rtc: pm8xxx: add support for uefi offset

On many Qualcomm platforms the PMIC RTC control and time registers are
read-only so that the RTC time can not be updated. Instead an offset
needs be stored i

rtc: pm8xxx: add support for uefi offset

On many Qualcomm platforms the PMIC RTC control and time registers are
read-only so that the RTC time can not be updated. Instead an offset
needs be stored in some machine-specific non-volatile memory, which the
driver can take into account.

Add support for storing a 32-bit offset from the GPS time epoch in a
UEFI variable so that the RTC time can be set on such platforms.

The UEFI variable is

882f8c2b-9646-435f-8de5-f208ff80c1bd-RTCInfo

and holds a 12-byte structure where the first four bytes is a GPS time
offset in little-endian byte order.

Note that this format is not arbitrary as the variable is shared with
the UEFI firmware (and Windows).

Tested-by: Jens Glathe <[email protected]>
Tested-by: Steev Klimaszewski <[email protected]>
Tested-by: Joel Stanley <[email protected]>
Tested-by: Sebastian Reichel <[email protected]> # Lenovo T14s Gen6
Signed-off-by: Johan Hovold <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <[email protected]>

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rtc: class: make rtc_class constant

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move

rtc: class: make rtc_class constant

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the rtc_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: Greg Kroah-Hartman <[email protected]>
Suggested-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Ricardo B. Marliere <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <[email protected]>

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rtc: Add API function to return alarm time bound by hardware limit

Add rtc_bound_alarmtime() to return the requested alarm timeout bound by
the maxmum alarm timeout that is supported by a given RTC.

rtc: Add API function to return alarm time bound by hardware limit

Add rtc_bound_alarmtime() to return the requested alarm timeout bound by
the maxmum alarm timeout that is supported by a given RTC.

Signed-off-by: Guenter Roeck <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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rtc: Add support for limited alarm timer offsets

Some alarm timers are based on time offsets, not on absolute times.
In some situations, the amount of time that can be scheduled in the
future is lim

rtc: Add support for limited alarm timer offsets

Some alarm timers are based on time offsets, not on absolute times.
In some situations, the amount of time that can be scheduled in the
future is limited. This may result in a refusal to suspend the system,
causing substantial battery drain.

Some RTC alarm drivers remedy the situation by setting the alarm time
to the maximum supported time if a request for an out-of-range timeout
is made. This is not really desirable since it may result in unexpected
early wakeups.

To reduce the impact of this problem, let RTC drivers report the maximum
supported alarm timer offset. The code setting alarm timers can then
decide if it wants to reject setting alarm timers to a larger value, if it
wants to implement recurring alarms until the actually requested alarm
time is met, or if it wants to accept the limited alarm time.

Only introduce the necessary variable into struct rtc_device.
Code to set and use the variable will follow with subsequent patches.

Cc: Brian Norris <[email protected]>
Signed-off-by: Guenter Roeck <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <[email protected]>

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rtc: remove uie_unsupported

uie_unsupported is not used by any drivers anymore, remove it.

Signed-off-by: Alexandre Belloni <[email protected]>
Link: https://lore.kernel.org/r/202203091

rtc: remove uie_unsupported

uie_unsupported is not used by any drivers anymore, remove it.

Signed-off-by: Alexandre Belloni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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rtc: add BSM parameter

BSM or Backup Switch Mode is a common feature on RTCs, allowing to select
how the RTC will decide when to switch from its primary power supply to the
backup power supply. It i

rtc: add BSM parameter

BSM or Backup Switch Mode is a common feature on RTCs, allowing to select
how the RTC will decide when to switch from its primary power supply to the
backup power supply. It is necessary to be able to set it from userspace as
there are uses cases where it has to be done dynamically.

Supported values are:
RTC_BSM_DISABLED: disabled
RTC_BSM_DIRECT: switching will happen as soon as Vbackup > Vdd
RTC_BSM_LEVEL: switching will happen around a threshold, usually with an
hysteresis
RTC_BSM_STANDBY: switching will not happen until Vdd > Vbackup, this is
useful to ensure the RTC doesn't draw any power until the device is first
powered on.

Signed-off-by: Alexandre Belloni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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rtc: class: don't call cdev_device_del() when cdev_device_add() failed

I got a null-ptr-deref report when doing fault injection test:

general protection fault, probably for non-canonical address 0x

rtc: class: don't call cdev_device_del() when cdev_device_add() failed

I got a null-ptr-deref report when doing fault injection test:

general protection fault, probably for non-canonical address 0xdffffc0000000022: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000110-0x0000000000000117]
RIP: 0010:device_del+0x132/0xdc0
Call Trace:
cdev_device_del+0x1a/0x80
devm_rtc_unregister_device+0x37/0x80
release_nodes+0xc3/0x3b0

If cdev_device_add() fails, 'dev->p' is not set, it causes
null-ptr-deref when calling cdev_device_del(). Registering
character device is optional, we don't return error code
here, so introduce a new flag 'RTC_NO_CDEV' to indicate
if it has character device, cdev_device_del() is called
when this bit is not set.

