rtc: st-lpc: Simplify clk handling in st_rtc_probe()

Use devm_clk_get_enabled() instead of hand writing it. This simplifies
error handling and removes some lines of code.

Also use dev_err_probe() which filters -EPROBE_DEFER.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/992dd8c31be0bb5b8a9d8b5e8e94807ab0848a66.1686251455.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: st-lpc: Release some resources in st_rtc_probe() in case of error

If an error occurs after clk_get(), the corresponding resources should be
released.

Use devm_clk_get() to fix it.

Fixes: b5b2bdfc2893 ("rtc: st: Add new driver for ST's LPC RTC")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/866af6adbc7454a7b4505eb6c28fbdc86ccff39e.1686251455.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: st-lpc: Add missing clk_disable_unprepare in st_rtc_probe()

The clk_disable_unprepare() should be called in the error handling
of clk_get_rate(), fix it.

Fixes: b5b2bdfc2893 ("rtc: st: Add new driver for ST's LPC RTC")
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Link: https://lore.kernel.org/r/20221123014805.1993052-1-cuigaosheng1@huawei.com
Signed-off-by: Alexandre Belloni <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: st-lpc: Constify st_rtc_ops

The only usage of st_rtc_ops is to assign its address to the ops field
in the rtc_device struct. which is a const pointer. Make it const to
allow the compiler to put it in read-only memory.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20200913122644.35515-1-rikard.falkeborn@gmail.com

rtc: st-lpc: Remove struct resource from struct st_rtc

struct resource in struct st_rtc is not used, remove it.

Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Link: https://lore.kernel.org/r/20191123091241.1905-1-nobuhiro1.iwamatsu@toshiba.co.jp
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20191006102953.57536-2-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-3-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-4-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-5-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-6-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-7-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-8-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-9-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-10-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-11-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-12-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-13-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-14-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-15-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-16-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-17-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-18-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-19-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-20-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-21-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-22-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-23-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-24-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-25-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-26-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-27-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-28-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-29-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-30-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-31-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-32-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-33-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-34-yuehaibing@huawei.com
Link: https://lore.kernel.org/r/20191006102953.57536-35-yuehaibing@huawei.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36

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 licence as published by
the free software foundation either version 2 of the licence 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 114 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

rtc: st-lpc: remove unnecessary check

The RTC core already ensures the alarm is set to a time in the future, it
is not necessary to check again in the driver.

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

rtc: st-lpc: add range

The RTC has a 64 bit counter.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: st-lpc: 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.

Acked-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: st-lpc: remove artificial limitation

The LPC RTC supports dates way beyond 2038, don't limit it artificially as
the kernel handles dates after 2038 properly.

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

rtc: st-lpc: make it robust against y2038/2106 bug

Make driver use u64 variables and functions to be sure that
it will support dates after year 2038.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Acked-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: st: Update IP layout information to include Clocksource

Initial submission adding support for this IP only included Watchdog and
the Real-Time Clock. Now the third (and final) device is enabled this
trivial patch is required to update the comment in the RTC driver to
encompass Clocksource.

Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

rtc: st: Add new driver for ST's LPC RTC

ST's Low Power Controller (LPC) controls two devices; watchdog and RTC.
Only one of the devices can be used at any one time. This is enforced
by the correlating MFD driver. This portion of the driver-set controls
the Real Time Clock.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Lee Jones <lee.jones@linaro.org>