OPP: Provide a simple implementation to configure multiple clocks

This provides a simple implementation to configure multiple clocks for a
device.
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/opp/core.c

@@ -843,6 +843,40 @@ _opp_config_clk_single(struct device *dev, struct opp_table *opp_table,
 	return ret;
 }
 
+/*
+ * Simple implementation for configuring multiple clocks. Configure clocks in
+ * the order in which they are present in the array while scaling up.
+ */
+int dev_pm_opp_config_clks_simple(struct device *dev,
+		struct opp_table *opp_table, struct dev_pm_opp *opp, void *data,
+		bool scaling_down)
+{
+	int ret, i;
+
+	if (scaling_down) {
+		for (i = opp_table->clk_count - 1; i >= 0; i--) {
+			ret = clk_set_rate(opp_table->clks[i], opp->rates[i]);
+			if (ret) {
+				dev_err(dev, "%s: failed to set clock rate: %d\n", __func__,
+					ret);
+				return ret;
+			}
+		}
+	} else {
+		for (i = 0; i < opp_table->clk_count; i++) {
+			ret = clk_set_rate(opp_table->clks[i], opp->rates[i]);
+			if (ret) {
+				dev_err(dev, "%s: failed to set clock rate: %d\n", __func__,
+					ret);
+				return ret;
+			}
+		}
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_config_clks_simple);
+
 static int _opp_config_regulator_single(struct device *dev,
 			struct dev_pm_opp *old_opp, struct dev_pm_opp *new_opp,
 			struct regulator **regulators, unsigned int count)

include/linux/pm_opp.h

@@ -159,6 +159,9 @@ int dev_pm_opp_unregister_notifier(struct device *dev, struct notifier_block *nb
 int dev_pm_opp_set_config(struct device *dev, struct dev_pm_opp_config *config);
 int devm_pm_opp_set_config(struct device *dev, struct dev_pm_opp_config *config);
 void dev_pm_opp_clear_config(int token);
+int dev_pm_opp_config_clks_simple(struct device *dev,
+		struct opp_table *opp_table, struct dev_pm_opp *opp, void *data,
+		bool scaling_down);
 
 struct dev_pm_opp *dev_pm_opp_xlate_required_opp(struct opp_table *src_table, struct opp_table *dst_table, struct dev_pm_opp *src_opp);
 int dev_pm_opp_xlate_performance_state(struct opp_table *src_table, struct opp_table *dst_table, unsigned int pstate);
@@ -342,6 +345,13 @@ static inline int devm_pm_opp_set_config(struct device *dev, struct dev_pm_opp_c
 
 static inline void dev_pm_opp_clear_config(int token) {}
 
+static inline int dev_pm_opp_config_clks_simple(struct device *dev,
+		struct opp_table *opp_table, struct dev_pm_opp *opp, void *data,
+		bool scaling_down)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline struct dev_pm_opp *dev_pm_opp_xlate_required_opp(struct opp_table *src_table,
 				struct opp_table *dst_table, struct dev_pm_opp *src_opp)
 {