Regulator: add suspend-finish API for regulator core.

The regulator core had suspend-prepare that turns off the regulators
when entering a system-wide suspend. However, it did not have
suspend-finish that pairs with suspend-prepare and the regulator core
has assumed that the regulator devices and their drivers support
autonomous recover at resume.

This patch adds regulator_suspend_finish that pairs with the
previously-existed regulator_suspend_prepare. The function
regulator_suspend_finish turns on the regulators that have always_on set
or positive use_count so that we can reset the regulator states
appropriately at resume.

In regulator_suspend_finish, if has_full_constraints, it disables
unnecessary regulators.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
--
Updates
v3
	comments corrected (Thanks to Igor)
v2
	disable unnecessary regulators (Thanks to Mark)
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index a2dc622..e611f67 100644 (file)
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -2656,6 +2656,47 @@ out:
 EXPORT_SYMBOL_GPL(regulator_suspend_prepare);
 
 /**
+ * regulator_suspend_finish - resume regulators from system wide suspend
+ *
+ * Turn on regulators that might be turned off by regulator_suspend_prepare
+ * and that should be turned on according to the regulators properties.
+ */
+int regulator_suspend_finish(void)
+{
+       struct regulator_dev *rdev;
+       int ret = 0, error;
+
+       mutex_lock(&regulator_list_mutex);
+       list_for_each_entry(rdev, &regulator_list, list) {
+               struct regulator_ops *ops = rdev->desc->ops;
+
+               mutex_lock(&rdev->mutex);
+               if ((rdev->use_count > 0  || rdev->constraints->always_on) &&
+                               ops->enable) {
+                       error = ops->enable(rdev);
+                       if (error)
+                               ret = error;
+               } else {
+                       if (!has_full_constraints)
+                               goto unlock;
+                       if (!ops->disable)
+                               goto unlock;
+                       if (ops->is_enabled && !ops->is_enabled(rdev))
+                               goto unlock;
+
+                       error = ops->disable(rdev);
+                       if (error)
+                               ret = error;
+               }
+unlock:
+               mutex_unlock(&rdev->mutex);
+       }
+       mutex_unlock(&regulator_list_mutex);
+       return ret;
+}
+EXPORT_SYMBOL_GPL(regulator_suspend_finish);
+
+/**
  * regulator_has_full_constraints - the system has fully specified constraints
  *
  * Calling this function will cause the regulator API to disable all

diff --git a/include/linux/regulator/machine.h b/include/linux/regulator/machine.h
index 761c745..c4c4fc4 100644 (file)
--- a/include/linux/regulator/machine.h
+++ b/include/linux/regulator/machine.h
@@ -186,6 +186,7 @@ struct regulator_init_data {
 };
 
 int regulator_suspend_prepare(suspend_state_t state);
+int regulator_suspend_finish(void);
 
 #ifdef CONFIG_REGULATOR
 void regulator_has_full_constraints(void);