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>

The current timeout for waiting for WRDY is not always sufficient. Always
increase it to 10000 even on JZ4740. This is technically only required on
JZ4780, where the current symptoms seen after a hard reboot are:

  jz4740-rtc 10003000.rtc: rtc core: registered 10003000.rtc as rtc0
  jz4740-rtc 10003000.rtc: Could not write to RTC registers
  jz4740-rtc: probe of 10003000.rtc failed with error -5

Suggested-by: Alex Smith <alex.smith@imgtec.com>
Cc: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Trivial fix in error message with duplicate 'write'

Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

By using kernel_halt() instead of machine_halt(), we can make the driver
build as a module.
However, jz4740 platforms not loading this module will not be able to power
off.

Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Revert "rtc: jz4740: make the driver builtin only"

This reverts commit b9168c539c0b2de756aaffd380384dbde8adbe07.

Since the driver is now calling machine_halt() that is not exported, it has
to be built in the kernel. Building it as a module will fail at linking
time.

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

jz4740_rtc_poweroff() is only called from the driver, stop exporting it.

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

The 'system-power-controller' singleton entry can be used in the
devicetree node of the jz4740-rtc driver to specify that the driver is
granted the right to power off the system through the registers of the
RTC unit.

See the documentation for more details:
Documentation/devicetree/bindings/rtc/ingenic,jz4740-rtc.txt

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Maarten ter Huurne <maarten@treewalker.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

See
Documentation/devicetree/bindings/rtc/ingenic,jz4740-rtc.txt
for a description of the bindings.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Maarten ter Huurne <maarten@treewalker.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The RTC unit present in the JZ4780 works mostly the same as the one in
the JZ4740. The major difference is that register writes need to be
explicitly enabled, by writing a magic code (0xA55A) to a "write
enable" register before each access.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Maarten ter Huurne <maarten@treewalker.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Check for rtc_class_ops structures that are only passed to
devm_rtc_device_register, rtc_device_register,
platform_device_register_data, all of which declare the corresponding
parameter as const.  Declare rtc_class_ops structures that have these
properties as const.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r disable optional_qualifier@
identifier i;
position p;
@@
static struct rtc_class_ops i@p = { ... };

@ok@
identifier r.i;
expression e1,e2,e3,e4;
position p;
@@
(
devm_rtc_device_register(e1,e2,&i@p,e3)
|
rtc_device_register(e1,e2,&i@p,e3)
|
platform_device_register_data(e1,e2,e3,&i@p,e4)
)

@bad@
position p != {r.p,ok.p};
identifier r.i;
@@
i@p

@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
 struct rtc_class_ops i = { ... };
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Acked-by: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>