Re: Changing the current RTC device interface

[Alan Cox <alan@lxorguk.ukuu.org.uk>]

On Tue, 2002-05-28 at 15:24, Abraham vd Merwe wrote:
> I have a board with multiple RTC chips (Built-in RTC in the processor +
> external battery backed RTC).
> 
> There are pros and cons to each RTC chip. The CPU's RTC doesn't have a
> battery, but have high resolution timing + multiple rtc counters/interrupts,
> so it is especially suited for apps that want to use /dev/rtc for high
> resolution timing.
> 
> On the other hand the external RTC chip can keep time, but its timing is
> crap (1hz to 8khz in steps of powers of two), so you don't want to use that
> for timing.
> 
> At the moment, Linux only allows for a single RTC device, so one can't reap
> the benefits of both chips mentioned above.
> 
> How about we get a major number assigned to rtc subsystem and then allows
> for multiple rtc devices.

I think you should wait until 2.5 has reached the point we have a
finished devicefs and 32bit dev_t. Basically we don't have enough device
numbering left for such trivialities right now.