rtc: ds1347: fix value written to century register

In `ds1347_set_time()`, the wrong value is being written to the
`DS1347_CENTURY_REG` register. It needs to be converted to BCD. Fix
it.

Fixes: 147dae76dbb9 ("rtc: ds1347: handle century register")
Cc: <stable@vger.kernel.org> # v5.5+
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20221027163249.447416-1-abbotti@mev.co.uk
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: rework rtc_register_device() resource management

rtc_register_device() is a managed interface but it doesn't use devres
by itself - instead it marks an rtc_device as "registered" and the devres
callback for devm_rtc_allocate_device() takes care of resource release.

This doesn't correspond with the design behind devres where managed
structures should not be aware of being managed. The correct solution
here is to register a separate devres callback for unregistering the
device.

While at it: rename rtc_register_device() to devm_rtc_register_device()
and add it to the list of managed interfaces in devres.rst. This way we
can avoid any potential confusion of driver developers who may expect
there to exist a corresponding unregister function.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201109163409.24301-8-brgl@bgdev.pl

rtc: ds1347: handle century register

The DS1347 can handle years from 0 to 9999, add century register support.

Link: https://lore.kernel.org/r/20191007134724.15505-10-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: ds1347: use regmap_update_bits

Use regmap_update_bits instead of open coding. Also add proper error
handling.

Link: https://lore.kernel.org/r/20191007134724.15505-9-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: ds1347: properly handle oscillator failures

The comment in the probe function stating that it disables oscillator stop
detection and glitch filtering is incorrect as it sets bits 3 and 4 while
it should be setting 5 and 6 to achieve that. Then, it is safe to assume
that the oscillator failure detection is actually enabled.

Properly handle oscillator failures by returning -EINVAL when the time and
date are know to be incorrect and reset the flag when the time is set.

Link: https://lore.kernel.org/r/20191007134724.15505-8-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: ds1347: set range

The DS1347 handle dates from year 0000 to 9999. Leap years are claimed to
be handled correctly in the datasheet.

Link: https://lore.kernel.org/r/20191007134724.15505-7-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: ds1347: convert to devm_rtc_allocate_device

This allows further improvement of the driver.

Link: https://lore.kernel.org/r/20191007134724.15505-6-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: ds1347: mask ALM OUT when reading time

Bit 7 of the minutes registers is ALM OUT. It indicates an alarm fired.
Mask it out when reading the time.

Link: https://lore.kernel.org/r/20191007134724.15505-5-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: ds1347: simplify getting .driver_data

Get 'driver_data' from 'struct device' directly. Going via spi_device is an
unnecessary step.

Link: https://lore.kernel.org/r/20191007134724.15505-4-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: ds1347: remove useless read

DS1347_SECONDS_REG is read at probe time but the value is simply discarded.
Remove that useless read.

Link: https://lore.kernel.org/r/20191007134724.15505-3-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: ds1347: remove verbose messages

Printing debugging (and opaque) information is not useful and only clutters
the boot log. Remove those messages.

Link: https://lore.kernel.org/r/20191007134724.15505-2-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

rtc: stop validating rtc_time in .read_time

The RTC core is always calling rtc_valid_tm after the read_time callback.
It is not necessary to call it just before returning from the callback.

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

rtc: ds1347: changed raw spi calls to register map calls

This patch changes calls of spi read write calls to register map
read and write calls in rtc ds1347

Signed-off-by: Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

spi: Drop owner assignment from spi_drivers

An spi_driver does not need to set an owner, it will be populated by the
driver core.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

rtc: add support for maxim dallas rtc ds1347

Add support for maxim dallas rtc ds1347

Signed-off-by: Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>