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>

If a previously-set alarm was disabled and then triggered, it may still
be pending when a new alarm is configured.

Then, if the alarm is enabled before the pending alarm is cleared, then
an interrupt is immediately raised.

Unfortunately, when the alarm is cleared and enabled during the same I²C
block write, the chip (at least the DS1339 I have) considers that the
alarm is enabled before it is cleared, and raises an interrupt.

This patch ensures that the pending alarm is cleared before the alarm is
enabled.
Signed-off-by: NNicolas Boullis <nboullis@debian.org>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

The i2c_smbus_read_i2c_block_data function returns 0 on success, not the
number of bytes written.

Hence, when there are 32 bytes or less to send, the
ds1307_native_smbus_write_block_data function returns 0 on success,
while it returns the number of bytes when there are more than 32.

The ds1307_write_block_data always returns the number of bytes on
success.
Signed-off-by: NNicolas Boullis <nboullis@debian.org>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

With commit 8bc2a407 ("rtc: ds1307: add support for the
DT property 'wakeup-source'") we lost the ability for rtc irq
functionality for devices that are actually hooked on a real IRQ
line and have capability to wakeup as well. This is not an expected
behavior. So, instead of just not requesting IRQ, skip the IRQ
requirement only if interrupts are not defined for the device.

Fixes: 8bc2a407 ("rtc: ds1307: add support for the DT property 'wakeup-source'")
Reported-by: NTony Lindgren <tony@atomide.com>
Cc: Michael Lange <linuxstuff@milaw.biz>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: NNishanth Menon <nm@ti.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

while retrieving temperature from ds3231, the result may be overflow
since s16 is too small for a multiplication with 250.

ie. if temp_buf[0] == 0x2d, the result (s16 temp) will be negative.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Tested-by: NMichael Tatarinov <kukabu@gmail.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

DS3231 has programmable square-wave output signal.
This enables to use this feature as a clock provider of
common clock framework.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: NMichael Turquette <mturquette@baylibre.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

DS3231 has the temperature registers with a resolution of 0.25
degree celsius.  This enables to get the value through hwmon.

	# cat /sys/class/i2c-adapter/i2c-2/2-0068/hwmon/hwmon0/temp1_input
	21000
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Acked-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

For RTC chips with no IRQ directly connected to the SoC, the RTC chip
can be forced as a wakeup source by stating that explicitly in
the device's .dts file using the "wakeup-source" boolean property.
This will guarantee the 'wakealarm' sysfs entry is available on the
device, if supported by the RTC.

With these changes to the driver rtc-ds1307 and the necessary entries
in the .dts file, I get an working ds1337 RTC on the Witty Pi extension
board by UUGear for the Raspberry Pi.

An example for the entry in the .dts file:

	rtc: ds1337@68 {
		compatible = "dallas,ds1337";
		reg = <0x68>;
		wakeup-source;

If the "wakeup-source" property is set, do not request an IRQ.
Set also UIE mode to unsupported, to get a working 'hwclock' binary.
Signed-off-by: NMichael Lange <linuxstuff@milaw.biz>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

This makes the generated code slightly smaller.
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

With the actual code, read_alarm() always returns -EINVAL when called
during the RTC device registration. This prevents from retrieving an
already configured alarm in hardware.

This patch fixes the issue by moving the HAS_ALARM bit configuration
(if supported by the hardware) above the rtc_device_register() call.
Signed-off-by: NSimon Guinot <simon.guinot@sequanux.org>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Since commit 3fffd128 ("i2c: allow specifying
separate wakeup interrupt in device tree") we have
automatic wakeup irq support for i2c devices. That
commit missed the fact that rtc-1307 had its own
wakeup irq handling and ended up introducing a
kernel splat for at least Beagle x15 boards.

Fix that by reverting original commit _and_ passing
correct interrupt names on DTS so i2c-core can
choose correct IRQ as wakeup.

Now that we have automatic wakeirq support, we can
revert the original commit which did it manually.

Fixes the following warning:

[   10.346582] WARNING: CPU: 1 PID: 263 at linux/drivers/base/power/wakeirq.c:43 dev_pm_attach_wake_irq+0xbc/0xd4()
[   10.359244] rtc-ds1307 2-006f: wake irq already initialized

Cc: Tony Lindgren <tony@atomide.com>
Cc: Nishanth Menon <nm@ti.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

mcp794xx alarm registers must be written in BCD format. However, the
alarm programming logic neglected this by adding one to the value
after bin2bcd conversion has been already done, writing bad values
to month register in case the alarm being set is in October. In this
case, the alarm month value becomes 0x0a instead of the expected 0x10.

Fix by moving the +1 addition within the bin2bcd call also.

Fixes: 1d1945d2 ("drivers/rtc/rtc-ds1307.c: add alarm support for mcp7941x chips")
Signed-off-by: NTero Kristo <t-kristo@ti.com>
Acked-by: NNishanth Menon <nm@ti.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

The change removes redundant sysfs binary file boundary checks, since
this task is already done on caller side in fs/sysfs/file.c
Signed-off-by: NVladimir Zapolskiy <vz@mleia.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

i2c_driver does not need to set an owner because i2c_register_driver()
will set it.
Signed-off-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

With the recent pinctrl-single changes, SoCs such as Texas
Instrument's OMAP processors can treat wake-up events from deeper idle
states as interrupts.

