[PATCH v2] regulator: core: Use ktime_get_boottime() to determine how long a regulator was off

From: Matthias Kaehlcke
Date: Wed Feb 22 2023 - 19:33:43 EST


For regulators with 'off-on-delay-us' the regulator framework currently
uses ktime_get() to determine how long the regulator has been off
before re-enabling it (after a delay if needed). A problem with using
ktime_get() is that it doesn't account for the time the system is
suspended. As a result a regulator with a longer 'off-on-delay' (e.g.
500ms) that was switched off during suspend might still incurr in a
delay on resume before it is re-enabled, even though the regulator
might have been off for hours. ktime_get_boottime() accounts for
suspend time, use it instead of ktime_get().

Fixes: a8ce7bd89689 ("regulator: core: Fix off_on_delay handling")
Cc: stable@xxxxxxxxxxxxxxx # 5.13+
Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
Reviewed-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
---
The issue already existed before the commit in the 'Fixes' tag, but
it's probably not worth backporting this to older kernels that
use jiffies instead of ktime.

Changes in v2:
- added 'Fixes' and Cc: stable tags
- added 'Reviewed-by' tag from Stephen

drivers/regulator/core.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index ae69e493913d..4fcd36055b02 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1584,7 +1584,7 @@ static int set_machine_constraints(struct regulator_dev *rdev)
}

if (rdev->desc->off_on_delay)
- rdev->last_off = ktime_get();
+ rdev->last_off = ktime_get_boottime();

/* If the constraints say the regulator should be on at this point
* and we have control then make sure it is enabled.
@@ -2673,7 +2673,7 @@ static int _regulator_do_enable(struct regulator_dev *rdev)
* this regulator was disabled.
*/
ktime_t end = ktime_add_us(rdev->last_off, rdev->desc->off_on_delay);
- s64 remaining = ktime_us_delta(end, ktime_get());
+ s64 remaining = ktime_us_delta(end, ktime_get_boottime());

if (remaining > 0)
_regulator_delay_helper(remaining);
@@ -2912,7 +2912,7 @@ static int _regulator_do_disable(struct regulator_dev *rdev)
}

if (rdev->desc->off_on_delay)
- rdev->last_off = ktime_get();
+ rdev->last_off = ktime_get_boottime();

trace_regulator_disable_complete(rdev_get_name(rdev));

--
2.39.2.722.g9855ee24e9-goog