get rid of lkmc package, move userland and kernel-modules to top

Rationale: we already had a non buildroot build system,
maintaining both will be hard, and having short paths is more awesome.

kernel_modules/irq.c

@@ -0,0 +1,64 @@
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#irq-ko */
+
+#include <linux/fs.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/uaccess.h> /* copy_from_user, copy_to_user */
+
+#define NAME "lkmc_irq"
+#define MAX_IRQS 256
+
+static int irqs[MAX_IRQS];
+static int major;
+
+/**
+ * Return value from kernel docs:*
+ *
+ * enum irqreturn
+ * @IRQ_NONE        interrupt was not from this device or was not handled
+ * @IRQ_HANDLED     interrupt was handled by this device
+ * @IRQ_WAKE_THREAD handler requests to wake the handler thread
+ */
+static irqreturn_t handler(int irq, void *dev)
+{
+	pr_info("handler irq = %d dev = %d\n", irq, *(int *)dev);
+	return IRQ_NONE;
+}
+
+static const struct file_operations fops;
+
+static int myinit(void)
+{
+	int ret, i;
+
+	major = register_chrdev(0, NAME, &fops);
+	for (i = 0; i < MAX_IRQS; ++i) {
+		ret = request_irq(
+			i,
+			handler,
+			IRQF_SHARED,
+			"myirqhandler0",
+			&major
+		);
+		irqs[i] = ret;
+		pr_info("request_irq irq = %d ret = %d\n", i, ret);
+	}
+	return 0;
+}
+
+static void myexit(void)
+{
+	int i;
+
+	for (i = 0; i < MAX_IRQS; ++i) {
+		if (!irqs[i]) {
+			free_irq(i, &major);
+		}
+	}
+	unregister_chrdev(major, NAME);
+}
+
+module_init(myinit)
+module_exit(myexit)
+MODULE_LICENSE("GPL");