feat(MP/kernel): create regulator

- contains the core of the module
- manual - auto mode for the temperature regulation

- use callback to communicate with temperature and led

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

@@ -0,0 +1,137 @@
+// workspace/src/06-mini-project/kernel/regulator/regulator.c
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+
+#include "regulator.h"
+#include "../sysfs/sysfs.h"
+
+/* Internal state of the regulator */
+static int current_mode = 1;        /* 1 = Auto, 0 = Manual */
+static uint32_t current_period = 2;   /* Current blinking period in ms */
+
+static struct task_struct *regulator_thread = NULL;
+
+static struct regulator_callbacks regulator_cbs = {0};
+
+/* --- Sysfs Callbacks --- */
+
+static uint32_t cb_get_temperature(void) {
+    return regulator_cbs.get_temperature();
+}
+
+static int cb_get_mode(void) {
+    return current_mode;
+}
+
+static void cb_set_mode(int mode) {
+    /* Accept only 0 or 1 as valid modes */
+    if (mode == 0 || mode == 1) {
+        current_mode = mode;
+        pr_info("regulator: Mode switched to %s\n", mode ? "Auto" : "Manual");
+    }
+}
+
+static uint32_t cb_get_period(void) {
+    return current_period;
+}
+
+static void cb_set_period(uint32_t freq) {
+    /* Allow period changes only in Manual mode */
+    if (current_mode == 0) {
+        current_period = freq;
+        regulator_cbs.adjust_period(current_period);
+        pr_info("regulator: Manual period set to %u ms\n", current_period);
+    } else {
+        pr_warn("regulator: Cannot set period manually in auto mode\n");
+    }
+}
+
+/* Pack callbacks into the structure expected by sysfs */
+static struct sysfs_callbacks sysfs_cbs = {
+    .get_temperature = cb_get_temperature,
+    .get_mode        = cb_get_mode,
+    .set_mode        = cb_set_mode,
+    .get_period   = cb_get_period,
+    .set_period   = cb_set_period,
+};
+
+/* --- Auto Mode Logic --- */
+
+static void process_auto_mode(void) {
+    uint32_t temp_milli = regulator_cbs.get_temperature();
+    uint32_t temp_c = temp_milli / 1000;
+    uint32_t new_period = 2;
+
+    /* Determine period based on temperature thresholds */
+    if (temp_c < 35) {
+        new_period = 500;
+    } else if (temp_c < 40) {
+        new_period = 200;
+    } else if (temp_c < 45) {
+        new_period = 100;
+    } else {
+        new_period = 50;
+    }
+
+    /* Apply only if the period has changed to avoid unnecessary hardware updates */
+    if (new_period != current_period) {
+        current_period = new_period;
+        regulator_cbs.adjust_period(current_period);
+        pr_info("regulator: Auto mode adjusted period to %u ms (Temp: %u C)\n",
+                current_period, temp_c);
+    }
+}
+
+/* Background thread checking the temperature periodically */
+static int regulator_thread_fn(void *data) {
+    while (!kthread_should_stop()) {
+        if (current_mode == 1) {
+            process_auto_mode();
+        }
+        msleep(1000);
+    }
+    return 0;
+}
+
+/* --- Public API --- */
+
+int regulator_init(struct regulator_callbacks *cbs) {
+
+    if (cbs == NULL) {
+        pr_err("regulator: Callbacks are NULL\n");
+        return -EINVAL;
+    }
+
+    // register callbacks
+    regulator_cbs = *cbs;
+
+    /* Initialize sysfs and inject our brain callbacks */
+    int ret = temp_regulator_sysfs_init(&sysfs_cbs);
+    if (ret != 0) {
+        return ret;
+    }
+
+    /* Start the background decision loop */
+    regulator_thread = kthread_run(regulator_thread_fn, NULL, "regulator_logic");
+    if (IS_ERR(regulator_thread)) {
+        temp_regulator_sysfs_exit();
+        return PTR_ERR(regulator_thread);
+    }
+
+    /* Set initial hardware state */
+    regulator_cbs.adjust_period(current_period);
+
+    return 0;
+}
+
+void regulator_exit(void) {
+
+    if (regulator_thread != NULL) {
+        kthread_stop(regulator_thread);
+        regulator_thread = NULL;
+    }
+
+    temp_regulator_sysfs_exit();
+}

src/06-mini-project/kernel/regulator/regulator.h

@@ -0,0 +1,20 @@
+// workspace/src/06-mini-project/kernel/regulator/regulator.h
+#ifndef REGULATOR_H
+#define REGULATOR_H
+
+#include <linux/types.h>
+
+/* Callbacks for adjusting period and getting temperature */
+struct regulator_callbacks {
+    void (*adjust_period)(int new_period_ms);
+    uint32_t (*get_temperature)(void);
+};
+
+
+/* Initialize the regulator logic, background thread, and sysfs. Register the callbacks with other parts */
+int regulator_init(struct regulator_callbacks *cbs);
+
+/* Stop the regulator logic and clean up */
+void regulator_exit(void);
+
+#endif /* REGULATOR_H */