Handle under-voltage events for crucial regulators to maintain system
stability and avoid issues during power drops.
Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
---
drivers/regulator/core.c | 38 +++++++++++++++++++++++++++++++
drivers/regulator/of_regulator.c | 2 ++
include/linux/regulator/machine.h | 10 ++++++++
3 files changed, 50 insertions(+)
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 3137e40fcd3e..a072f721f288 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -19,6 +19,7 @@
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/of.h>
+#include <linux/reboot.h>
#include <linux/regmap.h>
#include <linux/regulator/of_regulator.h>
#include <linux/regulator/consumer.h>
@@ -5061,6 +5062,41 @@ void regulator_bulk_free(int num_consumers,
}
EXPORT_SYMBOL_GPL(regulator_bulk_free);
+/**
+ * regulator_handle_critical - Handle events for system-critical regulators.
+ * @rdev: The regulator device.
+ * @event: The event being handled.
+ *
+ * This function handles critical events such as under-voltage, over-current,
+ * and unknown errors for regulators deemed system-critical. On detecting such
+ * events, it triggers a hardware protection shutdown with a defined timeout.
+ */
+static void regulator_handle_critical(struct regulator_dev *rdev,
+ unsigned long event)
+{
+ const char *reason = NULL;
+
+ if (!rdev->constraints->system_critical)
+ return;
+
+ switch (event) {
+ case REGULATOR_EVENT_UNDER_VOLTAGE:
+ reason = "System critical regulator: voltage drop detected";
+ break;
+ case REGULATOR_EVENT_OVER_CURRENT:
+ reason = "System critical regulator: over-current detected";
+ break;
+ case REGULATOR_EVENT_FAIL:
+ reason = "System critical regulator: unknown error";
+ }
+
+ if (!reason)
+ return;
+
+ hw_protection_shutdown(reason,
+ REGULATOR_DEF_UV_LESS_CRITICAL_WINDOW_MS);
+}
+
/**
* regulator_notifier_call_chain - call regulator event notifier
* @rdev: regulator source
@@ -5073,6 +5109,8 @@ EXPORT_SYMBOL_GPL(regulator_bulk_free);
int regulator_notifier_call_chain(struct regulator_dev *rdev,
unsigned long event, void *data)
{
+ regulator_handle_critical(rdev, event);
+
_notifier_call_chain(rdev, event, data);
return NOTIFY_DONE;
diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index 1b65e5e4e40f..3bdd6f1919a4 100644
--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -131,6 +131,8 @@ static int of_get_regulation_constraints(struct device *dev,
constraints->valid_ops_mask |= REGULATOR_CHANGE_STATUS;
constraints->pull_down = of_property_read_bool(np, "regulator-pull-down");
+ constraints->system_critical = of_property_read_bool(np,
+ "system-critical-regulator");
if (of_property_read_bool(np, "regulator-allow-bypass"))
constraints->valid_ops_mask |= REGULATOR_CHANGE_BYPASS;
diff --git a/include/linux/regulator/machine.h b/include/linux/regulator/machine.h
index 621b7f4a3639..e0ddfb5593c9 100644
--- a/include/linux/regulator/machine.h
+++ b/include/linux/regulator/machine.h
@@ -49,6 +49,13 @@ struct regulator;
#define DISABLE_IN_SUSPEND 1
#define ENABLE_IN_SUSPEND 2
+/*
+ * Default time window (in milliseconds) following a critical under-voltage
+ * event during which less critical actions can be safely carried out by the
+ * system.
+ */
+#define REGULATOR_DEF_UV_LESS_CRITICAL_WINDOW_MS 10
+
/* Regulator active discharge flags */
enum regulator_active_discharge {
REGULATOR_ACTIVE_DISCHARGE_DEFAULT,
@@ -127,6 +134,8 @@ struct notification_limit {
* @ramp_disable: Disable ramp delay when initialising or when setting voltage.
* @soft_start: Enable soft start so that voltage ramps slowly.
* @pull_down: Enable pull down when regulator is disabled.
+ * @system_critical: Set if the regulator is critical to system stability or
+ * functionality.
* @over_current_protection: Auto disable on over current event.
*
* @over_current_detection: Configure over current limits.
@@ -214,6 +223,7 @@ 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 system_critical:1; /* critical to system stability */
unsigned over_current_protection:1; /* auto disable on over current */
unsigned over_current_detection:1; /* notify on over current */
unsigned over_voltage_detection:1; /* notify on over voltage */
--
2.39.2
