OPP: Add dev_pm_opp_get_supplies()

We already have an API for getting voltage information for a single
regulator, dev_pm_opp_get_voltage(), but there is nothing available for
multiple regulator case.

This patch adds a new API, dev_pm_opp_get_supplies(), to get all
information related to the supplies for an OPP.
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/opp/core.c

@@ -117,6 +117,31 @@ unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage);
 
+/**
+ * dev_pm_opp_get_supplies() - Gets the supply information corresponding to an opp
+ * @opp:	opp for which voltage has to be returned for
+ * @supplies:	Placeholder for copying the supply information.
+ *
+ * Return: negative error number on failure, 0 otherwise on success after
+ * setting @supplies.
+ *
+ * This can be used for devices with any number of power supplies. The caller
+ * must ensure the @supplies array must contain space for each regulator.
+ */
+int dev_pm_opp_get_supplies(struct dev_pm_opp *opp,
+			    struct dev_pm_opp_supply *supplies)
+{
+	if (IS_ERR_OR_NULL(opp) || !supplies) {
+		pr_err("%s: Invalid parameters\n", __func__);
+		return -EINVAL;
+	}
+
+	memcpy(supplies, opp->supplies,
+	       sizeof(*supplies) * opp->opp_table->regulator_count);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_supplies);
+
 /**
  * dev_pm_opp_get_power() - Gets the power corresponding to an opp
  * @opp:	opp for which power has to be returned for

include/linux/pm_opp.h

@@ -129,6 +129,8 @@ void dev_pm_opp_put_opp_table(struct opp_table *opp_table);
 
 unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp);
 
+int dev_pm_opp_get_supplies(struct dev_pm_opp *opp, struct dev_pm_opp_supply *supplies);
+
 unsigned long dev_pm_opp_get_power(struct dev_pm_opp *opp);
 
 unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp);
@@ -217,6 +219,11 @@ static inline unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
 	return 0;
 }
 
+static inline int dev_pm_opp_get_supplies(struct dev_pm_opp *opp, struct dev_pm_opp_supply *supplies)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline unsigned long dev_pm_opp_get_power(struct dev_pm_opp *opp)
 {
 	return 0;