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.
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
---
drivers/regulator/core.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 23e852d38b88..2eda87520832 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1822,6 +1822,7 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
rdev->supply = NULL;
return ret;
}
+ rdev->use_count = 1;
}
return 0;
@@ -2491,7 +2492,7 @@ 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;
@@ -2539,7 +2540,7 @@ 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;
@@ -2648,7 +2649,7 @@ 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;
--
2.19.1.1215.g8438c0b245-goog
