Date: Sun, 4 Feb 2007 21:35:25 +0100 From: Milan Obuch <freebsd-hackers@dino.sk> To: freebsd-hackers@freebsd.org Subject: Re: Geode SC1100 i2c bus Message-ID: <200702042135.25962.freebsd-hackers@dino.sk> In-Reply-To: <20070204.132150.1288664462.imp@bsdimp.com> References: <200702031940.00128.freebsd-hackers@dino.sk> <200702040918.37825.freebsd-hackers@dino.sk> <20070204.132150.1288664462.imp@bsdimp.com>
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On Sunday 04 February 2007 21:21, M. Warner Losh wrote: > In message: <200702040918.37825.freebsd-hackers@dino.sk> > > Milan Obuch <freebsd-hackers@dino.sk> writes: > : On Sunday 04 February 2007 01:21, perryh@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 -- This address is used only for mailing list response. Do not send any personal messages to it, use milan in address instead.
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