drivers: sensor: add sensors for MAX31790

Add sensors for fan speed and fan fault for the PWM
controller MAX31790.

Signed-off-by: Benedikt Schmidt <benedikt.schmidt@embedded-solutions.at>

drivers/sensor/CMakeLists.txt

@@ -96,6 +96,7 @@ add_subdirectory_ifdef(CONFIG_LTR_F216A ltrf216a)
 add_subdirectory_ifdef(CONFIG_MAX17055 max17055)
 add_subdirectory_ifdef(CONFIG_MAX17262 max17262)
 add_subdirectory_ifdef(CONFIG_MAX30101 max30101)
+add_subdirectory_ifdef(CONFIG_MAX31790_SENSOR max31790)
 add_subdirectory_ifdef(CONFIG_MAX31855 max31855)
 add_subdirectory_ifdef(CONFIG_MAX31865 max31865)
 add_subdirectory_ifdef(CONFIG_MAX31875 max31875)

drivers/sensor/Kconfig

@@ -176,6 +176,7 @@ source "drivers/sensor/ltrf216a/Kconfig"
 source "drivers/sensor/max17055/Kconfig"
 source "drivers/sensor/max17262/Kconfig"
 source "drivers/sensor/max30101/Kconfig"
+source "drivers/sensor/max31790/Kconfig"
 source "drivers/sensor/max31855/Kconfig"
 source "drivers/sensor/max31865/Kconfig"
 source "drivers/sensor/max31875/Kconfig"

drivers/sensor/max31790/CMakeLists.txt

@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_library()
+
+zephyr_library_sources_ifdef(CONFIG_MAX31790_FAN_SPEED max31790_fan_speed.c)
+zephyr_library_sources_ifdef(CONFIG_MAX31790_FAN_FAULT max31790_fan_fault.c)

drivers/sensor/max31790/Kconfig

@@ -0,0 +1,25 @@
+# Copyright (c) 2024 SILA Embedded Solutions GmbH
+# SPDX-License-Identifier: Apache-2.0
+
+config MAX31790_SENSOR
+	bool "MAX31790 sensors"
+	default y
+	depends on MAX31790_FAN_SPEED || MAX31790_FAN_FAULT
+	help
+	  Enable sensors for the MAX31790 PWM controller.
+
+config MAX31790_FAN_SPEED
+	bool "MAX31790 fan speed sensor"
+	default y
+	depends on DT_HAS_MAXIM_MAX31790_FAN_SPEED_ENABLED
+	select MFD
+	help
+	  Enable driver for the MAX31790 fan speed sensor.
+
+config MAX31790_FAN_FAULT
+	bool "MAX31790 fan fault sensor"
+	default y
+	depends on DT_HAS_MAXIM_MAX31790_FAN_FAULT_ENABLED
+	select MFD
+	help
+	  Enable driver for the MAX31790 fan fault sensor.

drivers/sensor/max31790/max31790_fan_fault.c

@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2024 SILA Embedded Solutions GmbH
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT maxim_max31790_fan_fault
+
+#include <zephyr/drivers/mfd/max31790.h>
+#include <zephyr/drivers/sensor.h>
+#include <zephyr/drivers/sensor/max31790.h>
+#include <zephyr/logging/log.h>
+
+#include "max31790_fan_fault.h"
+
+LOG_MODULE_REGISTER(MAX31790_FAN_FAULT, CONFIG_SENSOR_LOG_LEVEL);
+
+static int max31790_fan_fault_sample_fetch(const struct device *dev, enum sensor_channel chan)
+{
+	const struct max31790_fan_fault_config *config = dev->config;
+	struct max31790_fan_fault_data *data = dev->data;
+	int result;
+	uint8_t value;
+
+	__ASSERT_NO_MSG(chan == SENSOR_CHAN_ALL);
+
+	result = i2c_reg_read_byte_dt(&config->i2c, MAX37190_REGISTER_FANFAULTSTATUS1, &value);
+	if (result != 0) {
+		return result;
+	}
+
+	data->value = value & 0x3F;
+
+	return 0;
+}
+
+static int max31790_fan_fault_channel_get(const struct device *dev, enum sensor_channel chan,
+					  struct sensor_value *val)
+{
+	struct max31790_fan_fault_data *data = dev->data;
+
+	if ((enum sensor_channel_max31790)chan != SENSOR_CHAN_MAX31790_FAN_FAULT) {
+		LOG_ERR("%s: requesting unsupported channel %i", dev->name, chan);
+		return -ENOTSUP;
+	}
+
+	val->val1 = data->value;
+	val->val2 = 0;
+	return 0;
+}
+
+static const struct sensor_driver_api max31790_fan_fault_api = {
+	.sample_fetch = max31790_fan_fault_sample_fetch,
+	.channel_get = max31790_fan_fault_channel_get,
+};
+
+static int max31790_fan_fault_init(const struct device *dev)
+{
+	const struct max31790_fan_fault_config *config = dev->config;
+
+	if (!i2c_is_ready_dt(&config->i2c)) {
+		LOG_ERR("I2C device not ready");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+#define MAX31790_FAN_FAULT_INIT(inst)                                                              \
+	static const struct max31790_fan_fault_config max31790_fan_fault_##inst##_config = {       \
+		.i2c = I2C_DT_SPEC_GET(DT_INST_PARENT(inst)),                                      \
+	};                                                                                         \
+                                                                                                   \
+	static struct max31790_fan_fault_data max31790_fan_fault_##inst##_data;                    \
+                                                                                                   \
+	SENSOR_DEVICE_DT_INST_DEFINE(inst, max31790_fan_fault_init, NULL,                          \
+			      &max31790_fan_fault_##inst##_data,                                   \
+			      &max31790_fan_fault_##inst##_config, POST_KERNEL,                    \
+			      CONFIG_SENSOR_INIT_PRIORITY, &max31790_fan_fault_api);
+
+DT_INST_FOREACH_STATUS_OKAY(MAX31790_FAN_FAULT_INIT);

