drivers: rtc: rpi_pico: Add alarm support to RPi Pico RTC driver

This adds support for the alarm functionality of the RPi Pico RTC.

Signed-off-by: Andrew Featherstone <andrew.featherstone@gmail.com>

drivers/rtc/rtc_rpi_pico.c

@@ -11,7 +11,11 @@
 #include <zephyr/logging/log.h>
 #include <zephyr/spinlock.h>
 
+#include <hardware/irq.h>
 #include <hardware/rtc.h>
+#include <hardware/regs/rtc.h>
+
+#include "rtc_utils.h"
 
 #define DT_DRV_COMPAT raspberrypi_pico_rtc
 
@@ -22,21 +26,72 @@
 #define TM_YEAR_REF 1900
 /* See section 4.8.1 of the RP2040 datasheet. */
 #define RP2040_RTC_YEAR_MAX 4095
+#ifdef CONFIG_RTC_ALARM
+static int rtc_rpi_pico_alarm_get_time(const struct device *dev, uint16_t id, uint16_t *mask,
+				       struct rtc_time *timeptr);
+#endif
 struct rtc_rpi_pico_data {
 	struct k_spinlock lock;
+
+#ifdef CONFIG_RTC_ALARM
+	struct rtc_time alarm_time;
+	uint16_t alarm_mask;
+	rtc_alarm_callback alarm_callback;
+	void *alarm_user_data;
+	bool alarm_pending;
+#endif /* CONFIG_RTC_ALARM */
 };
 
+static struct rtc_rpi_pico_data rtc_data;
+
 LOG_MODULE_REGISTER(rtc_rpi, CONFIG_RTC_LOG_LEVEL);
 
+#ifdef CONFIG_RTC_ALARM
+static void rtc_rpi_isr(const struct device *dev)
+{
+	struct rtc_rpi_pico_data *data = dev->data;
+
+	rtc_alarm_callback callback;
+	void *user_data;
+
+	rtc_disable_alarm();
+
+	K_SPINLOCK(&data->lock) {
+		callback = data->alarm_callback;
+		user_data = data->alarm_user_data;
+	}
+
+	if (callback != NULL) {
+		callback(dev, 0, user_data);
+	} else {
+		data->alarm_pending = true;
+	}
+	/* re-enable the alarm. */
+	rtc_enable_alarm();
+}
+#endif
+
 static int rtc_rpi_pico_init(const struct device *dev)
 {
 	int ret;
+#ifdef CONFIG_RTC_ALARM
+	struct rtc_rpi_pico_data *data = dev->data;
+#endif
 
 	ret = clock_control_on(CLK_DRV, CLK_ID);
 	if (ret < 0) {
 		return ret;
 	}
 
+#ifdef CONFIG_RTC_ALARM
+	data->alarm_mask = 0;
+	data->alarm_callback = NULL;
+	data->alarm_pending = false;
+
+	IRQ_CONNECT(DT_INST_IRQN(0), DT_INST_IRQ(0, priority), rtc_rpi_isr, DEVICE_DT_INST_GET(0),
+		    0);
+	irq_enable(DT_INST_IRQN(0));
+#endif
 	rtc_init();
 	return 0;
 }
@@ -101,12 +156,168 @@ static int rtc_rpi_pico_get_time(const struct device *dev, struct rtc_time *time
 	return err;
 }
 
