Merge remote-tracking branch 'regulator/topic/coupled' into regulator-next

2 files changed, 186 insertions, 71 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index df82e2a8442a..86ae1825cec1 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -22,6 +22,7 @@
 #include <linux/regmap.h>
 #include <linux/regulator/of_regulator.h>
 #include <linux/regulator/consumer.h>
+#include <linux/regulator/coupler.h>
 #include <linux/regulator/driver.h>
 #include <linux/regulator/machine.h>
 #include <linux/module.h>
@@ -49,6 +50,7 @@ static DEFINE_MUTEX(regulator_list_mutex);
 static LIST_HEAD(regulator_map_list);
 static LIST_HEAD(regulator_ena_gpio_list);
 static LIST_HEAD(regulator_supply_alias_list);
+static LIST_HEAD(regulator_coupler_list);
 static bool has_full_constraints;
 
 static struct dentry *debugfs_root;
@@ -92,7 +94,6 @@ struct regulator_supply_alias {
 
 static int _regulator_is_enabled(struct regulator_dev *rdev);
 static int _regulator_disable(struct regulator *regulator);
-static int _regulator_get_voltage(struct regulator_dev *rdev);
 static int _regulator_get_current_limit(struct regulator_dev *rdev);
 static unsigned int _regulator_get_mode(struct regulator_dev *rdev);
 static int _notifier_call_chain(struct regulator_dev *rdev,
@@ -101,15 +102,12 @@ 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);
 static void _regulator_put(struct regulator *regulator);
 
-static const char *rdev_get_name(struct regulator_dev *rdev)
+const char *rdev_get_name(struct regulator_dev *rdev)
 {
 	if (rdev->constraints && rdev->constraints->name)
 		return rdev->constraints->name;
@@ -423,8 +421,8 @@ static struct device_node *of_get_regulator(struct device *dev, const char *supp
 }
 
 /* Platform voltage constraint check */
-static int regulator_check_voltage(struct regulator_dev *rdev,
-				   int *min_uV, int *max_uV)
+int regulator_check_voltage(struct regulator_dev *rdev,
+			    int *min_uV, int *max_uV)
 {
 	BUG_ON(*min_uV > *max_uV);
 
@@ -456,9 +454,9 @@ static int regulator_check_states(suspend_state_t state)
 /* Make sure we select a voltage that suits the needs of all
  * regulator consumers
  */
-static int regulator_check_consumers(struct regulator_dev *rdev,
-				     int *min_uV, int *max_uV,
-				     suspend_state_t state)
+int regulator_check_consumers(struct regulator_dev *rdev,
+			      int *min_uV, int *max_uV,
+			      suspend_state_t state)
 {
 	struct regulator *regulator;
 	struct regulator_voltage *voltage;
@@ -569,7 +567,7 @@ static ssize_t regulator_uV_show(struct device *dev,
 	ssize_t ret;
 
 	regulator_lock(rdev);
-	ret = sprintf(buf, "%d\n", _regulator_get_voltage(rdev));
+	ret = sprintf(buf, "%d\n", regulator_get_voltage_rdev(rdev));
 	regulator_unlock(rdev);
 
 	return ret;
@@ -940,7 +938,7 @@ static int drms_uA_update(struct regulator_dev *rdev)
 			rdev_err(rdev, "failed to set load %d\n", current_uA);
 	} else {
 		/* get output voltage */
-		output_uV = _regulator_get_voltage(rdev);
+		output_uV = regulator_get_voltage_rdev(rdev);
 		if (output_uV <= 0) {
 			rdev_err(rdev, "invalid output voltage found\n");
 			return -EINVAL;
@@ -1053,7 +1051,7 @@ static void print_constraints(struct regulator_dev *rdev)
 
 	if (!constraints->min_uV ||
 	    constraints->min_uV != constraints->max_uV) {
-		ret = _regulator_get_voltage(rdev);
+		ret = regulator_get_voltage_rdev(rdev);
 		if (ret > 0)
 			count += scnprintf(buf + count, len - count,
 					   "at %d mV ", ret / 1000);
@@ -1112,7 +1110,7 @@ static int machine_constraints_voltage(struct regulator_dev *rdev,
 	if (rdev->constraints->apply_uV &&
 	    rdev->constraints->min_uV && rdev->constraints->max_uV) {
 		int target_min, target_max;
-		int current_uV = _regulator_get_voltage(rdev);
+		int current_uV = regulator_get_voltage_rdev(rdev);
 
