I haven't really heard of any sort of cause to the Texas war of independence outside of just "they were populated by Americans who wanted to be free" and I'm starting to think that it's entirely American aggression rather than any sort of oppression on the part of the Mexicans.
Santa Ana repealed the Mexican Constitution of 1824 and created a new one, which immediately touched off civil war - the Yucatan and Coahuila revolted, and there were also revolts elsewhere.
For Texas, there were several major reasons - slavery (Mexico had abolished it), local vs. federal control, outrage at Santa Anna, and immigration.
Many of the signers of the Texas Declaration of Independence were actually illegal immigrants (and many from the South), and Mexico was absolutely not happy that Americans were flooding into Texas and immediately getting into spats with local government.
For example, William Travis, of Alamo fame, arrived in Texas in 1831 and almost immediately joined a militia against Mexican rule.
To add to this, Mexico's original goal was to get homesteaders and colonists, but Texas was rife with land speculation much like the US during the period. Rather than getting new citizens that would assimilate to be Mexicans (as the original intent when Stephen Austin was approved to bring in colonists), what Mexico got were armed Americans that immediately got into confrontations with Mexican officials.