+#if defined(CONFIG_RTC_ALARM)
+static int rtc_rpi_pico_alarm_get_supported_fields(const struct device *dev, uint16_t id,
+						   uint16_t *supported_fields)
+{
+	ARG_UNUSED(dev);
+
+	if (id != 0) {
+		return -EINVAL;
+	}
+	*supported_fields = RTC_ALARM_TIME_MASK_SECOND | RTC_ALARM_TIME_MASK_MINUTE |
+			    RTC_ALARM_TIME_MASK_HOUR | RTC_ALARM_TIME_MASK_WEEKDAY |
+			    RTC_ALARM_TIME_MASK_MONTHDAY | RTC_ALARM_TIME_MASK_MONTH |
+			    RTC_ALARM_TIME_MASK_YEAR;
+
+	return 0;
+}
+
+static int rtc_rpi_pico_alarm_set_time(const struct device *dev, uint16_t id, uint16_t mask,
+				       const struct rtc_time *alarm)
+{
+	struct rtc_rpi_pico_data *data = dev->data;
+	int err = 0;
+	uint16_t mask_available;
+
+	(void)rtc_rpi_pico_alarm_get_supported_fields(NULL, 0, &mask_available);
+
+	if (mask & ~mask_available) {
+		return -EINVAL;
+	}
+
+	if (!rtc_utils_validate_rtc_time(alarm, mask)) {
+		return -EINVAL;
+	}
+
+	LOG_INF("Setting alarm");
+
+	rtc_disable_alarm();
+	if (mask == 0) {
+		/* Disable the alarm */
+		data->alarm_mask = 0;
+	}
+	k_spinlock_key_t key = k_spin_lock(&data->lock);
+
+	/* Clear before updating. */
+	rtc_hw->irq_setup_0 = 0;
+	rtc_hw->irq_setup_1 = 0;
+
+	/* Set the match enable bits for things we care about */
+	if (mask & RTC_ALARM_TIME_MASK_YEAR) {
+		hw_set_bits(&rtc_hw->irq_setup_0,
+			    RTC_IRQ_SETUP_0_YEAR_ENA_BITS |
+				    ((alarm->tm_year + TM_YEAR_REF) << RTC_IRQ_SETUP_0_YEAR_LSB));
+	}
+	if (mask & RTC_ALARM_TIME_MASK_MONTH) {
+		hw_set_bits(&rtc_hw->irq_setup_0,
+			    RTC_IRQ_SETUP_0_MONTH_ENA_BITS |
+				    (alarm->tm_mon << RTC_IRQ_SETUP_0_MONTH_LSB));
+	}
+	if (mask & RTC_ALARM_TIME_MASK_MONTHDAY) {
+		hw_set_bits(&rtc_hw->irq_setup_0,
+			    RTC_IRQ_SETUP_0_DAY_ENA_BITS |
+				    ((alarm->tm_mday + 1) << RTC_IRQ_SETUP_0_DAY_LSB));
+	}
+	if (mask & RTC_ALARM_TIME_MASK_WEEKDAY) {
+		hw_set_bits(&rtc_hw->irq_setup_1,
+			    RTC_IRQ_SETUP_1_DOTW_ENA_BITS |
+				    (alarm->tm_wday << RTC_IRQ_SETUP_1_DOTW_LSB));
+	}
+	if (mask & RTC_ALARM_TIME_MASK_HOUR) {
+		hw_set_bits(&rtc_hw->irq_setup_1,
+			    RTC_IRQ_SETUP_1_HOUR_ENA_BITS |
+				    (alarm->tm_hour << RTC_IRQ_SETUP_1_HOUR_LSB));
+	}
+	if (mask & RTC_ALARM_TIME_MASK_MINUTE) {
+		hw_set_bits(&rtc_hw->irq_setup_1,
+			    RTC_IRQ_SETUP_1_MIN_ENA_BITS |
+				    (alarm->tm_min << RTC_IRQ_SETUP_1_MIN_LSB));
+	}
+	if (mask & RTC_ALARM_TIME_MASK_SECOND) {
+		hw_set_bits(&rtc_hw->irq_setup_1,
+			    RTC_IRQ_SETUP_1_SEC_ENA_BITS |
+				    (alarm->tm_sec << RTC_IRQ_SETUP_1_SEC_LSB));
+	}
+	data->alarm_time = *alarm;
+	data->alarm_mask = mask;
+	k_spin_unlock(&data->lock, key);
+
+	/* Enable the IRQ at the peri */
+	rtc_hw->inte = RTC_INTE_RTC_BITS;
+
+	rtc_enable_alarm();
+
+	return err;
+}
+
+static int rtc_rpi_pico_alarm_get_time(const struct device *dev, uint16_t id, uint16_t *mask,
+				       struct rtc_time *timeptr)
+{
+	struct rtc_rpi_pico_data *data = dev->data;
+
+	if (id != 0) {
+		return -EINVAL;
+	}
+
+	K_SPINLOCK(&data->lock) {
+		*timeptr = data->alarm_time;
+		*mask = data->alarm_mask;
+	}
+
+	return 0;
+}
+
+static int rtc_rpi_pico_alarm_is_pending(const struct device *dev, uint16_t id)
+{
+	struct rtc_rpi_pico_data *data = dev->data;
+	int ret = 0;
+
+	if (id != 0) {
+		return -EINVAL;
+	}
+
+	K_SPINLOCK(&data->lock) {
+		ret = data->alarm_pending ? 1 : 0;
+		data->alarm_pending = false;
+	}
+
+	return ret;
+}
+
+static int rtc_rpi_pico_alarm_set_callback(const struct device *dev, uint16_t id,
+					   rtc_alarm_callback callback, void *user_data)
+{
+	struct rtc_rpi_pico_data *data = dev->data;
+
+	if (id != 0) {
+		return -EINVAL;
+	}
+
+	K_SPINLOCK(&data->lock) {
+		data->alarm_callback = callback;
+		data->alarm_user_data = user_data;
+		if ((callback == NULL) && (user_data == NULL)) {
+			rtc_disable_alarm();
+		}
+	}
+
+	return 0;
+}
+
+#endif /* CONFIG_RTC_ALARM */
+
 static const struct rtc_driver_api rtc_rpi_pico_driver_api = {
 	.set_time = rtc_rpi_pico_set_time,
 	.get_time = rtc_rpi_pico_get_time,
+#if defined(CONFIG_RTC_ALARM)
+	.alarm_get_supported_fields = rtc_rpi_pico_alarm_get_supported_fields,
+	.alarm_set_time = rtc_rpi_pico_alarm_set_time,
+	.alarm_get_time = rtc_rpi_pico_alarm_get_time,
+	.alarm_is_pending = rtc_rpi_pico_alarm_is_pending,
+	.alarm_set_callback = rtc_rpi_pico_alarm_set_callback,
+#endif /* CONFIG_RTC_ALARM */
 };
 
