kernel/linux.git/drivers/rtc/rtc-snvs.c, branch v6.19.11

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

2022-11-15T20:25:44+00:00

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

rtc: rework rtc_register_device() resource management

2020-11-19T11:50:12+00:00

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 Signed-off-by: Alexandre Belloni Link: https://lore.kernel.org/r/20201109163409.24301-8-brgl@bgdev.pl

rtc: snvs: Remove NULL pointer check before clk_*

2020-11-14T22:54:44+00:00

Because clk_* already checked NULL clock parameter, so the additional checks are unnecessary, just remove them. Signed-off-by: Xu Wang Signed-off-by: Alexandre Belloni Link: https://lore.kernel.org/r/20201113080305.65961-1-vulab@iscas.ac.cn

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