Comment # 15 on bug 1193064 from Takashi Iwai

How about rebinding?

echo -n "i2c-ELAN0000:00" > /sys/bus/i2c/drivers/i2c_hid/unbind
echo -n "i2c-ELAN0000:00" > /sys/bus/i2c/drivers/i2c_hid/bind

You can try the above while the touchpad is working, and verify that the first
call stops the touchpad and the second restores.  If that works, try the same
after the resume.  It might be a different file name than i2c_hid on the recent
system, so check the path beforehand.  (e.g. on my 5.16-rc kernel, it's
i2c_hid_acpi).