Messages in this thread | | | Date | Fri, 25 Mar 2011 22:55:23 +0000 | From | Jamie Iles <> | Subject | Re: [RFC PATCHv3 1/4] drivers/otp: add initial support for OTP memory |
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On Fri, Mar 25, 2011 at 06:50:36PM -0400, Mike Frysinger wrote: > On Fri, Mar 25, 2011 at 18:47, Jamie Iles wrote: > > On Fri, Mar 25, 2011 at 05:58:05PM -0400, Mike Frysinger wrote: > >> On Fri, Mar 25, 2011 at 13:14, Jamie Iles wrote: > >> > +/* We'll allow OTP devices to be named otpa-otpz. */ > >> > +#define MAX_OTP_DEVICES 26 > >> > >> mmm is that still true ? > > > > I think so - the actual devices should be otpa-otpz, but when you > > register regions they could be otpa1, otpa2, otpb1, otpb2 etc. > > > >> > >> > +static unsigned long registered_otp_map[BITS_TO_LONGS(MAX_OTP_DEVICES)]; > >> > +static DEFINE_MUTEX(otp_register_mutex); > >> > >> do we really need this ? if we let the minor number dictate > >> availability, then we can increment until that errors/wraps, and we > >> dont need to do any tracking ... > > > > OK, so it would be nice to get rid of this but afaict we still need to > > do some accounting of available minor numbers in the range that we've > > allocated. We could do a simple increment % 255 for the minor number > > but if OTP devices are removed at runtime then that may get fragmented > > and we would need to do retries of device_register() which feels a bit > > too easy to mess up. > > > > Certainly allocating one major number for OTP devices then allocating > > the minors one by one would be much better than what I have now. > > > > We probably also want it so that if you remove the OTP device that has > > had regions called otpaN then reinsert it they doesn't suddenly become > > otpbN. > > yeah that's true. guess i'll leave it be then ;).
OK, but it still might be worth pruning it down to a single major number or is that something worth doing later on if it becomes needed?
> whatever naming is picked in /dev/ should match the stuff in /sys/ btw ...
I think that's working ok. On my system I have:
/sys/bus/otp/devices/otpa/otpa1/ /sys/bus/otp/devices/otpa/otpa2/
and
/dev/otpa1 /dev/otpa2
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