Make Epson RX8130 device tree and ACPI aware.

Fixes: ee0981be ("rtc: ds1307: Add support for Epson RX8130CE")
Signed-off-by: NBastian Stender <bst@pengutronix.de>
Signed-off-by: NAlexandre 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: NSean Wang <sean.wang@mediatek.com>
Acked-by: NEddie Huang <eddie.huang@mediatek.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

This patch introduces the driver for the RTC on MT7622 SoC.
Signed-off-by: NSean Wang <sean.wang@mediatek.com>
Reviewed-by: NYingjoe Chen <yingjoe.chen@mediatek.com>
Signed-off-by: NAlexandre 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: NRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: NAlexandre 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: NRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: NAlexandre 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: NRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: NAlexandre 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: NAlexandre 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: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

This allows for future improvement of the driver.
Signed-off-by: NAlexandre 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: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

This allows for future improvement of the driver.
Signed-off-by: NAlexandre 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: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

This allows for future improvement of the driver.
Signed-off-by: NAlexandre 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: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

This allows for future improvement of the driver.
Signed-off-by: NAlexandre 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: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

If the RTC has no interrupt, there is little point in exposing the RTC
alarm capabilities, as it can't be used as a wakeup source nor can it
deliver an event to userspace.
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Use the devm_* APIs for allocating memory and mapping the memory in
the probe function to relieve the driver from having to deal with
this in the cleanup paths.
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

The AMBA device IDs should be marked const.  Make that so.
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

We don't need both "ret" and "err" when they do the same thing.  All the
functions called here return zero on success or negative error codes.
It's more clear to return a literal zero at the end instead of
"return ret;"
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

The current timeout for waiting for WRDY is not always sufficient. Always
increase it to 10000 even on JZ4740. This is technically only required on
JZ4780, where the current symptoms seen after a hard reboot are:

  jz4740-rtc 10003000.rtc: rtc core: registered 10003000.rtc as rtc0
  jz4740-rtc 10003000.rtc: Could not write to RTC registers
  jz4740-rtc: probe of 10003000.rtc failed with error -5
Suggested-by: NAlex Smith <alex.smith@imgtec.com>
Cc: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
Signed-off-by: NMathieu Malaterre <malat@debian.org>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Trivial fix in error message with duplicate 'write'
Signed-off-by: NMathieu Malaterre <malat@debian.org>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

The current code for checking and fixing the weekday in ds1307_probe
faces some issues:
- This check is applied to all chips even if its applicable (AFAIK)
  to mcp794xx only
- The check uses MCP794XX constants for registers and bits even though
  it's executed also on other chips (ok, this could be fixed easily)
- It relies on tm_wday being properly populated when core calls set_time
  and set_alarm. This is not guaranteed at all.

First two issue we could solve by moving the check to the
mcp794xx-specific initialization (where also VBATEN flag is set).

The proposed alternative is in the set_alarm path for mcp794xx only and
calculates the alarm weekday based on the current weekday in the RTC
timekeeping regs and the difference between alarm date and current date.
So we are fine with any weekday even if it doesn't match the date.

Still there are cases where this could fail, e.g.:
- rtc date/time + weekday have power-on-reset default values
- alarm is set to actual date/time + x
- set_time is called (may change diff between rtc weekday and actual
  weekday)

But similar issues we have with the current code too:
- rtc date/time + weekday have power-on-reset default values
- alarm is set to rtc date/time + x
- set_time is called before the alarm triggers

Using random rtc date/time with relative alarms simply can interfere
with set_time. I'm not totally convinced of either option yet.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

If there is any non expired timer in the queue, the RTC alarm is never set.
This is an issue when adding a timer that expires before the next non
expired timer.

Ensure the RTC alarm is set in that case.

Fixes: 2b2f5ff0 ("rtc: interface: ignore expired timers when enqueuing new timers")
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

The vendor string for Microcrystal is microcrystal.
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Octal permissions are preferred over symbolic permissions.
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Fix unnecessary or unbalanced braces.
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Alignment should always match open parenthesis.
Also remove two unnecessary blank lines
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Use the BIT macro were possbiel.
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

u32 should be used instead of uint32_t
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Use sizeof where possible to ensure we don't read/write more than the
allocated buffer.
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

ds1307->regs is never used before being read or initialized locally. There
is no point in keeping a copy in memory.

Also limit the size of the read buffer to what is really used, rename buf
to regs for consistency and use sizeof() where possible.
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Based on QNAP's arch/arm/mach-rtk119x/driver/rtk_rtc_drv.c code and
mach-rtk119x/driver/dc2vo/fpga/include/mis_reg.h register definitions.

The base year 2014 was observed on all of Zidoo X9S, ProBox2 Ava and
Beelink Lake I.
Signed-off-by: NAndreas Färber <afaerber@suse.de>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

include/linux/i2c is not for client devices. Move the header file to a
more appropriate location.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: NMark Brown <broonie@kernel.org>
Acked-by: NSebastian Reichel <sebastian.reichel@collabora.co.uk>
Acked-by: NJonathan Cameron <jic23@kernel.org>
Acked-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: NKishon Vijay Abraham I <kishon@ti.com>
Acked-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Acked-by: NThierry Reding <thierry.reding@gmail.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Acked-by: NDaniel Thompson <daniel.thompson@linaro.org>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Acked-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

The RTC can output its 32kHz clock outside of the SoC, for example to clock
a WiFi chip.

Create a new clock that other devices will be able to retrieve, while
maintaining the DT stability by providing a default name for that clock if
clock-output-names doesn't list one.
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Add device driver for a virtual RTC device in Android emulator.

The compatible string used by OS for binding the driver is defined
as "google,goldfish-rtc".
Signed-off-by: NMiodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: NGoran Ferenc <goran.ferenc@imgtec.com>
Signed-off-by: NAleksandar Markovic <aleksandar.markovic@imgtec.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

This adds support for reading and writing date/time from/to ds1341 chip.

ds1341 chip has other features - alarms, input clock (can be used instead
of intercal oscillator for better accuracy), output clock ("square wave
generation"). However, not all of that is available at the same time.
Same chip pins, CLKIN/nINTA and SQW/nINTB, can be used either for
input/output clocks, or for alarm interrupts. Role of these pins on
particular board depends on hardware wiring.

We can add device tree properties that describe if each of pins is wired
as clock, or as interrupt, or left unconnected, and enable support for
corresponding functionality based on that. But that is cumbersome, requires
hardware for testing, and has to deal with bit enabling/disabling output
clock also affects which pins alarm interrupts are routed to.

Another factor is that there are hardware setups (i.e. ZII RDU2) that
power DS1341 from SuperCap, which makes power saving critical. For such
setups, kernel driver should leave register bits that control mentioned
pins in the state configured by bootloader.

Given all that, it was decided to limit support to "only date/time" for
now. That is enough for common use case. Full (and cumbersome)
implementation can be added later if ever needed.
Signed-off-by: NNikita Yushchenko <nikita.yoush@cogentembedded.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Tested-by: NAleksander Morgado <aleksander@aleksander.es>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Remove member nvram_offset from struct ds1307 and use the value stored
in struct chip_desc directly.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Factor out offset to struct chip_desc and remove it from struct ds1307.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Factor out rtc_ops to struct chip_desc and use ds13xx_rtc_ops as default.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>