kernel/git/stable/linux.git/drivers/rtc/rtc-m41t93.c, branch linux-7.2.y

rtc: m41t93: Add watchdog support

2026-06-24T21:12:11+00:00

Implement watchdog feature for m41t93 rtc with 1s resolution. Implement alarm only support (WDIOF_ALARMONLY) in this commit. Define start, stop, ping, and set_timeout callbacks as needed by the watchdog framework. Use selftests/watchdog/watchdog-test kselftest for testing. Observed IRQ pin(12) of rtc chip going low after late pinging the watchdog. Signed-off-by: Akhilesh Patil Link: https://patch.msgid.link/77c2e9f4ab0811a919595d7a5476b00abd1c2803.1758379856.git.akhilesh@ee.iitb.ac.in Signed-off-by: Alexandre Belloni

rtc: m41t93: Add square wave clock provider support

2026-06-24T21:11:10+00:00

Implement support to configure square wave output (SQW) of m41t93 rtc via common clock framework clock provider api. Add clock provider callbacks to control output frequency ranging from 1Hz to 32KHz as supported by this rtc chip. Use clock framework debugfs interface or clock consumer DT node to test. Tested by measuring various frequencies on pull-up connected SWQ(7) pin of m41t93 rtc chip using logic analyzer. Signed-off-by: Akhilesh Patil Link: https://patch.msgid.link/a8c4d3741be4e9dfa52c57cbd653f561ba4ed934.1758379856.git.akhilesh@ee.iitb.ac.in Signed-off-by: Alexandre Belloni

rtc: m41t93: Add alarm support

2026-06-24T21:08:54+00:00

Implement alarm feature for rtc-m41t93 by adding necessary callbacks - set_alarm, read_alarm and alarm_irq_enable. Enable support to configure alarm 1 out of 2 alarms present in this rtc. Support only alarm configuration in this commit. This commit does not implement alarm irq handling. Use selftests/rtc/rtctest for testing. Tested by observing IRQ pin (pin 12 of SOX18 package) on logic analyzer going low after alarm condition is met. Signed-off-by: Akhilesh Patil Link: https://patch.msgid.link/1b272ff1a5392d5eb76e129a4785ac8424763356.1758379856.git.akhilesh@ee.iitb.ac.in Signed-off-by: Alexandre Belloni

rtc: m41t93: migrate to regmap api for register access

2026-06-24T21:08:39+00:00

Adapt driver to use regmap api with spi bus instead of direct spi subsystem calls to access device registers. Simplify and standardize the register interactions using more abstract and bus agnostic regmap api to reduce code duplication and improve maintainability. Define spi regmap config suitable for m41t93 spi bus protocol to achieve same transactions on spi bus. Tested on TI am62x sk board with m41t93 rtc chip connected over spi0. Validated set and get time using hwclock tool and verified spi bus transfers using logic analyzer. Signed-off-by: Akhilesh Patil Link: https://patch.msgid.link/180f9b6c3ee7c490fe3537c2d50a92cec359e4cd.1758379856.git.akhilesh@ee.iitb.ac.in Signed-off-by: Alexandre Belloni

rtc: m41t93: add device tree support

2026-06-24T20:55:02+00:00

Add device tree support for m41t93 rtc by adding of_match_table. Define compatible string - "st,m41t93" which can be used to instantiate this rtc device via DT node. Signed-off-by: Akhilesh Patil Link: https://patch.msgid.link/060ef5c5adaa444d2c623aa8ce4c540fa19d0f95.1758379856.git.akhilesh@ee.iitb.ac.in Signed-off-by: Alexandre Belloni

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55+00:00

Based on 2 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 version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Enrico Weigelt Reviewed-by: Kate Stewart Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman

rtc: m41t93: stop validating rtc_time in .read_time

2018-03-02T09:12:19+00:00

The RTC core is always calling rtc_valid_tm after the read_time callback. It is not necessary to call it just before returning from the callback. Signed-off-by: Alexandre Belloni

spi: Drop owner assignment from spi_drivers

2015-10-28T01:30:17+00:00

An spi_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Andrew F. Davis Acked-by: Jonathan Cameron Signed-off-by: Mark Brown

drivers/rtc/rtc-m41t93.c: remove empty function

2013-07-03T23:07:56+00:00

After the switch to devm_* functions and the removal of rtc_device_unregister(), the 'remove' function does not do anything. Delete it. Signed-off-by: Sachin Kamat Cc: Nikolaus Voss Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

rtc: rtc-m41t93: use spi_set_drvdata()

2013-04-30T01:28:35+00:00

Use the wrapper functions for getting and setting the driver data using spi_device instead of using dev_{get|set}_drvdata with &spi->dev, so we can directly pass a struct spi_device. Signed-off-by: Jingoo Han Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds