linux-kernel - Re: [PATCH v3 04/12] opp: Add dev_pm_opp_sync

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Date:   Mon, 18 Jan 2021 13:50:13 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Dmitry Osipenko <digetx@...il.com>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Mark Brown <broonie@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Peter Geis <pgwipeout@...il.com>,
        Nicolas Chauvet <kwizart@...il.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Kevin Hilman <khilman@...nel.org>,
        Peter De Schrijver <pdeschrijver@...dia.com>,
        Viresh Kumar <vireshk@...nel.org>,
        Stephen Boyd <sboyd@...nel.org>, Nishanth Menon <nm@...com>,
        Yangtao Li <tiny.windzz@...il.com>,
        Matt Merhar <mattmerhar@...tonmail.com>,
        linux-kernel@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-pm@...r.kernel.org
Subject: Re: [PATCH v3 04/12] opp: Add dev_pm_opp_sync_regulators()

On 18-01-21, 03:55, Dmitry Osipenko wrote:
> Extend OPP API with dev_pm_opp_sync_regulators() function, which syncs
> voltage state of regulators.
> 
> Tested-by: Peter Geis <pgwipeout@...il.com>
> Tested-by: Nicolas Chauvet <kwizart@...il.com>
> Tested-by: Matt Merhar <mattmerhar@...tonmail.com>
> Signed-off-by: Dmitry Osipenko <digetx@...il.com>
> ---
>  drivers/opp/core.c     | 45 ++++++++++++++++++++++++++++++++++++++++++
>  include/linux/pm_opp.h |  6 ++++++
>  2 files changed, 51 insertions(+)
> 
> diff --git a/drivers/opp/core.c b/drivers/opp/core.c
> index 7b4d07279638..99d18befc209 100644
> --- a/drivers/opp/core.c
> +++ b/drivers/opp/core.c
> @@ -2686,3 +2686,48 @@ void dev_pm_opp_remove_table(struct device *dev)
>  	dev_pm_opp_put_opp_table(opp_table);
>  }
>  EXPORT_SYMBOL_GPL(dev_pm_opp_remove_table);
> +
> +/**
> + * dev_pm_opp_sync_regulators() - Sync state of voltage regulators
> + * @dev:	device for which we do this operation
> + *
> + * Sync voltage state of the OPP table regulators.
> + *
> + * Return: 0 on success or a negative error value.
> + */
> +int dev_pm_opp_sync_regulators(struct device *dev)
> +{
> +	struct opp_table *opp_table;
> +	struct regulator *reg;
> +	int i, ret = 0;
> +
> +	/* Device may not have OPP table */
> +	opp_table = _find_opp_table(dev);
> +	if (IS_ERR(opp_table))
> +		return 0;
> +
> +	/* Regulator may not be required for the device */
> +	if (!opp_table->regulators)
> +		goto put_table;
> +
> +	mutex_lock(&opp_table->lock);

What exactly do you need this lock for ?

> +
> +	/* Nothing to sync if voltage wasn't changed */
> +	if (!opp_table->enabled)
> +		goto unlock;
> +
> +	for (i = 0; i < opp_table->regulator_count; i++) {
> +		reg = opp_table->regulators[i];
> +		ret = regulator_sync_voltage(reg);
> +		if (ret)
> +			break;
> +	}
> +unlock:
> +	mutex_unlock(&opp_table->lock);
> +put_table:
> +	/* Drop reference taken by _find_opp_table() */
> +	dev_pm_opp_put_opp_table(opp_table);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(dev_pm_opp_sync_regulators);
> diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
> index c24bd34339d7..1c3a09cc8dcd 100644
> --- a/include/linux/pm_opp.h
> +++ b/include/linux/pm_opp.h
> @@ -162,6 +162,7 @@ int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev, const struct cpumask *cp
>  int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask);
>  void dev_pm_opp_remove_table(struct device *dev);
>  void dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask);
> +int dev_pm_opp_sync_regulators(struct device *dev);
>  #else
>  static inline struct opp_table *dev_pm_opp_get_opp_table(struct device *dev)
>  {
> @@ -398,6 +399,11 @@ static inline void dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask
>  {
>  }
>  
> +static inline int dev_pm_opp_sync_regulators(struct device *dev)
> +{
> +	return -ENOTSUPP;
> +}
> +
>  #endif		/* CONFIG_PM_OPP */
>  
>  #if defined(CONFIG_PM_OPP) && defined(CONFIG_OF)
> -- 
> 2.29.2

-- 
viresh