regulator: core: Introduce API for regulators coupling customization

Right now regulator core supports only one type of regulators coupling,
the "voltage max-spread" which keeps voltages of coupled regulators in a
given range from each other. A more sophisticated coupling may be required
in practice, one example is the NVIDIA Tegra SoCs which besides the
max-spreading have other restrictions that must be adhered. Introduce API
that allow platforms to provide their own customized coupling algorithms.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 43 insertions, 20 deletions

diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index 6dca0ba044d8..db1cb2714b92 100644
--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -25,7 +25,8 @@ 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)
 {
@@ -34,8 +35,13 @@ 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))
@@ -167,9 +173,17 @@ 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))
@@ -246,6 +260,8 @@ static void of_get_regulation_constraints(struct device_node *np,
 		suspend_state = NULL;
 		suspend_np = NULL;
 	}
+
+	return 0;
 }
 
 /**
@@ -271,7 +287,9 @@ 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);
@@ -477,7 +495,8 @@ 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;
@@ -499,8 +518,10 @@ static bool of_coupling_find_node(struct device_node *src,
 
 		of_node_put(tmp);
 
-		if (found)
+		if (found) {
+			*index = i;
 			break;
+		}
 	}
 
 	return found;
@@ -521,22 +542,23 @@ 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);
 
@@ -553,22 +575,23 @@ 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: