regulator: pca9450: Support regulator-off-in-suspend

The PCA9450 uses each regulator's ENMODE field to control whether the
regulator remains enabled when the PMIC transitions from RUN to STANDBY
mode.

The driver does not currently implement set_suspend_disable(), so a
regulator configured with regulator-off-in-suspend remains enabled
during system suspend.

Implement set_suspend_disable() for the buck regulators and LDO3-LDO5.
The suspend and runtime controls share ENMODE, so first read the field
and leave it unchanged when it is 00b. This preserves the state of a
regulator that was already disabled at runtime. For an enabled regulator,
program 10b to keep it on in RUN and turn it off while PMIC_STBY_REQ is
asserted.

Most buck descriptors set enable_val to 01b, while BUCK2 uses 10b. When
enable_val is nonzero, regulator_is_enabled_regmap() checks for an exact
match. It would therefore report most bucks as disabled after their ENMODE
is changed from 01b to 10b, even though all valid nonzero ENMODE values
enable the regulator in RUN. Use a custom is_enabled() helper for the buck
operation tables that considers a nonzero ENMODE enabled. The LDO
descriptors leave enable_val at zero, for which the generic helper already
performs this nonzero check, so keep using it for the LDOs.

Runtime enable and disable operations remain unchanged: disable writes
00b and enable writes the regulator's default mode. The suspend callback
reapplies 10b on each suspend after any intervening runtime operation.

Keep LDO1 and LDO2 on regulator operations without
set_suspend_disable(), because these regulators supply the SNVS domain
and must remain enabled in STANDBY mode.

Measured on a custom i.MX8MP board, turning off NVCC_SD2 (LDO5) during
system suspend reduced power consumption by approximately 64 mW.

Signed-off-by: Fabio Estevam <festevam@nabladev.com>
Link: https://patch.msgid.link/20260818014059.351152-2-festevam@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

0 files changed, 0 insertions, 0 deletions