I found a use_count leakage towards supply regulator of rdev with
boot-on option.

┌───────────────────┐           ┌───────────────────┐
│  regulator_dev A  │           │  regulator_dev B  │
│     (boot-on)     │           │     (boot-on)     │
│    use_count=0    │◀──supply──│    use_count=1    │
│                   │           │                   │
└───────────────────┘           └───────────────────┘

In case of rdev(A) configured with `regulator-boot-on', the use_count
of supplying regulator(B) will increment inside
regulator_enable(rdev->supply).

Thus, B will acts like always-on, and further balanced
regulator_enable/disable cannot actually disable it anymore.

However, B was also configured with `regulator-boot-on', we wish it
could be disabled afterwards.
Signed-off-by: NRui Zhang <zr.zhang@vivo.com>
Link: https://lore.kernel.org/r/20221201033806.2567812-1-zr.zhang@vivo.comSigned-off-by: NMark Brown <broonie@kernel.org>

Use kfree_const() to free supply_name conditionally in create_regulator()
as supply_name may be allocated from kmalloc() or directly from .rodata
section.

Fixes: 87fe29b6 ("regulator: push allocations in create_regulator() outside of lock")
Signed-off-by: NWang ShaoBo <bobo.shaobowang@huawei.com>
Link: https://lore.kernel.org/r/20221123034616.3609537-1-bobo.shaobowang@huawei.comSigned-off-by: NMark Brown <broonie@kernel.org>

I got the the following report:

  OF: ERROR: memory leak, expected refcount 1 instead of 2,
  of_node_get()/of_node_put() unbalanced - destroy cset entry:
  attach overlay node /i2c/pmic@62/regulators/exten

In of_get_regulator(), the node is returned from of_parse_phandle()
with refcount incremented, after using it, of_node_put() need be called.

Fixes: 69511a45 ("regulator: map consumer regulator based on device tree")
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20221115091508.900752-1-yangyingliang@huawei.comSigned-off-by: NMark Brown <broonie@kernel.org>

We had an exclusive variant of the devm_regulator_get() API, but no
corresponding variant for the bulk API; let's add one now.  We add a
generalized version of the existing regulator_bulk_get() function that
additionally takes a get_type parameter and redefine
regulator_bulk_get() in terms of it, then do similarly with
devm_regulator_bulk_get(), and finally add the new
devm_regulator_bulk_get_exclusive().
Signed-off-by: NZev Weiss <zev@bewilderbeest.net>
Link: https://lore.kernel.org/r/20221031233704.22575-2-zev@bewilderbeest.netSigned-off-by: NMark Brown <broonie@kernel.org>

By using a ratio of delay to poll_enabled_time that is not integer
time_remaining underflows and does not exit the loop as expected.
As delay could be derived from DT and poll_enabled_time is defined
in the driver this can easily happen.

Use a signed iterator to make sure that the loop exits once
the remaining time is negative.
Signed-off-by: NPatrick Rudolph <patrick.rudolph@9elements.com>
Link: https://lore.kernel.org/r/20220909125954.577669-1-patrick.rudolph@9elements.comSigned-off-by: NMark Brown <broonie@kernel.org>

In "regulator: core: Resolve supply name earlier to prevent
double-init", we introduced a bug that prevented the regulator names
from registering properly with sysfs.

Reorder regulator_register such that supply names are properly resolved
and registered.

Fixes: 8a866d52 ("regulator: core: Resolve supply name earlier to prevent double-init")
Link: https://lore.kernel.org/all/58b92e75-f373-dae7-7031-8abd465bb874@samsung.com/Signed-off-by: NChristian Kohlschütter <christian@kohlschutter.com>
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20220829165543.24856-1-christian@kohlschutter.comSigned-off-by: NMark Brown <broonie@kernel.org>

Apparently the device trees of some boards have the property
"regulator-allow-set-load" for some of their regulators but then they
don't specify anything for "regulator-allowed-modes". That's not
really legit, but...

