[PATCH 5.9 067/133] regulator: defer probe when trying to get voltage from unresolved supply

From: Greg Kroah-Hartman
Date: Mon Nov 09 2020 - 08:23:50 EST


From: Michał Mirosław <mirq-linux@xxxxxxxxxxxx>

commit cf1ad559a20d1930aa7b47a52f54e1f8718de301 upstream.

regulator_get_voltage_rdev() is called in regulator probe() when
applying machine constraints. The "fixed" commit exposed the problem
that non-bypassed regulators can forward the request to its parent
(like bypassed ones) supply. Return -EPROBE_DEFER when the supply
is expected but not resolved yet.

Fixes: aea6cb99703e ("regulator: resolve supply after creating regulator")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Michał Mirosław <mirq-linux@xxxxxxxxxxxx>
Reported-by: Ondřej Jirman <megous@xxxxxxxxxx>
Reported-by: Corentin Labbe <clabbe.montjoie@xxxxxxxxx>
Tested-by: Ondřej Jirman <megous@xxxxxxxxxx>
Link: https://lore.kernel.org/r/a9041d68b4d35e4a2dd71629c8a6422662acb5ee.1604351936.git.mirq-linux@xxxxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/regulator/core.c | 2 ++
1 file changed, 2 insertions(+)

--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -4128,6 +4128,8 @@ int regulator_get_voltage_rdev(struct re
ret = rdev->desc->fixed_uV;
} else if (rdev->supply) {
ret = regulator_get_voltage_rdev(rdev->supply->rdev);
+ } else if (rdev->supply_name) {
+ return -EPROBE_DEFER;
} else {
return -EINVAL;
}