driver: sensor: add tachometer driver for rts5912

Add tachometer driver for Realtek rts5912.

Signed-off-by: Jhan BoChao <jhan_bo_chao@realtek.com>

boards/realtek/rts5912_evb/rts5912_evb.dts

@@ -53,3 +53,10 @@
 &swj_port {
 	status = "okay";
 };
+
+&tach0 {
+	status = "okay";
+	pinctrl-0 = <&tacho0_gpio052>;
+	pinctrl-names = "default";
+	pulses-per-round = <2>;
+};

drivers/sensor/CMakeLists.txt

@@ -22,6 +22,7 @@ add_subdirectory(nordic)
 add_subdirectory(nuvoton)
 add_subdirectory(nxp)
 add_subdirectory(pixart)
+add_subdirectory(realtek)
 add_subdirectory(renesas)
 add_subdirectory(rohm)
 add_subdirectory(seeed)

drivers/sensor/Kconfig

@@ -108,6 +108,7 @@ source "drivers/sensor/nordic/Kconfig"
 source "drivers/sensor/nuvoton/Kconfig"
 source "drivers/sensor/nxp/Kconfig"
 source "drivers/sensor/pixart/Kconfig"
+source "drivers/sensor/realtek/Kconfig"
 source "drivers/sensor/renesas/Kconfig"
 source "drivers/sensor/rohm/Kconfig"
 source "drivers/sensor/seeed/Kconfig"

drivers/sensor/realtek/CMakeLists.txt

@@ -0,0 +1,4 @@
+# Copyright (c) 2025, Realtek, SIBG-SD7
+# SPDX-License-Identifier: Apache-2.0
+
+add_subdirectory_ifdef(CONFIG_TACH_RTS5912 rts5912)

drivers/sensor/realtek/Kconfig

@@ -0,0 +1,4 @@
+# Copyright (c) 2025, Realtek, SIBG-SD7
+# SPDX-License-Identifier: Apache-2.0
+
+source "drivers/sensor/realtek/rts5912/Kconfig"

drivers/sensor/realtek/rts5912/CMakeLists.txt

@@ -0,0 +1,6 @@
+# Copyright (c) 2025, Realtek, SIBG-SD7
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_library()
+
+zephyr_library_sources(rts5912.c)

drivers/sensor/realtek/rts5912/Kconfig

@@ -0,0 +1,9 @@
+# Copyright (c) 2025, Realtek, SIBG-SD7
+# SPDX-License-Identifier: Apache-2.0
+
+config TACH_RTS5912
+	bool "RTS5912 Tachometer sensor"
+	default y
+	depends on DT_HAS_REALTEK_RTS5912_TACH_ENABLED
+	help
+	  Enable the Realtek RTS5912 tachometer sensor.

