regulator: Revert coupled regulator support again

Revert the last two commits of the voltage coupling mechanism patch set:

456e7cdf regulator: core: Change voltage setting path
69686176 regulator: core: Add voltage balancing mechanism

as they broke boot on OMAP again.
Reported-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

drivers/regulator/core.c

@@ -105,11 +105,6 @@ static int _notifier_call_chain(struct regulator_dev *rdev,
 				  unsigned long event, void *data);
 static int _regulator_do_set_voltage(struct regulator_dev *rdev,
 				     int min_uV, int max_uV);
-static int regulator_balance_voltage(struct regulator_dev *rdev,
-				     suspend_state_t state);
-static int regulator_set_voltage_rdev(struct regulator_dev *rdev,
-				      int min_uV, int max_uV,
-				      suspend_state_t state);
 static struct regulator *create_regulator(struct regulator_dev *rdev,
 					  struct device *dev,
 					  const char *supply_name);
@@ -201,66 +196,37 @@ static void regulator_unlock(struct regulator_dev *rdev)
 	}
 }
 
-static int regulator_lock_recursive(struct regulator_dev *rdev,
-				    unsigned int subclass)
+/**
+ * regulator_lock_supply - lock a regulator and its supplies
+ * @rdev:         regulator source
+ */
+static void regulator_lock_supply(struct regulator_dev *rdev)
 {
-	struct regulator_dev *c_rdev;
 	int i;
 
-	for (i = 0; i < rdev->coupling_desc.n_coupled; i++) {
-		c_rdev = rdev->coupling_desc.coupled_rdevs[i];
-
-		if (!c_rdev)
-			continue;
-
-		regulator_lock_nested(c_rdev, subclass++);
-
-		if (c_rdev->supply)
-			subclass =
-				regulator_lock_recursive(c_rdev->supply->rdev,
-							 subclass);
-	}
-
-	return subclass;
+	for (i = 0; rdev; rdev = rdev_get_supply(rdev), i++)
+		regulator_lock_nested(rdev, i);
 }
 
 /**
- * regulator_unlock_dependent - unlock regulator's suppliers and coupled
- *				regulators
- * @rdev:			regulator source
- *
- * Unlock all regulators related with rdev by coupling or suppling.
+ * regulator_unlock_supply - unlock a regulator and its supplies
+ * @rdev:         regulator source
  */
-static void regulator_unlock_dependent(struct regulator_dev *rdev)
+static void regulator_unlock_supply(struct regulator_dev *rdev)
 {
-	struct regulator_dev *c_rdev;
-	int i;
+	struct regulator *supply;
 
-	for (i = 0; i < rdev->coupling_desc.n_coupled; i++) {
-		c_rdev = rdev->coupling_desc.coupled_rdevs[i];
-
-		if (!c_rdev)
-			continue;
+	while (1) {
+		regulator_unlock(rdev);
+		supply = rdev->supply;
 
-		regulator_unlock(c_rdev);
+		if (!rdev->supply)
+			return;
 
-		if (c_rdev->supply)
-			regulator_unlock_dependent(c_rdev->supply->rdev);
+		rdev = supply->rdev;
 	}
 }
 
-/**
- * regulator_lock_dependent - lock regulator's suppliers and coupled regulators
- * @rdev:			regulator source
- *
- * This function as a wrapper on regulator_lock_recursive(), which locks
- * all regulators related with rdev by coupling or suppling.
- */
-static inline void regulator_lock_dependent(struct regulator_dev *rdev)
-{
-	regulator_lock_recursive(rdev, 0);
-}
-
 /**
  * of_get_regulator - get a regulator device node based on supply name
  * @dev: Device pointer for the consumer (of regulator) device
@@ -2293,11 +2259,6 @@ int regulator_enable(struct regulator *regulator)
 	struct regulator_dev *rdev = regulator->rdev;
 	int ret = 0;
 
-	if (rdev->coupling_desc.n_resolved != rdev->coupling_desc.n_coupled) {
-		rdev_err(rdev, "not all coupled regulators registered\n");
-		return -EPERM;
-	}
-
 	if (regulator->always_on)
 		return 0;
 
@@ -2307,12 +2268,9 @@ int regulator_enable(struct regulator *regulator)
 			return ret;
 	}
 