...before commit efb0cb50 ("regulator: qcom-rpmh: Implement
get_optimum_mode(), not set_load()") they used to get away with it, at
least on boards using RPMH regulators. That's because when a regulator
driver implements set_load() then the core doesn't look at
"regulator-allowed-modes" when trying to automatically adjust things
in response to the regulator's load. The core doesn't know what mode
we'll end up in, so how could it validate it?

Said another way: before commit efb0cb50 ("regulator: qcom-rpmh:
Implement get_optimum_mode(), not set_load()") some boards _were_
having the regulator mode adjusted despite listing no allowed
modes. After commit efb0cb50 ("regulator: qcom-rpmh: Implement
get_optimum_mode(), not set_load()") these same boards were now
getting an error returned when trying to use their regulators, since
simply enabling a regulator tries to update its load and that was
failing.

We don't really want to go back to the behavior from before commit
efb0cb50 ("regulator: qcom-rpmh: Implement get_optimum_mode(), not
set_load()"). Boards shouldn't have been changing modes if no allowed
modes were listed. However, the behavior after commit efb0cb50
("regulator: qcom-rpmh: Implement get_optimum_mode(), not set_load()")
isn't the best because now boards can't even turn their regulators on.

Let's choose to detect this case and return "no error" from
drms_uA_update(). The net-result will be _different_ behavior than we
had before commit efb0cb50 ("regulator: qcom-rpmh: Implement
get_optimum_mode(), not set_load()"), but this new behavior seems more
correct. If a board truly needed the mode switched then its device
tree should be updated to list the allowed modes.
Reported-by: NAndrew Halaney <ahalaney@redhat.com>
Fixes: efb0cb50 ("regulator: qcom-rpmh: Implement get_optimum_mode(), not set_load()")
Signed-off-by: NDouglas Anderson <dianders@chromium.org>
Tested-by: NAndrew Halaney <ahalaney@redhat.com>
Link: https://lore.kernel.org/r/20220824142229.RFT.v2.2.I6f77860e5cd98bf5c67208fa9edda4a08847c304@changeidSigned-off-by: NMark Brown <broonie@kernel.org>

The get_optimum_mode() for regulator drivers is passed the input
voltage and output voltage as well as the current. This is because, in
theory, the optimum mode can depend on all three things.

It turns out that for all regulator drivers in mainline only the
current is looked at when implementing get_optimum_mode(). None of the
drivers take the input or output voltage into account. Despite the
fact that none of the drivers take the input or output voltage into
account, though, the regulator framework will error out before calling
into get_optimum_mode() if it doesn't know the input or output
voltage.

The above behavior turned out to be a probelm for some boards when we
landed commit efb0cb50 ("regulator: qcom-rpmh: Implement
get_optimum_mode(), not set_load()"). Before that change we'd have no
problems running drms_uA_update() for RPMH regulators even if a
regulator's input or output voltage was unknown. After that change
drms_uA_update() started to fail. This is because typically boards
using RPMH regulators don't model the input supplies of RPMH
regulators. Input supplies for RPMH regulators nearly always come from
the output of other RPMH regulators (or always-on regulators) and RPMH
firmware is initialized with this knowledge and handles enabling (and
adjusting the voltage of) input supplies. While we could model the
parent/child relationship of the regulators in Linux, many boards
don't bother since it adds extra overhead.

Let's change the regulator core to make things work again. Now if we
fail to get the input or output voltage we'll still call into
get_optimum_mode() and we'll just pass error codes in for input_uV
and/or output_uV parameters.

Since no existing regulator drivers even look at input_uV and
output_uV we don't need to add this error handling anywhere right
now. We'll add some comments in the core so that it's obvious that (if
regulator drivers care) it's up to them to add the checks.
Reported-by: NAndrew Halaney <ahalaney@redhat.com>
Fixes: efb0cb50 ("regulator: qcom-rpmh: Implement get_optimum_mode(), not set_load()")
Signed-off-by: NDouglas Anderson <dianders@chromium.org>
Tested-by: NAndrew Halaney <ahalaney@redhat.com>
Link: https://lore.kernel.org/r/20220824142229.RFT.v2.1.I137e6bef4f6d517be7b081be926059321102fd3d@changeidSigned-off-by: NMark Brown <broonie@kernel.org>

This message shows up occasionally but in bursts (seen up to 30 times
per second on my ODROID N2+).

