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From: Maxime Ripard <maxime.ripard@bootlin.com>
To: Priit Laes <plaes@plaes.org>
Cc: Jernej Skrabec <jernej.skrabec@siol.net>,
	Stephen Boyd <sboyd@kernel.org>,
	Michael Turquette <mturquette@baylibre.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Chen-Yu Tsai <wens@csie.org>,
	linux-clk <linux-clk@vger.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC PATCH] clk: sunxi-ng: sun4i: Use CLK_SET_RATE_PARENT for mmc2 clock
Date: Wed, 6 Feb 2019 16:52:27 +0100	[thread overview]
Message-ID: <20190206155227.wbkzvsdgykir4wn5@flea> (raw)
In-Reply-To: <20190206100309.dhkm2l73qzkwgjzg@plaes.org>


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Hi,

On Wed, Feb 06, 2019 at 10:03:09AM +0000, Priit Laes wrote:
> > > I'm concerned for other users of the PLL-PERIPH clock. AFAIK
> > > all of them, except the HRTIMER, expect the clock rate to stay
> > > the same and not change underneath them. And SATA expects it to
> > > be at 600 MHz, as the datasheet says. And while it may not directly
> > > apply to the LIME2, eMMC on newer SoCs / boards run at the slightly
> > > reduced rate of 50 MHz just fine.
> > > 
> > > In the commit in question, clocks without CLK_SET_RATE_PARENT
> > > should be using the old code (now in the if conditional block),
> > > i.e. the behavior should not have changed.
> > > 
> > > I don't think this actually "fixes" whatever bug was introduced,
> > > but only papers over the issue, and possible introduces further
> > > issues for other users.
> > 
> > You're right, I've overlooked that it was pll-periph being
> > affected. I've dropped it for now.
> 
> Any ideas what could be done. I currently have no time to debug it,
> but it affects existing systems.

I can't find what would change with that commit either if the flag
isn't set, so looking at the register state before and after that
commit would help I guess?

Maxime

-- 
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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  reply	other threads:[~2019-02-06 15:52 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-02 15:52 [RFC PATCH] clk: sunxi-ng: sun4i: Use CLK_SET_RATE_PARENT for mmc2 clock Priit Laes
2019-02-05  9:45 ` Maxime Ripard
2019-02-05 13:44   ` Chen-Yu Tsai
2019-02-06  9:20     ` Maxime Ripard
2019-02-06 10:03       ` Priit Laes
2019-02-06 15:52         ` Maxime Ripard [this message]
2019-02-11 14:35           ` Priit Laes
2019-02-11 15:34             ` Maxime Ripard
2019-02-12  9:45               ` Priit Laes

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