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Date: Mon, 26 Feb 2018 11:25:57 +0100
From: Maxime Ripard <maxime.ripard@bootlin.com>
To: Chen-Yu Tsai <wens@csie.org>
Cc: Jernej Skrabec <jernej.skrabec@siol.net>,
        David Airlie <airlied@linux.ie>, Rob Herring <robh+dt@kernel.org>,
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Subject: Re: [PATCH 01/15] clk: sunxi-ng: Add check for minimal rate to NM
 PLLs
Message-ID: <20180226102557.7bgjs3txp7cbridn@flea.lan>
References: <20180224214545.3740-1-jernej.skrabec@siol.net>
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On Mon, Feb 26, 2018 at 05:43:01PM +0800, Chen-Yu Tsai wrote:
> On Mon, Feb 26, 2018 at 5:38 PM, Maxime Ripard
> <maxime.ripard@bootlin.com> wrote:
> > Hi,
> >
> > On Sat, Feb 24, 2018 at 10:45:31PM +0100, Jernej Skrabec wrote:
> >> Some NM PLLs doesn't work well when their output clock rate is set bel=
ow
> >> certain rate.
> >>
> >> Add support for that constrain.
> >
> > In such a case, you should round the rate to the minimum the clock can
> > operate at, and not return an error.
>=20
> That's true for round_rate. But what's the expected behavior of set_rate?
> AFAIK we presume all users call round_rate before set_rate, but that does=
n't
> seem to be true all the time.

One of the first things that happens during a set_rate is a round_rate:
https://elixir.bootlin.com/linux/v4.16-rc3/source/drivers/clk/clk.c#L1873

Maxime

--=20
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

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