[PATCH v2 10/48] opp: Add dev_pm_opp_set_voltage()

[Dmitry Osipenko]

Add dev_pm_opp_set_voltage() which allows OPP table users to set voltage
in accordance to a given OPP. In particular this is needed for driving
voltage of a generic power domain which uses OPPs and doesn't have a
clock.

Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
 drivers/opp/core.c     | 52 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/pm_opp.h | 11 +++++----
 2 files changed, 58 insertions(+), 5 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 500d6c716283..eab37b3a27bb 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -2541,3 +2541,55 @@ int dev_pm_opp_sync_regulators(struct device *dev)
 	return ret;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_sync_regulators);
+
+/**
+ * dev_pm_opp_set_voltage() - Change voltage of regulators
+ * @dev:	device for which we do this operation
+ * @opp:	opp based on which the voltages are to be configured
+ *
+ * Change voltage of the OPP table regulators.
+ *
+ * Return: 0 on success or a negative error value.
+ */
+int dev_pm_opp_set_voltage(struct device *dev, struct dev_pm_opp *opp)
+{
+	struct opp_table *opp_table;
+	struct regulator *reg;
+	int ret = 0;
+
+	/* Device may not have OPP table */
+	opp_table = _find_opp_table(dev);
+	if (IS_ERR(opp_table))
+		return 0;
+
+	/* Regulator may not be required for the device */
+	if (!opp_table->regulators)
+		goto put_table;
+
+	/* This function only supports single regulator per device */
+	if (WARN_ON(opp_table->regulator_count > 1)) {
+		dev_err(dev, "multiple regulators are not supported\n");
+		ret = -EINVAL;
+		goto put_table;
+	}
+
+	reg = opp_table->regulators[0];
+	ret = _set_opp_voltage(dev, reg, opp->supplies);
+
+	if (!opp_table->enabled) {
+		ret = regulator_enable(reg);
+		if (ret < 0) {
+			dev_warn(dev, "Failed to enable regulator: %d", ret);
+			goto put_table;
+		}
+
+		opp_table->enabled = true;
+	}
+
+put_table:
+	/* Drop reference taken by _find_opp_table() */
+	dev_pm_opp_put_opp_table(opp_table);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_set_voltage);
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 4c79faa2025e..f311a8b2ca04 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -157,6 +157,7 @@ int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
 void dev_pm_opp_remove_table(struct device *dev);
 void dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask);
 int dev_pm_opp_sync_regulators(struct device *dev);
+int dev_pm_opp_set_voltage(struct device *dev, struct dev_pm_opp *opp);
 #else
 static inline struct opp_table *dev_pm_opp_get_opp_table(struct device *dev)
 {
@@ -372,6 +373,11 @@ static inline int dev_pm_opp_sync_regulators(struct device *dev)
 	return -ENOTSUPP;
 }
 
+static inline int dev_pm_opp_set_voltage(struct device *dev, struct dev_pm_opp *opp)
+{
+	return -ENOTSUPP;
+}
+
 #endif		/* CONFIG_PM_OPP */
 
 #if defined(CONFIG_PM_OPP) && defined(CONFIG_OF)
@@ -448,11 +454,6 @@ static inline int dev_pm_opp_of_find_icc_paths(struct device *dev, struct opp_ta
 {
 	return -ENOTSUPP;
 }
-
-static inline int dev_pm_opp_sync_regulators(struct device *dev)
-{
-	return -ENOTSUPP;
-}
 #endif
 
 #endif		/* __LINUX_OPP_H__ */
-- 
2.29.2