Re: [RFC 5/5] [powerpc] Implement a p1010rdb clock source.

On 08/08/2011 02:48 PM, Robin Holt wrote:

quoted

quoted

OK.  Dug a bit more.  The p1010 built-in clocksource seems to be the
periphereal clock frequency which is system bus frequency divided
by 2.  The clock source can not be changed, but the clock divider can
by freezing the interface and setting the CTRL register.  This appears

quoted

Which bit(s) in the CTRL register is/are this?

PRESDIV bits 24-31.  Documented on the P1010 reference manual section 21.3.3.2.

We have and use these bits on arm, too. These bits are calculated and
set by the driver[1]. These bits are touched in freescale's 2.6.35
version of the flexcan driver, too.

From my point of view it makes no sense to specify this divider in the
OF-tree. We just need the frequency of the clock entering the flexcan
core. Which is, as you say, the system bus freq/2.

[1]
http://lxr.linux.no/linux+v3.0.1/drivers/net/can/flexcan.c#L597
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