linux-kernel - Re: [RFC 3/8] cpufreq: imx6q: Set max suspend

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Message-ID: <20170323043427.GE12094@vireshk-i7>
Date:   Thu, 23 Mar 2017 10:04:27 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Leonard Crestez <leonard.crestez@....com>
Cc:     Mark Brown <broonie@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <kernel@...gutronix.de>,
        Robin Gong <yibin.gong@....com>,
        Anson Huang <Anson.Huang@....com>,
        Irina Tirdea <irina.tirdea@....com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Fabio Estevam <fabio.estevam@....com>,
        Octavian Purdila <octavian.purdila@....com>,
        linux-pm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC 3/8] cpufreq: imx6q: Set max suspend_freq to avoid changes
 during suspend

On 22-03-17, 18:53, Leonard Crestez wrote:
> If the cpufreq driver tries to modify voltage/freq during suspend/resume
> it might need to control an external PMIC via I2C or SPI but those
> devices might be already suspended.
> 
> To avoid this scenario we just increase cpufreq to highest setpoint
> before suspend. This issue can easily be triggered by ldo-bypass but in
> theory any regulator set_voltage call can end up having to modify
> external supply voltages.
> 
> Signed-off-by: Leonard Crestez <leonard.crestez@....com>
> ---
>  drivers/cpufreq/imx6q-cpufreq.c | 2 ++
>  1 file changed, 2 insertions(+)

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

-- 
viresh