Geode SC1100 i2c bus

[Milan Obuch]

On Sunday 04 February 2007 21:21, M. Warner Losh wrote:
> In message: <200702040918.37825.freebsd-hackers at dino.sk>
>
>             Milan Obuch <freebsd-hackers at dino.sk> writes:
> : On Sunday 04 February 2007 01:21, perryh at pluto.rain.com wrote:
> : > > > The ACB is at the same level than Uart, so I had a look at sio
> : > > > source and got a big headache. I'm not really used to drivers
> : > > > nor kernel programming stuff, that's why I need your help.
> : > >
> : > > Why do you compare ACB and UART? In FreeBSD, sio is serial i/o
> : > > controller, not superIO, maybe you are confused... ACB and UART
> : > > does not have much in common...
> : >
> : > As I read the OP, both the ACB and the serial are in the same chip
> : > (the superIO), so it would seem reasonable to expect that the method
> : > of accessing the device registers in the (currently unsupported) ACB
> : > might be similar to the method of accessing the device registers in
> : > the (supported) serial port.
> :
> : You are right from the point of view 'how to access registers'. But what
> : OP wrote could be understand another way, too - he tried to modify sio to
> : create acb driver, which would not achieve the correct results. There is
> : i2c infrastructure in FreeBSD, acb driver should fit into its place there
> : and it is not that easy - I tried to understand it, but nobody could/was
> : willing to/did not care to help me understand it.
>
> I'm happy to help you understand it.
>
> Warner
>

Great, I will go through the code and will ask. What made me not achieve 
progress was lack of docs - this area is, ehm, under-documented, and lack of 
description in pcf, the only i2c hardware controller in source tree 
currently. Correct me, if I am wrong and there are more - but not smbus, they 
are not the same thing, even if very near to each other. SMbus controller in 
FreeBSD does not expose i2c device to userland, as far as I read it, but this 
was some time ago.
I need some time to prepare myself, but I would like to get this working. 
There are some projects waiting for it...
Regards,
Milan

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