PM / Domain: Implement of_genpd_opp_to_performance_state()

This implements of_genpd_opp_to_performance_state() which can be used
from the device drivers or the OPP core to find the performance state
encoded in the "required-opps" property of a node. Normally this would
be called only once for each OPP of the device for which the OPP table
of the device is getting generated.

Different platforms may encode the performance state differently using
the OPP table (they may simply return value of opp-hz or opp-microvolt,
or apply some algorithm on top of those values) and so a new callback
->opp_to_performance_state() is implemented to allow platform specific
drivers to convert the power domain OPP to a performance state value.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 5c0019d70d76..29e25dc0584c 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -2412,6 +2412,54 @@ int of_genpd_parse_idle_states(struct device_node *dn,
 }
 EXPORT_SYMBOL_GPL(of_genpd_parse_idle_states);
 
+/**
+ * of_genpd_opp_to_performance_state- Gets performance state of device's
+ * power domain corresponding to a DT node's "required-opps" property.
+ *
+ * @dev: Device for which the performance-state needs to be found.
+ * @opp_node: DT node where the "required-opps" property is present. This can be
+ *	the device node itself (if it doesn't have an OPP table) or a node
+ *	within the OPP table of a device (if device has an OPP table).
+ * @state: Pointer to return performance state.
+ *
+ * Returns performance state corresponding to the "required-opps" property of
+ * a DT node. This calls platform specific genpd->opp_to_performance_state()
+ * callback to translate power domain OPP to performance state.
+ *
+ * Returns performance state on success and 0 on failure.
+ */
+unsigned int of_genpd_opp_to_performance_state(struct device *dev,
+					       struct device_node *opp_node)
+{
+	struct generic_pm_domain *genpd;
+	struct dev_pm_opp *opp;
+	int state = 0;
+
+	genpd = dev_to_genpd(dev);
+	if (IS_ERR(genpd))
+		return 0;
+
+	if (unlikely(!genpd->set_performance_state))
+		return 0;
+
+	genpd_lock(genpd);
+
+	opp = of_dev_pm_opp_find_required_opp(&genpd->dev, opp_node);
+	if (IS_ERR(opp)) {
+		state = PTR_ERR(opp);
+		goto unlock;
+	}
+
+	state = genpd->opp_to_performance_state(genpd, opp);
+	dev_pm_opp_put(opp);
+
+unlock:
+	genpd_unlock(genpd);
+
+	return state;
+}
+EXPORT_SYMBOL_GPL(of_genpd_opp_to_performance_state);
+
 #endif /* CONFIG_PM_GENERIC_DOMAINS_OF */