driver: rtc: enable NXP sRTC driver. #94407

Holt-Sun · 2025-08-12T14:08:09Z

Add NXP sRTC device tree binding and NXP sRTC driver file.
Update NXP device and board device tree and prj conf files.
Add conf files in samples rtc for all supported boards.
Add conf files in test rtc to run pass test for supported boards.
Update readme doc.

JarmouniA · 2025-08-12T15:05:13Z

Please split the PR into multiple commits: driver, boards, samples, tests...

samples/drivers/rtc/README.rst

dts/bindings/rtc/nxp,srtc.yaml

dts/arm/nxp/nxp_k2x.dtsi

dts/arm/nxp/nxp_k32l2b3.dtsi

bjarki-andreasen

Device is not an RTC, its a low power counter, those use the counter API

tests/drivers/rtc/rtc_api/boards/frdm_k82f.conf

samples/drivers/rtc/README.rst

bjarki-andreasen · 2025-08-12T16:10:17Z

drivers/rtc/rtc_nxp_srtc.c

+static uint32_t nxp_srtc_convert_datetime_to_seconds(const struct rtc_time *timeptr)
+{
+	/* Number of days from begin of the non Leap-year*/
+	uint16_t monthDays[] = {0U,   0U,   31U,  59U,  90U,  120U, 151U,
+				181U, 212U, 243U, 273U, 304U, 334U};
+	uint32_t seconds;
+	uint16_t year = timeptr->tm_year + 1900;
+
+	/* Compute number of days from 1970 till given year*/
+	seconds = ((uint32_t)year - YEAR_RANGE_START) * DAYS_IN_A_YEAR;
+	/* Add leap year days */
+	seconds += (((uint32_t)year / 4U) - (YEAR_RANGE_START / 4U));
+	/* Add number of days till given month*/
+	seconds += monthDays[timeptr->tm_mon + 1];
+	/*
+	 * Add days in given month. We subtract the current day as it is
+	 * represented in the hours, minutes and seconds field
+	 */
+	seconds += ((uint32_t)timeptr->tm_mday - 1U);
+	/* For leap year if month less than or equal to Febraury, decrement day counter*/
+	if ((0U == (year & 3U)) && ((timeptr->tm_mon + 1) <= 2U) && 0U != seconds) {
+		seconds--;
+	}
+
+	assert(seconds < UINT32_MAX / SECONDS_IN_A_DAY);
+	seconds = (seconds * SECONDS_IN_A_DAY) + ((uint32_t)timeptr->tm_hour * SECONDS_IN_A_HOUR) +
+		  ((uint32_t)timeptr->tm_min * SECONDS_IN_A_MINUTE) + timeptr->tm_sec;
+
+	return seconds;
+}


no, converting between datetime and timestamp is not allowed in rtc drivers, if its needed, the device is not an rtc

https://docs.zephyrproject.org/latest/hardware/peripherals/rtc.html#overview "An RTC is a low power device which tracks time using broken-down time. It should not be confused with low-power counters which sometimes share the same name, acronym, or both."

The sRTC in RM is showed as standard RTC for NXP device:

And in our MCUXpresso SDK, it is configured and used as a real timer clock. Previously, this RTC is maintained in counter model because the RTC driver model is added since zephyr 3.4. With RTC driver model available, we think it is more suitable to treat it as standard RTC in zephyr:
1, Keep consistency with MCUXpresso SDK.
2. Keep consistency with chip reference manual(soc design)
3. Applied in RTC driver model, it can have typical RTC features which is not provided in counter model: clockout/wakeup, calibration, normal second update. It doesn't need to workaround the counter feature like channel.

If the sRTC does not fit the counter API, nor the RTC API, a new API is needed.

Both the zephyr counter model and RTC model can work with NXP RTC. The RTC driver model fits NXP RTC most. It makes sense to support both for customer selection.

The convertion functions from/to tick and rtc time wouldbe public, and tested. They would then be used by apps directly, or implicitly through this hypothesized rtc_counter.c driver.

@Holt-Sun, the idea is that a generic RTC driver is written using the counter API as a target instead of a hardware. That way, we only need to write a simple counter driver for these device which look more like a counter. Then any counter can be used immediately with RTC API by going through this translation driver. The user just use the normal RTC API, no difference.

And also I think bjarkinis right that this code is very complex and maybe not needing to be, and we don't want to maintain it , especially not on many different drivers repeated similarly. Probably using time.h from standard library is going both way simplify and way optimize things

@Holt-Sun, the idea is that a generic RTC driver is written using the counter API as a target instead of a hardware. That way, we only need to write a simple counter driver for these device which look more like a counter. Then any counter can be used immediately with RTC API by going through this translation driver. The user just use the normal RTC API, no difference.

