This patch adds the Spreadtrum RTC driver, which embedded in the
Spreadtrum SC27xx series PMICs.

Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This patch adds the binding documentation for Spreadtrum SC27xx series
RTC device.

Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

When alarm value is read at boot time, at91_alarm_year is not yet set to
the proper value so the year is always set to 1900.

This results in that kind of message at boot:
rtc rtc0: invalid alarm value: 1900-1-14 2:11:39

There is no way to recover from that as the alarm is now only read when
booting.

Instead, rely on the rtc core to figure out the proper year.

Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Calculating yday in the read_alarm callback is useless as this value is
never used later. Also, it was buggy anyway because at the time this is
done, tm_year is always 0 as the alarm register doesn't hold the year.

Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Use time64_t variables and related APIs for sysfs interfaces to
support setting time or alarm after the year 2038 on 32-bit system.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The new xgene_rtc_alarm_irq_enabled() function is only accessed
from PM code, which is inside of an #ifdef; this causes a harmless
build warning when CONFIG_PM is disabled:

drivers/rtc/rtc-xgene.c:108:12: error: 'xgene_rtc_alarm_irq_enabled' defined but not used [-Werror=unused-function]

Just remove the #ifdef and use __maybe_unused annotations instead,
to make the code more robust here.

Fixes: d0bcd82b

 ("rtc: xgene: Fix suspend/resume")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Loc Ho <lho@apm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This patch fixes suspend/resume functions properly for the APM X-Gene
SoC RTC driver.

Signed-off-by: Loc Ho <lho@apm.com>
Reviewed-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Allow setting the alarm and later enable it instead of enabling it
unconditionally.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The pcf8563_clkout_recalc_rate function erroneously ignores the
frequency index read from the CLKO register and always returns
32768 Hz.

Fixes: a39a6405

 ("rtc: pcf8563: add CLKOUT to common clock framework")
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The err variable is not being reset after a successful read. Explicitly
return 0 at the end of function call to account for all return paths.

Reported-by: Jens-Peter Oswald <oswald@lre.de>
Signed-off-by: Akshay Bhat <akshay.bhat@timesys.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Define for reserved register 31 had the incorrect address. Specify
the correct address.

Reported-by: Jens-Peter Oswald <oswald@lre.de>
Signed-off-by: Akshay Bhat <akshay.bhat@timesys.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Remove duplicate define for RX8010_YEAR

Signed-off-by: Akshay Bhat <akshay.bhat@timesys.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

m41t80_sqw_set_rate will be called with the result from
m41t80_sqw_round_rate, so might as well make
m41t80_sqw_set_rate(n) same as
m41t80_sqw_set_rate(m41t80_sqw_round_rate(n))

As Russell King wrote[1],
"clk_round_rate() is supposed to tell you what you end up with if you
ask clk_set_rate() to set the exact same value you passed in - but
clk_round_rate() won't modify the hardware."

[1]
http://lists.infradead.org/pipermail/linux-arm-kernel/2012-January/080175.html



Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This is a little more efficient and avoids the warning

 WARNING: possible circular locking dependency detected
 4.14.0-rc7-00010 #16 Not tainted
 ------------------------------------------------------
 kworker/2:1/70 is trying to acquire lock:
  (prepare_lock){+.+.}, at: [<c049300c>] clk_prepare_lock+0x80/0xf4

 but task is already holding lock:
  (i2c_register_adapter){+.+.}, at: [<c0690b04>]
		i2c_adapter_lock_bus+0x14/0x18

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #1 (i2c_register_adapter){+.+.}:
        rt_mutex_lock+0x44/0x5c
        i2c_adapter_lock_bus+0x14/0x18
        i2c_transfer+0xa8/0xbc
        i2c_smbus_xfer+0x20c/0x5d8
        i2c_smbus_read_byte_data+0x38/0x48
        m41t80_sqw_is_prepared+0x18/0x28

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This is a little more efficient, and avoids the warning

 WARNING: possible circular locking dependency detected
 4.14.0-rc7-00007 #14 Not tainted
 ------------------------------------------------------
 alsactl/330 is trying to acquire lock:
 (prepare_lock){+.+.}, at: [<c049300c>] clk_prepare_lock+0x80/0xf4

 but task is already holding lock:
 (i2c_register_adapter){+.+.}, at: [<c0690ae0>]
		i2c_adapter_lock_bus+0x14/0x18

