On Thu, Oct 25, 2018 at 02:47:59PM +0100, Richard Fitzgerald wrote:

> access. What does regmap debugfs do if you don't have a readables
> list? Just reading a debugfs shouldn't be able to kill the hardware.
> You might need to add a precious list which is more error prone
> than listing the valid readables we are using.

It assumes everything is readable unless it's explicitly told otherwise
or the register map is overall write only (like a 7x9 one).  You could
mark the registers as precious to cause it to only do explicit I/O
operations on them but that's not what you mean and won't be as good a
guarantee that nothing can trigger a read.