Many RTCs have an on board non volatile storage. It can be battery backed
RAM or an EEPROM. Use the nvmem subsystem to export it to both userspace
and in-kernel consumers.

This stays compatible with the previous (non documented) ABI that was using
/sys/class/rtc/rtcx/device/nvram to export that memory. But will warn about
the deprecation.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

While highly unlikely, it is possible to get an interrupt as soon as it is
requested. In that case, at91_rtc_interrupt() will be called with rtc ==
NULL.

Solve that by using devm_rtc_allocate_device/rtc_register_device.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Introduce rtc_register_device() to register an already allocated and
initialized struct rtc_device. It automatically sets up the owner and the
two steps allocation/registration will allow to remove race conditions in
the IRQ handling of some driver. It also allows to properly extend the core
without adding more arguments to rtc_device_register().
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Create rtc_device_get_id to allocate the id for an RTC.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Create rtc_allocate_device to allocate memory for a struct rtc_device and
initialize it.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This patch adds support for STM32H7 RTC. On STM32H7, the RTC bus interface
clock (APB clock) needs to be enabled.
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This patch documents support for STM32H7 Real Time Clock.
It introduces a new compatible and rework clock definitions.
On STM32H7 we have a 'pclk' clock for register access, in addition to
the 'rtc_ck' clock.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The ds1308 variant is very similar to the already supported ds1338
variant, it have more debug registers and a square wave clock output.
Signed-off-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

DS3232/DS3234 has the temperature registers with a resolution of 0.25
degree celsius. This enables to get the value through hwmon.

	# cat /sys/class/hwmon/hwmon0/temp1_input
	37250
Signed-off-by: Kirill Esipov <yesipov@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

We should change this post-op to a pre-op because we want the loop to
exit with "timeout" set to zero.

Fixes: 0a89b553 ("nuc900/rtc: change the waiting for device ready implement")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The Gemini RTC is actually a generic IP block from Faraday
Technology names FTRTC010. Rename the driver file and all
symbols to match this IP name.

The relationship can be clearly seen in the U-Boot driver
posted by Po-Yu Chuang for the Faraday A320 board:
https://lists.denx.de/pipermail/u-boot/2009-September/061326.html

Remove the dependency on ARCH_GEMINI but select the driver
for ARCH_GEMINI so we get a smooth transition. The IP block
is synthsized on different silicon and architectures.

Cc: Po-Yu Chuang <ratbert@faraday-tech.com>
Acked-by: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The Gemini RTC is actually a standard IP block from Faraday
Technology called FTRTC010. Rename the bindings, add the
generic compatible string and add definitions for the two
available clocks.

Cc: devicetree@vger.kernel.org
Cc: Po-Yu Chuang <ratbert@faraday-tech.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This makes the Gemini optionally take two clock references to
the PCLK and EXTCLK. As we are adding a clock framework to the
Gemini platform we need to make sure that we get the right
references.
Acked-by: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The driver has lots of places with chip-specific code what doesn't
necessarily facilitate maintenance.

Let's describe chip-specific differences in century bit handling
in struct chip_desc to improve this.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

After the switch to regmap we can now make use of regmap_update_bits
to simplify read/modify/write ops.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This adds support for the Broadcom STB wake-timer which is a timer in
the chip's 27Mhz clock domain that offers the ability to wake the system
(wake-up source) from suspend states (S2, S3, S5). It is supported using
the rtc framework allowing us to configure alarms for system wake-up.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Markus Mayer <mmayer@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Document the binding for the Broadcom STB SoCs wake-up timer node
allowing the system to generate alarms and exit low power states.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Add support for yet another RTC chip, Epson RX8130CE. This time around,
the chip has slightly permutated registers and also the register starts
at 0x10 instead of 0x0 .

So far, we only support the RTC and NVRAM parts of the chip, Alarm and
Timer is not supported.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Nishanth Menon <nm@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

clk_enable() can fail so handle such case.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

clk_prepare_enable() can fail so handle such case.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

All instances of struct s3c_rtc_data are in fact static const thus
put in rodata so we should not drop the const while getting the pointer
to them.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

There is no need for casting to void pointer for of_device_id data.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Minor cleanups to make the code easier to read. No functional changes.
1. Remove one space before labels as this is nowadays mostly preferred.
2. Fix indentation of arguments in function calls.
3. Split structure member declaration.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

In other error paths in probe, centralized exit point was used so make
this consistent.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This variable was never used. With GCC 6.2, we get the following warning:

drivers/rtc/rtc-mxc.c:44:18: warning: ‘PIE_BIT_DEF’ defined but not used [-Wunused-const-variable=]
 static const u32 PIE_BIT_DEF[MAX_PIE_NUM][2] = {
Signed-off-by: Diaz de Grenu, Jose <Jose.DiazdeGrenu@digi.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Provide an implementation of the callback
rtc_class_ops.alarm_irq_enable for rtc-opal driver. This callback is
called when the wake alarm is disabled via the command:

'echo 0 > /sys/class/rtc/rtc0/wakealarm'

Without this the Timed-Power-On(TPO) config remains set even when its
disabled by the above command and FSP will still force machine
boot at previously configured alarm time.