 		if (current_uV == -ENOTRECOVERABLE) {
 			/* This regulator can't be read and must be initialized */
@@ -1122,7 +1120,7 @@ static int machine_constraints_voltage(struct regulator_dev *rdev,
 			_regulator_do_set_voltage(rdev,
 						  rdev->constraints->min_uV,
 						  rdev->constraints->max_uV);
-			current_uV = _regulator_get_voltage(rdev);
+			current_uV = regulator_get_voltage_rdev(rdev);
 		}
 
 		if (current_uV < 0) {
@@ -3064,7 +3062,7 @@ static int _regulator_call_set_voltage(struct regulator_dev *rdev,
 	struct pre_voltage_change_data data;
 	int ret;
 
-	data.old_uV = _regulator_get_voltage(rdev);
+	data.old_uV = regulator_get_voltage_rdev(rdev);
 	data.min_uV = min_uV;
 	data.max_uV = max_uV;
 	ret = _notifier_call_chain(rdev, REGULATOR_EVENT_PRE_VOLTAGE_CHANGE,
@@ -3088,7 +3086,7 @@ static int _regulator_call_set_voltage_sel(struct regulator_dev *rdev,
 	struct pre_voltage_change_data data;
 	int ret;
 
-	data.old_uV = _regulator_get_voltage(rdev);
+	data.old_uV = regulator_get_voltage_rdev(rdev);
 	data.min_uV = uV;
 	data.max_uV = uV;
 	ret = _notifier_call_chain(rdev, REGULATOR_EVENT_PRE_VOLTAGE_CHANGE,
@@ -3201,7 +3199,7 @@ static int _regulator_do_set_voltage(struct regulator_dev *rdev,
 	unsigned int selector;
 	int old_selector = -1;
 	const struct regulator_ops *ops = rdev->desc->ops;
-	int old_uV = _regulator_get_voltage(rdev);
+	int old_uV = regulator_get_voltage_rdev(rdev);
 
 	trace_regulator_set_voltage(rdev_get_name(rdev), min_uV, max_uV);
 
@@ -3228,7 +3226,7 @@ static int _regulator_do_set_voltage(struct regulator_dev *rdev,
 				best_val = ops->list_voltage(rdev,
 							     selector);
 			else
-				best_val = _regulator_get_voltage(rdev);
+				best_val = regulator_get_voltage_rdev(rdev);
 		}
 
 	} else if (ops->set_voltage_sel) {
@@ -3350,7 +3348,7 @@ static int regulator_set_voltage_unlocked(struct regulator *regulator,
 	 * changing the voltage.
 	 */
 	if (!regulator_ops_is_valid(rdev, REGULATOR_CHANGE_VOLTAGE)) {
-		current_uV = _regulator_get_voltage(rdev);
+		current_uV = regulator_get_voltage_rdev(rdev);
 		if (min_uV <= current_uV && current_uV <= max_uV) {
 			voltage->min_uV = min_uV;
 			voltage->max_uV = max_uV;
@@ -3387,8 +3385,8 @@ out:
 	return ret;
 }
 
-static int regulator_set_voltage_rdev(struct regulator_dev *rdev, int min_uV,
-				      int max_uV, suspend_state_t state)
+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;
@@ -3416,7 +3414,7 @@ static int regulator_set_voltage_rdev(struct regulator_dev *rdev, int min_uV,
 
 		best_supply_uV += rdev->desc->min_dropout_uV;
 
-		current_supply_uV = _regulator_get_voltage(rdev->supply->rdev);
+		current_supply_uV = regulator_get_voltage_rdev(rdev->supply->rdev);
 		if (current_supply_uV < 0) {
 			ret = current_supply_uV;
 			goto out;
@@ -3467,7 +3465,7 @@ static int regulator_limit_voltage_step(struct regulator_dev *rdev,
 		return 1;
 
 	if (*current_uV < 0) {
-		*current_uV = _regulator_get_voltage(rdev);
+		*current_uV = regulator_get_voltage_rdev(rdev);
 
 		if (*current_uV < 0)
 			return *current_uV;
@@ -3496,11 +3494,10 @@ 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;
 	struct regulation_constraints *constraints = rdev->constraints;
-	int max_spread = constraints->max_spread;
 	int desired_min_uV = 0, desired_max_uV = INT_MAX;
 	int max_current_uV = 0, min_current_uV = INT_MAX;
 	int highest_min_uV = 0, target_uV, possible_uV;
-	int i, ret;
+	int i, ret, max_spread;
 	bool done;
 
