I'm running OpenBmc project on the x86 host. One of the applications from the OpenBmc ecosystem tries to find IPMI FRU devices on all available I2C buses. For that it would perform some transactions for every possible I2C device on every I2C bus to understand if it is an EEPROM or not. If the user doesn't want to scan some buses it can provide blocklist.json with addresses of the buses which shouldn't be scanned for FRU. But this blocklist operates with absolute addresses, which is why I want to be sure that my I2C buses would have fixed numbers on all systems. Also it can be the case when the user wants to make sure that buses behind different I2C muxes are numbered in a particular way. Shortly speaking, existing OpenBmc software relies on this alias functionality in a couple of different scenarios. There are many examples of its usage in the BMC DTS code for different machines. Therefore I wonder if it is possible to do the same with x86 via ACPI tables to support existing OpenBmc applications. Best regards, Konstantin Aladyshev On Wed, Feb 12, 2025 at 2:08 PM Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote: > > On Wed, Feb 12, 2025 at 11:18:44AM +0300, Konstantin Aladyshev wrote: > > Hello! > > > > Is it possible to assign fixed numbers to i2c buses via ACPI code? > > > > In DTS code it is done via aliases > > (https://docs.kernel.org/i2c/i2c-sysfs.html#caveat). > > > > For example: > > ``` > > aliases { > > i2c20 = &imux20; > > } > > > > &i2c1 { > > status = "okay"; > > > > i2c-mux@77 { > > ... > > imux20: i2c@0 { > > ... > > } > > ... > > } > > } > > ``` > > > > Is it possible to do something like that in ACPI code? > > Why? What the problem do you actually have? > > -- > With Best Regards, > Andy Shevchenko > >
