[LTD noup] sensor: add stub STM32F401x temperature driver

The next patch will fill in the necessary functionality.

Signed-off-by: Marti Bolivar <[email protected]>

drivers/sensor/Kconfig

@@ -107,3 +107,5 @@ source "drivers/sensor/th02/Kconfig"
 source "drivers/sensor/tmp007/Kconfig"
 
 source "drivers/sensor/tmp112/Kconfig"
+
+source "drivers/sensor/stm32/Kconfig"

drivers/sensor/Makefile

@@ -34,3 +34,4 @@ obj-$(CONFIG_SX9500) += sx9500/
 obj-$(CONFIG_TH02) += th02/
 obj-$(CONFIG_TMP007) += tmp007/
 obj-$(CONFIG_TMP112) += tmp112/
+obj-$(CONFIG_TEMP_STM32F401X) += stm32/

drivers/sensor/stm32/Kconfig

@@ -0,0 +1,24 @@
+# Kconfig - STM32F401x temperature sensor configuration options
+
+#
+# Copyright (c) 2016 ARM Ltd.
+# Copyright (c) 2017 Linaro Limited.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+menuconfig TEMP_STM32F401X
+	bool
+	prompt "STM32F401x Temperature Sensor"
+	depends on SENSOR && SOC_SERIES_STM32F4X
+	default n
+	help
+	  Enable driver for STM32F401x temperature sensor.
+
+config TEMP_STM32F401X_NAME
+	string
+	prompt "Driver name"
+	default "TEMP_0"
+	depends on TEMP_STM32F401X
+	help
+	  Device name with which the STM32F401x temperature sensor is identified.

drivers/sensor/stm32/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_TEMP_STM32F401X) += temp_stm32f401x.o

drivers/sensor/stm32/temp_stm32f401x.c

@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2017 Linaro Limited
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file
+ * @brief Temperature sensor driver for STM32F401x chips.
+ *
+ * @warning Temperature readings should be use for RELATIVE
+ *          TEMPERATURE CHANGES ONLY.
+ *
+ *          Inter-chip temperature sensor readings may vary by as much
+ *          as 45 degrees C.
+ */
+
+#include <device.h>
+#include <sensor.h>
+
+/* TODO */
+static int temp_stm32f401x_sample_fetch(struct device *dev,
+					enum sensor_channel chan)
+{
+	return 0;
+}
+
+/* TODO */
+static int temp_stm32f401x_channel_get(struct device *dev,
+				       enum sensor_channel chan,
+				       struct sensor_value *val)
+{
+	val->val1 = 0;
+	val->val2 = 0;
+	return 0;
+}
+
+static const struct sensor_driver_api temp_stm32f401x_driver_api = {
+	.sample_fetch = temp_stm32f401x_sample_fetch,
+	.channel_get = temp_stm32f401x_channel_get,
+};
+
+/* TODO */
+static int temp_stm32f401x_init(struct device *dev)
+{
+	return 0;
+}
+
+DEVICE_AND_API_INIT(temp_stm32f401x, CONFIG_TEMP_STM32F401X_NAME,
+		    temp_stm32f401x_init, NULL, NULL, POST_KERNEL,
+		    CONFIG_SENSOR_INIT_PRIORITY, &temp_stm32f401x_driver_api);