linux-stable.git/drivers/rtc/rtc-snvs.c, branch linux-5.10.y

rtc: snvs: Allow a time difference on clock register read

2023-01-14T09:16:05+00:00

[ Upstream commit 0462681e207ccc44778a77b3297af728b1cf5b9f ]

On an iMX6ULL the following message appears when a wakealarm is set:

echo 0 > /sys/class/rtc/rtc1/wakealarm
rtc rtc1: Timeout trying to get valid LPSRT Counter read

This does not always happen but is reproducible quite often (7 out of 10
times). The problem appears because the iMX6ULL is not able to read the
registers within one 32kHz clock cycle which is the base clock of the
RTC. Therefore, this patch allows a difference of up to 320 cycles
(10ms). 10ms was chosen to be big enough even on systems with less cpu
power (e.g. iMX6ULL). According to the reference manual a difference is
fine:
- If the two consecutive reads are similar, the value is correct.
The values have to be similar, not equal.

Fixes: cd7f3a249dbe ("rtc: snvs: Add timeouts to avoid kernel lockups")
Reviewed-by: Francesco Dolcini 
Signed-off-by: Stefan Eichenberger 
Signed-off-by: Francesco Dolcini 
Link: https://lore.kernel.org/r/20221106115915.7930-1-francesco@dolcini.it
Signed-off-by: Alexandre Belloni 
Signed-off-by: Sasha Levin

rtc: snvs: Add necessary clock operations for RTC APIs

2020-05-30T01:17:48+00:00

There could be still RTC registers access after RTC suspend
with clock disabled, need to add clock operations for each
RTC API to make sure accessing RTC registers is successfully.

Signed-off-by: Anson Huang 
Signed-off-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/1590113996-31845-2-git-send-email-Anson.Huang@nxp.com

rtc: snvs: Make SNVS clock always prepared

2020-05-30T01:17:48+00:00

In IRQ handler, ONLY clock enable/disable is called due to
clock prepare can NOT be called in interrupt context, but
clock enable/disable will return failure if prepare count
is 0, to fix this issue, just make SNVS clock always prepared
there, the SNVS clock has no prepare function implemented,
so it won't impact anything.

Signed-off-by: Anson Huang 
Signed-off-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/1590113996-31845-1-git-send-email-Anson.Huang@nxp.com

rtc: snvs: Use devm_add_action_or_reset() for calls to clk_disable_unprepare()

2020-03-16T10:55:55+00:00

Use devm_add_action_or_reset() for calls to clk_disable_unprepare(),
which can simplify the error handling.

Signed-off-by: Anson Huang 
Link: https://lore.kernel.org/r/1584109849-21402-1-git-send-email-Anson.Huang@nxp.com
Link: https://lore.kernel.org/r/1584233264-26025-1-git-send-email-Anson.Huang@nxp.com
Signed-off-by: Alexandre Belloni

rtc: snvs: Remove unused include of of_device.h

2020-02-18T21:39:23+00:00

There is nothing in use from of_device.h, remove it.

Signed-off-by: Anson Huang 
Link: https://lore.kernel.org/r/1581823666-16944-1-git-send-email-Anson.Huang@nxp.com
Signed-off-by: Alexandre Belloni

rtc: snvs: switch to rtc_time64_to_tm/rtc_tm_to_time64

2019-09-01T06:48:23+00:00

Call the 64bit versions of rtc_tm time conversion now that the range is
enforced by the core.

Link: https://lore.kernel.org/r/20190828205056.31321-2-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni

rtc: snvs: set range

2019-09-01T06:48:15+00:00

The SNVS is a 47-bit counter incremented at 32768Hz, it is then a 32-bit
second counter.

Link: https://lore.kernel.org/r/20190828205056.31321-1-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni

rtc: snvs: fix possible race condition

2019-08-29T15:53:12+00:00

The RTC IRQ is requested before the struct rtc_device is allocated,
this may lead to a NULL pointer dereference in IRQ handler.

To fix this issue, allocating the rtc_device struct before requesting
the RTC IRQ using devm_rtc_allocate_device, and use rtc_register_device
to register the RTC device.

Signed-off-by: Anson Huang 
Reviewed-by: Dong Aisheng 
Link: https://lore.kernel.org/r/20190716071858.36750-1-Anson.Huang@nxp.com
Signed-off-by: Alexandre Belloni

rtc: snvs: Use __maybe_unused instead of #if CONFIG_PM_SLEEP

2019-05-08T20:14:36+00:00

Use __maybe_unused for power management related functions
instead of #if CONFIG_PM_SLEEP to simply the code.

Signed-off-by: Anson Huang 
Reviewed-by: Dong Aisheng 
Signed-off-by: Alexandre Belloni

rtc: snvs: use devm_platform_ioremap_resource() to simplify code

2019-04-04T08:07:11+00:00

Use the new helper devm_platform_ioremap_resource() which wraps the
platform_get_resource() and devm_ioremap_resource() together, to
simplify the code.

Signed-off-by: Anson Huang 
Signed-off-by: Alexandre Belloni