linux-kernel - [PATCH V2 04/16] PM / OPP: Introduce dev_pm_opp_get_max_transition

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Date:	Thu, 28 Jan 2016 13:50:33 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	Rafael Wysocki <rjw@...ysocki.net>
Cc:	linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
	Stephen Boyd <sboyd@...eaurora.org>, nm@...com,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Len Brown <len.brown@...el.com>,
	linux-kernel@...r.kernel.org (open list),
	Pavel Machek <pavel@....cz>, Viresh Kumar <vireshk@...nel.org>
Subject: [PATCH V2 04/16] PM / OPP: Introduce dev_pm_opp_get_max_transition_latency()

In few use cases (like: cpufreq), it is desired to get the maximum
latency for changing OPPs. Add support for that.

Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
Reviewed-by: Stephen Boyd <sboyd@...eaurora.org>
---
 drivers/base/power/opp/core.c | 17 +++++++++++++++++
 include/linux/pm_opp.h        |  6 ++++++
 2 files changed, 23 insertions(+)

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index ffe2406af882..b0f5c72f0fc3 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -290,6 +290,23 @@ unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev)
 EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_volt_latency);
 
 /**
+ * dev_pm_opp_get_max_transition_latency() - Get max transition latency in
+ *					     nanoseconds
+ * @dev: device for which we do this operation
+ *
+ * Return: This function returns the max transition latency, in nanoseconds, to
+ * switch from one OPP to other.
+ *
+ * Locking: This function takes rcu_read_lock().
+ */
+unsigned long dev_pm_opp_get_max_transition_latency(struct device *dev)
+{
+	return dev_pm_opp_get_max_volt_latency(dev) +
+		dev_pm_opp_get_max_clock_latency(dev);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_transition_latency);
+
+/**
  * dev_pm_opp_get_suspend_opp() - Get suspend opp
  * @dev:	device for which we do this operation
  *
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 5daa43058ac1..59da3d9e11ea 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -35,6 +35,7 @@ bool dev_pm_opp_is_turbo(struct dev_pm_opp *opp);
 int dev_pm_opp_get_opp_count(struct device *dev);
 unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev);
 unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev);
+unsigned long dev_pm_opp_get_max_transition_latency(struct device *dev);
 struct dev_pm_opp *dev_pm_opp_get_suspend_opp(struct device *dev);
 
 struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
@@ -94,6 +95,11 @@ static inline unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev)
 	return 0;
 }
 
+static inline unsigned long dev_pm_opp_get_max_transition_latency(struct device *dev)
+{
+	return 0;
+}
+
 static inline struct dev_pm_opp *dev_pm_opp_get_suspend_opp(struct device *dev)
 {
 	return NULL;
-- 
2.7.0.79.gdc08a19