According to Matthias Kaehlcke's comment in 'regulator: core: silence
warning: "VDD1: ramp_delay not set"', this message should have been
removed after restructuring previous code that assumed that ramp_delay
being zero in that function was an error.

Link: https://lore.kernel.org/lkml/625675256c0d75805f088b4be17a3308dc1b7ea4.1477571498.git.hns@goldelico.com/T/Signed-off-by: NChristian Kohlschütter <christian@kohlschutter.com>
Link: https://lore.kernel.org/r/20220820131420.16608-1-christian@kohlschutter.comSigned-off-by: NMark Brown <broonie@kernel.org>

If regulator_enable() fails, enable_count is incremented still.
A consumer, assuming no matching regulator_disable() is necessary on
failure, will then get this error message upon regulator_put()
since enable_count is non-zero:

    [    1.277418] WARNING: CPU: 3 PID: 1 at drivers/regulator/core.c:2304 _regulator_put.part.0+0x168/0x170

The consumer could try to fix this in their driver by cleaning up on
error from regulator_enable() (i.e. call regulator_disable()), but that
results in the following since regulator_enable() failed and didn't
increment user_count:

    [    1.258112] unbalanced disables for vreg_l17c
    [    1.262606] WARNING: CPU: 4 PID: 1 at drivers/regulator/core.c:2899 _regulator_disable+0xd4/0x190

Fix this by decrementing enable_count upon failure to enable.

With this in place, just the reason for failure to enable is printed
as expected and developers can focus on the root cause of their issue
instead of thinking their usage of the regulator consumer api is
incorrect. For example, in my case:

    [    1.240426] vreg_l17c: invalid input voltage found

Fixes: 5451781d ("regulator: core: Only count load for enabled consumers")
Signed-off-by: NAndrew Halaney <ahalaney@redhat.com>
Reviewed-by: NDouglas Anderson <dianders@chromium.org>
Reviewed-by: NBrian Masney <bmasney@redhat.com>
Link: https://lore.kernel.org/r/20220819194336.382740-1-ahalaney@redhat.comSigned-off-by: NMark Brown <broonie@kernel.org>

Previously, an unresolved regulator supply reference upon calling
regulator_register on an always-on or boot-on regulator caused
set_machine_constraints to be called twice.

This in turn may initialize the regulator twice, leading to voltage
glitches that are timing-dependent. A simple, unrelated configuration
change may be enough to hide this problem, only to be surfaced by
chance.

One such example is the SD-Card voltage regulator in a NanoPI R4S that
would not initialize reliably unless the registration flow was just
complex enough to allow the regulator to properly reset between calls.

Fix this by re-arranging regulator_register, trying resolve the
regulator's supply early enough that set_machine_constraints does not
need to be called twice.
Signed-off-by: NChristian Kohlschütter <christian@kohlschutter.com>
Link: https://lore.kernel.org/r/20220818124646.6005-1-christian@kohlschutter.comSigned-off-by: NMark Brown <broonie@kernel.org>

In commit 6eabfc01 ("regulator: core: Allow specifying an initial
load w/ the bulk API") I changed the error handling but had a subtle
that caused us to always return no error even if there was an
error. Fix it.

Fixes: 6eabfc01 ("regulator: core: Allow specifying an initial load w/ the bulk API")
Signed-off-by: NDouglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20220809142738.1.I91625242f137c707bb345c51c80c5ecee02eeff3@changeidSigned-off-by: NMark Brown <broonie@kernel.org>

There are a number of drivers that follow a pattern that looks like
this:
1. Use the regulator bulk API to get a bunch of regulators.
2. Set the load on each of the regulators to use whenever the
   regulators are enabled.