drivers/sensor/realtek/rts5912/rts5912.c

@@ -0,0 +1,150 @@
+/*
+ * Copyright (c) 2025 Realtek, SIBG-SD7
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT realtek_rts5912_tach
+
+#include <errno.h>
+#include <zephyr/device.h>
+#include <zephyr/drivers/clock_control.h>
+#include <zephyr/drivers/clock_control/clock_control_rts5912.h>
+#include <zephyr/drivers/pinctrl.h>
+#include <zephyr/drivers/sensor.h>
+#include <zephyr/sys/sys_io.h>
+#include <zephyr/logging/log.h>
+
+#include "reg/reg_tacho.h"
+
+LOG_MODULE_REGISTER(tach_rts5912, CONFIG_SENSOR_LOG_LEVEL);
+
+struct tach_rts5912_config {
+	volatile struct tacho_regs *regs;
+	uint32_t clk_grp;
+	uint32_t clk_idx;
+	uint32_t clk_src;
+	uint32_t clk_div;
+	const struct device *clk_dev;
+	const struct pinctrl_dev_config *pcfg;
+	int pulses_per_round;
+};
+
+struct tach_rts5912_data {
+	uint16_t count;
+};
+
+#define COUNT_100KHZ_SEC  100000U
+#define SEC_TO_MINUTE     60U
+#define PIN_STUCK_TIMEOUT (100U * USEC_PER_MSEC)
+
+int tach_rts5912_sample_fetch(const struct device *dev, enum sensor_channel chan)
+{
+	const struct tach_rts5912_config *const cfg = dev->config;
+	struct tach_rts5912_data *const data = dev->data;
+	volatile struct tacho_regs *const tach = cfg->regs;
+
+	if (chan != SENSOR_CHAN_RPM && chan != SENSOR_CHAN_ALL) {
+		return -ENOTSUP;
+	}
+
+	tach->status = TACHO_STS_CNTRDY;
+
+	if (WAIT_FOR(tach->status & TACHO_STS_CNTRDY, PIN_STUCK_TIMEOUT, k_msleep(1))) {
+		/* See whether internal counter is already latched */
+		if (tach->status & TACHO_STS_CNTRDY) {
+			tach->status = TACHO_STS_CNTRDY;
+			data->count = (tach->ctrl & TACHO_CTRL_CNT_Msk) >> TACHO_CTRL_CNT_Pos;
+		}
+	} else {
+		data->count = 0;
+	}
+
+	return 0;
+}
+
+static int tach_rts5912_channel_get(const struct device *dev, enum sensor_channel chan,
+				    struct sensor_value *val)
+{
+	const struct tach_rts5912_config *const cfg = dev->config;
+	struct tach_rts5912_data *const data = dev->data;
+
+	if (chan != SENSOR_CHAN_RPM) {
+		return -ENOTSUP;
+	}
+
+	/* Convert the count per 100khz cycles to rpm */
+	if (data->count != 0U) {
+		val->val1 =
+			(SEC_TO_MINUTE * COUNT_100KHZ_SEC) / (cfg->pulses_per_round * data->count);
+	} else {
+		val->val1 = 0U;
+	}
+
+	val->val2 = 0U;
+
+	return 0;
+}
+
+static int tach_rts5912_init(const struct device *dev)
+{
+	const struct tach_rts5912_config *const cfg = dev->config;
+	volatile struct tacho_regs *const tach = cfg->regs;
+	int ret;
+
+	struct rts5912_sccon_subsys sccon_subsys = {
+		.clk_grp = cfg->clk_grp,
+		.clk_idx = cfg->clk_idx,
+	};
+
+	if (!device_is_ready(cfg->clk_dev)) {
+		return -ENODEV;
+	}
+
+	ret = clock_control_on(cfg->clk_dev, (clock_control_subsys_t)&sccon_subsys);
+	if (ret != 0) {
+		LOG_ERR("RTS5912 Tachometer clock control failed (%d)", ret);
+		return ret;
+	}
+
+#ifdef CONFIG_PINCTRL
+	ret = pinctrl_apply_state(cfg->pcfg, PINCTRL_STATE_DEFAULT);
+
+	if (ret != 0) {
+		LOG_ERR("RTS5912 pinctrl failed (%d)", ret);
+		return ret;
+	}
+#endif
+
+	/* write one clear the status */
+	tach->status = TACHO_STS_LIMIT | TACHO_STS_CHG | TACHO_STS_CNTRDY;
+	tach->ctrl &= ~TACHO_CTRL_SELEDGE_Msk;
+	tach->ctrl = ((0x01ul << TACHO_CTRL_SELEDGE_Pos) | TACHO_CTRL_READMODE | TACHO_CTRL_EN);
+
+	return 0;
+}
+
+static DEVICE_API(sensor, tach_rts5912_driver_api) = {
+	.sample_fetch = tach_rts5912_sample_fetch,
+	.channel_get = tach_rts5912_channel_get,
+};
+
+#define REALTEK_TACH_INIT(inst)                                                                    \
+	PINCTRL_DT_INST_DEFINE(inst);                                                              \
+                                                                                                   \
+	static const struct tach_rts5912_config tach_cfg_##inst = {                                \
+		.regs = (struct tacho_regs *const)DT_INST_REG_ADDR(inst),                          \
+		.pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(inst),                                      \
+		.clk_dev = DEVICE_DT_GET(DT_INST_CLOCKS_CTLR(inst)),                               \
+		.clk_grp = DT_INST_CLOCKS_CELL_BY_NAME(inst, tacho, clk_grp),                      \
+		.clk_idx = DT_INST_CLOCKS_CELL_BY_NAME(inst, tacho, clk_idx),                      \
+		.pulses_per_round = DT_INST_PROP(inst, pulses_per_round),                          \
+	};                                                                                         \
+                                                                                                   \
+	static struct tach_rts5912_data tach_data_##inst;                                          \
+                                                                                                   \
+	SENSOR_DEVICE_DT_INST_DEFINE(inst, tach_rts5912_init, NULL, &tach_data_##inst,             \
+				     &tach_cfg_##inst, POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY,   \
+				     &tach_rts5912_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(REALTEK_TACH_INIT)