Let's add support for the optional second interrupt for wake-up using
the generic wakeirq support added in commit 4990d4fe ("PM /
Wakeirq: Add automated device wake IRQ handling")

Finally, to pass the wake-up interrupt in the dts file,
interrupts-extended property needs to be passed.

This is similar in approach to commit 2a0b965c ("serial: omap: Add
support for optional wake-up") + ee83bd3b ("serial: omap: Switch
wake-up interrupt to generic wakeirq")
Signed-off-by: NNishanth Menon <nm@ti.com>
Reviewed-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Acked-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

It is always a good practice to keep the #includes sorted
Signed-off-by: NNishanth Menon <nm@ti.com>
Acked-by: NFelipe Balbi <balbi@ti.com>
Reviewed-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Since we are not doing anything fancy in remove function that requires
us to sequence IRQ free operation, we might as well switch over to devm_
equivalent of managed IRQ allocation and remove the explicit free_irq
since it'd be done automatically at remove.
Signed-off-by: NNishanth Menon <nm@ti.com>
Acked-by: NFelipe Balbi <balbi@ti.com>
Reviewed-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

The driver currently emulates the concept of threaded IRQ using a
workqueue, which it really does not need to. Instead, switch over to
threaded_irq handlers which is meant precisely for the same purpose.
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NNishanth Menon <nm@ti.com>
Reviewed-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

Alarm interrupt enable register is at offset 0x7, while the time
registers for the alarm follow that. When we program Alarm interrupt
enable prior to programming the time, it is possible that previous
time value could be close or match at the time of alarm enable
resulting in interrupt trigger which is unexpected (and does not match
the time we expect it to trigger).

To prevent this scenario from occuring, program the ALM0_EN bit only
after the alarm time is appropriately programmed.

Ofcourse, I2C programming is non-atomic, so there are loopholes where
the interrupt wont trigger if the time requested is in the past at
the time of programming the ALM0_EN bit. However, we will not have
unexpected interrupts while the time is programmed after the interrupt
are enabled.
Signed-off-by: NNishanth Menon <nm@ti.com>
Reviewed-by: NGrygorii Strashko <grygorii.strashko@linaro.org>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

MCP7940x is same RTC as MCP7941x.  The difference is that MCP7941x chips
contain additional EEPROM on a different i2c address.

DS1307 driver already supports MCP7941x, so just add a new i2c device id
and rename functions and defines accordingly.
Signed-off-by: NTomas Novotny <tomas@novotny.cz>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Some DS13XX devices have "trickle chargers".  Introduce a device tree
binding for specifying the trickle charger configuration for ds1339.

Only ds1339 dt binding is supported because this is the only chip I have.
I _assume_ the code would have worked on other allready supported chips.
However I cannot check the resistor values for the other chips or test
them.  For other chips the driver code works as earlier Eg.  it does not
check the dt bindings at all
Signed-off-by: NMatti Vaittinen <matti.vaittinen@nsn.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Pavel Machek <pavel@denx.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add alarm support for the Microchip RTC devices MCP794xx.  Note that two
programmable alarms are provided by the chip but only one is used by the
driver.
Signed-off-by: NSimon Guinot <simon.guinot@sequanux.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Gregory Clement <gregory.clement@free-electrons.com>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In order to allow the creation of the sysfs attribute wakealarm, this
patch moves the device_set_wakeup_capable() call above the RTC device
registration.
Signed-off-by: NSimon Guinot <simon.guinot@sequanux.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Gregory Clement <gregory.clement@free-electrons.com>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

RTC drivers must not return an error after device registration.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NAlessandro Zummo <a.zummo@towertech.it>
Reported-by: NAles Novak <alnovak@suse.cz>
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Srikanth Srinivasan <srikanth.srinivasan@freescale.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The variable want_irq is only assigned the values true and false.
Change its type to bool.

The simplified semantic patch that find this problem is as
follows (http://coccinelle.lip6.fr/):

@exists@
type T;
identifier b;
@@
- T
+ bool
  b = ...;
  ... when any
  b = \(true\|false\)
Signed-off-by: NPeter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.  This is a cosmetic change to make
the code simpler and enhance the readability.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

'client->irq' was not released on error. Fix it.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use devm_*() functions to make cleanup paths simpler.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The current usage of commas instead of semicolons is not wrong, but
affects the readability of the code.

Also, the code would break, if someone puts something between those two
assignments.
Signed-off-by: NSteffen Trumtrar <s.trumtrar@pengutronix.de>
Cc: Austin Boyle <Austin.Boyle@aviatnet.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

dev_dbg() is preferred to pr_debug().
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The rtc-ds1307 driver does not properly handle block operations bigger
than 32 bytes in either of the two modes supported (SMbus native, or
emulated if not supported by the SMbus platform driver).

It also does not properly handle userland-supplied input (block
operation length) through sysfs and may suffer a type of buffer overrun.

The driver has been modified with proper input validation, buffer sizes,
and now splits block transfers bigger than 32 bytes into separate
transfers.

Explanation : Buffer size allocated is I2C_SMBUS_BLOCK_MAX which equals
to 32 as per the SMbus spec.  Reads and write may be up to 56 bytes (to
the NVRAM).  This patch allocated a 255 byte buffer, the maximum
allowable (address is an u8).  It's not only a buffer problem, SMbus
only supports up to 32 bytes transfer at once, so it's needed to split
bigger transfers.

Patch successfully tested on 3.2.27; cleanly applies on 3.7-rc4.

[akpm@linux-foundation.org: rework code to avoid 80-column overflows]
Signed-off-by: NBertrand Achard <ba@cykian.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>