> This doesn't work. I see a number of these WARN_ON()s trigger and I
> think the reason is that i2c_init() always fails now. The cause seems to
> be that i2c_init() calls i2c_add_driver(&dummy_driver), which will now
> always fail, because is_register is set to true *after* that call. There
> is no way I see I2C working at all after this patch.

Same conclusion here. Too much trust applied to the original patch, mea
culpa and sorry! Will send the fixup (tested!) in a minute.