[v3,2/7] regulator: Handle system-critical under-voltage events
Commit Message
Introduce handling for system-critical regulators during under-voltage
events.
A new field 'system_critical' in regulation_constraints is added to mark
regulators critical to system stability or functionality. During an
under-voltage event, if the regulator is marked as system-critical, an
emergency hardware protection shutdown is triggered to prevent potential
system damage or malfunction.
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
drivers/regulator/core.c | 6 ++++++
drivers/regulator/of_regulator.c | 2 ++
include/linux/regulator/machine.h | 6 ++++++
3 files changed, 14 insertions(+)
Comments
On Wed, Oct 25, 2023 at 10:46:09AM +0200, Oleksij Rempel wrote:
> + if (rdev->constraints->system_critical &&
> + event == REGULATOR_EVENT_UNDER_VOLTAGE)
> + hw_protection_shutdown("System critical voltage drop detected",
> + REGULATOR_DEF_EMERG_SHUTDWN_TMO);
> +
This should probably be a switch statement for the event and also handle
REGULATOR_EVENT_FAIL, possibly other errors this would also be
appropriate handling but it's less immediately obvious and we can
always extend later.
@@ -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>
@@ -5073,6 +5074,11 @@ EXPORT_SYMBOL_GPL(regulator_bulk_free);
int regulator_notifier_call_chain(struct regulator_dev *rdev,
unsigned long event, void *data)
{
+ if (rdev->constraints->system_critical &&
+ event == REGULATOR_EVENT_UNDER_VOLTAGE)
+ hw_protection_shutdown("System critical voltage drop detected",
+ REGULATOR_DEF_EMERG_SHUTDWN_TMO);
+
_notifier_call_chain(rdev, event, data);
return NOTIFY_DONE;
@@ -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;
@@ -49,6 +49,9 @@ struct regulator;
#define DISABLE_IN_SUSPEND 1
#define ENABLE_IN_SUSPEND 2
+/* Default time in millisecond to wait for emergency shutdown */
+#define REGULATOR_DEF_EMERG_SHUTDWN_TMO 10
+
/* Regulator active discharge flags */
enum regulator_active_discharge {
REGULATOR_ACTIVE_DISCHARGE_DEFAULT,
@@ -127,6 +130,8 @@ 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 +219,7 @@ 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 */