 	*current_uV = -1;
@@ -3554,6 +3551,8 @@ static int regulator_get_optimal_voltage(struct regulator_dev *rdev,
 		}
 	}
 
+	max_spread = constraints->max_spread[0];
+
 	/*
 	 * Let target_uV be equal to the desired one if possible.
 	 * If not, set it to minimum voltage, allowed by other coupled
@@ -3571,7 +3570,7 @@ static int regulator_get_optimal_voltage(struct regulator_dev *rdev,
 		if (!_regulator_is_enabled(c_rdevs[i]))
 			continue;
 
-		tmp_act = _regulator_get_voltage(c_rdevs[i]);
+		tmp_act = regulator_get_voltage_rdev(c_rdevs[i]);
 		if (tmp_act < 0)
 			return tmp_act;
 
@@ -3613,7 +3612,7 @@ finish:
 	if (n_coupled > 1 && *current_uV == -1) {
 
 		if (_regulator_is_enabled(rdev)) {
-			ret = _regulator_get_voltage(rdev);
+			ret = regulator_get_voltage_rdev(rdev);
 			if (ret < 0)
 				return ret;
 
@@ -3635,9 +3634,11 @@ static int regulator_balance_voltage(struct regulator_dev *rdev,
 	struct regulator_dev **c_rdevs;
 	struct regulator_dev *best_rdev;
 	struct coupling_desc *c_desc = &rdev->coupling_desc;
+	struct regulator_coupler *coupler = c_desc->coupler;
 	int i, ret, n_coupled, best_min_uV, best_max_uV, best_c_rdev;
-	bool best_c_rdev_done, c_rdev_done[MAX_COUPLED];
 	unsigned int delta, best_delta;
+	unsigned long c_rdev_done = 0;
+	bool best_c_rdev_done;
 
 	c_rdevs = c_desc->coupled_rdevs;
 	n_coupled = c_desc->n_coupled;
@@ -3654,8 +3655,9 @@ static int regulator_balance_voltage(struct regulator_dev *rdev,
 		return -EPERM;
 	}
 
-	for (i = 0; i < n_coupled; i++)
-		c_rdev_done[i] = false;
+	/* Invoke custom balancer for customized couplers */
+	if (coupler && coupler->balance_voltage)
+		return coupler->balance_voltage(coupler, rdev, state);
 
 	/*
 	 * Find the best possible voltage change on each loop. Leave the loop
@@ -3682,7 +3684,7 @@ static int regulator_balance_voltage(struct regulator_dev *rdev,
 			 */
 			int optimal_uV = 0, optimal_max_uV = 0, current_uV = 0;
 
-			if (c_rdev_done[i])
+			if (test_bit(i, &c_rdev_done))
 				continue;
 
 			ret = regulator_get_optimal_voltage(c_rdevs[i],
@@ -3717,7 +3719,8 @@ static int regulator_balance_voltage(struct regulator_dev *rdev,
 		if (ret < 0)
 			goto out;
 
-		c_rdev_done[best_c_rdev] = best_c_rdev_done;
+		if (best_c_rdev_done)
+			set_bit(best_c_rdev, &c_rdev_done);
 
 	} while (n_coupled > 1);
 
@@ -3973,7 +3976,7 @@ out:
 }
 EXPORT_SYMBOL_GPL(regulator_sync_voltage);
 
-static int _regulator_get_voltage(struct regulator_dev *rdev)
+int regulator_get_voltage_rdev(struct regulator_dev *rdev)
 {
 	int sel, ret;
 	bool bypassed;
@@ -3990,7 +3993,7 @@ static int _regulator_get_voltage(struct regulator_dev *rdev)
 				return -EPROBE_DEFER;
 			}
 
-			return _regulator_get_voltage(rdev->supply->rdev);
+			return regulator_get_voltage_rdev(rdev->supply->rdev);
 		}
 	}
 
@@ -4006,7 +4009,7 @@ static int _regulator_get_voltage(struct regulator_dev *rdev)
 	} else if (rdev->desc->fixed_uV && (rdev->desc->n_voltages == 1)) {
 		ret = rdev->desc->fixed_uV;
 	} else if (rdev->supply) {
-		ret = _regulator_get_voltage(rdev->supply->rdev);
+		ret = regulator_get_voltage_rdev(rdev->supply->rdev);
 	} else {
 		return -EINVAL;
 	}
@@ -4031,7 +4034,7 @@ int regulator_get_voltage(struct regulator *regulator)
 	int ret;
 
 	regulator_lock_dependent(regulator->rdev, &ww_ctx);
-	ret = _regulator_get_voltage(regulator->rdev);
+	ret = regulator_get_voltage_rdev(regulator->rdev);
 	regulator_unlock_dependent(regulator->rdev, &ww_ctx);
 
 	return ret;
@@ -4769,8 +4772,60 @@ static int regulator_register_resolve_supply(struct device *dev, void *data)
 	return 0;
 }
 
