feat(MP/kernel): add temperature API

- init and exit fonction for the module
- read_temp(), to get the temperature

src/06-mini-project/kernel/Makefile

@@ -11,7 +11,15 @@ SOURCE := main
 ifneq ($(KERNELRELEASE),)
 obj-m += $(MODULE).o		## name of the generated module
 
-$(MODULE)-objs := $(SOURCE).o	## list of objects needed for that module
+# add folder sources
+SOURCES_C := $(wildcard $(src)/*.c)
+# add temperature sources
+SOURCES_C += $(wildcard $(src)/temperature/*.c)
+
+
+$(MODULE)-objs := $(patsubst $(src)/%.c, %.o, $(SOURCES_C))
+
+# $(MODULE)-objs := $(SOURCE).o	## list of objects needed for that module
 CFLAGS_$(SOURCE).o := -DDEBUG
 
 # Part executed when called from standard make in module source directory:
@@ -28,7 +36,6 @@ clean:
 
 install:
 	$(MAKE) -C $(KDIR) M=$(PWD) INSTALL_MOD_PATH=$(MODPATH) modules_install
-	install -D -m 0644 $(MODULE).conf $(MODPATH)/etc/modprobe.d/$(MODULE).conf
+	# install -D -m 0644 $(MODULE).conf $(MODPATH)/etc/modprobe.d/$(MODULE).conf
 
 endif
-

src/06-mini-project/kernel/main.c

@@ -2,13 +2,41 @@
 #include <linux/module.h>	// needed by all modules
 #include <linux/init.h>		// needed for macros
 #include <linux/kernel.h>	// needed for debugging
+#include <linux/kthread.h>
+#include <linux/delay.h>
+#include <linux/err.h>
 
 #include "linux/printk.h"
 
+#include "temperature/temp.h"
+
+static struct task_struct *temp_thread = NULL;
+
+/* Thread function that runs in the background */
+static int temp_thread_fn(void *data) {
+    pr_info("temp_regulator: Background thread started\n");
+
+    while (!kthread_should_stop()) {
+        read_temp();
+        /* Wait 1 second (1000 milliseconds) */
+        msleep(1000);
+    }
+
+    pr_info("temp_regulator: Background thread stopping\n");
+    return 0;
+}
+
 static int __init temp_regulator_init(void) {
     pr_info("Linux module temp_regulator loading...\n");
 
-    
+    int ret;
+
+    /* Initialize temperature sensor API */
+       ret = temp_init();
+       if (ret != 0) {
+           pr_err("temp_regulator: Initialization failed with error %d\n", ret);
+           return ret;
+       }
 
     pr_info("Linux module temp_regulator loaded\n");
     return 0;
@@ -18,7 +46,9 @@ static void __exit temp_regulator_exit(void) {
     pr_info("Linux module temp_regulator unloading...\n");
 
 
-    
+    /* Release sensor resources */
+    temp_exit();
+
     pr_info("Linux module temp_regulator unloaded\n");
 }
 

src/06-mini-project/kernel/temperature/temp.c

@@ -0,0 +1,83 @@
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include <linux/errno.h>
+
+#include "temp.h"
+
+#define TEMPERATURE_SENSOR_BASE_ADDR 0x01C25000
+#define TEMPERATURE_SENSOR_REG_SIZE  0x1000
+#define TEMPERATURE_REG_OFFSET       0x80
+
+static struct resource *temp_res = NULL;
+static void __iomem *temp_reg = NULL;
+
+int temp_init(void) {
+    /* Request physical memory region */
+    temp_res = request_mem_region(TEMPERATURE_SENSOR_BASE_ADDR,
+                                  TEMPERATURE_SENSOR_REG_SIZE,
+                                  "nanopi - temperature sensor");
+    if (temp_res == NULL) {
+        pr_warn("temp_regulator: Failed to reserve physical memory region\n");
+    }
+
+    /* Map the physical memory to virtual kernel memory */
+    temp_reg = ioremap(TEMPERATURE_SENSOR_BASE_ADDR, TEMPERATURE_SENSOR_REG_SIZE);
+    if (temp_reg == NULL) {
+        pr_err("temp_regulator: Failed to ioremap registers\n");
+        /* Clean up previously requested region */
+        release_mem_region(TEMPERATURE_SENSOR_BASE_ADDR, TEMPERATURE_SENSOR_REG_SIZE);
+        temp_res = NULL;
+        return -ENOMEM;
+    }
+
+    pr_info("temp_regulator: Temperature sensor memory successfully mapped\n");
+    return 0;
+}
+
+uint32_t read_temp(void) {
+    uint32_t temperature = 0;
+    uint32_t raw_val = 0;
+
+    if (temp_reg == NULL) {
+        pr_warn("temp_regulator: Cannot read temperature, sensor not initialized\n");
+        return 0;
+    }
+
+    /* Read the raw register value from THS0_DATA (offset 0x80) */
+    raw_val = ioread32(temp_reg + TEMPERATURE_REG_OFFSET);
+
+    /* Choose the correct formula according to the datasheet */
+    if (raw_val > 0x500) {
+        /* Temperature is lower than 70°C */
+        temperature = -1191 * (int32_t)raw_val / 10 + 223000;
+    } else {
+        /* Temperature is higher than or equal to 70°C */
+        temperature = -1452 * (int32_t)raw_val / 10 + 259000;
+    }
+
+    pr_info("temp_regulator: Temperature=%u.%03u C (register raw value: %u)\n",
+            temperature / 1000,
+            temperature % 1000,
+            raw_val);
+
+    return temperature;
+}
+
+void temp_exit(void) {
+    /* Unmap virtual address space */
+    if (temp_reg != NULL) {
+        iounmap(temp_reg);
+        temp_reg = NULL;
+    }
+
+    /* Release physical memory region */
+    if (temp_res != NULL) {
+        release_mem_region(TEMPERATURE_SENSOR_BASE_ADDR, TEMPERATURE_SENSOR_REG_SIZE);
+        temp_res = NULL;
+    }
+
+    pr_info("temp_regulator: Temperature sensor resources released\n");
+}

src/06-mini-project/kernel/temperature/temp.h

@@ -0,0 +1,27 @@
+#ifndef TEMP_H
+#define TEMP_H
+
+#include <linux/types.h>
+
+/**
+ * temp_init() - Request physical memory and map it into kernel virtual memory.
+ *
+ * Return: 0 on success, or a negative error code on failure.
+ */
+int temp_init(void);
+
+/**
+ * read_temp() - Read the current CPU temperature from the mapped registers.
+ * To convert it in degrees Celsius, divide by 1000.0
+ *
+ * Return: The calculated temperature value.
+ */
+uint32_t read_temp(void);
+
+
+/**
+ * temp_exit() - Unmap the virtual memory and release the requested physical memory region.
+ */
+void temp_exit(void);
+
+#endif /* TEMP_H */