where is the pcf8574 kernel module?

[stairwayoflight]

Hi,

I am trying to use the pcf8574 chip. The kernel from (feisty I believe) has the module, but when I try "modprobe pcf8574" on jaunty it says there is no such module.

I am building a kernel today (for something else) but for kicks I thought I'd see if I could build support for the chip. I'm following the directions here (http://ubuntuforums.org/showthread.php?t=56835).

So I installed linux-source, started with the old config, and did a make menuconfig. When I poked inside drivers->i2c->chips (I can't remember the exact location, but some i2c chips were there) there was no option to build a module for the pcf8574 that I could see. Also there were so few options, there was no way to "scroll down" to find it, etc.

I suppose it is really not on my system (I had a stock kernel at this point):


me@home:~$ ls /lib/modules/2.6.28-11-generic/kernel/drivers/i2c/chips
at24.ko ds1682.ko eeprom.ko max6875.ko pcf8591.ko tps65010.ko tsl2550.ko

Also, while my new kernel was compiling, I did a

find / -iname "pcf8574*" and got
/usr/src/linux-source-2.6.28/drivers/i2c/chips/pcf8574.cso I know its at least in the kernel source tree. Pardon me if I have missed the obvious, but what do I do to build this module for my kernel?

Regards,
Timothy

[tonuonu]

I have same question for next, 9.10 Ubuntu and no answer after extensive Googling yet.

[tonuonu]

Found something. Those modules are moved to GPIO and named pcf857x. So I did

sudo modprobe pcf857x

PCF8574 were not autodetected in my case. Looked further and found:

http://www.mjmwired.net/kernel/Documentation/i2c/instantiating-devices

In my case PCF8574-s are 0x38 and 0x39 on bus 0:

root@Unknown-00-10-dc-61-9e-47:~# i2cdetect 0
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-0.
I will probe address range 0x03-0x77.
Continue? [Y/n]
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: 20 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- 38 39 -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
root@Unknown-00-10-dc-61-9e-47:~#

Actually this is Velleman K8000 board.

root@Unknown-00-10-dc-61-9e-47:~# echo pcf8574 0x38 > /sys/class/i2c-adapter/i2c-0/new_device
root@Unknown-00-10-dc-61-9e-47:~# echo pcf8574 0x39 > /sys/class/i2c-adapter/i2c-0/new_device
root@Unknown-00-10-dc-61-9e-47:~#

They did appear:

root@Unknown-00-10-dc-61-9e-47:~# ls -la /sys/bus/i2c/devices/0-0038/
total 0
drwxr-xr-x 3 root root 0 2009-11-18 21:40 .
drwxr-xr-x 7 root root 0 2009-11-18 21:40 ..
-r--r--r-- 1 root root 4096 2009-11-18 21:40 modalias
-r--r--r-- 1 root root 4096 2009-11-18 21:40 name
drwxr-xr-x 2 root root 0 2009-11-18 21:40 power
lrwxrwxrwx 1 root root 0 2009-11-18 21:40 subsystem -> ../../../../../../bus/i2c
-rw-r--r-- 1 root root 4096 2009-11-18 21:40 uevent
root@Unknown-00-10-dc-61-9e-47:~#

unsure what to do next. Still no input-output controls. I see error in dmesg:

[33420.468728] i2c-adapter i2c-0: The new_device interface is still experimental and may change in a near future
[33420.468910] pcf857x: probe of 0-0038 failed with error -22
[33420.468919] i2c-adapter i2c-0: new_device: Instantiated device pcf8574 at 0x38
[33439.724806] i2c-adapter i2c-0: The new_device interface is still experimental and may change in a near future
[33439.724996] pcf857x: probe of 0-0039 failed with error -22
[33439.725006] i2c-adapter i2c-0: new_device: Instantiated device pcf8574 at 0x39

error 22 is

#define EINVAL 22 /* Invalid argument */

Error seems to come from dd.c:

root@Unknown-00-10-dc-61-9e-47:~/linux-2.6.31/drivers# grep "probe of" */*
ata/sata_mv.c: * mv_platform_probe - handle a positive probe of an soc Marvell
ata/sata_mv.c: * mv_pci_init_one - handle a positive probe of a PCI Marvell host
base/dd.c: "%s: probe of %s failed with error %d\n",
ieee1394/nodemgr.c: HPSB_DEBUG("Speed probe of node " NODE_BUS_FMT " yields %s",
scsi/ultrastor.c:/* ??? A probe of address 0x310 screws up NE2000 cards */
root@Unknown-00-10-dc-61-9e-47:~/linux-2.6.31/drivers#