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@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
(cherry picked from commit 050794aaebbb9f2c2c50b340b6998273e7c64189)
Signed-off-by: Alex Shi <alex.shi@linaro.org>

Author: vireshk

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;
 	int ret;
 
 	ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
@@ -228,6 +254,20 @@ static int cpufreq_init(struct cpufreq_policy *policy)
 			goto out_node_put;
 	}
 
+	/*
+	 * 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 (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 +313,7 @@ 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 +407,8 @@ 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 +426,9 @@ 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);