Re: [PATCH V2 11/16] cpufreq: dt: Pass regulator name to the OPP core

[Viresh Kumar]

On 01-02-16, 18:34, Stephen Boyd wrote:
> On 01/28, Viresh Kumar wrote:
> > +	cpu_reg = regulator_get_optional(dev, reg);
> > +	ret = PTR_ERR_OR_ZERO(cpu_reg);
> > +	if (!ret) {
> > +		regulator_put(cpu_reg);
> 
> What's the point of creating a regulator just to find the name?
> It seems like we should just look in the DT node of the CPU for
> cpu-supply vs cpu0-supply. Then we don't need to involve the
> regulator framework at all.

Yeah, this can be simplified a bit..

> >  static int allocate_resources(int cpu, struct device **cdev,
> >  			      struct regulator **creg, struct clk **cclk)
> >  {
> > @@ -383,6 +450,9 @@ static int cpufreq_exit(struct cpufreq_policy *policy)
> >  	cpufreq_cooling_unregister(priv->cdev);
> >  	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
> >  	dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
> > +	if (priv->reg_name)
> > +		dev_pm_opp_put_regulator(priv->cpu_dev);
> 
> Let's hope this goes away because it's always right next to
> dev_pm_opp_of_cpumask_remove_table() anyway. Same for reg_name.

We are calling it from cpufreq-dt in this particular case, but it can
be called from platform code as well.

-------------------------8<-------------------------
From: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Date: Tue, 8 Sep 2015 17:16:46 +0530
Subject: [PATCH 04/20] cpufreq: dt: Pass regulator name to the OPP core

OPP core can handle the regulators by itself, and but it needs to know
the name of the regulator to fetch. Add support for that.

Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
 drivers/cpufreq/cpufreq-dt.c | 51 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c
index 4c9f8a828f6f..d4651d684f11 100644
--- a/drivers/cpufreq/cpufreq-dt.c
+++ b/drivers/cpufreq/cpufreq-dt.c
@@ -34,6 +34,7 @@ struct private_data {
 	struct regulator *cpu_reg;
 	struct thermal_cooling_device *cdev;
 	unsigned int voltage_tolerance; /* in percentage */
+	const char *reg_name;
 };
 
 static struct freq_attr *cpufreq_dt_attr[] = {
@@ -119,6 +120,30 @@ static int set_target(struct cpufreq_policy *policy, unsigned int index)
 	return ret;
 }
 
+/*
+ * An earlier version of opp-v1 bindings used to name the regulator
+ * "cpu0-supply", we still need to handle that for backwards compatibility.
+ */
+static const char *find_supply_name(struct device *dev, struct device_node *np)
+{
+	struct property *pp;
+	int cpu = dev->id;
+
+	/* Try "cpu0" for older DTs */
+	if (!cpu) {
+		pp = of_find_property(np, "cpu0-supply", NULL);
+		if (pp)
+			return "cpu0";
+	}
+
+	pp = of_find_property(np, "cpu-supply", NULL);
+	if (pp)
+		return "cpu";
+
+	dev_dbg(dev, "no regulator for cpu%d\n", cpu);
+	return NULL;
+}
+
 static int allocate_resources(int cpu, struct device **cdev,
 			      struct regulator **creg, struct clk **cclk)
 {
@@ -200,6 +225,7 @@ static int cpufreq_init(struct cpufreq_policy *policy)
 	unsigned long min_uV = ~0, max_uV = 0;
 	unsigned int transition_latency;
 	bool opp_v1 = false;
+	const char *name = NULL;
 	int ret;
 
 	ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
@@ -229,6 +255,25 @@ static int cpufreq_init(struct cpufreq_policy *policy)
 	}
 
 	/*
+	 * OPP layer will be taking care of regulators now, but it needs to know
+	 * the name of the regulator first.
+	 */
+	name = find_supply_name(cpu_dev, np);
+	if (IS_ERR(name)) {
+		ret = PTR_ERR(name);
+		goto out_node_put;
+	}
+
+	if (name) {
+		ret = dev_pm_opp_set_regulator(cpu_dev, name);
+		if (ret) {
+			dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n",
+				policy->cpu, ret);
+			goto out_node_put;
+		}
+	}
+
+	/*
 	 * Initialize OPP tables for all policy->cpus. They will be shared by
 	 * all CPUs which have marked their CPUs shared with OPP bindings.
 	 *
@@ -273,6 +318,7 @@ static int cpufreq_init(struct cpufreq_policy *policy)
 		goto out_free_opp;
 	}
 
+	priv->reg_name = name;
 	of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance);
 
 	transition_latency = dev_pm_opp_get_max_clock_latency(cpu_dev);
@@ -366,6 +412,8 @@ static int cpufreq_init(struct cpufreq_policy *policy)
 	kfree(priv);
 out_free_opp:
 	dev_pm_opp_of_cpumask_remove_table(policy->cpus);
+	if (name)
+		dev_pm_opp_put_regulator(cpu_dev);
 out_node_put:
 	of_node_put(np);
 out_put_reg_clk:
@@ -383,6 +431,9 @@ static int cpufreq_exit(struct cpufreq_policy *policy)
 	cpufreq_cooling_unregister(priv->cdev);
 	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
 	dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
+	if (priv->reg_name)
+		dev_pm_opp_put_regulator(priv->cpu_dev);
+
 	clk_put(policy->clk);
 	if (!IS_ERR(priv->cpu_reg))
 		regulator_put(priv->cpu_reg);