-static struct rtc_rpi_pico_data rtc_data;
-
 DEVICE_DT_INST_DEFINE(0, &rtc_rpi_pico_init, NULL, &rtc_data, NULL, POST_KERNEL,
 		      CONFIG_RTC_INIT_PRIORITY, &rtc_rpi_pico_driver_api);

dts/arm/rpi_pico/rp2040.dtsi

@@ -404,7 +404,9 @@
 			compatible = "raspberrypi,pico-rtc";
 			reg = <0x4005c000 DT_SIZE_K(4)>;
 			interrupts = <25 RPI_PICO_DEFAULT_IRQ_PRIORITY>;
+			interrupt-names = "rtc";
 			resets = <&reset RPI_PICO_RESETS_RESET_RTC>;
+			alarms-count = <1>;
 			status = "disabled";
 		};
 	};

dts/bindings/rtc/raspberrypi,pico-rtc.yaml

@@ -5,7 +5,7 @@ description: RaspberryPi Pico RTC
 
 compatible: "raspberrypi,pico-rtc"
 
-include: [rtc.yaml, reset-device.yaml]
+include: [rtc-device.yaml, reset-device.yaml]
 
 properties:
   reg:

tests/drivers/rtc/rtc_api/src/test_alarm.c

@@ -55,21 +55,25 @@ ZTEST(rtc_api, test_alarm)
 
 		zassert_ok(ret, "Failed to get supported alarm fields");
 
-		int *fields[] = {
+		alarm_time_set = (struct rtc_time) {
-			&alarm_time_set.tm_sec,  &alarm_time_set.tm_min,  &alarm_time_set.tm_hour,
+			.tm_sec = 70,
-			&alarm_time_set.tm_mday, &alarm_time_set.tm_mon,  &alarm_time_set.tm_year,
+			.tm_min = 70,
-			&alarm_time_set.tm_wday, &alarm_time_set.tm_yday, &alarm_time_set.tm_nsec};
+			.tm_hour = 25,
+			.tm_mday = 35,
+			.tm_mon = 15,
+			.tm_year = 8000,
+			.tm_wday = 8,
+			.tm_yday = 370,
+			.tm_nsec = INT32_MAX,
+		};
 		uint16_t masks[] = {RTC_ALARM_TIME_MASK_SECOND,  RTC_ALARM_TIME_MASK_MINUTE,
 				    RTC_ALARM_TIME_MASK_HOUR,    RTC_ALARM_TIME_MASK_MONTHDAY,
 				    RTC_ALARM_TIME_MASK_MONTH,   RTC_ALARM_TIME_MASK_YEAR,
 				    RTC_ALARM_TIME_MASK_WEEKDAY, RTC_ALARM_TIME_MASK_YEARDAY,
 				    RTC_ALARM_TIME_MASK_NSEC};
-		int bad_values[] = {70, 70, 25, 35, 15, 8000, 8, 370, INT32_MAX};
+		ARRAY_FOR_EACH(masks, j)
-
-		ARRAY_FOR_EACH(fields, j)
 		{
 			if (masks[j] & alarm_time_mask_supported) {
-				*fields[j] = bad_values[j];
 				ret = rtc_alarm_set_time(rtc, i, masks[j], &alarm_time_set);
 				zassert_equal(
 					-EINVAL, ret,