There are existing uses for a devres version of of_regulator_get_optional()
in power domain drivers. On MediaTek platforms, power domains may have
regulator supplies tied to them. The driver currently tries to use
devm_regulator_get() to not have to manage the lifecycle, but ends up
doing it in a very hacky way by replacing the device node of the power
domain controller device to the device node of the power domain that is
currently being registered, getting the supply, and reverting the device
node.

Provide a better API so that the hack can be replaced.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://patch.msgid.link/20240925093807.1026949-3-wenst@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>

The to-be-introduced I2C component prober needs to enable regulator
supplies (and toggle GPIO pins) for the various components it intends
to probe. To support this, a new "pure DT lookup" method for getting
regulator supplies is needed, since the device normally requesting
the supply won't get created until after the component is probed to
be available.

Add a new of_regulator_get_optional() function for this. This mirrors
the existing regulator_get_optional() function, but is OF-specific.
The underlying code that supports the existing regulator_get*()
functions has been reworked in previous patches to support this
specific case.

Also convert an existing usage of "dev && dev->of_node" to
"dev_of_node(dev)".

Link: https://lore.kernel.org/all/20231220203537.83479-2-jernej.skrabec@gmail.com/ [1]
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://patch.msgid.link/20240925093807.1026949-2-wenst@chromium.org
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

Refactor of_get_*regulator() to decrease indentation and increase readability.
No functional changes intended.

Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://patch.msgid.link/20240904190856.1221459-1-andy.shevchenko@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

There's still a bit of OF-specific code in the regulator device lookup
function.

Move those bits of code over to of_regulator.c, and create a new
function of_regulator_dev_lookup() to encapsulate the code moved out of
regulator_dev_lookup().

Also mark of_find_regulator_by_node() as static, since there are no
other users in other compile units.

There are no functional changes. A line alignment was also fixed.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://patch.msgid.link/20240904090016.2841572-4-wenst@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>

of_regulator_bulk_get_all() has a comment section that pretty much
resembles a kerneldoc block, except that the block begins with "/*"
instead of "/**".

Fix that and also rework the "Return" section and the error code
terminology so that it is the same as the other kerneldoc blocks
in the same file.

Fixes: 27b9ecc7a9ba ("regulator: Add of_regulator_bulk_get_all")
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20240829085131.1361701-10-wenst@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>

kernel-doc complains about missing "Return" section for many documented
functions in the regulator OF-specific code. These all have descriptions
about the return values, just not in the format kernel-doc wants.

Convert these to use the proper "Return:" section header. The existing
descriptions have been reworded and moved around to fit the grammar and
formatting.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20240829085131.1361701-6-wenst@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>

Currently in of_regulator_bulk_get_all(), if any regulator request
fails, the error path releases all regulators already requested,
but leaves the |struct regulator_bulk_data| memory to the caller
to free, and also leaves the regulator consumer pointers dangling.
The latter behavior is not documented, and may not be what the
caller is expecting.

Instead, explicitly clean up everything on error, and make it clear
that the result pointer is only update if the whole request succeeds.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://patch.msgid.link/20240822072047.3097740-4-wenst@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>

If regulator_get() in of_regulator_bulk_get_all() returns an error, that
error gets overridden and -EINVAL is always passed out. This masks probe
deferral requests and likely won't work properly in all cases.

Fix this by letting of_regulator_bulk_get_all() return the original
error code.

Fixes: 27b9ecc7a9ba ("regulator: Add of_regulator_bulk_get_all")
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://patch.msgid.link/20240822072047.3097740-3-wenst@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>

Add 'uv_survival_time' field to regulation_constraints for specifying
survival time post critical under-voltage event. Update the regulator
notifier call chain and Device Tree property parsing to use this new
field, allowing a configurable timeout before emergency shutdown.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20231026144824.4065145-6-o.rempel@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

Handle under-voltage events for crucial regulators to maintain system
stability and avoid issues during power drops.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20231026144824.4065145-3-o.rempel@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>