linux-kernel - Re: [PATCH v2 4/4] PM / AVS: rockchip-cpu-avs: add driver handling Rockchip cpu avs

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Date:   Mon, 29 Aug 2016 11:38:01 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     sboyd@...eaurora.org, Finlye Xiao <finley.xiao@...k-chips.com>
Cc:     srinivas.kandagatla@...aro.org, maxime.ripard@...e-electrons.com,
        heiko@...ech.de, robh+dt@...nel.org, frowand.list@...il.com,
        sre@...nel.org, dbaryshkov@...il.com, dwmw2@...radead.org,
        mark.rutland@....com, khilman@...nel.org, nm@...com,
        rjw@...ysocki.net, linux-arm-kernel@...ts.infradead.org,
        linux-rockchip@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        wxt@...k-chips.com, jay.xu@...k-chips.com,
        rocky.hao@...k-chips.com, tim.chen@...k-chips.com,
        tony.xie@...k-chips.com, ulysses.huang@...k-chips.com,
        lin.huang@...k-chips.com
Subject: Re: [PATCH v2 4/4] PM / AVS: rockchip-cpu-avs: add driver handling
 Rockchip cpu avs

On 18-08-16, 16:52, Finlye Xiao wrote:
> +static int rockchip_adjust_opp_table(struct device *cpu_dev,
> +				     struct cpufreq_frequency_table *table,
> +				     int volt)
> +{
> +	struct opp_table *opp_table;
> +	struct cpufreq_frequency_table *pos;
> +	struct dev_pm_opp *opp;
> +
> +	if (!volt)
> +		return 0;
> +
> +	rcu_read_lock();
> +
> +	opp_table = _find_opp_table(cpu_dev);
> +	if (IS_ERR(opp_table)) {
> +		rcu_read_unlock();
> +		return PTR_ERR(opp_table);
> +	}
> +
> +	cpufreq_for_each_valid_entry(pos, table) {
> +		opp = dev_pm_opp_find_freq_exact(cpu_dev, pos->frequency * 1000,
> +						 true);
> +		if (IS_ERR(opp))
> +			continue;
> +
> +		opp->u_volt += volt;
> +		opp->u_volt_min += volt;
> +		opp->u_volt_max += volt;
> +	}
> +
> +	rcu_read_unlock();
> +
> +	return 0;
> +}

I wouldn't prefer altering the opp tables from individual drivers at all. At the
least, it should be done via some helpers exposed by the core.

But before that I would like to hear from Stephen a bit as I recall he was also
working on something similar.

-- 
viresh