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regulator: core: streamline supply resolution for always-on/boot-on regulators

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For always-on and boot-on regulators, regulator_register() is currently
trying to anticipate the requirement to resolve a supply early.

Unfortunately, this code executes too early, before we have potentially
updated the regulator's always_on constraint as part of
set_machine_constraints(), causing it to miss cases.

Rather than trying to hack it more, just defer to the outcome of
set_machine_constraints(). The latter returns early (without doing any
regulator initialisation) with -EPROBE_DEFER as of commit 'regulator:
core: move supply check earlier in set_machine_constraints()' and is
therefore safe to call multiple times to determine if supplies need to
be resolved early.

Commit 8a866d527a ("regulator: core: Resolve supply name earlier to
prevent double-init") (later updated by
commit 520fb17821 ("regulator: core: Fix regulator supply
registration with sysfs")) added these tests originally to avoid
calling set_machine_constraints() multiple times to try to avoid
voltage glitches due to all the regulator initialisation happening each
time. This isn't an issue anymore as per above.

Signed-off-by: André Draszik <andre.draszik@linaro.org>
Link: https://patch.msgid.link/20260109-regulators-defer-v2-4-1a25dc968e60@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
André Draszik 2026-01-09 08:38:40 +00:00 committed by Mark Brown
parent 86a8eeb0e9
commit 4f3323b752
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1 changed files with 4 additions and 15 deletions
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19
drivers/regulator/core.c
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@ -5937,7 +5937,6 @@ regulator_register(struct device *dev,
bool dangling_cfg_gpiod = false;
bool dangling_of_gpiod = false;
int ret, i;
bool resolved_early = false;
if (cfg == NULL)
return ERR_PTR(-EINVAL);
@ -6075,17 +6074,6 @@ regulator_register(struct device *dev,
goto wash;
}
if ((rdev->supply_name && !rdev->supply) &&
(rdev->constraints->always_on ||
rdev->constraints->boot_on)) {
ret = regulator_resolve_supply(rdev);
if (ret)
rdev_dbg(rdev, "unable to resolve supply early: %pe\n",
ERR_PTR(ret));
resolved_early = true;
}
if (config->ena_gpiod) {
ret = regulator_ena_gpio_request(rdev, config);
if (ret != 0) {
@ -6099,9 +6087,10 @@ regulator_register(struct device *dev,
}
ret = set_machine_constraints(rdev);
if (ret == -EPROBE_DEFER && !resolved_early) {
/* Regulator might be in bypass mode and so needs its supply
* to set the constraints
if (ret == -EPROBE_DEFER) {
/* Regulator might be in bypass mode or an always-on or boot-on
* regulator and so needs its supply to set the constraints or
* for enable.
*/
/* FIXME: this currently triggers a chicken-and-egg problem
* when creating -SUPPLY symlink in sysfs to a regulator