initial commit; version 0.1.0

Makefile

@@ -0,0 +1,8 @@
+KVER ?= $(shell uname -r)
+obj-m := fake-battery.o
+
+all:
+	$(MAKE) -C /lib/modules/$(KVER)/build M=$(PWD) modules
+
+clean:
+	$(MAKE) -C /lib/modules/$(KVER)/build M=$(PWD) clean

debian/changelog

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+fake-battery-dkms (0.1.0-1) stable; urgency=low
+
+    * Initial release
+
+ -- Vincent Schweiger <vincent.schweiger@icloud.com> Fri, 21 Aug 2026 19:39:00
+ +0200

debian/control

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+Source: fake-battery-dkms
+Maintainer: Vincent Schweiger <vincent.schweiger@icloud.com>
+Section: kernel
+Priority: optional
+Build-Depends: debhelper-compat (= 13),
+               dh-sequence-dkms,
+Standards-Version: 4.7.0
+Rules-Requires-Root: no
+
+Package: fake-battery-dkms
+Architecture: all
+Depends: ${misc:Depends}
+Description: Fake Battery
+ Creates a fake battery module

debian/dkms

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+dkms.conf

debian/install

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+#!/bin/sh
+
+for dir in fake-battery.c Makefile; do
+    echo ${dir} /usr/src/${PACKAGE_NAME}-${PACKAGE_VERSION}
+done

debian/rules

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+#!/usr/bin/make -f
+
+PACKAGE_NAME=$(shell grep PACKAGE_NAME= dkms.conf | cut -d= -f2 | cut -d\" -f2)
+PACKAGE_VERSION=$(shell grep PACKAGE_VERSION= dkms.conf | cut -d= -f2 | cut -d\" -f2)
+export PACKAGE_NAME PACKAGE_VERSION
+
+%:
+	dh $@ --with dkms
+
+# Nothing to configure, build or auto-install (this all happens after
+# installation using dkms)
+override_dh_auto_configure:
+override_dh_auto_build:
+override_dh_auto_install:

debian/source/format

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+3.0 (quilt)

dkms.conf

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+PACKAGE_VERSION="0.1.0"
+PACKAGE_NAME="fake-battery"
+CLEAN=true
+BUILT_MODULE_NAME[0]="fake-battery"
+BUILT_MODULE_LOCATION[0]=""
+DEST_MODULE_LOCATION[0]="/extra"
+MAKE[0]="make KVER=$kernelver -C ${dkms_tree}/${PACKAGE_NAME}/${PACKAGE_VERSION}/build"
+AUTOINSTALL="yes"
+

fake-battery.c

@@ -0,0 +1,112 @@
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/power_supply.h>
+#include <linux/init.h>
+
+static struct power_supply *fake_battery;
+static struct power_supply_desc battery_desc;
+
+static enum power_supply_property fake_battery_props[] = {
+    POWER_SUPPLY_PROP_STATUS,
+    POWER_SUPPLY_PROP_HEALTH,
+    POWER_SUPPLY_PROP_PRESENT,
+    POWER_SUPPLY_PROP_TECHNOLOGY,
+    POWER_SUPPLY_PROP_CAPACITY,
+    POWER_SUPPLY_PROP_CAPACITY_LEVEL,
+    POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
+    POWER_SUPPLY_PROP_CHARGE_FULL,
+    POWER_SUPPLY_PROP_CHARGE_NOW,
+    POWER_SUPPLY_PROP_VOLTAGE_NOW,
+    POWER_SUPPLY_PROP_CURRENT_NOW,
+    POWER_SUPPLY_PROP_TEMP,
+};
+
+static int fake_battery_get_property(struct power_supply *psy,
+                                     enum power_supply_property psp,
+                                     union power_supply_propval *val)
+{
+    switch (psp) {
+    case POWER_SUPPLY_PROP_STATUS:
+        val->intval = POWER_SUPPLY_STATUS_FULL;
+        break;
+    case POWER_SUPPLY_PROP_HEALTH:
+        val->intval = POWER_SUPPLY_HEALTH_GOOD;
+        break;
+    case POWER_SUPPLY_PROP_PRESENT:
+        val->intval = 1;
+        break;
+    case POWER_SUPPLY_PROP_TECHNOLOGY:
+        val->intval = POWER_SUPPLY_TECHNOLOGY_LIPO;
+        break;
+    case POWER_SUPPLY_PROP_CAPACITY:
+        val->intval = 100;
+        break;
+    case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
+        val->intval = POWER_SUPPLY_CAPACITY_LEVEL_FULL;
+        break;
+    case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
+        val->intval = 5000000;  /* 5000 mAh */
+        break;
+    case POWER_SUPPLY_PROP_CHARGE_FULL:
+        val->intval = 5000000;  /* 5000 mAh */
+        break;
+    case POWER_SUPPLY_PROP_CHARGE_NOW:
+        val->intval = 5000000;  /* 5000 mAh (fully charged) */
+        break;
+    case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+        val->intval = 4200000;  /* 4.2V */
+        break;
+    case POWER_SUPPLY_PROP_CURRENT_NOW:
+        val->intval = 0;        /* Not charging */
+        break;
+    case POWER_SUPPLY_PROP_TEMP:
+        val->intval = 250;      /* 25°C in 0.1°C units */
+        break;
+    default:
+        return -EINVAL;
+    }
+    return 0;
+}
+
+static int __init fake_battery_init(void)
+{
+    int ret;
+
+    pr_info("fake_battery: Loading fake battery module\n");
+
+    // Initialize the power supply descriptor
+    battery_desc.name = "fake-battery";
+    battery_desc.type = POWER_SUPPLY_TYPE_BATTERY;
+    battery_desc.properties = fake_battery_props;
+    battery_desc.num_properties = ARRAY_SIZE(fake_battery_props);
+    battery_desc.get_property = fake_battery_get_property;
+
+    // Register the power supply
+    fake_battery = power_supply_register(NULL, &battery_desc, NULL);
+    if (IS_ERR(fake_battery)) {
+        ret = PTR_ERR(fake_battery);
+        pr_err("fake_battery: Failed to register power supply: %d\n", ret);
+        return ret;
+    }
+
+    pr_info("fake_battery: Fake battery registered successfully\n");
+    pr_info("fake_battery: Battery status: 100%% charged\n");
+
+    return 0;
+}
+
+static void __exit fake_battery_exit(void)
+{
+    pr_info("fake_battery: Unloading fake battery module\n");
+    if (fake_battery)
+        power_supply_unregister(fake_battery);
+}
+
+module_init(fake_battery_init);
+module_exit(fake_battery_exit);
+
+MODULE_AUTHOR("Vincent Schweiger");
+MODULE_DESCRIPTION("Fake battery module that reports a fully charged battery");
+MODULE_VERSION("0.1.0");
+MODULE_LICENSE("GPL");