Messages in this thread | | | Date | Tue, 24 Jun 2014 12:12:49 +0100 | From | Mark Brown <> | Subject | Re: [PATCH] regmap: Add Kconfig option for debugfs register writes |
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On Wed, Jun 18, 2014 at 11:01:59PM +0200, Markus Pargmann wrote: > On Wed, Jun 18, 2014 at 01:11:27AM +0100, Mark Brown wrote:
> > This is deliberately hard to enable in order to make it clear that it > > should never, ever be used in production as a bodge around writing > > drivers and generally in order to reduce the risk to the rest of the > > system. Enabling this will typically give userspace full access to > > components like PMICs which have the potential to cause physical damage > > to the system if misused.
> The userspace already has full access to all those registers if you > want. For example memory mapped registeres can be written through > /dev/mem. I2C registers can easily be changed using i2c-tools or the > /dev/i2c-* devices. So you are already able to write a userspace driver > if you really want to.
Right, but in all cases except for /dev/mem the API ensures that you can't simultaneously run a kernel and userspace driver. It's not the userspace driver bit that's the problem but rather having both at the same time.
> I think this kconfig option would make it easier to debug hardware or > driver issues, as it is much more comfortable to have a clean kconfig > option.
Well, a major goal of doing things this way is to make it seem wrong to be using this too much! :P [unhandled content-type:application/pgp-signature] | |