Ok, I will use another PR to go with this way.

@bjarki-andreasen, @decsny and all other reviewers, i have created new PR #95087 to go with the "a generic RTC driver is written using the counter API as a target instead of a hardware.". In this PR, standard library from time.h are used to convert ticks and times as requested. Please kindly review.

Holt-Sun · 2025-08-14T07:15:29Z

Please split the PR into multiple commits: driver, boards, samples, tests...

Done. Thanks.

drivers/rtc/Kconfig.nxp_rtc

Holt-Sun · 2025-08-20T08:34:21Z

There are 2 build failures which will be fixed in another 2 PRs

Upgrade RTC driver version to 2.4.0 and add clockout feature macro guards hal_nxp#589 (comment)
tests: ram_context_for_isr: exclude frdm_k32l2b3/k32l2b31a. #94706

hakehuang · 2025-08-20T08:41:21Z

samples/drivers/rtc/sample.yaml

      - stm32f3_disco
      - mimxrt700_evk/mimxrt798s/cm33_cpu0
      - mimxrt700_evk/mimxrt798s/cm33_cpu1
+      - frdm_k22f


those platforms share the same config, maybe you can use a

sample.drivers.nxp_rtc filter: dt_compat_enabled("nxp-rtc") extra_configs: - CONFIG_RTC_ALARM=y - CONFIG_RTC_UPDATE=y - CONFIG_RTC_CALIBRATION=y

and move below to common

common: tags: - samples - rtc - api depends_on: - rtc harness: console harness_config: type: one_line regex: - "RTC date and time: 2024-11-17 04:19:01"

and change the origin on with another filter

sample.drivers.rtc: filter: not dt_compat_enabled("nxp-rtc")

dts/bindings/rtc/nxp,rtc.yaml

.

Support more RTC features like clock-output, time-seconds-frequency, etc. Signed-off-by: Holt Sun <[email protected]>

Add NXP RTC driver based on RTC driver model. Signed-off-by: Holt Sun <[email protected]>

Update rtc device tree data for k2x and k8x. Signed-off-by: Holt Sun <[email protected]>

1. Add confs for nxp boards. 2. Update doc. Signed-off-by: Holt Sun <[email protected]>

Set rtc status ok and add it into board alias. Signed-off-by: Holt Sun <[email protected]>

Add rtc test confs for nxp boards. Signed-off-by: Holt Sun <[email protected]>

sonarqubecloud · 2025-08-22T09:56:18Z

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

decsny · 2025-08-28T13:26:40Z

@Holt-Sun can we close this PR?

bjarki-andreasen

My opinion is clear, but given the fact that this driver does not impose any changes on the RTC API itself, the driver is ok.

I added some comments, specifically related to using time.h and checking the struct rtc_time passed to the driver is actually provided in a state which can be converted to a timestamp, which is not necessarily the case, given most RTCs support only matching on certain fields.

bjarki-andreasen · 2025-08-28T13:11:38Z

drivers/rtc/rtc_nxp_rtc.c

+static uint32_t nxp_rtc_convert_datetime_to_seconds(const struct rtc_time *timeptr)
+{
+	/* Number of days from begin of the non Leap-year*/
+	uint16_t monthDays[] = {0U,   0U,   31U,  59U,  90U,  120U, 151U,
+				181U, 212U, 243U, 273U, 304U, 334U};
+	uint32_t seconds;
+	uint16_t year = timeptr->tm_year + 1900;
+
+	/* Compute number of days from 1970 till given year*/
+	seconds = ((uint32_t)year - YEAR_RANGE_START) * DAYS_IN_A_YEAR;
+	/* Add leap year days */
+	seconds += (((uint32_t)year / 4U) - (YEAR_RANGE_START / 4U));
+	/* Add number of days till given month*/
+	seconds += monthDays[timeptr->tm_mon + 1];
+	/*
+	 * Add days in given month. We subtract the current day as it is
+	 * represented in the hours, minutes and seconds field
+	 */
+	seconds += ((uint32_t)timeptr->tm_mday - 1U);
+	/* For leap year if month less than or equal to Febraury, decrement day counter*/
+	if ((0U == (year & 3U)) && ((timeptr->tm_mon + 1) <= 2U) && 0U != seconds) {
+		seconds--;
+	}
+
+	assert(seconds < UINT32_MAX / SECONDS_IN_A_DAY);
+	seconds = (seconds * SECONDS_IN_A_DAY) + ((uint32_t)timeptr->tm_hour * SECONDS_IN_A_HOUR) +
+		  ((uint32_t)timeptr->tm_min * SECONDS_IN_A_MINUTE) + timeptr->tm_sec;
+
+	return seconds;
+}


use time.h, the rtc API and its types are built to be compatible with it, just typecast struct rtc_time to struct tm

