Re: [RFC/NOT FOR MERGING 2/3] serial: omap: remove hwmod dependency

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On Friday 15 February 2013 10:00 PM, Tony Lindgren wrote:
* Santosh Shilimkar <santosh.shilimkar@xxxxxx> [130215 05:34]:
On Friday 15 February 2013 06:57 PM, Russell King - ARM Linux wrote:
On Fri, Feb 15, 2013 at 06:56:47PM +0530, Santosh Shilimkar wrote:
Whats your view on use of arch_ioremap_caller() hook ? This can allow
us to avoid the dual ioremap() issue discussed here if the hook
maintains the list of mapped ios.

I was even thinking of having such intelligence within the core
ioremap code but thought that might be too invasive.

Why do you even need it?  There's no problem with ioremapping the same
space multiple times (you end up with multiple mappings but that
shouldn't be a problem, except for the additional space used.)

It just waste of iospace and Tony insisted to have just single ioremap()
hence all this discussion

The main goal is to avoid duplicating data both in hwmod and DT.
That's pretty much solved as we can have the driver probe populate
the common data for hwmod from DT as Santosh has already demonstrated.

Right.

Then we also want the driver specific idle and reset code to be done
in the drivers rather than in hwmod and glue it together with hwmod
using runtime PM. The biggest issue there is how do we reset and idle
some piece of hardware for PM purposes when there's no driver loaded.

Driver idle functions is getting sorted out. There is no need for driver
to fiddle around it since PM runtime back-end can take care of of it.
One attempt to clean that is here [1]

For the reset, we need to have a generic runtime hook as discussed and
that should take care of reset as well. That way driver just calls
generic

For the duplicate ioremapping, I don't think there's any need to
do it if we get things right.

Good to know. So overall, I think we do have a way to move forward
and get right things done.

Regards,
Santosh

[1] http://www.mail-archive.com/linux-omap@xxxxxxxxxxxxxxx/msg85177.html
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