drivers: counter: rts5912: add support slow timer counter driver

Port rts5912 slow timer counter driver on Zephyr

Signed-off-by: Titan Chen <titan.chen@realtek.com>

drivers/counter/CMakeLists.txt

@@ -54,3 +54,4 @@ zephyr_library_sources_ifdef(CONFIG_COUNTER_RTC_MAX32           counter_max32_rt
 zephyr_library_sources_ifdef(CONFIG_COUNTER_NXP_MRT             counter_nxp_mrt.c)
 zephyr_library_sources_ifdef(CONFIG_COUNTER_RA_AGT              counter_renesas_ra_agt.c)
 zephyr_library_sources_ifdef(CONFIG_COUNTER_RENESAS_RZ_GTM      counter_renesas_rz_gtm.c)
+zephyr_library_sources_ifdef(CONFIG_COUNTER_REALTEK_RTS5912_SLWTMR     counter_realtek_rts5912_slwtmr.c)

drivers/counter/Kconfig

@@ -106,4 +106,6 @@ source "drivers/counter/Kconfig.renesas_ra"
 
 source "drivers/counter/Kconfig.renesas_rz"
 
+source "drivers/counter/Kconfig.rts5912_slwtmr"
+
 endif # COUNTER

drivers/counter/Kconfig.rts5912_slwtmr

@@ -0,0 +1,12 @@
+# Realtek counter configuration options
+
+# Copyright (c) 2025 Realtek Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+config COUNTER_REALTEK_RTS5912_SLWTMR
+	bool "Realtek rts5912 series slow timer counter driver"
+	default y
+	depends on DT_HAS_REALTEK_RTS5912_SLWTIMER_ENABLED
+	help
+	  Enable counter driver for Realtek RTS5912 MCU series. Such driver
+	  will expose the slow timer devices present on the MCU.