drivers/sensor/max31790/max31790_fan_fault.h

@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2024 SILA Embedded Solutions GmbH
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_DRIVERS_SENSOR_MAX31790_MAX31790_FAN_FAULT_H_
+#define ZEPHYR_DRIVERS_SENSOR_MAX31790_MAX31790_FAN_FAULT_H_
+
+#include <zephyr/drivers/i2c.h>
+
+struct max31790_fan_fault_config {
+	struct i2c_dt_spec i2c;
+};
+
+struct max31790_fan_fault_data {
+	uint16_t value;
+};
+
+#endif /* ZEPHYR_DRIVERS_SENSOR_MAX31790_MAX31790_FAN_FAULT_H_ */

drivers/sensor/max31790/max31790_fan_speed.c

@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2024 SILA Embedded Solutions GmbH
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT maxim_max31790_fan_speed
+
+#include <zephyr/drivers/mfd/max31790.h>
+#include <zephyr/drivers/sensor.h>
+#include <zephyr/logging/log.h>
+#include <zephyr/sys/byteorder.h>
+
+#include "max31790_fan_speed.h"
+
+#define FACTOR_RPM_TO_HZ           60
+#define TACH_COUNT_FREQUENCY       (MAX31790_OSCILLATOR_FREQUENCY_IN_HZ / 4)
+#define TACH_COUNTS_PER_REVOLUTION 2
+
+LOG_MODULE_REGISTER(MAX31790_FAN_SPEED, CONFIG_SENSOR_LOG_LEVEL);
+
+static int max31790_fan_speed_sample_fetch(const struct device *dev, enum sensor_channel chan)
+{
+	const struct max31790_fan_speed_config *config = dev->config;
+	struct max31790_fan_speed_data *data = dev->data;
+	uint16_t tach_count;
+	uint8_t fan_dynamics;
+	uint8_t number_tach_periods_counted;
+	uint8_t speed_range;
+	uint8_t register_address;
+	int result;
+
+	__ASSERT_NO_MSG(chan == SENSOR_CHAN_ALL);
+
+	register_address = MAX37190_REGISTER_TACHCOUNTMSB(config->channel_id);
+	result = i2c_write_read_dt(&config->i2c, &register_address, sizeof(register_address),
+				   &tach_count, sizeof(tach_count));
+	tach_count = sys_be16_to_cpu(tach_count);
+	if (result != 0) {
+		return result;
+	}
+
+	result = i2c_reg_read_byte_dt(
+		&config->i2c, MAX31790_REGISTER_FANDYNAMICS(config->channel_id), &fan_dynamics);
+	if (result != 0) {
+		return result;
+	}
+
+	tach_count = tach_count >> 5;
+	speed_range = MAX31790_FANXDYNAMCIS_SPEED_RANGE_GET(fan_dynamics);
+
+	switch (speed_range) {
+	case 0:
+		number_tach_periods_counted = 1;
+		break;
+	case 1:
+		number_tach_periods_counted = 2;
+		break;
+	case 2:
+		number_tach_periods_counted = 4;
+		break;
+	case 3:
+		number_tach_periods_counted = 8;
+		break;
+	case 4:
+		number_tach_periods_counted = 16;
+		break;
+	case 5:
+		__fallthrough;
+	case 6:
+		__fallthrough;
+	case 7:
+		number_tach_periods_counted = 32;
+		break;
+	default:
+		LOG_ERR("%s: invalid speed range %i", dev->name, speed_range);
+		return -EINVAL;
+	}
+
+	if (tach_count == 0) {
+		LOG_WRN("%s: tach count is zero", dev->name);
+		data->rpm = UINT16_MAX;
+	} else {
+		LOG_DBG("%s: %i tach periods counted, %i tach count", dev->name,
+			number_tach_periods_counted, tach_count);
+		data->rpm = FACTOR_RPM_TO_HZ * TACH_COUNT_FREQUENCY * number_tach_periods_counted /
+			    (tach_count * TACH_COUNTS_PER_REVOLUTION);
+	}
+
+	return 0;
+}
+
+static int max31790_fan_speed_channel_get(const struct device *dev, enum sensor_channel chan,
+					  struct sensor_value *val)
+{
+	struct max31790_fan_speed_data *data = dev->data;
+
+	if (chan != SENSOR_CHAN_RPM) {
+		LOG_ERR("%s: requesting unsupported channel %i", dev->name, chan);
+		return -ENOTSUP;
+	}
+
+	val->val1 = data->rpm;
+	val->val2 = 0;
+	return 0;
+}
+
+static const struct sensor_driver_api max31790_fan_speed_api = {
+	.sample_fetch = max31790_fan_speed_sample_fetch,
+	.channel_get = max31790_fan_speed_channel_get,
+};
+
+static int max31790_fan_speed_init(const struct device *dev)
+{
+	const struct max31790_fan_speed_config *config = dev->config;
+
+	if (!i2c_is_ready_dt(&config->i2c)) {
+		LOG_ERR("I2C device not ready");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+#define MAX31790_FAN_SPEED_INIT(inst)                                                              \
+	static const struct max31790_fan_speed_config max31790_fan_speed_##inst##_config = {       \
+		.i2c = I2C_DT_SPEC_GET(DT_INST_PARENT(inst)),                                      \
+		.channel_id = DT_INST_PROP(inst, channel) - 1,                                     \
+	};                                                                                         \
+                                                                                                   \
+	static struct max31790_fan_speed_data max31790_fan_speed_##inst##_data;                    \
+                                                                                                   \
+	SENSOR_DEVICE_DT_INST_DEFINE(inst, max31790_fan_speed_init, NULL,                          \
+			      &max31790_fan_speed_##inst##_data,                                   \
+			      &max31790_fan_speed_##inst##_config, POST_KERNEL,                    \
+			      CONFIG_SENSOR_INIT_PRIORITY, &max31790_fan_speed_api);
+
+DT_INST_FOREACH_STATUS_OKAY(MAX31790_FAN_SPEED_INIT);

