linux-kernel - Re: [PATCH v2 2/4] cpufreq: imx6q: Set max suspend

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Message-ID: <1491379425.2904.0.camel@pengutronix.de>
Date:   Wed, 05 Apr 2017 10:03:45 +0200
From:   Lucas Stach <l.stach@...gutronix.de>
To:     Leonard Crestez <leonard.crestez@....com>
Cc:     Viresh Kumar <viresh.kumar@...aro.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Sascha Hauer <kernel@...gutronix.de>,
        Shawn Guo <shawnguo@...nel.org>,
        Mark Brown <broonie@...nel.org>,
        Robin Gong <yibin.gong@....com>,
        Anson Huang <Anson.Huang@....com>,
        Irina Tirdea <irina.tirdea@....com>,
        Fabio Estevam <fabio.estevam@....com>,
        Octavian Purdila <octavian.purdila@....com>,
        Liam Girdwood <lgirdwood@...il.com>, linux-pm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/4] cpufreq: imx6q: Set max suspend_freq to avoid
 changes during suspend

Am Dienstag, den 04.04.2017, 20:04 +0300 schrieb Leonard Crestez:
> 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. This issue is likely to happen
> whenever the LDOs have their vin-supply set.
> 
> To avoid this scenario we just increase cpufreq to the maximum before
> suspend.
> 
> Signed-off-by: Leonard Crestez <leonard.crestez@....com>

Reviewed-by: Lucas Stach <l.stach@...gutronix.de>

> ---
>  drivers/cpufreq/imx6q-cpufreq.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
> index be90ee3..786122e 100644
> --- a/drivers/cpufreq/imx6q-cpufreq.c
> +++ b/drivers/cpufreq/imx6q-cpufreq.c
> @@ -161,8 +161,13 @@ static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index)
>  
>  static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
>  {
> +	int ret;
> +
>  	policy->clk = arm_clk;
> -	return cpufreq_generic_init(policy, freq_table, transition_latency);
> +	ret = cpufreq_generic_init(policy, freq_table, transition_latency);
> +	policy->suspend_freq = policy->max;
> +
> +	return ret;
>  }
>  
>  static struct cpufreq_driver imx6q_cpufreq_driver = {
> @@ -173,6 +178,7 @@ static struct cpufreq_driver imx6q_cpufreq_driver = {
>  	.init = imx6q_cpufreq_init,
>  	.name = "imx6q-cpufreq",
>  	.attr = cpufreq_generic_attr,
> +	.suspend = cpufreq_generic_suspend,
>  };
>  
>  static int imx6q_cpufreq_probe(struct platform_device *pdev)