drivers/counter/counter_realtek_rts5912_slwtmr.c

@@ -0,0 +1,339 @@
+/*
+ * Copyright (c) 2025 Realtek Corporation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT realtek_rts5912_slwtimer
+
+/**
+ * @file
+ * @brief Realtek RTS5912 Counter driver
+ *
+ * This is the driver for the 32-bit counters on the Realtek SoCs.
+ *
+ * Notes:
+ * - The counters are running in down counting mode.
+ * - Interrupts are triggered (if enabled) when the counter
+ *   reaches zero.
+ * - These are not free running counters where there are separate
+ *   compare values for interrupts. When setting single shot alarms,
+ *   the counter values are changed so that interrupts are triggered
+ *   when the counters reach zero.
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/drivers/counter.h>
+#include <zephyr/drivers/clock_control.h>
+#include <zephyr/drivers/clock_control/clock_control_rts5912.h>
+#include <zephyr/logging/log.h>
+#include "reg/reg_slwtmr.h"
+LOG_MODULE_REGISTER(counter_realtek_rts5912_slwtmr, CONFIG_COUNTER_LOG_LEVEL);
+
+struct counter_rts5912_config {
+	struct counter_config_info info;
+	void (*config_func)(void);
+	volatile struct slwtmr_type *base_address;
+	uint16_t prescaler;
+#if (CONFIG_CLOCK_CONTROL)
+	const struct device *clk_dev;
+	struct rts5912_sccon_subsys sccon_cfg;
+#endif
+};
+
+struct counter_rts5912_data {
+	counter_alarm_callback_t alarm_cb;
+	counter_top_callback_t top_cb;
+	void *user_data;
+};
+
+static int counter_rts5912_start(const struct device *dev)
+{
+	const struct counter_rts5912_config *config = dev->config;
+	volatile struct slwtmr_type *counter = config->base_address;
+
+	if (counter->ctrl & SLWTMR_CTRL_EN) {
+		return -EALREADY;
+	}
+
+	counter->ctrl |= SLWTMR_CTRL_EN;
+
+	LOG_DBG("%p Counter started", dev);
+
+	return 0;
+}
+
+static int counter_rts5912_stop(const struct device *dev)
+{
+	const struct counter_rts5912_config *config = dev->config;
+	volatile struct slwtmr_type *counter = config->base_address;
+
+	if (!(counter->ctrl & SLWTMR_CTRL_EN)) {
+		/* Already stopped, nothing to do */
+		return 0;
+	}
+
+	/* disable timer and disable interrupt. */
+	counter->ctrl = 0;
+	counter->ldcnt = counter->cnt;
+
+	/* w1c interrupt pending status */
+	counter->insts |= SLWTMR_INTSTS_STS;
+
+	LOG_DBG("%p Counter stopped", dev);
+
+	return 0;
+}
+
+static int counter_rts5912_get_value(const struct device *dev, uint32_t *ticks)
+{
+	const struct counter_rts5912_config *config = dev->config;
+	volatile struct slwtmr_type *counter = config->base_address;
+
+	*ticks = counter->cnt;
+	return 0;
+}
+
+static int counter_rts5912_set_alarm(const struct device *dev, uint8_t chan_id,
+				     const struct counter_alarm_cfg *alarm_cfg)
+{
+	const struct counter_rts5912_config *config = dev->config;
+	volatile struct slwtmr_type *counter = config->base_address;
+	struct counter_rts5912_data *data = dev->data;
+
+	if (chan_id != 0) {
+		LOG_ERR("Invalid channel id %u", chan_id);
+		return -ENOTSUP;
+	}
+
+	/* Interrupts are only triggered when the counter reaches 0.
+	 * So only relative alarms are supported.
+	 */
+	if (alarm_cfg->flags & COUNTER_ALARM_CFG_ABSOLUTE) {
+		return -ENOTSUP;
+	}
+
+	if (data->alarm_cb != NULL) {
+		return -EBUSY;
+	}
+
+	if (!alarm_cfg->callback) {
+		return -EINVAL;
+	}
+
+	if (alarm_cfg->ticks > config->info.max_top_value) {
+		return -EINVAL;
+	}
+	/* disable timer and disable interrupt */
+	counter->ctrl = 0;
+
+	counter->ldcnt = alarm_cfg->ticks;
+
+	data->alarm_cb = alarm_cfg->callback;
+	data->user_data = alarm_cfg->user_data;
+	/* w1c interrupt status */
+	counter->insts |= SLWTMR_INTSTS_STS;
+	/* enable interrupt */
+	counter->ctrl |= SLWTMR_CTRL_INTEN_EN;
+
+	LOG_DBG("%p Counter alarm set to %u ticks", dev, alarm_cfg->ticks);
+	/* enable timer and re-load PRcnt to cnt */
+	counter->ctrl |= SLWTMR_CTRL_EN;
+
+	return 0;
+}
+
+static int counter_rts5912_cancel_alarm(const struct device *dev, uint8_t chan_id)
+{
+	const struct counter_rts5912_config *config = dev->config;
+	volatile struct slwtmr_type *counter = config->base_address;
+	struct counter_rts5912_data *data = dev->data;
+
+	if (chan_id != 0) {
+		LOG_ERR("Invalid channel id %u", chan_id);
+		return -ENOTSUP;
+	}
+
+	counter->ctrl = 0;
+
+	data->alarm_cb = NULL;
+	data->user_data = NULL;
+
+	LOG_DBG("%p Counter alarm canceled", dev);
+
+	return 0;
+}
+
+static uint32_t counter_rts5912_get_pending_int(const struct device *dev)
+{
+	const struct counter_rts5912_config *config = dev->config;
+	volatile struct slwtmr_type *counter = config->base_address;
+
+	return counter->insts;
+}
+
+static uint32_t counter_rts5912_get_top_value(const struct device *dev)
+{
+	const struct counter_rts5912_config *config = dev->config;
+	volatile struct slwtmr_type *counter = config->base_address;
+
+	return counter->ldcnt;
+}
+
+static int counter_rts5912_set_top_value(const struct device *dev,
+					 const struct counter_top_cfg *cfg)
+{
+	const struct counter_rts5912_config *config = dev->config;
+	volatile struct slwtmr_type *counter = config->base_address;
+	struct counter_rts5912_data *data = dev->data;
+	int ret = 0;
+
+	if (data->alarm_cb) {
+		return -EBUSY;
+	}
+
+	if (cfg->ticks > config->info.max_top_value) {
+		return -EINVAL;
+	}
+
+	counter->ctrl = 0;
+
+	counter->ldcnt = cfg->ticks;
+
+	data->top_cb = cfg->callback;
+	data->user_data = cfg->user_data;
+
+	if (data->top_cb) {
+		/* w1c interrupt status */
+		counter->insts |= SLWTMR_INTSTS_STS;
+		/* enable interrupt */
+		counter->ctrl |= SLWTMR_CTRL_INTEN_EN;
+		/* enable periodic alarm mode */
+		counter->ctrl |= SLWTMR_CTRL_MDSELS_PERIOD;
+	} else {
+		/* disable interrupt */
+		counter->ctrl &= ~SLWTMR_CTRL_INTEN_EN;
+	}
+
+	LOG_DBG("%p Counter top value was set to %u", dev, cfg->ticks);
+
+	counter->ctrl |= SLWTMR_CTRL_EN;
+	return ret;
+}
+
+static void counter_rts5912_isr(const struct device *dev)
+{
+	const struct counter_rts5912_config *config = dev->config;
+	volatile struct slwtmr_type *counter = config->base_address;
+	struct counter_rts5912_data *data = dev->data;
+	counter_alarm_callback_t alarm_cb;
+	void *user_data;
+	/* disable timer */
+	counter->ctrl &= ~SLWTMR_CTRL_EN;
+	/* disable interrupt */
+	counter->ctrl &= ~SLWTMR_CTRL_INTEN_EN;
+	/* clear interrupt pending status */
+	counter->insts |= SLWTMR_INTSTS_STS;
+
+	LOG_DBG("%p Counter ISR", dev);
+
+	if (data->alarm_cb) {
+		/* Alarm is one-shot, so disable callback */
+		alarm_cb = data->alarm_cb;
+		data->alarm_cb = NULL;
+		user_data = data->user_data;
+
+		alarm_cb(dev, 0, counter->cnt, user_data);
+	} else if (data->top_cb) {
+		data->top_cb(dev, data->user_data);
+		/* periodic alarm mode, enable interrupt */
+		counter->ctrl |= SLWTMR_CTRL_INTEN_EN;
+		/* enable timer again */
+		counter->ctrl |= SLWTMR_CTRL_EN;
+	}
+}
+
+static uint32_t counter_rts5912_get_freq(const struct device *dev)
+{
+	const struct counter_rts5912_config *config = dev->config;
+
+	return config->info.freq;
+}
+
+static DEVICE_API(counter, counter_rts5912_api) = {
+	.start = counter_rts5912_start,
+	.stop = counter_rts5912_stop,
+	.get_value = counter_rts5912_get_value,
+	.set_alarm = counter_rts5912_set_alarm,
+	.cancel_alarm = counter_rts5912_cancel_alarm,
+	.set_top_value = counter_rts5912_set_top_value,
+	.get_pending_int = counter_rts5912_get_pending_int,
+	.get_top_value = counter_rts5912_get_top_value,
+	.get_freq = counter_rts5912_get_freq,
+};
+
+static int counter_rts5912_init(const struct device *dev)
+{
+	const struct counter_rts5912_config *config = dev->config;
+	volatile struct slwtmr_type *counter = config->base_address;
+	int ret;
+
+#if defined(CONFIG_CLOCK_CONTROL)
+	if (!device_is_ready(config->clk_dev)) {
+		return -ENODEV;
+	}
+	ret = clock_control_on(config->clk_dev, (clock_control_subsys_t)&config->sccon_cfg);
+	if (ret != 0) {
+		return ret;
+	}
+#endif
+
+	counter_rts5912_stop(dev);
+	/* Set preload and actually pre-load the counter */
+	counter->ldcnt = config->info.max_top_value;
+	counter->cnt = config->info.max_top_value;
+
+	config->config_func();
+	LOG_DBG("Init Complete");
+	return 0;
+}
+
+#define DEV_CONFIG_CLK_DEV_INIT(n)                                                                 \
+	.clk_dev = DEVICE_DT_GET(DT_INST_CLOCKS_CTLR(n)),                                          \
+	.sccon_cfg = {                                                                             \
+		.clk_grp = DT_INST_CLOCKS_CELL_BY_NAME(n, slwtmr, clk_grp),                        \
+		.clk_idx = DT_INST_CLOCKS_CELL_BY_NAME(n, slwtmr, clk_idx),                        \
+	}
+
+#define COUNTER_RTS5912_INIT(inst)                                                                 \
+	static void counter_rts5912_irq_config_##inst(void);                                       \
+                                                                                                   \
+	static struct counter_rts5912_data counter_rts5912_dev_data_##inst;                        \
+                                                                                                   \
+	static struct counter_rts5912_config counter_rts5912_dev_config_##inst = {                 \
+		.info =                                                                            \
+			{                                                                          \
+				.max_top_value = DT_INST_PROP(inst, max_value),                    \
+				.freq = DT_INST_PROP(inst, clock_frequency) /                      \
+					(1 << DT_INST_PROP(inst, prescaler)),                      \
+				.flags = 0,                                                        \
+				.channels = 1,                                                     \
+			},                                                                         \
+                                                                                                   \
+		.config_func = counter_rts5912_irq_config_##inst,                                  \
+		.base_address = (struct slwtmr_type *)DT_INST_REG_ADDR(inst),                      \
+		.prescaler = DT_INST_PROP(inst, prescaler),                                        \
+		DEV_CONFIG_CLK_DEV_INIT(inst)};                                                    \
+                                                                                                   \
+	DEVICE_DT_INST_DEFINE(inst, counter_rts5912_init, NULL, &counter_rts5912_dev_data_##inst,  \
+			      &counter_rts5912_dev_config_##inst, POST_KERNEL,                     \
+			      CONFIG_COUNTER_INIT_PRIORITY, &counter_rts5912_api);                 \
+                                                                                                   \
+	static void counter_rts5912_irq_config_##inst(void)                                        \
+	{                                                                                          \
+		IRQ_CONNECT(DT_INST_IRQN(inst), DT_INST_IRQ(inst, priority), counter_rts5912_isr,  \
+			    DEVICE_DT_INST_GET(inst), 0);                                          \
+		irq_enable(DT_INST_IRQN(inst));                                                    \
+	}
+
+DT_INST_FOREACH_STATUS_OKAY(COUNTER_RTS5912_INIT)

