using a vanilla 3.7 Linux kernel for the i.MX28 EVK I started porting some drivers from the Freescale SDK based on 2.6.35.
The OTP driver allows reading the OTP cells via the sysfs but fails to write. I tracked the problem to a call to clk_get(). The name of the required clock seems to have changed from "hclk" to "hbus", but fixing that didn't help. sysfs shows a clock named "hbus". So what else could go wrong?