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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Lucas Stach <l.stach@pengutronix.de>,
        Leonard Crestez <leonard.crestez@nxp.com>
Cc: Shawn Guo <shawnguo@kernel.org>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Anson Huang <Anson.Huang@nxp.com>,
        Fabio Estevam <fabio.estevam@nxp.com>,
        Dong Aisheng <aisheng.dong@nxp.com>, Bai Ping <ping.bai@nxp.com>,
        kernel@pengutronix.de, linux-pm@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] cpufreq: imx6q: Fix imx6sx low frequency support
Date: Thu, 31 Aug 2017 01:31:38 +0200
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In-Reply-To: <1503922071.2347.0.camel@pengutronix.de>
References: <4304e578a343c9acaed46b7e205d49bb63323f80.1503918257.git.leonard.crestez@nxp.com> <1503922071.2347.0.camel@pengutronix.de>
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On Monday, August 28, 2017 2:07:51 PM CEST Lucas Stach wrote:
> Am Montag, den 28.08.2017, 14:05 +0300 schrieb Leonard Crestez:
> > This patch contains the minimal changes required to support imx6sx OPP
> > of 198 Mhz. Without this patch cpufreq still reports success but the
> > frequency is not changed, the "arm" clock will still be at 396000000 in
> > clk_summary.
> > 
> > In order to do this PLL1 needs to be still kept enabled while changing
> > the ARM clock. This is a hardware requirement: when ARM_PODF is changed
> > in CCM we need to check the busy bit of CCM_CDHIPR bit 16 arm_podf_busy,
> > and this bit is sync with PLL1 clock, so if PLL1 NOT enabled, this
> > bit will never get clear.
> > 
> > Keep pll1_sys explicitly enabled until after the rate is change to deal
> > with this. Otherwise from the clk framework perspective pll1_sys is
> > unused and gets turned off.
> > 
> > Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
> 
> Reviewed-by: Lucas Stach <l.stach@pengutronix.de>

Patch applied, thanks!