drivers: comparator: implement stm32 comparator driver

implement the driver for the stm32 comparator peripheral

Signed-off-by: Alexander Kozhinov <[email protected]>

Author: KozhinovAlexander

drivers/comparator/CMakeLists.txt

@@ -15,3 +15,4 @@ zephyr_library_sources_ifdef(CONFIG_COMPARATOR_NRF_COMP comparator_nrf_comp.c)
 zephyr_library_sources_ifdef(CONFIG_COMPARATOR_NRF_LPCOMP comparator_nrf_lpcomp.c)
 zephyr_library_sources_ifdef(CONFIG_COMPARATOR_SHELL comparator_shell.c)
 zephyr_library_sources_ifdef(CONFIG_COMPARATOR_RENESAS_RA comparator_renesas_ra.c)
+zephyr_library_sources_ifdef(CONFIG_COMPARATOR_STM32_COMP comparator_stm32_comp.c)

drivers/comparator/Kconfig

@@ -27,5 +27,6 @@ rsource "Kconfig.nrf_comp"
 rsource "Kconfig.nrf_lpcomp"
 rsource "Kconfig.shell"
 rsource "Kconfig.renesas_ra"
+rsource "Kconfig.stm32_comp"
 
 endif # COMPARATOR

drivers/comparator/Kconfig.stm32_comp

@@ -0,0 +1,9 @@
+# Copyright (c) 2025 Alexander Kozhinov <[email protected]>
+# SPDX-License-Identifier: Apache-2.0
+
+config COMPARATOR_STM32_COMP
+	bool "ST STM32 comparator driver"
+	default y
+	depends on DT_HAS_ST_STM32_COMP_ENABLED
+	select PINCTRL
+	select EXTI_STM32

