[PATCH v3 2/2] ARM: am335x: Changed timer

Jan Lübbe jlu at pengutronix.de
Fri Jul 17 07:57:48 PDT 2015

On Fr, 2015-07-17 at 15:39 +0200, Daniel Schultz wrote:
> The dmtimer0 is too inaccurate to be used for measurements.
> We switch to the more accurate dmtimer2.

Ah, OK, after looking at the TRM again, the real reason for the
inaccuracy seems to be that the 32KiHz for dmtimer0 is *not* derived
from the RTC crystal, but from an internal RC oscillator.

The kernel uses dmtimer1 for the clocksource by switching it to the
M_OSC in the PRCM.

The dmtimer2 is used for clockevents and runs from M_OSC by default.
While we could set the dmtimer1 source to M_OSC in the clock setup, it
seems simpler to just use dmtimer2.

The commit message should explain the reasoning behind the switch.

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