drivers: sensors: Add tachometer driver for MEC family

Introduce the tach driver for the microchip XEC SoCs.

Signed-off-by: Francisco Munoz <francisco.munoz.ruiz@intel.com>

drivers/sensor/CMakeLists.txt

@@ -61,6 +61,7 @@ add_subdirectory_ifdef(CONFIG_TMP112		tmp112)
 add_subdirectory_ifdef(CONFIG_TMP116		tmp116)
 add_subdirectory_ifdef(CONFIG_VL53L0X		vl53l0x)
 add_subdirectory_ifdef(CONFIG_TEMP_KINETIS	nxp_kinetis_temp)
+add_subdirectory_ifdef(CONFIG_TACH_XEC		mchp_tach_xec)
 
 zephyr_sources_ifdef(CONFIG_USERSPACE sensor_handlers.c)
 zephyr_sources_ifdef(CONFIG_SENSOR_SHELL sensor_shell.c)

drivers/sensor/Kconfig

@@ -113,6 +113,8 @@ source "drivers/sensor/max30101/Kconfig"
 
 source "drivers/sensor/max44009/Kconfig"
 
+source "drivers/sensor/mchp_tach_xec/Kconfig"
+
 source "drivers/sensor/mcp9808/Kconfig"
 
 source "drivers/sensor/mpu6050/Kconfig"

drivers/sensor/mchp_tach_xec/CMakeLists.txt

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_library()
+
+zephyr_library_sources_ifdef(CONFIG_TACH_XEC tach_mchp_xec.c)

drivers/sensor/mchp_tach_xec/Kconfig

@@ -0,0 +1,10 @@
+# Mcrochip mec150x tachometer sensor configuration options
+
+# Copyright (c) 2020 Intel Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+config TACH_XEC
+	bool "XEC Tachometer sensor"
+	depends on SOC_FAMILY_MEC
+	help
+	  Enable the Microchip XEC tachometer sensor.

drivers/sensor/mchp_tach_xec/tach_mchp_xec.c

@@ -0,0 +1,145 @@
+/*
+ * Copyright (c) 2020 Intel Corporation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#include <errno.h>
+#include <device.h>
+#include <drivers/sensor.h>
+#include <soc.h>
+#include <logging/log.h>
+
+LOG_MODULE_REGISTER(tach_xec, CONFIG_SENSOR_LOG_LEVEL);
+
+struct tach_xec_config {
+	u32_t base_address;
+};
+
+struct tach_xec_data {
+	u16_t count;
+};
+
+#define FAN_STOPPED		0xFFFFU
+#define COUNT_100KHZ_SEC	100000U
+#define SEC_TO_MINUTE		60U
+#define PIN_STS_TIMEOUT		20U
+
+#define TACH_XEC_REG_BASE(_dev)				\
+	((TACH_Type *)					\
+	 ((const struct tach_xec_config * const)	\
+	  _dev->config->config_info)->base_address)
+
+#define TACH_XEC_CONFIG(_dev)				\
+	(((const struct counter_xec_config * const)	\
+	  _dev->config->config_info))
+
+#define TACH_XEC_DATA(_dev)				\
+	((struct tach_xec_data *)dev->driver_data)
+
+
+int tach_xec_sample_fetch(struct device *dev, enum sensor_channel chan)
+{
+	ARG_UNUSED(chan);
+
+	TACH_Type *tach = TACH_XEC_REG_BASE(dev);
+	struct tach_xec_data *data = TACH_XEC_DATA(dev);
+	u8_t poll_count = 0;
+
+	while (poll_count < PIN_STS_TIMEOUT) {
+		/* See whether internal counter is already latched */
+		if (tach->STATUS & MCHP_TACH_STS_CNT_RDY) {
+			data->count =
+				tach->CONTROL >> MCHP_TACH_CTRL_COUNTER_POS;
+			break;
+		}
+
+		poll_count++;
+
+		/* Allow other threads to run while we sleep */
+		k_usleep(USEC_PER_MSEC);
+	}
+
+	if (poll_count == PIN_STS_TIMEOUT) {
+		return -EINVAL;
+	}
+
+	/* We interprept a fan stopped or jammed as 0 */
+	if (data->count == FAN_STOPPED) {
+		data->count = 0U;
+	}
+
+	return 0;
+}
+
+static int tach_xec_channel_get(struct device *dev,
+				enum sensor_channel chan,
+				struct sensor_value *val)
+{
+	struct tach_xec_data *data = TACH_XEC_DATA(dev);
+
+	if (chan != SENSOR_CHAN_RPM) {
+		return -ENOTSUP;
+	}
+
+	/* Convert the count per 100khz cycles to rpm */
+	if (data->count != FAN_STOPPED && data->count != 0U) {
+		val->val1 = (SEC_TO_MINUTE * COUNT_100KHZ_SEC)/data->count;
+		val->val2 = 0U;
+	} else {
+		val->val1 =  0U;
+	}
+
+	val->val2 = 0U;
+
+	return 0;
+}
+
+static int tach_xec_init(struct device *dev)
+{
+	TACH_Type *tach = TACH_XEC_REG_BASE(dev);
+
+	tach->CONTROL = MCHP_TACH_CTRL_READ_MODE_100K_CLOCK	|
+			MCHP_TACH_CTRL_EDGES_5			|
+			MCHP_TACH_CTRL_FILTER_EN		|
+			MCHP_TACH_CTRL_EN;
+
+	return 0;
+}
+
+static const struct sensor_driver_api tach_xec_driver_api = {
+	.sample_fetch = tach_xec_sample_fetch,
+	.channel_get = tach_xec_channel_get,
+};
+
+#define TACH_XEC_DEVICE(id)						\
+	static const struct tach_xec_config tach_xec_dev_config##id = {	\
+		.base_address =						\
+		DT_INST_##id##_MICROCHIP_XEC_TACH_BASE_ADDRESS,		\
+	};								\
+									\
+	static struct tach_xec_data tach_xec_dev_data##id;		\
+									\
+	DEVICE_AND_API_INIT(tach##id,					\
+			    DT_INST_##id##_MICROCHIP_XEC_TACH_LABEL,	\
+			    tach_xec_init,				\
+			    &tach_xec_dev_data##id,			\
+			    &tach_xec_dev_config##id,			\
+			    POST_KERNEL,				\
+			    CONFIG_SENSOR_INIT_PRIORITY,		\
+			    &tach_xec_driver_api)			\
+
+#ifdef DT_INST_0_MICROCHIP_XEC_TACH
+TACH_XEC_DEVICE(0);
+#endif
+
+#ifdef DT_INST_1_MICROCHIP_XEC_TACH
+TACH_XEC_DEVICE(1);
+#endif
+
+#ifdef DT_INST_2_MICROCHIP_XEC_TACH
+TACH_XEC_DEVICE(2);
+#endif
+
+#ifdef DT_INST_3_MICROCHIP_XEC_TACH
+TACH_XEC_DEVICE(3);
+#endif