drivers/comparator/comparator_stm32_comp.c

@@ -0,0 +1,345 @@
+/*
+ * Copyright (c) 2025 Alexander Kozhinov <[email protected]>
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/irq.h>
+#include <zephyr/kernel.h>
+#include <zephyr/pm/device.h>
+#include <zephyr/logging/log.h>
+#include <zephyr/sys/util_macro.h>
+#include <zephyr/drivers/pinctrl.h>
+#include <zephyr/drivers/comparator.h>
+#include <zephyr/drivers/clock_control.h>
+#include <zephyr/drivers/clock_control/stm32_clock_control.h>
+#include <zephyr/drivers/interrupt_controller/intc_exti_stm32.h>
+
+#include <stm32_ll_comp.h>
+#include <stm32_ll_system.h>
+
+LOG_MODULE_REGISTER(stm32_comp, CONFIG_COMPARATOR_LOG_LEVEL);
+
+#define DT_DRV_COMPAT st_stm32_comp
+
+#define LL_COMP_INPUT_PLUS_IN0		LL_COMP_INPUT_PLUS_IO1
+#define LL_COMP_INPUT_PLUS_IN1		LL_COMP_INPUT_PLUS_IO2
+
+#define LL_COMP_INPUT_MINUS_IN0		LL_COMP_INPUT_MINUS_IO1
+#define LL_COMP_INPUT_MINUS_IN1		LL_COMP_INPUT_MINUS_IO2
+
+#define STM32_COMP_DT_INST_P_IN(inst)	\
+	CONCAT(LL_COMP_INPUT_PLUS_, DT_INST_STRING_TOKEN(inst, positive_input))
+
+#define STM32_COMP_DT_INST_N_IN(inst)	\
+	CONCAT(LL_COMP_INPUT_MINUS_, DT_INST_STRING_TOKEN(inst, negative_input))
+
+#define STM32_COMP_DT_INST_HYST_MODE(inst)	\
+	CONCAT(LL_COMP_HYSTERESIS_, DT_INST_STRING_TOKEN(inst, hysteresis))
+
+#define STM32_COMP_DT_INST_INV_OUT(inst)	\
+	CONCAT(LL_COMP_OUTPUTPOL_, DT_INST_STRING_TOKEN(inst, invert_output))
+
+#define STM32_COMP_DT_INST_BLANK_SEL(inst)	\
+	CONCAT(LL_COMP_BLANKINGSRC_, DT_INST_STRING_TOKEN(inst, st_blank_sel))
+
+#define STM32_COMP_DT_INST_LOCK(inst)		DT_INST_PROP(inst, st_lock_enable)
+
+#define STM32_COMP_DT_MILLER_EFFECT_HOLD_DISABLE(inst)	\
+	DT_INST_PROP_OR(inst, st_miller_effect_hold_disable, false)
+
+#define STM32_COMP_DT_EXTI_LINE_NUMBER(inst)	DT_INST_PROP(inst, st_exti_line)
+
+/* Value 0 always relates to the default value of COMP PWRMODE bit field */
+#define STM32_COMP_DT_POWER_MODE(inst)						\
+	COND_CODE_1(DT_INST_NODE_HAS_PROP(inst, st_power_mode),			\
+		(CONCAT(LL_COMP_POWERMODE_,					\
+			DT_INST_STRING_TOKEN(inst, st_power_mode))),		\
+			(0))
+
+struct stm32_comp_config {
+	COMP_TypeDef *comp;
+	struct stm32_pclken *pclken;
+	const struct pinctrl_dev_config *pincfg;
+	void (*irq_init)(void);
+	uint32_t irq_nr;
+	uint32_t exti_line_number;
+	bool lock_enable;
+	bool miller_effect_hold_disable;
+	uint32_t power_mode;
+	uint32_t input_plus;
+	uint32_t input_minus;
+	uint32_t hysteresis;
+	uint32_t invert_output;
+	uint32_t blank_sel;
+};
+
+struct stm32_comp_data {
+	comparator_callback_t callback;
+	void *user_data;
+};
+
+static bool stm32_comp_is_resumed(const struct device *dev)
+{
+#ifdef CONFIG_PM_DEVICE
+	enum pm_device_state state;
+
+	(void)pm_device_state_get(dev, &state);
+	return state == PM_DEVICE_STATE_ACTIVE;
+#else
+	return true;
+#endif /* CONFIG_PM_DEVICE */
+}
+
+static int stm32_comp_get_output(const struct device *dev)
+{
+	const struct stm32_comp_config *cfg = dev->config;
+	COMP_TypeDef *comp = cfg->comp;
+
+	return LL_COMP_ReadOutputLevel(comp);
+}
+
+static int stm32_comp_set_trigger(const struct device *dev, enum comparator_trigger trigger)
+{
+	const struct stm32_comp_config *cfg = dev->config;
+	struct stm32_comp_data *data = dev->data;
+	stm32_exti_trigger_type exti_trigger = 0U;
+	COMP_TypeDef *comp = cfg->comp;
+	int ret = 0;
+
+	switch (trigger) {
+	case COMPARATOR_TRIGGER_NONE:
+		exti_trigger = STM32_EXTI_TRIG_NONE;
