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

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 8a866d527ac0 ("regulator: core: Resolve supply name earlier to
prevent double-init") (later updated by
commit 520fb178212d ("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>

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 9ce0eef1dcfcb39a072675e44a5577ae85d51982..08bdb1e4175e6d47d154e7a2d859a9d39dcfd021 100644 (file)
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -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