Hello Dmitry, On 01/16/2018 02:55 PM, Dmitry Mastykin wrote: > On Sun, 3 Dec 2017 22:40:50 +0100, Javier Martinez Canillas > <javierm@xxxxxxxxxx> wrote: > >> The buses should honor the firmware interface used to register the device, >> but the I2C core reports a MODALIAS of the form i2c:<device> even for I2C >> devices registered via OF. >> >> This means that user-space will never get an OF stype uevent MODALIAS even >> when the drivers modules contain aliases exported from both the I2C and OF >> device ID tables. For example, an Atmel maXTouch Touchscreen registered by >> a DT node with compatible "atmel,maxtouch" has the following module alias: >> >> $ cat /sys/class/i2c-adapter/i2c-8/8-004b/modalias >> i2c:maxtouch >> >> So udev won't be able to auto-load a module for an OF-only device driver. >> Many OF-only drivers duplicate the OF device ID table entries in an I2C ID >> table only has a workaround for how the I2C core reports the module alias. >> >> This patch changes the I2C core to report an OF related MODALIAS uevent if >> the device was registered via OF. So for the previous example, after this >> patch, the reported MODALIAS for the Atmel maXTouch will be the following: >> >> $ cat /sys/class/i2c-adapter/i2c-8/8-004b/modalias >> of:NtrackpadT<NULL>Catmel,maxtouch >> >> NOTE: This patch may break out-of-tree drivers that were relying on this >> behavior, and only had an I2C device ID table even when the device >> was registered via OF. There are no remaining drivers in mainline >> that do this, but out-of-tree drivers have to be fixed and define >> a proper OF device ID table to have module auto-loading working. >> > > Hello Javier, > thank you for your patch! > Thanks a lot for testing! Hopefully Wolfram will review/merge this soon, otherwise in the meantime drivers are going to add I2C device ID tables just as a workaround or new drivers won't include a OF device ID tables since these aren't really required today. I made sure that all the drivers in mainline were fixed before posting this, but haven't checked since then. Best regards, -- Javier Martinez Canillas Software Engineer - Desktop Hardware Enablement Red Hat
