I understand that, but I'm trying to figure out why of_iomap() is okay for hundreds of other drivers, but not this one. I've used it dozens of times myself, without ever worrying about overlapping
regions.
The driver would work fine with just of_iomap(). But the resource range check comes basically for free and it does help to catch errors, so I'd recommend on using it rather than not using it.
There's also the fact that it's a devm_ function which means less error handling code that we can break which is nice. There's probably a case for an improved OF helper here...
Using this instead of of_iomap() is because "devm_" and resource range check as Lars and Mark said, and there are more than one SAI device here which will be added later, maybe the resource range check is needed.
Thanks. -- BRS Xiubo