The probe function is not allowed to fail after registering the RTC because
the following may happen:

CPU0:                                CPU1:
sys_load_module()
 do_init_module()
  do_one_initcall()
   cmos_do_probe()
    rtc_device_register()
     __register_chrdev()
     cdev->owner = struct module*
                                     open("/dev/rtc0")
    rtc_device_unregister()
  module_put()
  free_module()
   module_free(mod->module_core)
   /* struct module *module is now
      freed */
                                      chrdev_open()
                                       spin_lock(cdev_lock)
                                       cdev_get()
                                        try_module_get()
                                         module_is_live()
                                         /* dereferences already
                                            freed struct module* */

Switch to devm_rtc_allocate_device/rtc_register_device to register the rtc
as late as possible.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

At probe time, printing a message when the time is invalid doesn't have
much value. Also, as the comment suggest, this is a leftover from
development wherhe this was used to set the RTc to a default time.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

It is not necessary to print a message when the time is invalid as
userspace will already get an error (and an optional dev_dbg message).
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

It is not necessary to print a message when the time is invalid as
userspace will already get an error (and an optional dev_dbg message).
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

It is not necessary to print a message when the time is invalid as
userspace will already get an error (and an optional dev_dbg message).
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

It is not necessary to print a message when the time is invalid as
userspace will already get an error (and an optional dev_dbg message).
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

The RTC core is always validating the rtc_time struct before calling
.set_time. It is not necessary to do it again in .set_time.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

The RTC core is always validating the rtc_time struct before calling
.set_time or .set_alarm. It is not necessary to do it again.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

The RTC core is always validating the rtc_time struct before calling
.set_time or .set_alarm. It is not necessary to do it again.
Also, rtc_time_to_tm never generates an invalid rtc_tm (it can be out of
range though).
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

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>

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>

isl12022_get_datetime and isl12022_set_datetime are only used after casting
dev to an i2c_client. Remove that useless indirection.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc_time64_to_tm never generates an invalid tm. It is not necessary to
validate it. Also, the RTC core is always calling rtc_valid_tm after the
read_time callback.
Reviewed-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

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>

The RTC core is always calling rtc_valid_tm after the read_time callback.
It is not necessary to call it before returning from the callback.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

The RTC core is always calling rtc_valid_tm after the read_time callback.
It is not necessary to call it before returning from the callback.
Acked-by: Steve Twiss <stwiss.opensource@diasemi.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

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.
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

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>

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_time_to_tm never generates an invalid tm. It is not necessary to
validate it.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc_time64_to_tm never generates an invalid tm. It is not necessary to
validate it.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Returning a valid time when the time is invalid is a bad practice, because
then userspace is not able to react on the information. Also, it doesn't
make sense to return epoch because it is already the default time.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Returning a valid time when the time is invalid is a bad practice, because
then userspace is not able to react on the information. Also, it doesn't
make sense to return epoch because it is already the default time.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Setting the rtc to a valid time when the time is invalid is a bad practice,
because then userspace doesn't know it shouldn't trust the RTC.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Returning a valid time when the time is invalid is a bad practice, because
then userspace is not able to react on the information. Also, it doesn't
make sense to return epoch because it is already the default time.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Returning a valid time when the time is invalid is a bad practice, because
then userspace is not able to react on the information. Also, it doesn't
make sense to return epoch because it is already the default time.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

The shifting of buf[5] by 24 bits to the left will be promoted to
a 32 bit signed int and then sign-extended to an unsigned long. If
the top bit of buf[5] is set then all then all the upper bits sec
end up as also being set because of the sign-extension. Fix this by
casting buf[5] to an unsigned long before the shift.

Detected by CoverityScan, CID#1465292 ("Unintended sign extension")

Fixes: 0e149233 ("rtc: add rtc-tx4939 driver")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Free Electrons is now Bootlin.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Since commit 34ce71a9 ("ALSA: timer: remove legacy rtctimer"), the
rtc_register/rtc_control/rtc_unregister API is unused. As it is highly
unlikely to be needed again, remove it.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Fix the iomem pointer notation in order to fix the following sparse
warnings:

drivers/rtc/rtc-mxc_v2.c:280:18: warning: incorrect type in argument 1 (different address spaces)
drivers/rtc/rtc-mxc_v2.c:280:18:    expected void const volatile [noderef] <asn:2>*addr
drivers/rtc/rtc-mxc_v2.c:280:18:    got void *[noderef] <asn:2>ioaddr
drivers/rtc/rtc-mxc_v2.c:329:44: warning: incorrect type in argument 1 (different address spaces)
drivers/rtc/rtc-mxc_v2.c:329:44:    expected void *[noderef] <asn:2>ioaddr
drivers/rtc/rtc-mxc_v2.c:329:44:    got void [noderef] <asn:2>*
drivers/rtc/rtc-mxc_v2.c:339:44: warning: incorrect type in argument 1 (different address spaces)
drivers/rtc/rtc-mxc_v2.c:339:44:    expected void *[noderef] <asn:2>ioaddr
drivers/rtc/rtc-mxc_v2.c:339:44:    got void [noderef] <asn:2>*
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

After successful
sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
sr will be 0.
As a result
sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
			sr & ~ISL1208_REG_SR_WRTC);
is equal to
sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR, 0);
which clears all flags in SR.

Add an additional read of SR, to have value of SR in sr again.
Signed-off-by: Denis Osterland <Denis.Osterland@diehl.com>
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Instead of adding a binary sysfs attribute from the driver, use the core to
register an nvmem device.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

The probe function is not allowed to fail after registering the RTC. Call
rtc_register_device() at the end.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

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

The rtc-tx4939 driver now compiles correctly on other architectures, add
COMPILE_TEST to improve code coverage.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Copy RTC definitions from arch/mips/include/asm/txx9/tx4939.h to the RTC
driver so it doesn't depend on arch/mips anymore.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Instead of adding a binary sysfs attribute from the driver, use the core to
register an nvmem device.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

The probe function is not allowed to fail after registering the RTC. Call
rtc_register_device() at the end.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

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

Currently, the IRQs are disabled when the rtc driver is removed (e.g. when
shutting down the platform).
This means that the RTC will be unable to wakeup the platform.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>