On 06/27/2016 02:13 PM, Wolfram Sang wrote: > Please read the above specification to understand how 10 bit addresses > are transferred over the wire. I think reading it will answer most of > your questions. Wikipedia brought me to this PDF file here: http://www.nxp.com/documents/user_manual/UM10204.pdf Section 3.1.11 "10-bit addressing" along with section 3.1.12 "Reserved addresses" indeed specify that the 7 bit addresses 0x78-0x7B are reserved for 10 bit addressing. The way it is written in the spec (1111 0XX) probably caused people to confuse it for 0xF0-0xF3 which I found in some messages on the mailing list. But that still leaves the question of where the 0xA... in the kernel docs came from. >> Is there a specific reason I can override i2cdetect but not i2cdump? > > Probably not. More likely, nobody needed it until now. Which is > understandable since the device you have has to be considered broken > regarding the I2C standard. But I think patches adding that could be > acceptable. Jean has the last word on this. > Section 3.1.12 ends with some musings about the assignment of addresses in "local systems". More specifically, it ends with the sentence "If it is known that the reserved address is never going to be used for its intended purpose, a reserved address can be used for a slave address." I _do_ know that there are no 10 bit addressed slaves in my application, so the spec allows me to use at those 4 slave address. Apparently it is not my device that is broken. -- 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
