This allows for future improvement of the driver.
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. This allows to use the in-kernel
interface to access the nvram.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

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>

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>

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: Alexandre Belloni <alexandre.belloni@bootlin.com>

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

sirfsoc_rtc_ioctl() doesn't implement any actual ioctl, remove it.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.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: Alexandre Belloni <alexandre.belloni@bootlin.com>

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

A documented ABI already exists to get information about the alarm. It is
the only one that is used.
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>

Avoid using memset as gcc can properly initialize structures.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Because nvmem_config is only used and copied at nvmem registration, remove
it from struct rtc_device.

All the rtc drivers using nvmem are now calling rtc_nvmem_register
directly.
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>

Avoid allocating memory for struct nvmem_config.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Call rtc_nvmem_register instead of letting the core do it and stop using
the nvmem_config member of struct rtc_device.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Avoid allocating memory for struct nvmem_config.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Call rtc_nvmem_register instead of letting the core do it and stop using
the nvmem_config member of struct rtc_device.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Call rtc_nvmem_register instead of letting the core do it and stop using
the nvmem_config member of struct rtc_device.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Move m48t86_nvmem_cfg to the stack of m48t86_rtc_probe. This results in a
very small code size reduction and make it safer on systems with two
similar RTCs:

   text	   data	    bss	    dec	    hex	filename
   1733	    164	      0	   1897	    769	drivers/rtc/rtc-m48t86.o.before
   1793	    100	      0	   1893	    765	drivers/rtc/rtc-m48t86.o.after
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Call rtc_nvmem_register instead of letting the core do it and stop using
the nvmem_config member of struct rtc_device.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Move ds1511_nvmem_cfg to the stack of ds1511_rtc_probe. This results in a
very small code size reduction and make it safer on systems with two
similar RTCs:

   text	   data	    bss	    dec	    hex	filename
   2128	    164	      4	   2296	    8f8	drivers/rtc/rtc-ds1511.o.before
   2175	    100	      4	   2279	    8e7	drivers/rtc/rtc-ds1511.o.after
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Call rtc_nvmem_register instead of letting the core do it and stop using
the nvmem_config member of struct rtc_device.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Avoid allocating memory for struct nvmem_config as it is only necessary at
the nvmem registration.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Call rtc_nvmem_register instead of letting the core do it and stop using
the nvmem_config member of struct rtc_device.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

This makes to code safer on system using two similar RTCs.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Call rtc_nvmem_register instead of letting the core do it and stop using
the nvmem_config member of struct rtc_device.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Export rtc_nvmem_register() so it can be called from drivers instead of
only the core.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Switch the parent of the nvmem device to the parent of the rtc device so it
can be registered before the RTC.

This is a small change in the ABI as the nvmem moves out of the
/sys/class/rtc/rtcX folder to be under the parent device folder (that is
where the previous nvram files where registered).

However, it is still available under its correct location,
/sys/bus/nvmem/devices which is the one that should be used by userspace
applications.

The other benefit is that the nvmem device can stay registered even if the
rtc registration fails. Or it is possible to not register the rtc if the
nvmem registration failed.

Finally, it makes a lot of sense for devices that actually have different
i2c or spi addresses for the RTC and the EEPROM. That is basically how it
would end up when using MFD or even completely separate devices.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Make rtc_nvmem_register return -EBUSY when an nvmem is already registered
for that RTC.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

In case of error, make rtc_nvmem_register() able to return an error value
to its caller.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

To be able to remove nvmem_config from struct rtc_device, pass it as a
parameter to rtc_nvmem_register.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

The nvmem interface appaeared in linux 4.13
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Pointe bp is being initialized and this value is never read, it
is being updated to the same value later just before it is going to
be used. Remove the initialization as it is never read and keep
the setting of bp closer to the use of bp.

Cleans up clang warnings:
drivers/rtc/rtc-ds1302.c:115:7: warning: Value stored to 'bp' during
its initialization is never read
drivers/rtc/rtc-ds1302.c:46:7: warning: Value stored to 'bp' during
its initialization is never read
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Fix the following warning in MIPS allmodconfig by adding a
MODULE_LICENSE() at the end of rtc-goldfish.c, based on the file header
comment which says GNU General Public License version 2:

WARNING: modpost: missing MODULE_LICENSE() in drivers/rtc/rtc-goldfish.o

Fixes: f22d9cdc ("rtc: goldfish: Add RTC driver for Android emulator")
Signed-off-by: James Hogan <jhogan@kernel.org>
Cc: Miodrag Dinic <miodrag.dinic@mips.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: linux-rtc@vger.kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

If we convert one large time values to rtc_time, in the original formula
'days * 86400' can be overflowed in 'unsigned int' type to make the formula
get one incorrect remain seconds value. Thus we can use div_s64_rem()
function to avoid this situation.
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

It will be more helpful to add some tracepoints to track RTC actions when
debugging RTC driver. Below sample is that we set/read the RTC time, then
set 2 alarms, so we can see the trace logs:

set/read RTC time:
kworker/0:1-67 [000] 21.814245: rtc_set_time: UTC (1510301580) (0)
kworker/0:1-67 [000] 21.814312: rtc_read_time: UTC (1510301580) (0)

set the first alarm timer:
kworker/0:1-67 [000] 21.829238: rtc_timer_enqueue: RTC timer:(ffffffc15eb49bc8) expires:1510301700000000000 period:0
kworker/0:1-67 [000] 22.018279: rtc_set_alarm: UTC (1510301700) (0)

set the second alarm timer:
kworker/0:1-67 [000] 22.230284: rtc_timer_enqueue: RTC timer:(ffffff80088e6430) expires:1510301820000000000 period:0

the first alarm timer was expired:
kworker/0:1-67 [000] 145.155584: rtc_timer_dequeue: RTC timer:(ffffffc15eb49bc8) expires:1510301700000000000 period:0
kworker/0:1-67 [000] 145.155593: rtc_timer_fired: RTC timer:(ffffffc15eb49bc8) expires:1510301700000000000 period:0
kworker/0:1-67 [000] 145.172504: rtc_set_alarm: UTC (1510301820) (0)

the second alarm timer was expired:
kworker/0:1-67 [000] 269.102353: rtc_timer_dequeue: RTC timer:(ffffff80088e6430) expires:1510301820000000000 period:0
kworker/0:1-67 [000] 269.102360: rtc_timer_fired: RTC timer:(ffffff80088e6430) expires:1510301820000000000 period:0

disable alarm irq:
kworker/0:1-67 [000] 269.102469: rtc_alarm_irq_enable: disable RTC alarm IRQ (0)
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

except, again, POLLFREE and POLL_BUSY_LOOP.

With this, we finally get to the promised end result:

 - POLL{IN,OUT,...} are plain integers and *not* in __poll_t, so any
   stray instances of ->poll() still using those will be caught by
   sparse.

 - eventpoll.c and select.c warning-free wrt __poll_t

 - no more kernel-side definitions of POLL... - userland ones are
   visible through the entire kernel (and used pretty much only for
   mangle/demangle)

 - same behavior as after the first series (i.e. sparc et.al. epoll(2)
   working correctly).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>