+int regulator_coupler_register(struct regulator_coupler *coupler)
+{
+	mutex_lock(&regulator_list_mutex);
+	list_add_tail(&coupler->list, &regulator_coupler_list);
+	mutex_unlock(&regulator_list_mutex);
+
+	return 0;
+}
+
+static struct regulator_coupler *
+regulator_find_coupler(struct regulator_dev *rdev)
+{
+	struct regulator_coupler *coupler;
+	int err;
+
+	/*
+	 * Note that regulators are appended to the list and the generic
+	 * coupler is registered first, hence it will be attached at last
+	 * if nobody cared.
+	 */
+	list_for_each_entry_reverse(coupler, &regulator_coupler_list, list) {
+		err = coupler->attach_regulator(coupler, rdev);
+		if (!err) {
+			if (!coupler->balance_voltage &&
+			    rdev->coupling_desc.n_coupled > 2)
+				goto err_unsupported;
+
+			return coupler;
+		}
+
+		if (err < 0)
+			return ERR_PTR(err);
+
+		if (err == 1)
+			continue;
+
+		break;
+	}
+
+	return ERR_PTR(-EINVAL);
+
+err_unsupported:
+	if (coupler->detach_regulator)
+		coupler->detach_regulator(coupler, rdev);
+
+	rdev_err(rdev,
+		"Voltage balancing for multiple regulator couples is unimplemented\n");
+
+	return ERR_PTR(-EPERM);
+}
+
 static void regulator_resolve_coupling(struct regulator_dev *rdev)
 {
+	struct regulator_coupler *coupler = rdev->coupling_desc.coupler;
 	struct coupling_desc *c_desc = &rdev->coupling_desc;
 	int n_coupled = c_desc->n_coupled;
 	struct regulator_dev *c_rdev;
@@ -4786,6 +4841,12 @@ static void regulator_resolve_coupling(struct regulator_dev *rdev)
 		if (!c_rdev)
 			continue;
 
+		if (c_rdev->coupling_desc.coupler != coupler) {
+			rdev_err(rdev, "coupler mismatch with %s\n",
+				 rdev_get_name(c_rdev));
+			return;
+		}
+
 		regulator_lock(c_rdev);
 
 		c_desc->coupled_rdevs[i] = c_rdev;
@@ -4799,10 +4860,12 @@ static void regulator_resolve_coupling(struct regulator_dev *rdev)
 
 static void regulator_remove_coupling(struct regulator_dev *rdev)
 {
+	struct regulator_coupler *coupler = rdev->coupling_desc.coupler;
 	struct coupling_desc *__c_desc, *c_desc = &rdev->coupling_desc;
 	struct regulator_dev *__c_rdev, *c_rdev;
 	unsigned int __n_coupled, n_coupled;
 	int i, k;
+	int err;
 
 	n_coupled = c_desc->n_coupled;
 
@@ -4832,21 +4895,33 @@ static void regulator_remove_coupling(struct regulator_dev *rdev)
 		c_desc->coupled_rdevs[i] = NULL;
 		c_desc->n_resolved--;
 	}
+
+	if (coupler && coupler->detach_regulator) {
+		err = coupler->detach_regulator(coupler, rdev);
+		if (err)
+			rdev_err(rdev, "failed to detach from coupler: %d\n",
+				 err);
+	}
+
+	kfree(rdev->coupling_desc.coupled_rdevs);
+	rdev->coupling_desc.coupled_rdevs = NULL;
 }
 
 static int regulator_init_coupling(struct regulator_dev *rdev)
 {
-	int n_phandles;
+	int err, n_phandles;
+	size_t alloc_size;
 
 	if (!IS_ENABLED(CONFIG_OF))
 		n_phandles = 0;
 	else
 		n_phandles = of_get_n_coupled(rdev);
 
