linux-kernel - Re: [PATCH V2 6/8] PM / OPP: Separate out _generic_opp_set

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Date:   Tue, 25 Oct 2016 11:59:07 -0700
From:   Stephen Boyd <sboyd@...eaurora.org>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Rafael Wysocki <rjw@...ysocki.net>, nm@...com,
        Viresh Kumar <vireshk@...nel.org>,
        linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>, robh@...nel.org,
        d-gerlach@...com, broonie@...nel.org
Subject: Re: [PATCH V2 6/8] PM / OPP: Separate out _generic_opp_set_rate()

On 10/20, Viresh Kumar wrote:
> Later patches would add support for custom opp_set_rate callbacks. This

I know the OPP consumer function has "rate" in the name, but it
makes more sense to call the callback set_opp instead because we
could be doing a lot more than setting the opp rate.

> patch separates out the code for generic opp_set_rate handler in order
> to prepare for that.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
> diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
> index 45c70ce07864..96f04392daef 100644
> --- a/drivers/base/power/opp/core.c
> +++ b/drivers/base/power/opp/core.c
> @@ -596,6 +596,73 @@ static int _set_opp_voltage(struct device *dev, struct regulator *reg,
>  	return ret;
>  }
>  
> +static inline int
> +_generic_opp_set_rate_clk_only(struct device *dev, struct clk *clk,
> +			       unsigned long old_freq, unsigned long freq)
> +{
> +	int ret;
> +
> +	/* Change frequency */
> +	dev_dbg(dev, "%s: switching OPP: %lu Hz --> %lu Hz\n",
> +		__func__, old_freq, freq);

Perhaps this should stay at the beginning of OPP transitions?
Otherwise it can get confusing when multiple switching OPP
messages appear on OPP transition failures.

> +
> +	ret = clk_set_rate(clk, freq);
> +	if (ret) {
> +		dev_err(dev, "%s: failed to set clock rate: %d\n", __func__,
> +			ret);
> +	}
> +
> +	return ret;
> +}
> +
> diff --git a/drivers/base/power/opp/opp.h b/drivers/base/power/opp/opp.h
> index d3f0861f9bff..6629c53c0aa1 100644
> --- a/drivers/base/power/opp/opp.h
> +++ b/drivers/base/power/opp/opp.h
> @@ -47,22 +47,6 @@ extern struct list_head opp_tables;
>   */
>  
>  /**
> - * struct dev_pm_opp_supply - Power supply voltage/current values
> - * @u_volt:	Target voltage in microvolts corresponding to this OPP
> - * @u_volt_min:	Minimum voltage in microvolts corresponding to this OPP
> - * @u_volt_max:	Maximum voltage in microvolts corresponding to this OPP
> - * @u_amp:	Maximum current drawn by the device in microamperes
> - *
> - * This structure stores the voltage/current values for a single power supply.
> - */
> -struct dev_pm_opp_supply {
> -	unsigned long u_volt;
> -	unsigned long u_volt_min;
> -	unsigned long u_volt_max;
> -	unsigned long u_amp;
> -};
> -
> -/**
>   * struct dev_pm_opp - Generic OPP description structure
>   * @node:	opp table node. The nodes are maintained throughout the lifetime
>   *		of boot. It is expected only an optimal set of OPPs are
> diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
> index 0606b70a8b97..73713a8424b1 100644
> --- a/include/linux/pm_opp.h
> +++ b/include/linux/pm_opp.h
> @@ -17,6 +17,7 @@
>  #include <linux/err.h>
>  #include <linux/notifier.h>
>  
> +struct clk;

Is struct regulator also forward declared?

>  struct dev_pm_opp;
>  struct device;
>  
> @@ -24,6 +25,36 @@ enum dev_pm_opp_event {
>  	OPP_EVENT_ADD, OPP_EVENT_REMOVE, OPP_EVENT_ENABLE, OPP_EVENT_DISABLE,
>  };
>  
> +/**
> + * struct dev_pm_opp_supply - Power supply voltage/current values
> + * @u_volt:	Target voltage in microvolts corresponding to this OPP
> + * @u_volt_min:	Minimum voltage in microvolts corresponding to this OPP
> + * @u_volt_max:	Maximum voltage in microvolts corresponding to this OPP
> + * @u_amp:	Maximum current drawn by the device in microamperes
> + *
> + * This structure stores the voltage/current values for a single power supply.
> + */
> +struct dev_pm_opp_supply {
> +	unsigned long u_volt;
> +	unsigned long u_volt_min;
> +	unsigned long u_volt_max;
> +	unsigned long u_amp;
> +};

This structure moved during this series. Can we avoid that and
already have it in the right place to begin with?

> +
> +struct dev_pm_opp_info {
> +	unsigned long rate;
> +	struct dev_pm_opp_supply *supplies;
> +};
> +
> +struct dev_pm_set_rate_data {

dev_pm_set_opp_data?

> +	struct dev_pm_opp_info old_opp;
> +	struct dev_pm_opp_info new_opp;
> +
> +	struct regulator **regulators;
> +	unsigned int regulator_count;
> +	struct clk *clk;
> +};

The above two structures don't get kernel doc?

> +
>  #if defined(CONFIG_PM_OPP)
>  
>  unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp);
> -- 
> 2.7.1.410.g6faf27b
> 

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