On Thu, 2008-08-21 at 11:32 -0500, Scott Wood wrote: > On Thu, Aug 21, 2008 at 12:10:12AM -0700, David Miller wrote: > > Mostly straightforward stuff _except_ for the I2C address encoding. > > > > What I2C IEEE1275 device binding was used to write that code in > > of_i2c.c? Is it some PowerPC specific thing? Was it "invented" > > by the embedded folks (I hope not)? > > Yes, it was "invented". There was no documented i2c OF binding that I > could find, and AFAIR nobody came forward with examples of existing > practice at the time. Well, there were examples in the powermac code :-) > > And, furthermore, the device address is shifted up 1 bit higher > > than the Linux I2C layer expects. It includes the low direction > > bit, bit 0, so we have to shift it down by 1 bit before we give > > it to the Linux I2C layer. > > Yuck. Apple does the same. IE. I take the address from "reg" and shift it right by one bit before passing it to linux. > > 2) When CONFIG_SPARC, shift the device address down by one bit before > > giving it to the Linux I2C layer. > > Maybe we should distinguish by the type of I2C bus node instead. Or fix the embedded stuff :-) Ben. -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
