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>

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>

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>

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>

Factor out irq_handler to struct chip_desc and use ds1307_irq as default.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Change the usage of variable want_irq to reflect its name. Don't set
it to true in case wakeup is enabled but no interrupt number is given.
In addition set variable ds1307_can_wakeup_device if chip->alarm
is set only.
This allows to simplify the code and make it better understandable.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Constify struct chip_desc variables.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Instead of storing the trickle_charger_setup value in struct chip_desc
we can let function ds1307_trickle_init return it because it's used
in the probe function only.
This allows us to constify struct chip_desc variables in a next step.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Factor out the bbsqi bit to struct chip_desc.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

The irq number is used in the probe function only, so we don't have
to store it in struct ds1307.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Current max_register setting breaks reading nvram on certain chips and
also reading the standard registers on RX8130 where register map starts
at 0x10.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Fixes: 11e5890b "rtc: ds1307: convert driver to regmap"
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Commit 8b44f5be ("ARM: dts: armada: replace isil,irq2-can-wakeup-machine with wakeup-source property")
removed the last usage of "isil,irq2-can-wakeup-machine" almost
two years ago. So I think we can get rid of supporting this
legacy binding.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

ds1307_remove() is now empty, remove it
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 removes a possible race condition and crash and allows for further
improvement of the driver.
Signed-off-by: NAlexandre 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: NSean Nyekjaer <sean.nyekjaer@prevas.dk>
Signed-off-by: NAlexandre 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: NHeiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NAlexandre 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: NHeiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NAlexandre 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: NMarek 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: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

ds1307->rtc->name is a copy of ds1307->name, use it instead.
Signed-off-by: NAlexandre 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: NDavid Lowe <dave-lowe@ntlworld.com>
Signed-off-by: NAlexandre 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: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

m41t0 was added to the I2C device ID table but not the OF table. Fix that.
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

The m41t0 variant is very similar to the already supported m41t00
variant, with the notable exception of the oscillator fail bit.
The data sheet notes:

  If the oscillator fail (OF) bit is internally set to a '1,' this
  indicates that the oscillator has either stopped, or was stopped
  for some period of time and can be used to judge the validity of
  the clock and date data.

The bit will get cleared with a regular write of the system time,
so no changes are needed to clear it.
Signed-off-by: NStefan Agner <stefan@agner.ch>
Signed-off-by: NAlexandre 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. This is working on the assumption that a
I2C device registered via OF will always match a legacy I2C device ID and
that the MODALIAS reported will always be of the form i2c:<device>.

But this could change in the future so the correct approach is to have an
OF device ID table if the devices are registered via OF.
Signed-off-by: NJavier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

This patch enables ACPI support for rtc-ds1307 driver.
Signed-off-by: NTin Huynh <tnhuynh@apm.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Intersil ISL12057 is a drop-in replacement for DS1337. It can be supported
by the ds1307 driver.
Acked-by: NArnaud Ebalard <arno@natisbad.org>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Add an option to properly support the century bit of ds1337 and compatibles
and ds1340.
Because the driver had a bug until now, it is not possible to switch users
to the fixed code directly as RTCs in the field will wrongly have the
century bit set.
Acked-by: NArnaud Ebalard <arno@natisbad.org>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Since commit d68778b8 ("rtc: initialize output parameter for read
alarm to "uninitialized"") there is no need to explicitly set
unsupported members to -1. So drop the respective assignments from
drivers.
Signed-off-by: NUwe Kleine-König <uwe@kleine-koenig.org>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

The reset value of weekday is 0x1. This is wrong since
the reset values of the day/month/year make up to Jan 1 2001.
When computed weekday comes out to be Monday. On a scale
of 1-7(Sunday - Saturday) it should be 0x2. So we should not
be relying on the reset value.

Hence compute the wday using the current date/month/year values.
Check if reset wday is any different from the computed wday,
If different then set the wday which we computed using
date/month/year values.

Document Referred:
http://ww1.microchip.com/downloads/en/DeviceDoc/20002266F.pdf

Fixes: 1d1945d2 "drivers/rtc/rtc-ds1307.c: add alarm support for mcp7941x chips"
Signed-off-by: NKeerthy <j-keerthy@ti.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

This flag is a no-op now (see commit 47b0eeb3 "clk: Deprecate
CLK_IS_ROOT", 2016-02-02) so remove it.

Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Michael Tatarinov <kukabu@gmail.com>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>