-	if (n_phandles + 1 > MAX_COUPLED) {
-		rdev_err(rdev, "too many regulators coupled\n");
-		return -EPERM;
-	}
+	alloc_size = sizeof(*rdev) * (n_phandles + 1);
+
+	rdev->coupling_desc.coupled_rdevs = kzalloc(alloc_size, GFP_KERNEL);
+	if (!rdev->coupling_desc.coupled_rdevs)
+		return -ENOMEM;
 
 	/*
 	 * Every regulator should always have coupling descriptor filled with
@@ -4860,23 +4935,35 @@ static int regulator_init_coupling(struct regulator_dev *rdev)
 	if (n_phandles == 0)
 		return 0;
 
-	/* regulator, which can't change its voltage, can't be coupled */
-	if (!regulator_ops_is_valid(rdev, REGULATOR_CHANGE_VOLTAGE)) {
-		rdev_err(rdev, "voltage operation not allowed\n");
+	if (!of_check_coupling_data(rdev))
 		return -EPERM;
-	}
 
-	if (rdev->constraints->max_spread <= 0) {
-		rdev_err(rdev, "wrong max_spread value\n");
-		return -EPERM;
+	rdev->coupling_desc.coupler = regulator_find_coupler(rdev);
+	if (IS_ERR(rdev->coupling_desc.coupler)) {
+		err = PTR_ERR(rdev->coupling_desc.coupler);
+		rdev_err(rdev, "failed to get coupler: %d\n", err);
+		return err;
 	}
 
-	if (!of_check_coupling_data(rdev))
+	return 0;
+}
+
+static int generic_coupler_attach(struct regulator_coupler *coupler,
+				  struct regulator_dev *rdev)
+{
+	if (rdev->coupling_desc.n_coupled > 2) {
+		rdev_err(rdev,
+			 "Voltage balancing for multiple regulator couples is unimplemented\n");
 		return -EPERM;
+	}
 
 	return 0;
 }
 
+static struct regulator_coupler generic_regulator_coupler = {
+	.attach_regulator = generic_coupler_attach,
+};
+
 /**
  * regulator_register - register regulator
  * @regulator_desc: regulator to register
@@ -5038,7 +5125,9 @@ regulator_register(const struct regulator_desc *regulator_desc,
 	if (ret < 0)
 		goto wash;
 
+	mutex_lock(&regulator_list_mutex);
 	ret = regulator_init_coupling(rdev);
+	mutex_unlock(&regulator_list_mutex);
 	if (ret < 0)
 		goto wash;
 
@@ -5087,6 +5176,7 @@ regulator_register(const struct regulator_desc *regulator_desc,
 unset_supplies:
 	mutex_lock(&regulator_list_mutex);
 	unset_regulator_supplies(rdev);
+	regulator_remove_coupling(rdev);
 	mutex_unlock(&regulator_list_mutex);
 wash:
 	kfree(rdev->constraints);
@@ -5340,7 +5430,7 @@ static void regulator_summary_show_subtree(struct seq_file *s,
 		   rdev->use_count, rdev->open_count, rdev->bypass_count,
 		   regulator_opmode_to_str(opmode));
 
-	seq_printf(s, "%5dmV ", _regulator_get_voltage(rdev) / 1000);
+	seq_printf(s, "%5dmV ", regulator_get_voltage_rdev(rdev) / 1000);
 	seq_printf(s, "%5dmA ",
 		   _regulator_get_current_limit_unlocked(rdev) / 1000);
 
@@ -5542,6 +5632,8 @@ static int __init regulator_init(void)
 #endif
 	regulator_dummy_init();
 
+	regulator_coupler_register(&generic_regulator_coupler);
+
 	return ret;
 }
 
diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index 0ead1164e4d6..397918ebba55 100644
--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -21,7 +21,8 @@ static const char *const regulator_states[PM_SUSPEND_MAX + 1] = {
 	[PM_SUSPEND_MAX]	= "regulator-state-disk",
 };
 
-static void of_get_regulation_constraints(struct device_node *np,
+static int of_get_regulation_constraints(struct device *dev,
+					struct device_node *np,
 					struct regulator_init_data **init_data,
 					const struct regulator_desc *desc)
 {
@@ -30,8 +31,13 @@ static void of_get_regulation_constraints(struct device_node *np,
 	struct device_node *suspend_np;
 	unsigned int mode;
 	int ret, i, len;
+	int n_phandles;
 	u32 pval;
 