dts/bindings/counter/realtek,rts5912-slwtimer.yaml

@@ -7,7 +7,7 @@ description: Realtek RTS5912 32-bit slow timer
 
 compatible: "realtek,rts5912-slwtimer"
 
-include: rtc.yaml
+include: base.yaml
 
 properties:
   reg:
@@ -22,7 +22,9 @@ properties:
     description: Maximum counter value the instance can handle
 
   clock-frequency:
+    type: int
     required: true
+    description: Clock frequency information for timer operation
 
   prescaler:
     type: int

soc/realtek/ec/rts5912/reg/reg_slwtmr.h

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2025 Realtek, SIBG-SD7
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_SOC_REALTEK_RTS5912_REG_SLWTMR_H
+#define ZEPHYR_SOC_REALTEK_RTS5912_REG_SLWTMR_H
+
+/**
+ * @brief SLOW Timer Controller (SLWTMR)
+ */
+
+struct slwtmr_type {
+	uint32_t ldcnt;
+	uint32_t cnt;
+	uint32_t ctrl;
+	uint32_t insts;
+};
+
+/* CTRL */
+#define SLWTMR_CTRL_EN BIT(0)
+
+#define SLWTMR_CTRL_MDSELS_ONESHOT 0
+#define SLWTMR_CTRL_MDSELS_PERIOD  BIT(1)
+
+#define SLWTMR_CTRL_INTEN_EN BIT(2)
+/* INTSTS */
+#define SLWTMR_INTSTS_STS    BIT(0)
+
+#endif /* ZEPHYR_SOC_REALTEK_RTS5912_REG_SLWTMR_H */