rtc: remove redundant of_match_ptr()

Signed-off-by: Zhu Wang <wangzhu9@huawei.com>
Link: https://lore.kernel.org/r/20230808115213.154377-2-wangzhu9@huawei.com
Link: https://lore.kernel.org/r/20230808115213.154377-3-wangzhu9@huawei.com
Link: https://lore.kernel.org/r/20230808115213.154377-4-wangzhu9@huawei.com
Link: https://lore.kernel.org/r/20230808115213.154377-5-wangzhu9@huawei.com
Link: https://lore.kernel.org/r/20230808115213.154377-6-wangzhu9@huawei.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: Explicitly include correct DT includes

The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230724205456.767430-1-robh@kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: armada38x: use devm_platform_ioremap_resource_byname()

Convert platform_get_resource_byname(),devm_ioremap_resource() to a single
call to devm_platform_ioremap_resource_byname(), as this is exactly what
this function does.

Signed-off-by: Ye Xingchen <ye.xingchen@zte.com.cn>
Link: https://lore.kernel.org/r/202303221130316049449@zte.com.cn
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: armada38x: remove armada38x_rtc_ops_noirq

Clear RTC_FEATURE_ALARM to signal that alarms are not available instead of
having a supplementary struct rtc_class_ops with a NULL .set_alarm.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210110231752.1418816-4-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: armada38x: Use of_device_get_match_data()

Use the more modern API to get the match data out of the of match table.
This saves some code, lines, and nicely avoids referencing the match
table when it is undefined with configurations where CONFIG_OF=n.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Gregory Clement <gregory.clement@bootlin.com>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: <linux-rtc@vger.kernel.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20191004214334.149976-4-swboyd@chromium.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: remove superfluous error message

The RTC core now has error messages in case of registration failure, there
is no need to have other messages in the drivers.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20190818220041.17833-2-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: Remove dev_err() usage after platform_get_irq()

We don't need dev_err() messages when platform_get_irq() fails now that
platform_get_irq() prints an error message itself when something goes
wrong. Let's remove these prints with a simple semantic patch.

// <smpl>
@@
expression ret;
struct platform_device *E;
@@

ret =
(
platform_get_irq(E, ...)
|
platform_get_irq_byname(E, ...)
);

if ( \( ret < 0 \| ret <= 0 \) )
{
(
-if (ret != -EPROBE_DEFER)
-{ ...
-dev_err(...);
-... }
|
...
-dev_err(...);
)
...
}
// </smpl>

While we're here, remove braces on if statements that only have one
statement (manually).

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: linux-rtc@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20190730181557.90391-40-swboyd@chromium.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 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 as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

rtc: armada38x: switch to rtc_time64_to_tm/rtc_tm_to_time64

Call the 64bit versions of rtc_time_to_tm and rtc_tm_to_time now that the
range is enforced by the core.

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

rtc: armada38x: add range

The RTC is a 32bit seconds counter.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Tested-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: armada38x: fix possible race condition

The IRQ is requested before the struct rtc is allocated and registered, but
this struct is used in the IRQ handler. This may lead to a NULL pointer
dereference.

Switch to devm_rtc_allocate_device/rtc_register_device to allocate the rtc
before requesting the IRQ.

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

rtc: armada38x: reset after rtc power loss

When the RTC block looses power it needs a reset sequence to make it
usable again. Otherwise, writes to the time register have no effect.

This reset sequence combines information from the mvebu_rtc driver in
the Marvell provided U-Boot, and the SolidRun provided U-Boot repo.

Tested on the Armada 388 based SolidRun Clearfog Base.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Acked-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: armada38x: add support for trimming the RTC

Add support for trimming the RTC using the offset mechanism. This RTC
supports two modes: low update mode and high update mode. Low update
mode has finer precision than high update mode, so we use the low mode
where possible.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: armada38x: Add support for Armada 7K/8K

The Armada 7K/8K use the same RTC IP than the Armada 38x. However the SOC
integration differs in 2 points:
- MBUS bridge timing initialization
- IRQ configuration at SoC level

Moreover the Armada 7K/8K have an issue preventing to get the interrupt
from alarm 1. This commit allows to use alarm 2 for these A7K/8K but to
still use alarm 1 for the Armada 38x.

