linux-kernel - Re: [PATCH] PM / OPP: fix debugfs files for 64-bit

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Message-ID: <Pine.LNX.4.44L0.1510081023080.1502-100000@iolanthe.rowland.org>
Date:	Thu, 8 Oct 2015 10:25:56 -0400 (EDT)
From:	Alan Stern <stern@...land.harvard.edu>
To:	Viresh Kumar <viresh.kumar@...aro.org>
cc:	Arnd Bergmann <arnd@...db.de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...eaurora.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
	Nishanth Menon <nm@...com>,
	Dmitry Torokhov <dtor@...omium.org>,
	<linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] PM / OPP: fix debugfs files for 64-bit

On Thu, 8 Oct 2015, Viresh Kumar wrote:

> > In my patch, I assumed that if 32-bit architectures work fine today, then
> > we don't need more range on 64-bit architectures either.
> 
> The problem here is that we haven't fixed it properly.
> - clock framework expects it to be unsigned long
> - DT is sending a 64 bit value in Hz
> - But we are storing and exposing it in u32
> 
> That's weird, isn't it?
> 
> So, either we update clock API and other similar APIs to u64 or u32
> (which may not be the right thing to do), Or we keep it unsigned long
> here as well and add debugfs_create_ulong().

I don't see why debugfs can't accomodate C's builtin types, rather than 
insisting on predetermined sizes.  After, the printf family of 
functions does that: %u vs. %lu.  In fact, there's no way to tell 
printf that a particular value is 32 bits or 64 bits.

Alan Stern

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