Elan I2C trackpad driver for Acer C720P (Celeron 2957U), Acer C740, Acer C910, Acer CB5-571, Asus C200, Asus C300 and many other chromebooks.
Tested on Acer C720P & C740 chromebooks with Elan I2C trackpad. May need minor adjustments for trackpad size on others; feel free to send a pull request.
Based on cypress crostrackpad3 driver.
Huge thanks to the vmulti and Linux Kernel projects, which I used for references. Also, thanks to Microsoft for open sourcing the Synaptics RMI I2C driver, which I also used as a reference.