-	regulator_lock_dependent(rdev);
+	mutex_lock(&rdev->mutex);
 	ret = _regulator_enable(rdev);
-	/* balance only if there are regulators coupled */
-	if (rdev->coupling_desc.n_coupled > 1)
-		regulator_balance_voltage(rdev, PM_SUSPEND_ON);
-	regulator_unlock_dependent(rdev);
+	mutex_unlock(&rdev->mutex);
 
 	if (ret != 0 && rdev->supply)
 		regulator_disable(rdev->supply);
@@ -2418,11 +2376,9 @@ int regulator_disable(struct regulator *regulator)
 	if (regulator->always_on)
 		return 0;
 
-	regulator_lock_dependent(rdev);
+	mutex_lock(&rdev->mutex);
 	ret = _regulator_disable(rdev);
-	if (rdev->coupling_desc.n_coupled > 1)
-		regulator_balance_voltage(rdev, PM_SUSPEND_ON);
-	regulator_unlock_dependent(rdev);
+	mutex_unlock(&rdev->mutex);
 
 	if (ret == 0 && rdev->supply)
 		regulator_disable(rdev->supply);
@@ -2471,12 +2427,10 @@ int regulator_force_disable(struct regulator *regulator)
 	struct regulator_dev *rdev = regulator->rdev;
 	int ret;
 
-	regulator_lock_dependent(rdev);
+	mutex_lock(&rdev->mutex);
 	regulator->uA_load = 0;
 	ret = _regulator_force_disable(regulator->rdev);
-	if (rdev->coupling_desc.n_coupled > 1)
-		regulator_balance_voltage(rdev, PM_SUSPEND_ON);
-	regulator_unlock_dependent(rdev);
+	mutex_unlock(&rdev->mutex);
 
 	if (rdev->supply)
 		while (rdev->open_count--)
@@ -2624,9 +2578,9 @@ int regulator_is_enabled(struct regulator *regulator)
 	if (regulator->always_on)
 		return 1;
 
-	regulator_lock_dependent(regulator->rdev);
+	mutex_lock(&regulator->rdev->mutex);
 	ret = _regulator_is_enabled(regulator->rdev);
-	regulator_unlock_dependent(regulator->rdev);
+	mutex_unlock(&regulator->rdev->mutex);
 
 	return ret;
 }
@@ -3035,12 +2989,8 @@ static int regulator_set_voltage_unlocked(struct regulator *regulator,
 	int ret = 0;
 	int old_min_uV, old_max_uV;
 	int current_uV;
-
-	if (rdev->coupling_desc.n_resolved != rdev->coupling_desc.n_coupled) {
-		rdev_err(rdev, "not all coupled regulators registered\n");
-		ret = -EPERM;
-		goto out;
-	}
+	int best_supply_uV = 0;
+	int supply_change_uV = 0;
 
 	/* If we're setting the same range as last time the change
 	 * should be a noop (some cpufreq implementations use the same
@@ -3084,27 +3034,6 @@ static int regulator_set_voltage_unlocked(struct regulator *regulator,
 	if (ret < 0)
 		goto out2;
 
-	/* for not coupled regulators this will just set the voltage */
-	ret = regulator_balance_voltage(rdev, state);
-	if (ret < 0)
-		goto out2;
-
-out:
-	return 0;
-out2:
-	voltage->min_uV = old_min_uV;
-	voltage->max_uV = old_max_uV;
-
-	return ret;
-}
-
-static int regulator_set_voltage_rdev(struct regulator_dev *rdev, int min_uV,
-				      int max_uV, suspend_state_t state)
-{
-	int best_supply_uV = 0;
-	int supply_change_uV = 0;
-	int ret;
-
 	if (rdev->supply &&
 	    regulator_ops_is_valid(rdev->supply->rdev,
 				   REGULATOR_CHANGE_VOLTAGE) &&
@@ -3116,13 +3045,13 @@ static int regulator_set_voltage_rdev(struct regulator_dev *rdev, int min_uV,
 		selector = regulator_map_voltage(rdev, min_uV, max_uV);
 		if (selector < 0) {
 			ret = selector;
-			goto out;
+			goto out2;
 		}
 
 		best_supply_uV = _regulator_list_voltage(rdev, selector, 0);
 		if (best_supply_uV < 0) {
 			ret = best_supply_uV;
-			goto out;
+			goto out2;
 		}
 