Let's make this easier by just allowing the drivers to pass the load
in.

As part of this change we need to move the error printing in
regulator_bulk_get() around; let's switch to the new dev_err_probe()
to simplify it.
Signed-off-by: NDouglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20220726103631.v2.4.Ie85f68215ada39f502a96dcb8a1f3ad977e3f68a@changeidSigned-off-by: NMark Brown <broonie@kernel.org>

Regulators marked with "regulator-always-on" or "regulator-boot-on"
as well as an "off-on-delay-us", may run into cycling issues that are
hard to detect.

This is caused by the "last_off" state not being initialized in this
case.

Fix the "last_off" initialization by setting it to the current kernel
time upon initialization, regardless of always_on/boot_on state.
Signed-off-by: NChristian Kohlschütter <christian@kohlschutter.com>
Link: https://lore.kernel.org/r/FAFD5B39-E9C4-47C7-ACF1-2A04CD59758D@kohlschutter.comSigned-off-by: NMark Brown <broonie@kernel.org>

Since the introduction of regulator->enable_count, a driver that did
an exclusive get on an already-enabled regulator would end up with
enable_count initialized to 0 but rdev->use_count initialized to 1.
With that starting point the regulator is effectively stuck enabled,
because if the driver attempted to disable it it would fail the
enable_count underflow check in _regulator_handle_consumer_disable().

The EXCLUSIVE_GET path in _regulator_get() now initializes
enable_count along with rdev->use_count so that the regulator can be
disabled without underflowing the former.
Signed-off-by: NZev Weiss <zev@bewilderbeest.net>
Fixes: 5451781d ("regulator: core: Only count load for enabled consumers")
Link: https://lore.kernel.org/r/20220505043152.12933-1-zev@bewilderbeest.netSigned-off-by: NMark Brown <broonie@kernel.org>

If a regulator provides a get_error_flags() operation, its sysfs
attributes will now include an entry for each defined
REGULATOR_ERROR_* flag.
Signed-off-by: NZev Weiss <zev@bewilderbeest.net>
Link: https://lore.kernel.org/r/20220504065252.6955-3-zev@bewilderbeest.netSigned-off-by: NMark Brown <broonie@kernel.org>

These delays can be relatively large (e.g., hundreds of microseconds to
several milliseconds on RK3399 Gru systems). Per
Documentation/timers/timers-howto.rst, that should usually use a
sleeping delay. Let's use the existing regulator delay helper to handle
both large and small delays appropriately. This avoids burning a bunch
of CPU time and hurting scheduling latencies when hitting regulators a
lot (e.g., during cpufreq).

The sleep vs. delay issue choice has been made differently over time --
early versions of RK3399 Gru PWM-regulator support used usleep_range()
in pwm-regulator.c. More of this got moved into the regulator core,
in commits like:

73e705bf regulator: core: Add set_voltage_time op

At the same time, the sleep turned into a delay.

It's OK to sleep in _regulator_do_set_voltage(), as we aren't in an
atomic context. (All our callers grab various mutexes already.)

I avoid using fsleep() because it uses a usleep_range() of [N to N*2],
and usleep_range() very commonly biases to the high end of the range. We
don't want to double the expected delay, especially for long delays.
Signed-off-by: NBrian Norris <briannorris@chromium.org>
Reviewed-by: NMatthias Kaehlcke <mka@chromium.org>
Link: https://lore.kernel.org/r/20220420141511.v2.2.If0fc61a894f537b052ca41572aff098cf8e7e673@changeidSigned-off-by: NMark Brown <broonie@kernel.org>

I want to use it in other contexts besides _regulator_do_enable().
Signed-off-by: NBrian Norris <briannorris@chromium.org>
Link: https://lore.kernel.org/r/20220420141511.v2.1.I31ef0014c9597d53722ab513890f839f357fdfb3@changeidSigned-off-by: NMark Brown <broonie@kernel.org>

While we currently assume that regulators with no control available are
just uncontionally enabled this isn't always as clearly displayed to
users as is desirable, for example the code for disabling unused
regulators will log that it is about to disable them. Clean this up a
bit by setting always_on during constraint evaluation if we have no
available mechanism for controlling the regualtor so things that check
the constraint will do the right thing.
Signed-off-by: NMark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220325144637.1543496-1-broonie@kernel.orgSigned-off-by: NMark Brown <broonie@kernel.org>

The check done by regulator_late_cleanup() to detect whether a regulator
is on was inconsistent with the check done by _regulator_is_enabled().
While _regulator_is_enabled() takes the enable GPIO into account,
regulator_late_cleanup() was not doing that.

This resulted in a false positive, e.g. when a GPIO-controlled fixed
regulator was used, which was not enabled at boot time, e.g.

reg_disp_1v2: reg_disp_1v2 {
	compatible = "regulator-fixed";
	regulator-name = "display_1v2";
	regulator-min-microvolt = <1200000>;
	regulator-max-microvolt = <1200000>;
	gpio = <&tlmm 148 0>;
	enable-active-high;
};

Such regulator doesn't have an is_enabled() operation. Nevertheless
it's state can be determined based on the enable GPIO. The check in
regulator_late_cleanup() wrongly assumed that the regulator is on and
tried to disable it.
Signed-off-by: NOliver Barta <oliver.barta@aptiv.com>
Link: https://lore.kernel.org/r/20220208084645.8686-1-oliver.barta@aptiv.comSigned-off-by: NMark Brown <broonie@kernel.org>

Fixed regulator can't change voltage and regulator_sync_voltage()
returns -EINVAL in this case. Make regulator_sync_voltage() to succeed
for regulators that are incapable to change voltage.

On NVIDIA Tegra power management driver needs to sync voltage and we have
one device (Trimslice) that uses fixed regulator which is getting synced.
The syncing error isn't treated as fatal, but produces a noisy error
message. This patch silences that error.
Signed-off-by: NDmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20211021183308.27786-1-digetx@gmail.comSigned-off-by: NMark Brown <broonie@kernel.org>

We lowered all the other constraint related log messages to debug level so
lower the logging of what supplies we're configuring to debug level too.
Signed-off-by: NMark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210929140717.3769-1-broonie@kernel.orgSigned-off-by: NMark Brown <broonie@kernel.org>

i915 will soon gain an eviction path that trylock a whole lot of locks
for eviction, getting dmesg failures like below:

  BUG: MAX_LOCK_DEPTH too low!
  turning off the locking correctness validator.
  depth: 48  max: 48!
  48 locks held by i915_selftest/5776:
   #0: ffff888101a79240 (&dev->mutex){....}-{3:3}, at: __driver_attach+0x88/0x160
   #1: ffffc900009778c0 (reservation_ww_class_acquire){+.+.}-{0:0}, at: i915_vma_pin.constprop.63+0x39/0x1b0 [i915]
   #2: ffff88800cf74de8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_vma_pin.constprop.63+0x5f/0x1b0 [i915]
   #3: ffff88810c7f9e38 (&vm->mutex/1){+.+.}-{3:3}, at: i915_vma_pin_ww+0x1c4/0x9d0 [i915]
   #4: ffff88810bad5768 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915]
   #5: ffff88810bad60e8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915]
  ...
   #46: ffff88811964d768 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915]
   #47: ffff88811964e0e8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915]
  INFO: lockdep is turned off.

Fixing eviction to nest into ww_class_acquire is a high priority, but
it requires a rework of the entire driver, which can only be done one
step at a time.

As an intermediate solution, add an acquire context to
ww_mutex_trylock, which allows us to do proper nesting annotations on
the trylocks, making the above lockdep splat disappear.

This is also useful in regulator_lock_nested, which may avoid dropping
regulator_nesting_mutex in the uncontended path, so use it there.

TTM may be another user for this, where we could lock a buffer in a
fastpath with list locks held, without dropping all locks we hold.

[peterz: rework actual ww_mutex_trylock() implementations]
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/YUBGPdDDjKlxAuXJ@hirez.programming.kicks-ass.net

Voltage-controlled regulators depend on their supply regulator for
retrieving their voltage, and so they might return -EPROBE_DEFER at this
stage. Our caller already attempts to resolve supplies and retry, so we
shouldn't be printing this error to logs.

Quiets log messages like this, on Rockchip RK3399 Gru/Kevin boards:

[    1.033057] ppvar_bigcpu: failed to get the current voltage: -EPROBE_DEFER
...
[    1.036735] ppvar_litcpu: failed to get the current voltage: -EPROBE_DEFER
...
[    1.040366] ppvar_gpu: failed to get the current voltage: -EPROBE_DEFER
...
[    1.044086] ppvar_centerlogic: failed to get the current voltage: -EPROBE_DEFER

Cc: Chen-Yu Tsai <wenst@chromium.org>
Signed-off-by: NBrian Norris <briannorris@chromium.org>
Link: https://lore.kernel.org/r/20210826124015.1.Iab79c6dd374ec48beac44be2fcddd165dd26476b@changeidSigned-off-by: NMark Brown <broonie@kernel.org>

Add DT property parsing code and setting callback for regulator over/under
voltage, over-current and temperature error limits.
Signed-off-by: NMatti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Link: https://lore.kernel.org/r/e7b8007ba9eae7076178bf3363fb942ccb1cc9a5.1622628334.git.matti.vaittinen@fi.rohmeurope.comSigned-off-by: NMark Brown <broonie@kernel.org>

Provide helper function for IC's implementing regulator notifications
when an IRQ fires. The helper also works for IRQs which can not be acked.
Helper can be set to disable the IRQ at handler and then re-enabling it
on delayed work later. The helper also adds regulator_get_error_flags()
errors in cache for the duration of IRQ disabling.
Signed-off-by: NMatti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/ebdf86d8c22b924667ec2385330e30fcbfac0119.1622628334.git.matti.vaittinen@fi.rohmeurope.comSigned-off-by: NMark Brown <broonie@kernel.org>

The rdev print helpers are a nice way to print messages related to a
specific regulator device. Move them from core.c to internal.h

As the rdev print helpers use rdev_get_name() export it from core.c. Also
move the declaration from coupler.h to driver.h because the rdev name is
not just a coupled regulator property. I guess the main audience for
rdev_get_name() will be the regulator core and drivers.
Signed-off-by: NMatti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Link: https://lore.kernel.org/r/dc7fd70dc31de4d0e820b7646bb78eeb04f80735.1622628333.git.matti.vaittinen@fi.rohmeurope.comSigned-off-by: NMark Brown <broonie@kernel.org>

Use DEVICE_ATTR_RO() helper instead of plain DEVICE_ATTR(),
which makes the code a bit shorter and easier to read.
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20210529115226.25376-1-yuehaibing@huawei.comSigned-off-by: NMark Brown <broonie@kernel.org>

Some NVIDIA Tegra devices use a CPU soft-reset method for the reboot and
in this case we need to restore the coupled voltages to the state that is
suitable for hardware during boot. Add new regulator_sync_voltage_rdev()
helper which is needed by regulator drivers in order to sync voltage of
a coupled regulators.
Acked-by: NMark Brown <broonie@kernel.org>
Signed-off-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NThierry Reding <treding@nvidia.com>

For the boot-on/always-on regulators the set_machine_constrainst() is
called before resolving rdev->supply. Thus the code would try to enable
rdev before enabling supplying regulator. Enforce resolving supply
regulator before enabling rdev.

Fixes: aea6cb99 ("regulator: resolve supply after creating regulator")
Signed-off-by: NDmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20210519221224.2868496-1-dmitry.baryshkov@linaro.orgSigned-off-by: NMark Brown <broonie@kernel.org>

The jiffies-based off_on_delay implementation has a couple of problems
that cause it to sometimes not actually delay for the required time:

 (1) If, for example, the off_on_delay time is equivalent to one jiffy,
     and the ->last_off_jiffy is set just before a new jiffy starts,
     then _regulator_do_enable() does not wait at all since it checks
     using time_before().

 (2) When jiffies overflows, the value of "remaining" becomes higher
     than "max_delay" and the code simply proceeds without waiting.

Fix these problems by changing it to use ktime_t instead.

[Note that since jiffies doesn't start at zero but at INITIAL_JIFFIES
 ("-5 minutes"), (2) above also led to the code not delaying if
 the first regulator_enable() is called when the ->last_off_jiffy is not
 initialised, such as for regulators with ->constraints->boot_on set.
 It's not clear to me if this was intended or not, but I've preserved
 this behaviour explicitly with the check for a non-zero ->last_off.]
Signed-off-by: NVincent Whitchurch <vincent.whitchurch@axis.com>
Link: https://lore.kernel.org/r/20210423114524.26414-1-vincent.whitchurch@axis.comSigned-off-by: NMark Brown <broonie@kernel.org>

We currently do not respect off_on_delay the first time we turn on a
regulator.  This is problematic since the regulator could have been
turned off by the bootloader, or it could it have been turned off during
the probe of the regulator driver (such as when regulator-fixed requests
the enable GPIO), either of which could potentially have happened less
than off_on_delay microseconds ago before the first time a client
requests for the regulator to be turned on.

We can't know exactly when the regulator was turned off, but initialise
off_on_delay to the current time when registering the regulator, so that
we guarantee that we respect the off_on_delay in all cases.
Signed-off-by: NVincent Whitchurch <vincent.whitchurch@axis.com>
Link: https://lore.kernel.org/r/20210422083044.11479-1-vincent.whitchurch@axis.comSigned-off-by: NMark Brown <broonie@kernel.org>

s/regulator may on/regulator may already be enabled/
s/or left on/or was left on/

The aim of this patch is to make the comment more readable and to make
it clear, that this is about a regulator, that is already enabled instead
of a regulator that may be switched on.
Signed-off-by: NSebastian Fricke <sebastian.fricke@posteo.net>
Link: https://lore.kernel.org/r/20210421055236.13148-1-sebastian.fricke@posteo.netSigned-off-by: NMark Brown <broonie@kernel.org>

Shifted the closing */ of multiline comment to a new line
This is done to maintain code uniformity
Signed-off-by: NShubhankar Kuranagatti <shubhankarvk@gmail.com>
Link: https://lore.kernel.org/r/20210420034718.t7wudu6xcfpahflv@kewl-virtual-machineSigned-off-by: NMark Brown <broonie@kernel.org>

Sometimes regulator_get() gets called twice for the same supply on the
same device. This may happen e.g. when a framework / library is used
which uses the regulator; and the driver itself also needs to enable
the regulator in some cases where the framework will not enable it.

Commit ff268b56 ("regulator: core: Don't spew backtraces on
duplicate sysfs") already takes care of the backtrace which would
trigger when creating a duplicate consumer symlink under
/sys/class/regulator/regulator.%d in this scenario.

Commit c33d4423 ("debugfs: make error message a bit more verbose")
causes a new error to get logged in this scenario:

[   26.938425] debugfs: Directory 'wm5102-codec-MICVDD' with parent 'spi-WM510204:00-MICVDD' already present!

There is no _nowarn variant of debugfs_create_dir(), but we can detect
and avoid this problem by checking the return value of the earlier
sysfs_create_link_nowarn() call.

Add a check for the earlier sysfs_create_link_nowarn() failing with
-EEXIST and skip the debugfs_create_dir() call in that case, avoiding
this error getting logged.

Fixes: c33d4423 ("debugfs: make error message a bit more verbose")
Cc: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Reviewed-by: NCharles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20210122183250.370571-1-hdegoede@redhat.comSigned-off-by: NMark Brown <broonie@kernel.org>

Make regulator_sync_voltage() to re-balance voltage state of a coupled
regulators instead of changing the voltage directly.

