On Saturday, November 9, 2019, Peter Maydell <peter.maydell@linaro.org> wrote:

On Fri, 8 Nov 2019 at 19:32, Aleksandar Markovic
<aleksandar.m.mail@gmail.com> wrote:
>
> > [a] Is there any particular reason that you picked DS3231 ? Linux kernel
> > has drivers for DS3232/34 only [1]. I did read the datasheets of both
> > 3232 & 3231 and found that they are quite similar except for the 236
> > bytes of SRAM support found only in 3232.
> >
>
> Yes, DS3231 is a part of a board we want to support in future.

We should probably prefer to go with a device that's a
missing part of a board we already support -- generally
the project prefers not to take device models that don't
have a use, ie they go in with the board model rather
than before. This also means we have some way of testing
the code :-)

All agreed, Peter.

However, there is an additional interesting aspect here:

DS3231 is a fairly common module for RasPi. (and, is common for some other systems with non-arm cpus too)

I hoped that setting up RasPi emulation with newly created RTC device would be a peace of cake, but it might be that I was wrong. I see certain inconsistency between our command line switches "-rtc" and "-watchdog". Using "-watchdog", a watchdog timer model can be specified, but for "-rtc", it looks, there is no such posibility.

Given modularity of RasPi, wouldn't it be nice for end users to be able to specify an RTC via command line?

If usage of command line is ruled out, what would be an alternative way to integrate particular RTC support in RasPi (for any QEMU-supported RTC, not only (for now, just envisioned) DS3231)?

Sory if I missed something big here.

Yours,

Aleksandar

thanks
-- PMM