regulator: Add over current protection (OCP) support

Some regulators can automatically shut down when they detect an
over current event. Add an op (set_over_current_protection) and a
DT property + constraint to support this capability.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/regulator/regulator.txt

@@ -42,6 +42,7 @@ Optional properties:
 - regulator-system-load: Load in uA present on regulator that is not captured by
   any consumer request.
 - regulator-pull-down: Enable pull down resistor when the regulator is disabled.
+- regulator-over-current-protection: Enable over current protection.
 
 Deprecated properties:
 - regulator-compatible: If a regulator chip contains multiple

drivers/regulator/core.c

@@ -1081,6 +1081,15 @@ static int set_machine_constraints(struct regulator_dev *rdev,
 		}
 	}
 
+	if (rdev->constraints->over_current_protection
+		&& ops->set_over_current_protection) {
+		ret = ops->set_over_current_protection(rdev);
+		if (ret < 0) {
+			rdev_err(rdev, "failed to set over current protection\n");
+			goto out;
+		}
+	}
+
 	print_constraints(rdev);
 	return 0;
 out:

drivers/regulator/of_regulator.c

@@ -107,6 +107,9 @@ static void of_get_regulation_constraints(struct device_node *np,
 	if (!of_property_read_u32(np, "regulator-system-load", &pval))
 		constraints->system_load = pval;
 
+	constraints->over_current_protection = of_property_read_bool(np,
+					"regulator-over-current-protection");
+
 	for (i = 0; i < ARRAY_SIZE(regulator_states); i++) {
 		switch (i) {
 		case PM_SUSPEND_MEM:

include/linux/regulator/driver.h

@@ -148,6 +148,7 @@ struct regulator_ops {
 	int (*get_current_limit) (struct regulator_dev *);
 
 	int (*set_input_current_limit) (struct regulator_dev *, int lim_uA);
+	int (*set_over_current_protection) (struct regulator_dev *);
 
 	/* enable/disable regulator */
 	int (*enable) (struct regulator_dev *);

include/linux/regulator/machine.h

@@ -147,6 +147,7 @@ struct regulation_constraints {
 	unsigned ramp_disable:1; /* disable ramp delay */
 	unsigned soft_start:1;	/* ramp voltage slowly */
 	unsigned pull_down:1;	/* pull down resistor when regulator off */
+	unsigned over_current_protection:1; /* auto disable on over current */
 };
 
 /**