PM: runtime: Improve kerneldoc of pm_runtime_get_if_active()

The kerneldoc comment of pm_runtime_get_if_active() doesn't list the
second argument of the function properly, so fix that and while at it
clarify that comment somewhat and add some markup to it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>

drivers/base/power/runtime.c

@@ -1085,24 +1085,26 @@ int __pm_runtime_resume(struct device *dev, int rpmflags)
 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
 
 /**
- * pm_runtime_get_if_active - Conditionally bump up the device's usage counter.
+ * pm_runtime_get_if_active - Conditionally bump up device usage counter.
  * @dev: Device to handle.
+ * @ign_usage_count: Whether or not to look at the current usage counter value.
  *
- * Return -EINVAL if runtime PM is disabled for the device.
+ * Return -EINVAL if runtime PM is disabled for @dev.
  *
- * Otherwise, if the device's runtime PM status is RPM_ACTIVE and either
- * ign_usage_count is true or the device's usage_count is non-zero, increment
- * the counter and return 1. Otherwise return 0 without changing the counter.
+ * Otherwise, if the runtime PM status of @dev is %RPM_ACTIVE and either
+ * @ign_usage_count is %true or the runtime PM usage counter of @dev is not
+ * zero, increment the usage counter of @dev and return 1. Otherwise, return 0
+ * without changing the usage counter.
  *
- * If ign_usage_count is true, the function can be used to prevent suspending
- * the device when its runtime PM status is RPM_ACTIVE.
+ * If @ign_usage_count is %true, this function can be used to prevent suspending
+ * the device when its runtime PM status is %RPM_ACTIVE.
  *
- * If ign_usage_count is false, the function can be used to prevent suspending
- * the device when both its runtime PM status is RPM_ACTIVE and its usage_count
- * is non-zero.
+ * If @ign_usage_count is %false, this function can be used to prevent
+ * suspending the device when both its runtime PM status is %RPM_ACTIVE and its
+ * runtime PM usage counter is not zero.
  *
- * The caller is resposible for putting the device's usage count when ther
- * return value is greater than zero.
+ * The caller is resposible for decrementing the runtime PM usage counter of
+ * @dev after this function has returned a positive value for it.
  */
 int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count)
 {