Hello, Maciej moved on to work on something else and kindly allowed me to take over the coupled regulators patches [0] which I'll try to finalize. I recently started to work on adding DVFS support to the CPUFreq driver of NVIDIA Tegra20/30 which require the coupled regulators functionality. Both Tegra20 and Tegra30 have the voltage "max-spread" constraint. Tegra30 has an additional constraint, the "max-step" voltage. What is done in this series: 1. Re-worked the original "Add voltage balancing mechanism" patch from Maciej by: 1) Fixing infinite loop within regulator_balance_voltage(). 2) Handling suspend_state_t properly. 3) Fixing broken compilation of the patch. 2. Added pair of patches to clean up regulator-couple resolving. 3. Changed device tree binding of the regulator-coupled-max-spread property to make it more flexible. 4. Added new device tree property, the regulator-max-step-microvolt. 5. Implemented wait/wound mutex which was suggested by Lucas Stach in the review comment to [0]. I've tested w/w locking extensively (including CONFIG_DEBUG_WW_MUTEX_SLOWPATH) and quite confident that everything is okay. 6. Patches were tested with KASAN on Tegra20 / Tegra30, I tried to cover various cases and verified that voltage constraints not violated under different circumstances. Please review, thanks. [0] https://lkml.org/lkml/2018/4/23/619 Dmitry Osipenko (9): regulator: core: Mutually resolve regulators coupling regulator: core: Don't allow to get regulator until all couples resolved dt-bindings: regulator: Change regulator-coupled-max-spread property regulator: core: Limit regulators coupling to a single couple dt-bindings: regulator: Document new regulator-max-step-microvolt property regulator: core: Add new max_uV_step constraint regulator: core: Decouple regulators on regulator_unregister() regulator: core: Use ww_mutex for regulators locking regulator: core: Properly handle case where supply is the couple Maciej Purski (2): regulator: core: Add voltage balancing mechanism regulator: core: Change voltage setting path .../bindings/regulator/regulator.txt | 7 +- drivers/regulator/core.c | 821 +++++++++++++++--- drivers/regulator/of_regulator.c | 4 + include/linux/regulator/driver.h | 5 +- include/linux/regulator/machine.h | 3 + 5 files changed, 713 insertions(+), 127 deletions(-) -- 2.19.0