+	n_phandles = of_count_phandle_with_args(np, "regulator-coupled-with",
+						NULL);
+	n_phandles = max(n_phandles, 0);
+
 	constraints->name = of_get_property(np, "regulator-name", NULL);
 
 	if (!of_property_read_u32(np, "regulator-min-microvolt", &pval))
@@ -163,9 +169,17 @@ static void of_get_regulation_constraints(struct device_node *np,
 	if (!of_property_read_u32(np, "regulator-system-load", &pval))
 		constraints->system_load = pval;
 
-	if (!of_property_read_u32(np, "regulator-coupled-max-spread",
-				  &pval))
-		constraints->max_spread = pval;
+	if (n_phandles) {
+		constraints->max_spread = devm_kzalloc(dev,
+				sizeof(*constraints->max_spread) * n_phandles,
+				GFP_KERNEL);
+
+		if (!constraints->max_spread)
+			return -ENOMEM;
+
+		of_property_read_u32_array(np, "regulator-coupled-max-spread",
+					   constraints->max_spread, n_phandles);
+	}
 
 	if (!of_property_read_u32(np, "regulator-max-step-microvolt",
 				  &pval))
@@ -242,6 +256,8 @@ static void of_get_regulation_constraints(struct device_node *np,
 		suspend_state = NULL;
 		suspend_np = NULL;
 	}
+
+	return 0;
 }
 
 /**
@@ -267,7 +283,9 @@ struct regulator_init_data *of_get_regulator_init_data(struct device *dev,
 	if (!init_data)
 		return NULL; /* Out of memory? */
 
-	of_get_regulation_constraints(node, &init_data, desc);
+	if (of_get_regulation_constraints(dev, node, &init_data, desc))
+		return NULL;
+
 	return init_data;
 }
 EXPORT_SYMBOL_GPL(of_get_regulator_init_data);
@@ -473,7 +491,8 @@ int of_get_n_coupled(struct regulator_dev *rdev)
 
 /* Looks for "to_find" device_node in src's "regulator-coupled-with" property */
 static bool of_coupling_find_node(struct device_node *src,
-				  struct device_node *to_find)
+				  struct device_node *to_find,
+				  int *index)
 {
 	int n_phandles, i;
 	bool found = false;
@@ -495,8 +514,10 @@ static bool of_coupling_find_node(struct device_node *src,
 
 		of_node_put(tmp);
 
-		if (found)
+		if (found) {
+			*index = i;
 			break;
+		}
 	}
 
 	return found;
@@ -517,22 +538,23 @@ static bool of_coupling_find_node(struct device_node *src,
  */
 bool of_check_coupling_data(struct regulator_dev *rdev)
 {
-	int max_spread = rdev->constraints->max_spread;
 	struct device_node *node = rdev->dev.of_node;
 	int n_phandles = of_get_n_coupled(rdev);
 	struct device_node *c_node;
+	int index;
 	int i;
 	bool ret = true;
 
-	if (max_spread <= 0) {
-		dev_err(&rdev->dev, "max_spread value invalid\n");
-		return false;
-	}
-
 	/* iterate over rdev's phandles */
 	for (i = 0; i < n_phandles; i++) {
+		int max_spread = rdev->constraints->max_spread[i];
 		int c_max_spread, c_n_phandles;
 
+		if (max_spread <= 0) {
+			dev_err(&rdev->dev, "max_spread value invalid\n");
+			return false;
+		}
+
 		c_node = of_parse_phandle(node,
 					  "regulator-coupled-with", i);
 
@@ -549,22 +571,23 @@ bool of_check_coupling_data(struct regulator_dev *rdev)
 			goto clean;
 		}
 
-		if (of_property_read_u32(c_node, "regulator-coupled-max-spread",
-					 &c_max_spread)) {
+		if (!of_coupling_find_node(c_node, node, &index)) {
+			dev_err(&rdev->dev, "missing 2-way linking for coupled regulators\n");
 			ret = false;
 			goto clean;
 		}
 
-		if (c_max_spread != max_spread) {
-			dev_err(&rdev->dev,
-				"coupled regulators max_spread mismatch\n");
+		if (of_property_read_u32_index(c_node, "regulator-coupled-max-spread",
+					       index, &c_max_spread)) {
 			ret = false;
 			goto clean;
 		}
 
-		if (!of_coupling_find_node(c_node, node)) {
-			dev_err(&rdev->dev, "missing 2-way linking for coupled regulators\n");
+		if (c_max_spread != max_spread) {
+			dev_err(&rdev->dev,
+				"coupled regulators max_spread mismatch\n");
 			ret = false;
+			goto clean;
 		}
 
 clean: