Add dummy battery module to the system...
Hopefully this can be modified to create the actual code needed to monitor the battery of the argon-oneUp.
This commit is contained in:
Jeff Curless
328
battery/dummy_battery.c
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328
battery/dummy_battery.c
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@@ -0,0 +1,328 @@
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// SPDX-License-Identifier: GPL-2.0
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// Simple dummy battery driver (out-of-tree module)
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// Registers a power_supply "dummy-battery" with a few common properties
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// and a small work loop to simulate charge/discharge.
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//
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// Build (out-of-tree):
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// make -C /lib/modules/$(uname -r)/build M=$PWD modules
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// Use:
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// sudo insmod dummy_battery.ko start_capacity=82 discharge_rate=1
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// See:
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// ls -l /sys/class/power_supply/dummy-battery
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//
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// References:
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// - Linux power_supply class docs
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// - In-tree drivers/power/supply/test_power.c (example test driver)
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/power_supply.h>
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#include <linux/platform_device.h>
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#include <linux/mutex.h>
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#include <linux/workqueue.h>
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#include <linux/jiffies.h>
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#define DRV_NAME "dummy_battery"
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#define DFLT_CAPACITY 75 // percent
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#define DFLT_VOLTAGE_UV 4000000 // 4.0V
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#define DFLT_CURRENT_UA 50000 // 50 mA (sign: + = charging, - = discharging)
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#define DFLT_TEMP_DECIC 300 // 30.0 C
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#define TICK_MS 1000 // 1s tick
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struct dummy_batt {
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struct power_supply *psy;
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struct power_supply_desc desc;
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struct delayed_work sim_work;
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struct mutex lock;
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/* Simulated state */
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int capacity; // 0..100 (%)
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int voltage_uV; // microvolts
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int current_uA; // microamps (signed)
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int temp_deciC; // 0.1 C units
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bool online_ac; // AC adapter present?
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int status;
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};
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static int start_capacity = DFLT_CAPACITY; // initial SoC (%)
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module_param(start_capacity, int, 0644);
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MODULE_PARM_DESC(start_capacity, "Initial battery capacity in percent (0-100)");
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static int discharge_rate = 1; // % per tick when discharging
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module_param(discharge_rate, int, 0644);
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MODULE_PARM_DESC(discharge_rate, "Capacity percent drop per second while discharging");
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static int charge_rate = 2; // % per tick when charging
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module_param(charge_rate, int, 0644);
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MODULE_PARM_DESC(charge_rate, "Capacity percent rise per second while charging");
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static bool start_charging; // start in charging state?
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module_param(start_charging, bool, 0644);
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MODULE_PARM_DESC(start_charging, "Start as charging (true) or discharging (false)");
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static bool start_online_ac; // start with AC online?
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module_param(start_online_ac, bool, 0644);
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MODULE_PARM_DESC(start_online_ac, "Start with AC (mains) online (true/false)");
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/* --- Property list --- */
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static enum power_supply_property dummy_props[] = {
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POWER_SUPPLY_PROP_STATUS,
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POWER_SUPPLY_PROP_PRESENT,
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POWER_SUPPLY_PROP_ONLINE, // AC online
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POWER_SUPPLY_PROP_CAPACITY, // %
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POWER_SUPPLY_PROP_VOLTAGE_NOW, // uV
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POWER_SUPPLY_PROP_CURRENT_NOW, // uA
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POWER_SUPPLY_PROP_TEMP, // 0.1C
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POWER_SUPPLY_PROP_HEALTH,
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POWER_SUPPLY_PROP_TECHNOLOGY,
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POWER_SUPPLY_PROP_SCOPE,
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};
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/* --- Get properties --- */
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static int dummy_get_property(struct power_supply *psy,
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enum power_supply_property psp,
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union power_supply_propval *val)
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{
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struct dummy_batt *db = power_supply_get_drvdata(psy);
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mutex_lock(&db->lock);
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switch (psp) {
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case POWER_SUPPLY_PROP_STATUS:
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val->intval = db->status;
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break;
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case POWER_SUPPLY_PROP_PRESENT:
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val->intval = 1; // battery is always present
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break;
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case POWER_SUPPLY_PROP_ONLINE:
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// represents AC adapter presence for this battery device
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val->intval = db->online_ac ? 1 : 0;
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break;
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case POWER_SUPPLY_PROP_CAPACITY:
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val->intval = db->capacity;
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break;
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case POWER_SUPPLY_PROP_VOLTAGE_NOW:
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val->intval = db->voltage_uV;
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break;
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case POWER_SUPPLY_PROP_CURRENT_NOW:
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val->intval = db->current_uA;
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break;
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case POWER_SUPPLY_PROP_TEMP:
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val->intval = db->temp_deciC;
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break;
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case POWER_SUPPLY_PROP_HEALTH:
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val->intval = POWER_SUPPLY_HEALTH_GOOD;
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break;
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case POWER_SUPPLY_PROP_TECHNOLOGY:
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val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
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break;
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case POWER_SUPPLY_PROP_SCOPE:
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val->intval = POWER_SUPPLY_SCOPE_SYSTEM;
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break;
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default:
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mutex_unlock(&db->lock);
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return -EINVAL;
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}
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mutex_unlock(&db->lock);
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return 0;
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}
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/* Optional: allow some properties to be set via sysfs writes for fun */
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static int dummy_set_property(struct power_supply *psy,
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enum power_supply_property psp,
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const union power_supply_propval *val)
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{
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struct dummy_batt *db = power_supply_get_drvdata(psy);
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mutex_lock(&db->lock);
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switch (psp) {
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case POWER_SUPPLY_PROP_ONLINE:
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db->online_ac = val->intval ? true : false;
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db->status = db->online_ac ? POWER_SUPPLY_STATUS_CHARGING
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: POWER_SUPPLY_STATUS_DISCHARGING;
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break;
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case POWER_SUPPLY_PROP_STATUS:
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/* Allow forcing status. Note: AC ONLINE won't auto-toggle */
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switch (val->intval) {
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case POWER_SUPPLY_STATUS_CHARGING:
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case POWER_SUPPLY_STATUS_DISCHARGING:
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case POWER_SUPPLY_STATUS_NOT_CHARGING:
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case POWER_SUPPLY_STATUS_FULL:
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db->status = val->intval;
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break;
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default:
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mutex_unlock(&db->lock);
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return -EINVAL;
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}
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break;
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case POWER_SUPPLY_PROP_CAPACITY:
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if (val->intval < 0 || val->intval > 100) {
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mutex_unlock(&db->lock);
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return -ERANGE;
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}
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db->capacity = val->intval;
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break;
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default:
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mutex_unlock(&db->lock);
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return -EINVAL;
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}
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mutex_unlock(&db->lock);
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// Tell userspace things changed
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power_supply_changed(psy);
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return 0;
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}
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static int dummy_property_is_writeable(struct power_supply *psy,
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enum power_supply_property psp)
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{
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switch (psp) {
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case POWER_SUPPLY_PROP_ONLINE:
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case POWER_SUPPLY_PROP_STATUS:
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case POWER_SUPPLY_PROP_CAPACITY:
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return 1;
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default:
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return 0;
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}
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}
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/* --- Simulation loop --- */
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static void dummy_sim_work(struct work_struct *work)
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{
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struct dummy_batt *db = container_of(to_delayed_work(work),
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struct dummy_batt, sim_work);
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bool changed = false;
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mutex_lock(&db->lock);
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if (db->status == POWER_SUPPLY_STATUS_CHARGING && db->capacity < 100) {
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db->capacity += charge_rate;
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if (db->capacity >= 100) {
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db->capacity = 100;
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db->status = POWER_SUPPLY_STATUS_FULL;
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}
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changed = true;
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} else if (db->status == POWER_SUPPLY_STATUS_DISCHARGING && db->capacity > 0) {
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db->capacity -= discharge_rate;
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if (db->capacity <= 0) {
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db->capacity = 0;
