Re: [RFC 2/4] [flexcan] Introduce a flexcan_clk set of functions.

On Fri, Aug 05, 2011 at 02:29:46PM +0200, Marc Kleine-Budde wrote:

On 08/05/2011 01:36 PM, Robin Holt wrote:

quoted

I implemented the coding style changes below (Sorry I missed the two
the first time).

np :)

quoted

As for a better implementation, I guess I would need to understand what
is being attempted here.  I only marginally understand the flexcan
hardware on the Freescale P1010 and certainly am clueless about arm
implementations of flexcan.  I just skimmed over freescale's site

The arm side is working already :)
However we just support the busclock on ARM [1]. For the first shot
stick to that clock, too.

[1] (http://lxr.linux.no/linux+v3.0/drivers/net/can/flexcan.c#L857)

quoted

and it looks like I would be looking at their i.MX25, i.MX28, i.MX35,
and i.MX53 family of processors.  I will attempt to find some useful
documentation of those and look at the kernel sources for what the clk_*
functions are trying to accomplish.

I _THINK_ I understand.  It looks like I could implement this as a powerpc
p1010 specific thing and get the same effect without impacting flexcan.c.
I also think I understand that the i.MX25 family of processors do
essentially the same thing the p1010 is doing for determining the
clock rate.

It seems that arch/powerpc/platforms/512x/clock.c implements a clock
interface. I think the p1010 should implement something similar. (Note:
I'm not a ppc guy :)

I'm looking forward for new patches.

I agree.  I think I will have that implemented shortly after I get to the
office (about an hour for drive, etc).  I think I am going to implement
a simple match on the dev_id of flexcan.0 or flexcan.1 and otherwise
return failure.

I also looked at implementing the CLOCKDEV_LOOKUP but think that is
going to drive me to drink.

Thanks,
Robin