 		best_supply_uV += rdev->desc->min_dropout_uV;
@@ -3130,7 +3059,7 @@ static int regulator_set_voltage_rdev(struct regulator_dev *rdev, int min_uV,
 		current_supply_uV = _regulator_get_voltage(rdev->supply->rdev);
 		if (current_supply_uV < 0) {
 			ret = current_supply_uV;
-			goto out;
+			goto out2;
 		}
 
 		supply_change_uV = best_supply_uV - current_supply_uV;
@@ -3142,7 +3071,7 @@ static int regulator_set_voltage_rdev(struct regulator_dev *rdev, int min_uV,
 		if (ret) {
 			dev_err(&rdev->dev, "Failed to increase supply voltage: %d\n",
 					ret);
-			goto out;
+			goto out2;
 		}
 	}
 
@@ -3152,7 +3081,7 @@ static int regulator_set_voltage_rdev(struct regulator_dev *rdev, int min_uV,
 		ret = _regulator_do_set_suspend_voltage(rdev, min_uV,
 							max_uV, state);
 	if (ret < 0)
-		goto out;
+		goto out2;
 
 	if (supply_change_uV < 0) {
 		ret = regulator_set_voltage_unlocked(rdev->supply,
@@ -3166,186 +3095,10 @@ static int regulator_set_voltage_rdev(struct regulator_dev *rdev, int min_uV,
 
 out:
 	return ret;
-}
-
-static int regulator_get_optimal_voltage(struct regulator_dev *rdev)
-{
-	struct coupling_desc *c_desc = &rdev->coupling_desc;
-	struct regulator_dev **c_rdevs = c_desc->coupled_rdevs;
-	int max_spread = rdev->constraints->max_spread;
-	int n_coupled = c_desc->n_coupled;
-	int desired_min_uV, desired_max_uV, min_current_uV = INT_MAX;
-	int max_current_uV = 0, highest_min_uV = 0, target_uV, possible_uV;
-	int i, ret;
-
-	/* If consumers don't provide any demands, set voltage to min_uV */
-	desired_min_uV = rdev->constraints->min_uV;
-	desired_max_uV = rdev->constraints->max_uV;
-	ret = regulator_check_consumers(rdev,
-					&desired_min_uV,
-					&desired_max_uV, PM_SUSPEND_ON);
-	if (ret < 0)
-		goto out;
-
-	/*
-	 * If there are no coupled regulators, simply set the voltage demanded
-	 * by consumers.
-	 */
-	if (n_coupled == 1) {
-		ret = desired_min_uV;
-		goto out;
-	}
-
-	/* Find highest min desired voltage */
-	for (i = 0; i < n_coupled; i++) {
-		int tmp_min = 0;
-		int tmp_max = INT_MAX;
-
-		if (!_regulator_is_enabled(c_rdevs[i]))
-			continue;
-
-		ret = regulator_check_consumers(c_rdevs[i],
-						&tmp_min,
-						&tmp_max, PM_SUSPEND_ON);
-		if (ret < 0)
-			goto out;
-
-		if (tmp_min > highest_min_uV)
-			highest_min_uV = tmp_min;
-	}
-
-	/*
-	 * Let target_uV be equal to the desired one if possible.
-	 * If not, set it to minimum voltage, allowed by other coupled
-	 * regulators.
-	 */
-	target_uV = max(desired_min_uV,  highest_min_uV - max_spread);
-
-	/*
-	 * Find min and max voltages, which currently aren't
-	 * violating max_spread
-	 */
-	for (i = 0; i < n_coupled; i++) {
-		int tmp_act;
-
-		/*
-		 * Don't check the regulator, which is about
-		 * to change voltage
-		 */
-		if (c_rdevs[i] == rdev)
-			continue;
-		if (!_regulator_is_enabled(c_rdevs[i]))
-			continue;
-
-		tmp_act = _regulator_get_voltage(c_rdevs[i]);
-		if (tmp_act < 0) {
-			ret = tmp_act;
-			goto out;
-		}
-
-		if (tmp_act < min_current_uV)
-			min_current_uV = tmp_act;
-
-		if (tmp_act > max_current_uV)
-			max_current_uV = tmp_act;
-	}
-
-	/* There aren't any other regulators enabled */
-	if (max_current_uV == 0) {
-		possible_uV = target_uV;
-	} else {
-		/*
-		 * Correct target voltage, so as it currently isn't
-		 * violating max_spread
-		 */
-		possible_uV = max(target_uV, max_current_uV - max_spread);
-		possible_uV = min(possible_uV, min_current_uV + max_spread);
-	}
-
-	if (possible_uV > desired_max_uV) {
-		ret = -EINVAL;
-		goto out;
-	}
-	ret = possible_uV;
-
-out:
-	return ret;
-}
-
-static int regulator_balance_voltage(struct regulator_dev *rdev,
-				     suspend_state_t state)
-{
-	struct regulator_dev **c_rdevs;
-	struct regulator_dev *best_rdev;
-	struct coupling_desc *c_desc = &rdev->coupling_desc;
-	int n_coupled;
-	int i, best_delta, best_uV, ret = 1;
-
-	c_rdevs = c_desc->coupled_rdevs;
-	n_coupled = c_desc->n_coupled;
-
-	/*
-	 * if system is in a state other than PM_SUSPEND_ON, don't check
-	 * other coupled regulators
-	 */
-	if (state != PM_SUSPEND_ON)
-		n_coupled = 1;
-
-	/*
-	 * Find the best possible voltage change on each loop. Leave the loop
-	 * if there isn't any possible change.
-	 */
-	while (1) {
-		best_delta = 0;
-		best_uV = 0;
-		best_rdev = NULL;
-
-		/*
-		 * Find highest difference between optimal voltage
-		 * and current voltage.
-		 */
-		for (i = 0; i < n_coupled; i++) {
-			/*
-			 * optimal_uV is the best voltage that can be set for
-			 * i-th regulator at the moment without violating
-			 * max_spread constraint in order to balance
-			 * the coupled voltages.
-			 */
-			int optimal_uV, current_uV;
-
-			optimal_uV = regulator_get_optimal_voltage(c_rdevs[i]);
-			if (optimal_uV < 0) {
-				ret = optimal_uV;
-				goto out;
-			}
-
-			current_uV = _regulator_get_voltage(c_rdevs[i]);
-			if (current_uV < 0) {
-				ret = optimal_uV;
-				goto out;
-			}
-
-			if (abs(best_delta) < abs(optimal_uV - current_uV)) {
-				best_delta = optimal_uV - current_uV;
-				best_rdev = c_rdevs[i];
-				best_uV = optimal_uV;
-			}
-		}
-
-		/* Nothing to change, return successfully */
-		if (!best_rdev) {
-			ret = 0;
-			goto out;
-		}
-
-		ret = regulator_set_voltage_rdev(best_rdev, best_uV,
-						 best_uV, state);
-
-		if (ret < 0)
-			goto out;
-	}
+out2:
+	voltage->min_uV = old_min_uV;
+	voltage->max_uV = old_max_uV;
 
