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Date: Wed, 7 Oct 2015 18:19:49 +0100
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@codeaurora.org>, Arnd Bergmann <arnd@arndb.de>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
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        Nishanth Menon <nm@ti.com>, Dmitry Torokhov <dtor@chromium.org>,
        linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] PM / OPP: fix debugfs files for 64-bit
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On Wed, Oct 07, 2015 at 06:33:24PM +0530, Viresh Kumar wrote:
> Cc'ing Mike and Stephen..
> 
> On 07-10-15, 13:57, Greg Kroah-Hartman wrote:
> > On Wed, Oct 07, 2015 at 04:51:49PM +0530, Viresh Kumar wrote:
> > > On 07-10-15, 12:07, Greg Kroah-Hartman wrote:
> > > > Why would you be wanting to create a "unsigned long" as an api anyway?
> > > > Just force it to be u64 all the time, can't you do that?
> > > 
> > > Okay, so the variable in question (lets say frequency) is an 'unsigned
> > > long' and that's how all the APIs of clock framework expect/define
> > > it.
> > > 
> > > And you are probably saying that we do this:
> > > 
> > > unsigned long freq;
> > > 
> > > debugfs_create_u64((u64 *)&freq);
> > > 
> > > Right? Or are you asking to update clock APIs to be converted to u64?
> > 
> > Yes, they should be u64 as I doubt you want to debug problems that you
> > have in the driver where it works on a 64bit system but doesn't on a
> > 32bit one.
> 
> Firstly changing the clock API (and other similar APIs) to make
> frequency u64 instead of 'unsigned long', looks like a giant effort.
> There are too many users of those API, etc..
> 
> Over that, it might be good performance wise to use u32 for 32 bit
> systems and u64 for 64 bit one, to represent clock frequency and maybe
> that's why we chose unsigned long there.

Ok, then stop exporting it in debugfs and everyone will be happy :)

greg k-h