drivers/sensor/max31790/max31790_fan_speed.h

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2024 SILA Embedded Solutions GmbH
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_DRIVERS_SENSOR_MAX31790_MAX31790_FAN_SPEED_H_
+#define ZEPHYR_DRIVERS_SENSOR_MAX31790_MAX31790_FAN_SPEED_H_
+
+#include <zephyr/drivers/i2c.h>
+
+struct max31790_fan_speed_config {
+	struct i2c_dt_spec i2c;
+	uint8_t channel_id;
+};
+
+struct max31790_fan_speed_data {
+	uint16_t rpm;
+};
+
+#endif /* ZEPHYR_DRIVERS_SENSOR_MAX31790_MAX31790_FAN_SPEED_H_ */

dts/bindings/sensor/maxim,max31790-fan-fault.yaml

@@ -0,0 +1,10 @@
+# Copyright (c) 2024 SILA Embedded Solutions GmbH
+# SPDX-License-Identifier: Apache-2.0
+
+description: fan fault measurement of Maxim Integrated MAX31790 PWM Controller
+
+compatible: "maxim,max31790-fan-fault"
+
+include: [sensor-device.yaml]
+
+on-bus: max31790

dts/bindings/sensor/maxim,max31790-fan-speed.yaml

@@ -0,0 +1,23 @@
+# Copyright (c) 2024 SILA Embedded Solutions GmbH
+# SPDX-License-Identifier: Apache-2.0
+
+description: fan speed measurement of Maxim Integrated MAX31790 PWM Controller
+
+compatible: "maxim,max31790-fan-speed"
+
+include: [sensor-device.yaml]
+
+on-bus: max31790
+
+properties:
+  channel:
+    type: int
+    enum:
+      - 1
+      - 2
+      - 3
+      - 4
+      - 5
+      - 6
+    required: true
+    description: PWM channel number

include/zephyr/drivers/sensor/max31790.h

@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2024 SILA Embedded Solutions GmbH
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_DRIVERS_SENSOR_MAX31790_H_
+#define ZEPHYR_INCLUDE_DRIVERS_SENSOR_MAX31790_H_
+
+#include <zephyr/drivers/sensor.h>
+
+/* MAX31790 specific channels */
+enum sensor_channel_max31790 {
+	SENSOR_CHAN_MAX31790_FAN_FAULT = SENSOR_CHAN_PRIV_START,
+};
+
+#endif /* ZEPHYR_INCLUDE_DRIVERS_SENSOR_MAX31790_H_ */