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

rtc: armada38x: Prepare driver to manage different versions

In order to prepare the introduction of the A7K/A8K version of the RTC,
this commit introduces a new data structure. This structure allows to
handle the differences between the integration of the RTC IP in the
SoCs. It will be:
- MBUS bridge timing initialization
- IRQ configuration at SoC level

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

rtc: armada38x: make struct rtc_class_ops const

Armada38x wants to modify its rtc_class_ops to remove the interrupt
handling when there is no usable interrupt, but this means we leave
function pointers in writable memory.

Since rtc_class_ops is small, arrange to have two instances, one for
when we have interrupts, and one for when we have none, both marked
const. This allows the compiler to place them in read-only memory,
which is better than placing them in __ro_after_init.

Thanks to Bhumika Goyal <bhumirks@gmail.com> for pointing out that
the structure was writable and submitting a patch to add
__ro_after_init.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: armada38x: Follow the new recommendation for errata implementation

According to RES-3124064:

The device supports CPU write and read access to the RTC time register.
However, due to this restriction, read and write from/to internal RTC
register may fail.

Workaround:
General setup:
1. Configure the RTC Mbus Bridge Timing Control register (offset 0x184A0)
to value 0xFD4D4FFF
Write RTC WRCLK Period to its maximum value (0x3FF)
Write RTC WRCLK setup to 0x29
Write RTC WRCLK High Time to 0x53 (default value)
Write RTC Read Output Delay to its maximum value (0x1F)
Mbus - Read All Byte Enable to 0x1 (default value)
2. Configure the RTC Test Configuration Register (offset 0xA381C) bit3
to '1' (Reserved, Marvell internal)

For any RTC register read operation:
1. Read the requested register 100 times.
2. Find the result that appears most frequently and use this result
as the correct value.

For any RTC register write operation:
1. Issue two dummy writes of 0x0 to the RTC Status register (offset
0xA3800).
2. Write the time to the RTC Time register (offset 0xA380C).

This patch is based on the work of Shaker Daibes

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

rtc: Fix module autoload for OF platform drivers

These platform drivers have a OF device ID table but the OF module
alias information is not created so module autoloading won't work.

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Acked-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: armada38x: Align RTC set time procedure with the official errata

According to the Armada38x functional errata FE-3124064, writing to
the RTC TIME register may fail. As a workaround, after writing to RTC
TIME register, issue a dummy write of 0x0 twice to the RTC Status
register. This is the updated implementation of the Errata that
eliminates the need of the long 100ms delay during the RTC set time
procedure.

[gregory.clement@free-electrons.com]: removed the mutex and use the
spinlock again

Signed-off-by: Nadav Haklai <nadavh@marvell.com>
Reviewed-by: Neta Zur Hershkovits <neta@marvell.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: armada38x: Remove unused variable from armada38x_rtc_set_time()

Remove the 'flags' variable in order to fix the following warning:

drivers/rtc/rtc-armada38x.c:91:22: warning: unused variable 'flags' [-Wunused-variable]

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

drivers/rtc/rtc-armada38x.c: remove unused local `flags'

Reported-by: Fengguang Wu <fengguang.wu@gmail.com>
Cc: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

rtc: armada38x: fix concurrency access in armada38x_rtc_set_time

While setting the time, the RTC TIME register should not be accessed.
However due to hardware constraints, setting the RTC time involves
sleeping during 100ms. This sleep was done outside the critical section
protected by the spinlock, so it was possible to read the RTC TIME
register and get an incorrect value. This patch introduces a mutex for
protecting the RTC TIME access, unlike the spinlock it is allowed to
sleep in a critical section protected by a mutex.

The RTC STATUS register can still be used from the interrupt handler but
it has no effect on setting the time.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Andrew Lunn <andrew@lunn.ch>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: <stable@vger.kernel.org> [4.0]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-armada38x: add a new RTC driver for recent mvebu SoCs

The new mvebu SoCs come with a new RTC driver. This patch adds the
support for this new IP which is currently found in the Armada 38x
SoCs.

This RTC provides two alarms, but only the first one is used in the
driver. The RTC also allows using periodic interrupts.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reviewed-by: Arnaud Ebalard <arno@natisbad.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Boris BREZILLON <boris.brezillon@free-electrons.com>
Cc: Lior Amsalem <alior@marvell.com>
Cc: Tawfik Bayouk <tawfik@marvell.com>
Cc: Nadav Haklai <nadavh@marvell.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>