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regulator: core: fix use_count leakage when handling boot-on

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[ Upstream commit 0591b14ce0398125439c759f889647369aa616a0 ]

I found a use_count leakage towards supply regulator of rdev with
boot-on option.

┌───────────────────┐           ┌───────────────────┐
│  regulator_dev A  │           │  regulator_dev B  │
│     (boot-on)     │           │     (boot-on)     │
│    use_count=0    │◀──supply──│    use_count=1    │
│                   │           │                   │
└───────────────────┘           └───────────────────┘

In case of rdev(A) configured with `regulator-boot-on', the use_count
of supplying regulator(B) will increment inside
regulator_enable(rdev->supply).

Thus, B will acts like always-on, and further balanced
regulator_enable/disable cannot actually disable it anymore.

However, B was also configured with `regulator-boot-on', we wish it
could be disabled afterwards.

Signed-off-by: Rui Zhang <zr.zhang@vivo.com>
Link: https://lore.kernel.org/r/20221201033806.2567812-1-zr.zhang@vivo.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Rui Zhang 2022-12-01 11:38:06 +08:00 committed by Greg Kroah-Hartman
parent 87fd18016a
commit 5bfc53df28
1 changed files with 7 additions and 1 deletions
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8
drivers/regulator/core.c
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@ -1387,7 +1387,13 @@ static int set_machine_constraints(struct regulator_dev *rdev)
if (rdev->supply_name && !rdev->supply)
return -EPROBE_DEFER;
if (rdev->supply) {
/* If supplying regulator has already been enabled,
* it's not intended to have use_count increment
* when rdev is only boot-on.
*/
if (rdev->supply &&
(rdev->constraints->always_on ||
!regulator_is_enabled(rdev->supply))) {
ret = regulator_enable(rdev->supply);
if (ret < 0) {
_regulator_put(rdev->supply);