Reported-by: Hulk Robot <[email protected]>
Signed-off-by: Yang Yingliang <[email protected]>
Signed-off-by: Alexandre Belloni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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rtc: introduce features bitfield

Introduce a bitfield to allow the drivers to announce the available
features for an RTC.

The main use case would be to better handle alarms, that could be present
o

rtc: introduce features bitfield

Introduce a bitfield to allow the drivers to announce the available
features for an RTC.

The main use case would be to better handle alarms, that could be present
or not or have a minute resolution or may need a correct week day to be set.

Use the newly introduced RTC_FEATURE_ALARM bit to then test whether alarms
are available instead of relying on the presence of ops->set_alarm.

Signed-off-by: Alexandre Belloni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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ntp: Make the RTC sync offset less obscure

The current RTC set_offset_nsec value is not really intuitive to
understand.

tsched twrite(t2.tv_sec - 1) t2 (seconds increment)

The offset is

ntp: Make the RTC sync offset less obscure

The current RTC set_offset_nsec value is not really intuitive to
understand.

tsched twrite(t2.tv_sec - 1) t2 (seconds increment)

The offset is calculated from twrite based on the assumption that t2 -
twrite == 1s. That means for the MC146818 RTC the offset needs to be
negative so that the write happens 500ms before t2.

It's easier to understand when the whole calculation is based on t2. That
avoids negative offsets and the meaning is obvious:

t2 - twrite: The time defined by the chip when seconds increment
after the write.

twrite - tsched: The time for the transport to the point where the chip
is updated.

==> set_offset_nsec = t2 - tsched
ttransport = twrite - tsched
tRTCinc = t2 - twrite
==> set_offset_nsec = ttransport + tRTCinc

tRTCinc is a chip property and can be obtained from the data sheet.

ttransport depends on how the RTC is connected. It is close to 0 for
directly accessible RTCs. For RTCs behind a slow bus, e.g. i2c, it's the
time required to send the update over the bus. This can be estimated or
even calibrated, but that's a different problem.

Adjust the implementation and update comments accordingly.

Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Alexandre Belloni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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ntp, rtc: Move rtc_set_ntp_time() to ntp code

rtc_set_ntp_time() is not really RTC functionality as the code is just a
user of RTC. Move it into the NTP code which allows further cleanups.

Requeste

ntp, rtc: Move rtc_set_ntp_time() to ntp code

rtc_set_ntp_time() is not really RTC functionality as the code is just a
user of RTC. Move it into the NTP code which allows further cleanups.

Requested-by: Alexandre Belloni <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Acked-by: Alexandre Belloni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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rtc: rework rtc_register_device() resource management

rtc_register_device() is a managed interface but it doesn't use devres
by itself - instead it marks an rtc_device as "registered" and the devres

rtc: rework rtc_register_device() resource management

rtc_register_device() is a managed interface but it doesn't use devres
by itself - instead it marks an rtc_device as "registered" and the devres
callback for devm_rtc_allocate_device() takes care of resource release.

This doesn't correspond with the design behind devres where managed
structures should not be aware of being managed. The correct solution
here is to register a separate devres callback for unregistering the
device.

While at it: rename rtc_register_device() to devm_rtc_register_device()
and add it to the list of managed interfaces in devres.rst. This way we
can avoid any potential confusion of driver developers who may expect
there to exist a corresponding unregister function.

Signed-off-by: Bartosz Golaszewski <[email protected]>
Signed-off-by: Alexandre Belloni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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rtc: add devm_ prefix to rtc_nvmem_register()

rtc_nvmem_register() is a managed interface. It doesn't require any
release function to be called at driver detach. To avoid confusing
driver authors, l

rtc: add devm_ prefix to rtc_nvmem_register()

rtc_nvmem_register() is a managed interface. It doesn't require any
release function to be called at driver detach. To avoid confusing
driver authors, let's rename it to devm_rtc_nvmem_register() and add it
to the list of managed interfaces in Documentation/.

Signed-off-by: Bartosz Golaszewski <[email protected]>
Signed-off-by: Alexandre Belloni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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rtc: nvmem: remove nvram ABI

The nvram sysfs attributes have been deprecated at least since v4.13, more
than 3 years ago and nobody ever complained about the deprecation warning.

Remove the sysfs a

rtc: nvmem: remove nvram ABI

The nvram sysfs attributes have been deprecated at least since v4.13, more
than 3 years ago and nobody ever complained about the deprecation warning.

Remove the sysfs attributes now.

[Bartosz: remove the declaration of rtc_nvmem_unregister()]

Signed-off-by: Alexandre Belloni <[email protected]>
Signed-off-by: Bartosz Golaszewski <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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rtc: cleanup obsolete comment about struct rtc_class_ops

Commit ea369ea6d828 ("rtc: remove .open() and .release()") removes
open/release callback from struct rtc_class_ops.

Also commit 80d4bb515b78

rtc: cleanup obsolete comment about struct rtc_class_ops

Commit ea369ea6d828 ("rtc: remove .open() and .release()") removes
open/release callback from struct rtc_class_ops.

