On Thu, 10 Nov 2011 07:58:35 -0800, Jeffrey (Sheng-Hui) Chu wrote: > > > > -----Original Message----- > > From: Jean Delvare [mailto:khali@xxxxxxxxxxxx] > > Sent: Thursday, November 10, 2011 10:08 AM > > To: Linux I2C > > Cc: Jeffrey (Sheng-Hui) Chu > > Subject: 10-bit address support > > > > Hi all, > > > > After Sheng-Hui's fix to i2c-algo-bit, it would seem that we are almost > > there with 10-bit slave address support. There's one remaining thing > > that worries me though: the 7-bit and 10-bit address spaces overlap. > > From Documentation/i2c/ten-bit-addresses: > > > > "The sets of addresses do not intersect: the 7 bit address 0x10 is not > > the same as the 10 bit address 0x10 (though a single device could > > respond to both of them)." > > From my understanding of the spec, there is no overlap. > The 10-bit client at 0x10 will be addressed by the following address sequence: > 0Xf0 0X10 <data-out> or 0xf0 0x10 <restart> 0xf1<data-in> > > The 7-bit client at 0x10 will be addressed by the following address sequence: > 0x20 <data-out> or 0x21 <data-in> > > 0xf0 is equivalent to 7-bit address of 0x78 which is a reserved address in 7-bit space. A compliant 7-bit client should not use or respond to this address. what you wrote above is completely exact, but is also completely unrelated to what I explained. The overlapping that currently exists is in the device names inside the kernel. It's a pure software issue. > Don't need to do any workaround. IMHO I'm certain we do. -- Jean Delvare -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