+		break;
+	case COMPARATOR_TRIGGER_RISING_EDGE:
+		exti_trigger = STM32_EXTI_TRIG_RISING;
+		break;
+	case COMPARATOR_TRIGGER_FALLING_EDGE:
+		exti_trigger = STM32_EXTI_TRIG_FALLING;
+		break;
+	case COMPARATOR_TRIGGER_BOTH_EDGES:
+		exti_trigger = STM32_EXTI_TRIG_BOTH;
+		break;
+	default:
+		LOG_ERR("%s: Unsupported trigger mode %d", dev->name, trigger);
+		return -ENOTSUP;
+	}
+
+	irq_disable(cfg->irq_nr);
+	LL_COMP_Disable(comp);
+
+	ret = stm32_exti_enable(cfg->exti_line_number, exti_trigger,
+				STM32_EXTI_MODE_IT);
+	if (ret != 0) {
+		LOG_ERR("%s: EXTI init failed (%d)", dev->name, ret);
+		return ret;
+	}
+
+	if (stm32_comp_is_resumed(dev)) {
+		LL_COMP_Enable(comp);
+	}
+
+	if (data->callback != NULL) {
+		irq_enable(cfg->irq_nr);
+	}
+
+	return ret;
+}
+
+static int stm32_comp_trigger_is_pending(const struct device *dev)
+{
+	const struct stm32_comp_config *cfg = dev->config;
+
+	if (stm32_exti_is_pending(cfg->exti_line_number)) {
+		stm32_exti_clear_pending(cfg->exti_line_number);
+		return 1;
+	}
+	return 0;
+}
+
+static int stm32_comp_set_trigger_callback(const struct device *dev, comparator_callback_t callback,
+					   void *user_data)
+{
+	const struct stm32_comp_config *cfg = dev->config;
+	struct stm32_comp_data *data = dev->data;
+
+	irq_disable(cfg->irq_nr);
+
+	data->callback = callback;
+	data->user_data = user_data;
+
+	irq_enable(cfg->irq_nr);
+
+	if (data->callback != NULL && stm32_comp_trigger_is_pending(dev)) {
+		callback(dev, user_data);
+	}
+
+	return 0;
+}
+
+static int stm32_comp_pm_callback(const struct device *dev, enum pm_device_action action)
+{
+	const struct stm32_comp_config *cfg = dev->config;
+	COMP_TypeDef *comp = cfg->comp;
+
+	if (LL_COMP_IsLocked(comp)) {
+		LOG_ERR("%s is locked", dev->name);
+		return -EACCES;
+	}
+
+	if (action == PM_DEVICE_ACTION_RESUME) {
+		LL_COMP_Enable(comp);
+		if (cfg->lock_enable) {
+			LL_COMP_Lock(comp);
+		}
+	}
+
+	if (IS_ENABLED(CONFIG_PM_DEVICE) && action == PM_DEVICE_ACTION_SUSPEND) {
+		LL_COMP_Disable(comp);
+	}
+
+	return 0;
+}
+
+static void stm32_comp_irq_handler(const struct device *dev)
+{
+	const struct stm32_comp_config *cfg = dev->config;
+	struct stm32_comp_data *data = dev->data;
+
+	if (stm32_exti_is_pending(cfg->exti_line_number)) {
+		stm32_exti_clear_pending(cfg->exti_line_number);
+	}
+
+	if (data->callback == NULL) {
+		return;
+	}
+
+	data->callback(dev, data->user_data);
+}
+
+static int stm32_comp_init(const struct device *dev)
+{
+	const struct device *const clk = DEVICE_DT_GET(STM32_CLOCK_CONTROL_NODE);
+	const struct stm32_comp_config *cfg = dev->config;
+	COMP_TypeDef *comp = cfg->comp;
+	int ret = 0;
+
+	if (!device_is_ready(clk)) {
+		LOG_ERR("%s clock control device not ready", dev->name);
+		return -ENODEV;
+	}
+
+	/* Enable COMP bus clock */
+	ret = clock_control_on(clk, &cfg->pclken[0]);
+	if (ret != 0) {
+		LOG_ERR("%s clock op failed (%d)", dev->name, ret);
+		return ret;
+	}
+
+	/* Enable COMP clock source */
+#ifndef CONFIG_SOC_SERIES_STM32G4X
+	/* stm32g4 clock configuration is not necessary,
+	 * since it is enough to turn APB2 clock on (see: RM0440 Rev 8 767/2138)
+	 */
+	ret = clock_control_configure(clk, &cfg->pclken[1], NULL);
+	if (ret != 0) {
+		LOG_ERR("%s clock configure failed (%d)", dev->name, ret);
+		return ret;
+	}
+#endif /* !CONFIG_SOC_SERIES_STM32G4X */
+
+	/* Configure COMP inputs as specified in Device Tree, if any */