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #1 (i2c_register_adapter){+.+.}:
        rt_mutex_lock+0x44/0x5c
        i2c_adapter_lock_bus+0x14/0x18
        i2c_transfer+0xa8/0xbc
        i2c_smbus_xfer+0x20c/0x5d8
        i2c_smbus_read_byte_data+0x38/0x48
        m41t80_sqw_recalc_rate+0x24/0x58

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Previously it was returning the best of
32768, 8192, 1024, 64, 2, 0

Now, best of
32768, 8192, 4096, 2048, 1024, 512, 256, 128,
64, 32, 16, 8, 4, 2, 1, 0

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Previously it was returning -EINVAL upon success.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Note that alarms are not currently implemented.

64 bytes of nvmem is supported and exposed in
sysfs (# is the instance number, starting with 0):

	/sys/bus/nvmem/devices/pcf85363-#/nvmem

Signed-off-by: Eric Nelson <eric@nelint.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Tested-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Register an nvmem device to expose the 3 scratch registers (total of 12
bytes) to both userspace and kernel space.

Reviewed-by: Sekhar Nori <nsekhar@ti.com>
Tested-by: Keerthy <j-keerthy@ti.com>
Reviewed-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This removes a possible race condition and crash and allows for further
improvement of the driver.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

If pinctrl_register() fails probe will return with an error without locking
the RTC and disabling pm_runtime.
Set ret and jump to err instead.

Fixes: 97ea1906

 ("rtc: omap: Support ext_wakeup configuration")
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The driver doesn't have a struct of_device_id table but supported devices
are registered via Device Trees. Worse, the compatible is documented but
doesn't currently match the driver.

Add the proper compatible to the driver.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Make Epson RX8130 device tree and ACPI aware.

Fixes: ee0981be

 ("rtc: ds1307: Add support for Epson RX8130CE")
Signed-off-by: Bastian Stender <bst@pengutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

I work for MediaTek on maintaining the MediaTek SoC based RTC driver for
the existing SoCs and keep adding support for the following SoCs in the
future.

Cc: Eddie Huang <eddie.huang@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Give a better description for original MediaTek RTC driver as PMIC based
RTC in order to distinguish SoC based RTC. Also turning all words with
Mediatek to MediaTek here.

Cc: Eddie Huang <eddie.huang@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Acked-by: Eddie Huang <eddie.huang@mediatek.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This patch introduces the driver for the RTC on MT7622 SoC.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Reviewed-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Add device-tree binding for MediaTek SoC based RTC

Cc: devicetree@vger.kernel.org
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Add support for reading and writing the RTC offset register, converting
it to the corresponding parts-per-billion value.

When setting the drift, the PCF8523 has two modes: one applies the
adjustment every two hours, the other applies the adjustment every
minute.  We select between these two modes according to which ever
gives the closest PPB value to the one requested.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Add support for trimming the RTC using the offset mechanism.  This RTC
supports two modes: low update mode and high update mode.  Low update
mode has finer precision than high update mode, so we use the low mode
where possible.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The RTC offset correction documentation is not very clear about the
exact relationship between "offset" and the effect it has on the RTC.
Supplement the documentation with an equation giving the relationship.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Instead of adding a binary sysfs attribute from the driver (which suffers
from a race condition as the attribute appears after the device), use the
core to register an nvmem device.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Disabling interrupts when removing the driver is bad practice as this will
prevent some platform from waking up when using that RTC.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This allows for future improvement of the driver.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

There is a race condition that can happen if abx80x_probe() fails after the
rtc registration succeeded. Solve that by moving the registration at the
end of the probe function.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This allows for future improvement of the driver.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Instead of adding a binary sysfs attribute from the driver (which suffers
from a race condition as the attribute appears after the device), use the
core to register an nvmem device.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This allows for future improvement of the driver.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Instead of adding a binary sysfs attribute from the driver (which suffers
from a race condition as the attribute appears after the device), use the
core to register an nvmem device.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

This allows for future improvement of the driver.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

On some platforms, the interrupt for the PL031 is optional.  Avoid
trying to claim the interrupt if it's not specified.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>