smbus & i2c: why i2c is not enabled on ich?

[Bernd Walter]

On Sun, Sep 21, 2008 at 01:55:45PM +0200, Paolo Pisati wrote:
> 
> Any reason why i2c mode in not enable in ichsmb?

Because the controller is a SMB controller and not a I2C one.
SMB is more specific than I2C in that it defines complete I2C
sequences.
With SMB you don't have the individual control over all I2C
phases.
You can do SMB with an I2C controller, but you can't do raw
I2C with an SMB controller.
Use SMB to address your devices - SMB is good enough to handle
most I2C cases.

> ichsmb0 at pci0:0:31:3:    class=0x0c0500 card=0x82d81043 chip=0x266a8086 rev=0x04 hdr=0x00
>     vendor     = 'Intel Corporation'
>     device     = '82801FB (ICH6) SMBus Controller'
>     class      = serial bus
>     subclass   = SMBus
> 
> piso at nano:~/eeebsd >sudo pciconf -rb pci0:0:31:3: 0x40
> 01 
> piso at nano:~/eeebsd >sudo ./scan_smbus 
> res: 0 slave = 0x44 data = 
> res: 0 slave = 0x50 data = 
> res: 0 slave = 0x69 data = 
> res: 0 slave = 0xC4 data = 
> res: 0 slave = 0xD0 data = 
> res: 0 slave = 0xE9 data = 
> piso at nano:~/eeebsd >sudo pciconf -wb pci0:0:31:3: 0x40 5
> piso at nano:~/eeebsd >sudo pciconf -rb pci0:0:31:3: 0x40
> 05 
> piso at nano:~/eeebsd >sudo ./scan_smbus
> res: 0 slave = 0x44 data = FF FF FF FF 
> res: 0 slave = 0x50 data = 0A 60 40 00 05 30 45 00 82 08 00 00 0C 04 
> res: 0 slave = 0x69 data = FF F7 00 00 01 0F 07 E0 18 46 1B 24 D8 63 00 
> res: 0 slave = 0xC4 data = FF FF FF FF 
> res: 0 slave = 0xD0 data = 0A 60 40 00 05 30 45 00 82 08 00 00 0C 04 
> res: 0 slave = 0xE9 data = FF F7 00 00 01 0F 07 E0 18 46 1B 24 D8 63 00 
> 
> FYI this is on an asus eeepc.
> --
> bye,
> P.
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-- 
B.Walter <bernd at bwct.de> http://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.