When we called regulator_enable() on a regulator we'd end up
propagating that call all the way up the chain every time. This is a
bit of a waste of time. A child regulator already refcounts its own
enables so it should avoid passing on to its parent unless the
refcount transitioned between 0 and 1.
Historically this hasn't been a huge problem since we skipped dealing
with enable for always-on regulators. In a previous patch, however,
we removed the always-on optimization. On one system, the debugfs
regulator_summary was now showing a "use_count" of 33 for a top-level
regulator.
Let's implement this optimization. This turns out to be fairly
trivial with the recent reorganization of the regulator core.
NOTE: as part of this patch I'll make "always-on" regulators start
with a use count of 1. This keeps the counts clean when recursively
resolving regulators.
ALSO NOTE: this commit also contains somewhat of a bug fix to
regulator_force_disable(). It was incorrectly looping over
"rdev->open_count" when it should have been looping over use_count.
We have to touch that code anyway (since we should no longer loop at
all), so we'll fix it together in one patch. Also: since this comes
after commit f8702f9e4aa7 ("regulator: core: Use ww_mutex for
regulators locking") we can now move to use _regulator_disable() for
our supply and keep it in the lock.
Signed-off-by: Douglas Anderson <diand...@chromium.org>
---
NOTE: this patch is based atop the patch ("regulator: core: Only count
load for enabled consumers") because that patch changed the signature
of _regulator_disable() and this patch touches calls to
_regulator_disable(). If desired the order of the two patches could
be swapped.
Changes in v2:
- Squashed in ("Remove loop disabling supplies in regulator_force_disable()")
drivers/regulator/core.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 1271b5406ad7..dbe2f2e6e625 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1824,6 +1824,7 @@ static int regulator_resolve_supply(struct regulator_dev
*rdev)
rdev->supply = NULL;
return ret;
}
+ rdev->use_count = 1;
}
return 0;
@@ -2493,7 +2494,7 @@ static int _regulator_enable(struct regulator *regulator)
lockdep_assert_held_once(&rdev->mutex.base);
- if (rdev->supply) {
+ if (rdev->use_count == 0 && rdev->supply) {
ret = _regulator_enable(rdev->supply);
if (ret < 0)
return ret;
@@ -2541,7 +2542,7 @@ static int _regulator_enable(struct regulator *regulator)
_regulator_handle_consumer_disable(regulator);
err_disable_supply:
- if (rdev->supply)
+ if (rdev->use_count == 0 && rdev->supply)
_regulator_disable(rdev->supply);
return ret;
@@ -2650,7 +2651,7 @@ static int _regulator_disable(struct regulator *regulator)
if (ret == 0 && rdev->coupling_desc.n_coupled > 1)
ret = regulator_balance_voltage(rdev, PM_SUSPEND_ON);
- if (ret == 0 && rdev->supply)
+ if (ret == 0 && rdev->use_count == 0 && rdev->supply)
ret = _regulator_disable(rdev->supply);
return ret;
@@ -2735,11 +2736,10 @@ int regulator_force_disable(struct regulator *regulator)
ret = drms_uA_update(rdev);
}
- regulator_unlock_dependent(rdev, &ww_ctx);
+ if (rdev->use_count != 0 && rdev->supply)
+ _regulator_disable(rdev->supply);
- if (rdev->supply)
- while (rdev->open_count--)
- regulator_disable(rdev->supply);
+ regulator_unlock_dependent(rdev, &ww_ctx);
return ret;
}
--
2.19.1.1215.g8438c0b245-goog
