From mboxrd@z Thu Jan 1 00:00:00 1970 From: santosh.shilimkar@ti.com (Santosh Shilimkar) Date: Sat, 16 Feb 2013 11:01:00 +0530 Subject: [RFC/NOT FOR MERGING 2/3] serial: omap: remove hwmod dependency In-Reply-To: <20130215163031.GA5724@atomide.com> References: <20130214171253.GC7144@atomide.com> <20130214175650.GA25891@arwen.pp.htv.fi> <20130214181217.GA11806@atomide.com> <20130214192719.GB26679@arwen.pp.htv.fi> <20130214193911.GD11806@atomide.com> <20130215101610.GR17852@n2100.arm.linux.org.uk> <511E3797.2070802@ti.com> <20130215132726.GT17852@n2100.arm.linux.org.uk> <511E38C3.7080404@ti.com> <20130215163031.GA5724@atomide.com> Message-ID: <511F1994.90101@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Friday 15 February 2013 10:00 PM, Tony Lindgren wrote: > * Santosh Shilimkar [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 at vger.kernel.org/msg85177.html