PM / OPP: Introduce dev_pm_opp_get_max_volt_latency()

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

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index 71545becfca1bf7183ff4a3758659a91a8d15a0a..ffe2406af8825d0936620b9c734b829b51bc8a46 100644 (file)
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -230,6 +230,65 @@ unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_clock_latency);
 
+/**
+ * dev_pm_opp_get_max_volt_latency() - Get max voltage latency in nanoseconds
+ * @dev: device for which we do this operation
+ *
+ * Return: This function returns the max voltage latency in nanoseconds.
+ *
+ * Locking: This function takes rcu_read_lock().
+ */
+unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev)
+{
+       struct device_opp *dev_opp;
+       struct dev_pm_opp *opp;
+       struct regulator *reg;
+       unsigned long latency_ns = 0;
+       unsigned long min_uV = ~0, max_uV = 0;
+       int ret;
+
+       rcu_read_lock();
+
+       dev_opp = _find_device_opp(dev);
+       if (IS_ERR(dev_opp)) {
+               rcu_read_unlock();
+               return 0;
+       }
+
+       reg = dev_opp->regulator;
+       if (IS_ERR_OR_NULL(reg)) {
+               /* Regulator may not be required for device */
+               if (reg)
+                       dev_err(dev, "%s: Invalid regulator (%ld)\n", __func__,
+                               PTR_ERR(reg));
+               rcu_read_unlock();
+               return 0;
+       }
+
+       list_for_each_entry_rcu(opp, &dev_opp->opp_list, node) {
+               if (!opp->available)
+                       continue;
+
+               if (opp->u_volt_min < min_uV)
+                       min_uV = opp->u_volt_min;
+               if (opp->u_volt_max > max_uV)
+                       max_uV = opp->u_volt_max;
+       }
+
+       rcu_read_unlock();
+
+       /*
+        * The caller needs to ensure that dev_opp (and hence the regulator)
+        * isn't freed, while we are executing this routine.
+        */
+       ret = regulator_set_voltage_time(reg, min_uV, max_uV);
+       if (ret > 0)
+               latency_ns = ret * 1000;
+
+       return latency_ns;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_volt_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 c70a18ac9c8a73ef41877b1d88fcb7a4b9feffd2..5daa43058ac1060c80240248ca0dacf8327e1954 100644 (file)
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -34,6 +34,7 @@ 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);
 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,
@@ -88,6 +89,11 @@ static inline unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev)
        return 0;
 }
 
+static inline unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev)
+{
+       return 0;
+}
+
 static inline struct dev_pm_opp *dev_pm_opp_get_suspend_opp(struct device *dev)
 {
        return NULL;