+	ret = pinctrl_apply_state(cfg->pincfg, PINCTRL_STATE_DEFAULT);
+	if (ret < 0 && ret != -ENOENT) {
+		/*
+		 * If the COMP is used only with internal channels, then no pinctrl is
+		 * provided in Device Tree, and pinctrl_apply_state returns -ENOENT,
+		 * but this should not be treated as an error.
+		 */
+		LOG_ERR("%s pinctrl setup failed (%d)", dev->name, ret);
+		return ret;
+	}
+
+	if (LL_COMP_IsLocked(comp)) {
+		/* COMP instance shall not be locked */
+		LOG_ERR("%s COMP instance is locked", dev->name);
+		return -EACCES;
+	}
+
+#ifndef CONFIG_SOC_SERIES_STM32G4X
+	LL_COMP_SetPowerMode(comp, cfg->power_mode);
+#endif /* !CONFIG_SOC_SERIES_STM32G4X */
+
+	LL_COMP_SetInputMinus(comp, cfg->input_minus);
+	LL_COMP_SetInputPlus(comp, cfg->input_plus);
+	LL_COMP_SetInputHysteresis(comp, cfg->hysteresis);
+	LL_COMP_SetOutputPolarity(comp, cfg->invert_output);
+	LL_COMP_SetOutputBlankingSource(comp, cfg->blank_sel);
+
+#if defined(CONFIG_SOC_SERIES_STM32G4X)
+	/* Undocumented bit, refer to st,miller-effect-hold-disable DT binding */
+	WRITE_BIT(comp->CSR, 1, cfg->miller_effect_hold_disable);
+#endif /* CONFIG_SOC_SERIES_STM32G4X */
+
+	cfg->irq_init();
+
+	return pm_device_driver_init(dev, stm32_comp_pm_callback);
+}
+
+static DEVICE_API(comparator, stm32_comp_comp_api) = {
+	.get_output = stm32_comp_get_output,
+	.set_trigger = stm32_comp_set_trigger,
+	.set_trigger_callback = stm32_comp_set_trigger_callback,
+	.trigger_is_pending = stm32_comp_trigger_is_pending,
+};
+
+#define STM32_COMP_IRQ_HANDLER_SYM(inst)	stm32_comp_irq_init_##inst
+
+#define STM32_COMP_IRQ_HANDLER_DEFINE(inst)					\
+										\
+	static void STM32_COMP_IRQ_HANDLER_SYM(inst)(void)			\
+	{									\
+		IRQ_CONNECT(DT_INST_IRQN(inst), DT_INST_IRQ(inst, priority),	\
+			stm32_comp_irq_handler, DEVICE_DT_INST_GET(inst), 0);	\
+		irq_enable(DT_INST_IRQN(inst));					\
+	}
+
+#define STM32_COMP_DEVICE(inst)							\
+										\
+	static struct stm32_pclken comp_##inst##_clk[] = STM32_DT_INST_CLOCKS(inst);	\
+										\
+	PINCTRL_DT_INST_DEFINE(inst);						\
+										\
+	static struct stm32_comp_data stm32_comp_data_##inst;			\
+										\
+	STM32_COMP_IRQ_HANDLER_DEFINE(inst)					\
+	static const struct stm32_comp_config stm32_comp_config_##inst = {	\
+		.comp = (COMP_TypeDef *)DT_INST_REG_ADDR(inst),			\
+		.pclken = comp_##inst##_clk,					\
+		.pincfg = PINCTRL_DT_INST_DEV_CONFIG_GET(inst),			\
+		.irq_init = STM32_COMP_IRQ_HANDLER_SYM(inst),			\
+		.irq_nr = DT_INST_IRQN(inst),					\
+		.exti_line_number = STM32_COMP_DT_EXTI_LINE_NUMBER(inst),	\
+		.lock_enable = STM32_COMP_DT_INST_LOCK(inst),			\
+		.miller_effect_hold_disable =					\
+			STM32_COMP_DT_MILLER_EFFECT_HOLD_DISABLE(inst),		\
+		.power_mode = STM32_COMP_DT_POWER_MODE(inst),			\
+		.input_plus = STM32_COMP_DT_INST_P_IN(inst),			\
+		.input_minus = STM32_COMP_DT_INST_N_IN(inst),			\
+		.hysteresis = STM32_COMP_DT_INST_HYST_MODE(inst),		\
+		.invert_output = STM32_COMP_DT_INST_INV_OUT(inst),		\
+		.blank_sel = STM32_COMP_DT_INST_BLANK_SEL(inst)			\
+	};									\
+										\
+	PM_DEVICE_DT_INST_DEFINE(inst, stm32_comp_pm_callback);			\
+										\
+	DEVICE_DT_INST_DEFINE(inst,						\
+			stm32_comp_init,					\
+			PM_DEVICE_DT_INST_GET(inst),				\
+			&stm32_comp_data_##inst,				\
+			&stm32_comp_config_##inst,				\
+			POST_KERNEL,						\
+			CONFIG_COMPARATOR_INIT_PRIORITY,			\
+			&stm32_comp_comp_api					\
+		);
+
+DT_INST_FOREACH_STATUS_OKAY(STM32_COMP_DEVICE)