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From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= 
	<u.kleine-koenig@pengutronix.de>
Subject: Re: [RFC PATCH 2/5] clk: Introduce 'clk_round_rate_nearest()'
Date: Tue, 20 May 2014 09:51:58 +0200
Message-ID: <20140520075158.GK16662@pengutronix.de>
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To: =?iso-8859-1?Q?S=F6ren?= Brinkmann <soren.brinkmann@xilinx.com>
Cc: Mike Turquette <mturquette@linaro.org>, "Rafael J. Wysocki" <rjw@rjwysocki.net>, Viresh Kumar <viresh.kumar@linaro.org>, Russell King <linux@arm.linux.org.uk>, Michal Simek <michal.simek@xilinx.com>, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, cpufreq@vger.kernel.org, linux-arm-kernel@lists.infradead.org

Hello,

On Mon, May 19, 2014 at 10:29:05AM -0700, S=F6ren Brinkmann wrote:
> With the improvements suggested by you I have this now:
>=20
> long clk_round_rate_nearest(struct clk *clk, unsigned long rate)
> {
> 	unsigned long lower, upper;
>=20
> 	lower =3D clk_round_rate(clk, rate);
> 	if (lower >=3D rate)
> 		return lower;
>=20
> 	upper =3D clk_round_rate(clk, rate + (rate - lower) - 1);
> 	if (upper =3D=3D lower)
> 		return upper;
>=20
> 	lower =3D rate + 1;
> 	while (lower < upper) {
> 		unsigned long rounded, mid;
>=20
> 		mid =3D lower + ((upper - lower) >> 1);
> 		rounded =3D clk_round_rate(clk, mid);
> 		if (rounded < lower)
> 			lower =3D mid + 1;
> 		else
> 			upper =3D rounded;
> 	}
>=20
> 	return upper;
> }
This is nearly my version now. I just lacks the overflow check when
calculating upper and I skipped the early return if (upper =3D=3D lower=
).
(Instead the while condition evaluates to false on the first hit and
returns with the same result.)

Other than that I added a few comments. :-)

Something we still should resolve is the return type. It should match
clk_round_rate, but should both be signed or unsigned?=20

Uwe

--=20
Pengutronix e.K.                           | Uwe Kleine-K=F6nig        =
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