Tested-by: Peter Geis <pgwipeout@gmail.com> # Ouya T30
Tested-by: Dmitry Osipenko <digetx@gmail.com> # A500 T20 and Nexus7 T30
Tested-by: Nicolas Chauvet <kwizart@gmail.com> # PAZ00 T20
Tested-by: Matt Merhar <mattmerhar@protonmail.com> # Ouya T30
Signed-off-by: NDmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20210122174311.28230-1-digetx@gmail.comSigned-off-by: NMark Brown <broonie@kernel.org>

With commit eaa7995c (regulator: core: avoid
regulator_resolve_supply() race condition) we started holding the rdev
lock while resolving supplies, an operation that requires holding the
regulator_list_mutex. This results in lockdep warnings since in other
places we take the list mutex then the mutex on an individual rdev.

Since the goal is to make sure that we don't call set_supply() twice
rather than a concern about the cost of resolution pull the rdev lock
and check for duplicate resolution down to immediately before we do the
set_supply() and drop it again once the allocation is done.

Fixes: eaa7995c (regulator: core: avoid regulator_resolve_supply() race condition)
Reported-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NMark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210122132042.10306-1-broonie@kernel.orgSigned-off-by: NMark Brown <broonie@kernel.org>

The final step in regulator_register() is to call
regulator_resolve_supply() for each registered regulator
(including the one in the process of being registered).  The
regulator_resolve_supply() function first checks if rdev->supply
is NULL, then it performs various steps to try to find the supply.
If successful, rdev->supply is set inside of set_supply().

This procedure can encounter a race condition if two concurrent
tasks call regulator_register() near to each other on separate CPUs
and one of the regulators has rdev->supply_name specified.  There
is currently nothing guaranteeing atomicity between the rdev->supply
check and set steps.  Thus, both tasks can observe rdev->supply==NULL
in their regulator_resolve_supply() calls.  This then results in
both creating a struct regulator for the supply.  One ends up
actually stored in rdev->supply and the other is lost (though still
present in the supply's consumer_list).

Here is a kernel log snippet showing the issue:

[   12.421768] gpu_cc_gx_gdsc: supplied by pm8350_s5_level
[   12.425854] gpu_cc_gx_gdsc: supplied by pm8350_s5_level
[   12.429064] debugfs: Directory 'regulator.4-SUPPLY' with parent
               '17a00000.rsc:rpmh-regulator-gfxlvl-pm8350_s5_level'
               already present!

Avoid this race condition by holding the rdev->mutex lock inside
of regulator_resolve_supply() while checking and setting
rdev->supply.
Signed-off-by: NDavid Collins <collinsd@codeaurora.org>
Link: https://lore.kernel.org/r/1610068562-4410-1-git-send-email-collinsd@codeaurora.orgSigned-off-by: NMark Brown <broonie@kernel.org>

The function regulator_set_device_supply() is referenced a few times in
comments in regulator/core.c; however this function was removed a long
time ago by commit a5766f11 ("regulator: core - Rework machine API to
remove string based functions."). Update those references to point to
set_consumer_device_supply(), which replaced the old function.
Signed-off-by: NDaniel Scally <djrscally@gmail.com>
Link: https://lore.kernel.org/r/20210103165541.784360-1-djrscally@gmail.comSigned-off-by: NMark Brown <broonie@kernel.org>

Selectors lower than linear_min_sel should not be considered invalid.
Thus return zero in case _regulator_list_voltage(),
regulator_list_hardware_vsel() or regulator_list_voltage_table()
receives such selectors as argument.

Fixes: bdcd1177 ("regulator: core: validate selector against linear_min_sel")
Reported-by: NJon Hunter <jonathanh@nvidia.com>
Signed-off-by: NClaudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/1606325147-606-1-git-send-email-claudiu.beznea@microchip.comSigned-off-by: NMark Brown <broonie@kernel.org>