0 (unused)
> i2c-dev 3776 0
> i2c-pport 1440 0
> i2c-algo-bit 7880 0 [i2c-pport]
> i2c-core 14464 0 [i2c-proc i2c-dev i2c-algo-bit]
> eepro100 18572 1 (autoclean)
> mii 2288 0 (autoclean) [eepro100]
>
> dmesg gives me the following:
> i2c-core.o: i2c core module version 2.8.0 (20030714)
> i2c-pport.o: i2c
> Primitive parallel port adapter module version 2.8.0
> (20030714)
> i2c-pport.o: found device at 0x378.
> i2c-dev.o: Registered 'Primitive Parallel port adaptor' as minor 0
>
> when i make a:
> strace i2cset 0 0x20 0x0 1
> i get the following:
>
> nanosleep({5, 0}, {5, 0}) = 0
> ioctl(3, 0x720, 0xbffffcf0) = -1 EPERM (Operation not
> permitted)
> write(2, "Warning - write failed\n", 23Warning - write failed
> ) = 23
> ioctl(3, 0x720, 0xbffffcf0) = -1 EPERM (Operation not
> permitted)
> write(2, "Warning - readback failed\n", 26Warning - readback failed
> ) = 26
>
> debian:/home/olli# cat /dev/i2c-0
> cat: /dev/i2c-0: Remote I/O error
>
> it seems that there is a i/o problem.
>
> debian:/home/olli# cat /proc/bus/i2c
> i2c-0 i2c Primitive Parallel port adaptor Bit-shift
> algorithm
> debian:/home/olli# cat /proc/bus/i2c-0
> debian:/home/olli#
>
> debian:/proc/sys/dev/sensors# ls -la
> total 0
> dr-xr-xr-x 2 root root 0 Aug 10 19:15 .
> dr-xr-xr-x 5 root root 0 Aug 10 19:15 ..
> -rw-r--r-- 1 root root 0 Aug 10 19:15 chips
> debian:/proc/sys/dev/sensors# cat chips
> debian:/proc/sys/dev/sensors#
>
> an i2cdump 0 0x20 does not get any values from the chip.
>
> do you have any idea why i can not get a connection to the chip?
>
> thank
>
> oliver joa
>
>