The callback is implemented as function opal_tpo_alarm_irq_enable()
which calls opal_set_tpo_time() with alarm.enabled == 0. A branch is
added to opal_set_tpo_time() to handle this case by passing y_m_d ==
h_m_s_ms == 0 to opal as arguments for opal_tpo_write() call.
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc->name is only used in messages were it is superfluous. Remove it
completely from the structure.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

ds1307->rtc->name is a copy of ds1307->name, use it instead.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

pcf8563->rtc->name is a copy of pcf8563_driver.driver.name, use it instead
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc->name is superfluous here because the rtc is already registered at that
point and its name has already been printed.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The name sysfs attribute is not useful in its current form because of all
the drivers:
 - 3 are using the feature correctly
 - 2 are clearly misusing it
 - 60 are using driver.name, either directly or indirectly
 - 46 are using pdev->name
 - 8 are using client->name
 - 31 are using a variation of driver.name (addition or removal of rtc-,
   -rtc, _rtc, rtc_)

Make it uniform and use the driver name and the device name.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- adjust identation of the titles;
- mark a table as such;
- don't capitalize chapter names.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

In function __rtc_read_alarm() its possible for an alarm time-stamp to
be invalid even after replacing missing components with current
time-stamp. The condition 'alarm->time.tm_year < 70' will trigger this
case and will cause the call to 'rtc_tm_to_time64(&alarm->time)'
return a negative value for variable t_alm.

While handling alarm rollover this negative t_alm (assumed to seconds
offset from '1970-01-01 00:00:00') is converted back to rtc_time via
rtc_time64_to_tm() which results in this error log with seemingly
garbage values:

"rtc rtc0: invalid alarm value: -2-1--1041528741
2005511117:71582844:32"

This error was generated when the rtc driver (rtc-opal in this case)
returned an alarm time-stamp of '00-00-00 00:00:00' to indicate that
the alarm is disabled. Though I have submitted a separate fix for the
rtc-opal driver, this issue may potentially impact other
existing/future rtc drivers.

To fix this issue the patch validates the alarm time-stamp just after
filling up the missing datetime components and if rtc_valid_tm() still
reports it to be invalid then bails out of the function without
handling the rollover.
Reported-by: Steve Best <sbest@redhat.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

On PowerNV platform when Timed-Power-On(TPO) is disabled, read of
stored TPO yields value with all date components set to '0' inside
opal_get_tpo_time(). The function opal_to_tm() then converts it to an
offset from year 1900 yielding alarm-time == "1900-00-01
00:00:00". This causes problems with __rtc_read_alarm() that
expecting an offset from "1970-00-01 00:00:00" and returned alarm-time
results in a -ve value for time64_t. Which ultimately results in this
error reported in kernel logs with a seemingly garbage value:

"rtc rtc0: invalid alarm value: -2-1--1041528741
2005511117:71582844:32"

We fix this by explicitly handling the case of all alarm date-time
components being '0' inside opal_get_tpo_time() and returning -ENOENT
in such a case. This signals generic rtc that no alarm is set and it
bails out from the alarm initialization flow without reporting the
above error.
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Reported-by: Steve Best <sbest@redhat.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Some devices supported by the m41t80 driver have a programmable
square-wave output signal (see M41T80_FEATURE_SQ).

This enables to use this feature as a clock provider of common
clock framework.
Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

In order to use the proper clock framework to control this feature.
Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This patch is only relevant for RTC with the SQ_ALT feature which
means the clock output frequency divider is stored in the weekday
register.

Current implementation discards the previous dividers value and clear
them as soon as the time is set.
Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Currently setting an alarm clears the SQWE bit which means that the
clock output is disabled no matter its previous state.
Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This patch extends the fixes for ds1337, ds1339, ds3231 in commit
8bc2a407 ("rtc: ds1307: add support for the DT property
'wakeup-source'") to mcp794xx devices, so that those parts can similarly be
used as a wakeup source without an IRQ to the processor.

Tested on Raspberry Pi ZeroW with MCP79400.
Signed-off-by: David Lowe <dave-lowe@ntlworld.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This patch converts the ds1307 driver to using regmap. It's a rather
big patch and I can test with DS3231 only. With this chip it's
working fine.

I'd appreciate if people with other supported hardware could test as
well.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>