dts/arm/realtek/ec/rts5912.dtsi

@@ -267,6 +267,15 @@
 			interrupt-parent = <&nvic>;
 			status = "disabled";
 		};
+
+		tach0: tach@4000fd00 {
+			compatible = "realtek,rts5912-tach";
+			reg = <0x4000fd00 0x40>;
+			clocks = <&sccon RTS5912_SCCON_PERIPH_GRP0 PERIPH_GRP0_TACH0_CLKPWR>;
+			clock-names = "tacho";
+			interrupts = <192 0>;
+			status = "disabled";
+		};
 	};
 
 	swj_port: swj-port {

dts/bindings/tach/realtek,rts5912-tach.yaml

@@ -0,0 +1,28 @@
+# SPDX-License-Identifier: Apache-2.0
+#
+# Copyright (c) 2025 Realtek Semiconductor Corporation, SIBG-SD7
+#
+
+description: Realtek rts5912 tachometer controller
+
+compatible: "realtek,rts5912-tach"
+
+include: [tach.yaml, pinctrl-device.yaml, sensor-device.yaml]
+
+properties:
+  reg:
+    required: true
+
+  interrupts:
+    required: true
+
+  pinctrl-0:
+    required: true
+
+  pinctrl-names:
+    required: true
+
+  pulses-per-round:
+    type: int
+    required: true
+    description: number of pulses per round of tachometer's input

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

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2025 Realtek, SIBG-SD7
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_SOC_REALTEK_RTS5912_REG_TACHO_H
+#define ZEPHYR_SOC_REALTEK_RTS5912_REG_TACHO_H
+
+struct tacho_regs {
+	uint32_t ctrl;
+	uint32_t status;
+	uint32_t limit_high;
+	uint32_t limit_low;
+	uint32_t int_en;
+};
+
+/* CTRL */
+#define TACHO_CTRL_EN          BIT(0UL)
+#define TACHO_CTRL_FILTEREN    BIT(1UL)
+#define TACHO_CTRL_SELEDGE_Pos (2UL)
+#define TACHO_CTRL_SELEDGE_Msk GENMASK(3, TACHO_CTRL_SELEDGE_Pos)
+#define TACHO_CTRL_READMODE    BIT(4UL)
+#define TACHO_CTRL_CNT_Pos     (16UL)
+#define TACHO_CTRL_CNT_Msk     GENMASK(31, TACHO_CTRL_CNT_Pos)
+/* STS */
+#define TACHO_STS_LIMIT        BIT(0UL)
+#define TACHO_STS_PIN          BIT(1UL)
+#define TACHO_STS_CHG          BIT(2UL)
+#define TACHO_STS_CNTRDY       BIT(3UL)
+/* LIMITH */
+#define TACHO_LIMITH_VAL_Pos   (0UL)
+#define TACHO_LIMITH_VAL_Msk   GENMASK(15, TACHO_LIMITH_VAL_Pos)
+/* LIMITL */
+#define TACHO_LIMITL_VAL_Pos   (0UL)
+#define TACHO_LIMITL_VAL_Msk   GENMASK(15, TACHO_LIMITL_VAL_Pos)
+/* INTEN */
+#define TACHO_INTEN_LIMITEN    BIT(0UL)
+#define TACHO_INTEN_CNTRDYEN   BIT(1UL)
+#define TACHO_INTEN_CHGEN      BIT(2UL)
+
+#endif /* ZEPHYR_SOC_REALTEK_RTS5912_REG_TACHO_H */