Applied in new PR #95087

bjarki-andreasen · 2025-08-28T13:16:50Z

drivers/rtc/rtc_nxp_rtc.c

+	if (id != 0 || (mask && (timeptr == 0)) ||
+	    (timeptr && !rtc_utils_validate_rtc_time(timeptr, mask))) {
+		return -EINVAL;
+	}


the alarm time only needs to initialize the fields set in mask, the time could have arbitrary values in every field but tm_hour, and if that's the only field specified in the mask, it will validate just fine, while the later conversion to seconds will explode. Add a check here to enforce every field needed for the conversion to a timestamp is set, then validate that.

This is usually not necessary, but for this driver it definitely is

drivers/rtc/rtc_nxp_rtc.c

bjarki-andreasen · 2025-08-28T13:21:03Z

tests/drivers/rtc/rtc_api/boards/frdm_k22f.conf

+#
+# SPDX-License-Identifier: Apache-2.0
+#
+


Since this driver needs every field of the alarm time initialized, specify this using the CONFIG_TEST_RTC_ALARM_TIME_MASK=79 adjusting the mask to match what is needed for the datetime to unix timestamp conversion.

In new PR, the CONFIG_TEST_RTC_ALARM_TIME_MASK is 255.

tests/drivers/rtc/rtc_api_helpers/boards/frdm_k22f.conf

Holt-Sun · 2025-08-28T15:21:42Z

After discussion, we will provide a generic counter RTC API using counter APIs to work which is going on in #95087 (comment)

zephyrbot added platform: NXP NXP area: Samples Samples area: RTC Real Time Clock platform: NXP Drivers NXP Semiconductors, drivers labels Aug 12, 2025

zephyrbot requested review from DerekSnell, EmilioCBen, George-Stefan, MaochenWang1, PetervdPerk-NXP, axelnxp, bjarki-andreasen, butok, dbaluta, decsny, dleach02, kartben, manuargue, mmahadevan108 and nashif August 12, 2025 14:09

zephyrbot assigned bjarki-andreasen Aug 12, 2025

Holt-Sun force-pushed the gap-rtc-enable-drivertype-srtc branch from 67c3838 to 278b300 Compare August 12, 2025 14:56

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Upgrade RTC driver version to 2.4.0 and add clockout feature macro guards zephyrproject-rtos/hal_nxp#589

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Holt-Sun added 6 commits August 22, 2025 17:35

dts: bindings: rtc: update NXP RTC device tree binding (nxp,rtc.yaml)

49f61fe

Support more RTC features like clock-output, time-seconds-frequency, etc. Signed-off-by: Holt Sun <[email protected]>

drivers: rtc: add NXP RTC driver.

88b68f6

Add NXP RTC driver based on RTC driver model. Signed-off-by: Holt Sun <[email protected]>

dts: arm: nxp: support rtc in nxp kinetis device.

bdb7267

Update rtc device tree data for k2x and k8x. Signed-off-by: Holt Sun <[email protected]>

samples: rtc: support nxp boards.

18bd6a6

1. Add confs for nxp boards. 2. Update doc. Signed-off-by: Holt Sun <[email protected]>

boards: nxp: dts: enable rtc in nxp board dts.

69e13ce

Set rtc status ok and add it into board alias. Signed-off-by: Holt Sun <[email protected]>

tests: rtc: enable rtc test for nxp boards.

78ace67

Add rtc test confs for nxp boards. Signed-off-by: Holt Sun <[email protected]>

Holt-Sun force-pushed the gap-rtc-enable-drivertype-srtc branch from 5c164d9 to 78ace67 Compare August 22, 2025 09:39

Holt-Sun mentioned this pull request Aug 28, 2025

tests: ram_context_for_isr: exclude frdm_k32l2b3/k32l2b31a. #94706

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bjarki-andreasen requested changes Aug 28, 2025

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Holt-Sun closed this Aug 28, 2025

driver: rtc: enable NXP sRTC driver. #94407

driver: rtc: enable NXP sRTC driver. #94407

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