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db->status = POWER_SUPPLY_STATUS_NOT_CHARGING;
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}
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changed = true;
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}
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/* Simple linear voltage model: 3.5V @0% .. 4.2V @100% */
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db->voltage_uV = 3500000 + (db->capacity * 7000); // 3.5V + 0.007V * %
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/* Current sign tracks status */
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if (db->status == POWER_SUPPLY_STATUS_CHARGING)
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db->current_uA = 80000; // +80 mA
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else if (db->status == POWER_SUPPLY_STATUS_DISCHARGING)
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db->current_uA = -50000; // -50 mA
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else
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db->current_uA = 0;
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mutex_unlock(&db->lock);
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if (changed)
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power_supply_changed(db->psy);
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/* Reschedule */
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schedule_delayed_work(&db->sim_work, msecs_to_jiffies(TICK_MS));
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}
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/* --- Platform plumbing (we create our own pdev) --- */
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static struct platform_device *dummy_pdev;
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static int dummy_probe(struct platform_device *pdev)
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{
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struct power_supply_config cfg = {};
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struct dummy_batt *db;
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int ret;
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db = devm_kzalloc(&pdev->dev, sizeof(*db), GFP_KERNEL);
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if (!db)
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return -ENOMEM;
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mutex_init(&db->lock);
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db->desc.name = "dummy-battery";
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db->desc.type = POWER_SUPPLY_TYPE_BATTERY;
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db->desc.properties = dummy_props;
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db->desc.num_properties = ARRAY_SIZE(dummy_props);
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db->desc.get_property = dummy_get_property;
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db->desc.set_property = dummy_set_property;
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db->desc.property_is_writeable = dummy_property_is_writeable;
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/* Initial state */
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db->capacity = clamp(start_capacity, 0, 100);
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db->voltage_uV = DFLT_VOLTAGE_UV;
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db->current_uA = DFLT_CURRENT_UA;
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db->temp_deciC = DFLT_TEMP_DECIC;
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db->online_ac = start_online_ac;
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db->status = start_charging ? POWER_SUPPLY_STATUS_CHARGING
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: POWER_SUPPLY_STATUS_DISCHARGING;
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cfg.drv_data = db;
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db->psy = devm_power_supply_register(&pdev->dev, &db->desc, &cfg);
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if (IS_ERR(db->psy)) {
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ret = PTR_ERR(db->psy);
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dev_err(&pdev->dev, "power_supply_register failed: %d\n", ret);
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return ret;
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}
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INIT_DELAYED_WORK(&db->sim_work, dummy_sim_work);
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schedule_delayed_work(&db->sim_work, msecs_to_jiffies(TICK_MS));
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platform_set_drvdata(pdev, db);
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dev_info(&pdev->dev, "dummy-battery registered, start_capacity=%d%%\n", db->capacity);
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return 0;
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}
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static void dummy_remove(struct platform_device *pdev)
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{
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struct dummy_batt *db = platform_get_drvdata(pdev);
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cancel_delayed_work_sync(&db->sim_work);
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}
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static struct platform_driver dummy_driver = {
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.probe = dummy_probe,
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.remove = dummy_remove,
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.driver = {
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.name = DRV_NAME,
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},
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};
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static int __init dummy_init(void)
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{
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int ret;
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dummy_pdev = platform_device_register_simple(DRV_NAME, -1, NULL, 0);
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if (IS_ERR(dummy_pdev))
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return PTR_ERR(dummy_pdev);
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ret = platform_driver_register(&dummy_driver);
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if (ret) {
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platform_device_unregister(dummy_pdev);
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return ret;
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}
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pr_info(DRV_NAME ": loaded\n");
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return 0;
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}
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module_init(dummy_init);
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static void __exit dummy_exit(void)
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{
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platform_driver_unregister(&dummy_driver);
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platform_device_unregister(dummy_pdev);
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pr_info(DRV_NAME ": unloaded\n");
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}
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module_exit(dummy_exit);
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MODULE_AUTHOR("You");
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MODULE_DESCRIPTION("Dummy battery power_supply driver");
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MODULE_LICENSE("GPL");
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