On Sat, 24 Nov 2018, Michael Schmitz wrote: > > Am 20.11.2018 um 23:02 schrieb Andreas Schwab: > > On Nov 20 2018, Linus Walleij <linus.wall...@linaro.org> wrote: > > > > > Yes you already see the same as I see: this chip MK68901 has no less > > > than four timers. I bet the kernel is just using one of them, out of > > > habit. > > > > Note that not all timers can be used freely. Some of them are > > hardwired to generate the clock for the serial interfaces. > > Timer A is used by the DMA sound driver - no workaround possible there. > > Timer B is used by the framebuffer driver, but it's used only once to > reprogram the screen base address at driver init. This one could > potentially be used after framebuffer init to improve the clocksource > accuracy. >
I don't think it would make a good clocksource as MFP timers are all 8 bits wide. It could be used as a clock event device in the course of a GENERIC_CLOCKEVENTS conversion (discussed elsewhere in this thread), though the longest timed interrupt inverval would be only 21 ms. -- > Timer D is already used to generate timer interrupts used to poll the > ROM port network card / USB adapters. This timer is initialized early in > the boot process, which prevents using the MFP UART as serial console > (something that I hadn't properly considered before). I'll send a patch > for that. I'll also consider using timer B or timer C interrupts instead > to poll ROM port hardware. > > There are no serial drivers anymore that could use the MFP UART > hardware, so that point is somewhat moot at present. > > Cheers, > > Michael > > > Andreas. > > >