Also commit 80d4bb515b78 ("RTC: Cleanup rtc_class_ops->irq_set_state")
and commit 696160fec162 ("RTC: Cleanup rtc_class_ops->irq_set_freq()")
removes irq callbacks.

So, just remove related comments so that readers will not be confused.

Signed-off-by: Misono Tomohiro <[email protected]>
Signed-off-by: Alexandre Belloni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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rtc: remove rtc_time_to_tm and rtc_tm_to_time

There are no callers of the 32bit versions of rtc_time conversion
functions, drop them.

Link: https://lore.kernel.org/r/20200330201510.861217-1-alexand

rtc: remove rtc_time_to_tm and rtc_tm_to_time

There are no callers of the 32bit versions of rtc_time conversion
functions, drop them.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <[email protected]>

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rtc: rv3029: let the core handle rtc range

Despite the comment, the RV3029 uses a 7bit BCD register for the year,
making 2079 the last supported year.

Link: https://lore.kernel.org/r/20191214221022

rtc: rv3029: let the core handle rtc range

Despite the comment, the RV3029 uses a 7bit BCD register for the year,
making 2079 the last supported year.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <[email protected]>

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rtc: introduce lock helpers

Introduce rtc_lock and rtc_unlock to shorten the code when locking and
unlocking ops_lock from drivers.

Link: https://lore.kernel.org/r/20191019205034.6382-1-alexandre.b

rtc: introduce lock helpers

Introduce rtc_lock and rtc_unlock to shorten the code when locking and
unlocking ops_lock from drivers.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <[email protected]>

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rtc: add timestamp for end of 2199

Some RTCs handle date up to 2199.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <alexandre

rtc: add timestamp for end of 2199

Some RTCs handle date up to 2199.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <[email protected]>

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rtc: add a timestamp for year 0

A few RTCs handle dates from year 0 to year 9999. Add a timestamp even if
years before 1970 will probably never be used.

Link: https://lore.kernel.org/r/201910071347

rtc: add a timestamp for year 0

A few RTCs handle dates from year 0 to year 9999. Add a timestamp even if
years before 1970 will probably never be used.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <[email protected]>

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rtc: drop set_mms and set_mmss64

There are no users of set_mms and set_mmss64 as they have all been
converted to set_time and are handling the tm to time conversion on their
own.

Signed-off-by: Ale

rtc: drop set_mms and set_mmss64

There are no users of set_mms and set_mmss64 as they have all been
converted to set_time and are handling the tm to time conversion on their
own.

Signed-off-by: Alexandre Belloni <[email protected]>

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rtc: Fix timestamp value for RTC_TIMESTAMP_BEGIN_1900

Printing "mktime64(1900, 1, 1, 0, 0, 0)" gives -2208988800.

Fixes: 83bbc5ac63326433 ("rtc: Add useful timestamp definitions")
Signed-off-by: Ge

rtc: Fix timestamp value for RTC_TIMESTAMP_BEGIN_1900

Printing "mktime64(1900, 1, 1, 0, 0, 0)" gives -2208988800.

Fixes: 83bbc5ac63326433 ("rtc: Add useful timestamp definitions")
Signed-off-by: Geert Uytterhoeven <[email protected]>
Signed-off-by: Alexandre Belloni <[email protected]>

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rtc: da9063: set range

The DA9062 and DA9063 have a year register that can go up to 0x3F.

Acked-by: Steve Twiss <[email protected]>
Signed-off-by: Alexandre Belloni <alexandre.belloni@b

rtc: da9063: set range

The DA9062 and DA9063 have a year register that can go up to 0x3F.

Acked-by: Steve Twiss <[email protected]>
Signed-off-by: Alexandre Belloni <[email protected]>

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rtc: sh: set range

The SH RTC is a BCD RTC with some version having 4 digits for the year.

The range for the RTCs with only 2 digits for the year was unfortunately
shifted to handle 1999 to 2098.

rtc: sh: set range

The SH RTC is a BCD RTC with some version having 4 digits for the year.

The range for the RTCs with only 2 digits for the year was unfortunately
shifted to handle 1999 to 2098.

Reviewed-by: Geert Uytterhoeven <[email protected]>
Signed-off-by: Alexandre Belloni <[email protected]>

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rtc: remove rtc_class_ops.read_callback

Since commit 416f0e8056f7 ("RTC: sa1100: Update the sa1100 RTC driver."),
the last user of .read_callback is gone. It has been 8 years and now new
user appear

rtc: remove rtc_class_ops.read_callback

Since commit 416f0e8056f7 ("RTC: sa1100: Update the sa1100 RTC driver."),
the last user of .read_callback is gone. It has been 8 years and now new
user appeared. Simply remove it.

Signed-off-by: Alexandre Belloni <[email protected]>

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rtc: enforce rtc_timer_init private_data type

All the remaining users of rtc_timers are passing the rtc_device as private
data. Enforce that and rename private_data to rtc.

Suggested-by: Arnd Bergm

rtc: enforce rtc_timer_init private_data type

All the remaining users of rtc_timers are passing the rtc_device as private
data. Enforce that and rename private_data to rtc.

Suggested-by: Arnd Bergmann <[email protected]>
Signed-off-by: Alexandre Belloni <[email protected]>

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