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>
The time and date register of the pcf8223 are undefined after a power
reset. Properly handle the OS bit and return -EINVAL when that bit is set.
It is properly removed when setting the time.
This solves an issue where the time and date may be valid for
rtc_valid_tm() but is not the current time.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
When the chip increments the YEAR register and it already holds
bin2bcd(99) it reads as 0 afterwards. With this behaviour the last valid
day (without trickery) that has a representation is 2099-12-31 23:59:59.
So refuse to write later dates.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Alexandre 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: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
PCF8523 uses 1-12 to represent month according to datasheet.
link: www.nxp.com/documents/data_sheet/PCF8523.pdf.
Signed-off-by: Chris Cui <chris.wei.cui@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After the switch to devm_* functions and the removal of
rtc_device_unregister(), the 'remove' function does not do anything.
Delete it.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
devm_rtc_device_register() is device managed and makes cleanup
paths simpler.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Implement reading of the battery voltage low signal for rtc-pcf8523.
The bit is read-only and cannot be cleared by software, so no
clear function is implemented.
[akpm@linux-foundation.org: omit pcf8563_rtc_ioctl() if CONFIG_RTC_INTF_DEV=n]
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Reviewed-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add an RTC driver for PCF8523 chips by NXP Semiconductors. No support is
currently provided for the alarm and interrupt functions. Only the time
and date functionality is implemented.
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Russell King