-out:
 	return ret;
 }
 
@@ -3371,12 +3124,12 @@ int regulator_set_voltage(struct regulator *regulator, int min_uV, int max_uV)
 {
 	int ret = 0;
 
-	regulator_lock_dependent(regulator->rdev);
+	regulator_lock_supply(regulator->rdev);
 
 	ret = regulator_set_voltage_unlocked(regulator, min_uV, max_uV,
 					     PM_SUSPEND_ON);
 
-	regulator_unlock_dependent(regulator->rdev);
+	regulator_unlock_supply(regulator->rdev);
 
 	return ret;
 }
@@ -3454,12 +3207,12 @@ int regulator_set_suspend_voltage(struct regulator *regulator, int min_uV,
 	if (regulator_check_states(state) || state == PM_SUSPEND_ON)
 		return -EINVAL;
 
-	regulator_lock_dependent(regulator->rdev);
+	regulator_lock_supply(regulator->rdev);
 
 	ret = _regulator_set_suspend_voltage(regulator, min_uV,
 					     max_uV, state);
 
-	regulator_unlock_dependent(regulator->rdev);
+	regulator_unlock_supply(regulator->rdev);
 
 	return ret;
 }
@@ -3651,11 +3404,11 @@ int regulator_get_voltage(struct regulator *regulator)
 {
 	int ret;
 
-	regulator_lock_dependent(regulator->rdev);
+	regulator_lock_supply(regulator->rdev);
 
 	ret = _regulator_get_voltage(regulator->rdev);
 
-	regulator_unlock_dependent(regulator->rdev);
+	regulator_unlock_supply(regulator->rdev);
 
 	return ret;
 }