battery: Add the battery hooking API
This is a patch that implements a generic hooking API for the generic ACPI battery driver. With this new generic API, drivers can expose platform specific behaviour via sysfs attributes in /sys/class/power_supply/BATn/ in a generic way. A perfect example of the need for this API are Lenovo ThinkPads. Lenovo ThinkPads have a ACPI extension that allows the setting of start and stop charge thresholds in the EC and battery firmware via ACPI. The thinkpad_acpi module can use this API to expose sysfs attributes that it controls inside the ACPI battery driver sysfs tree, under /sys/class/power_supply/BATN/. The file drivers/acpi/battery.h has been moved to include/acpi/battery.h and the includes inside ac.c, sbs.c, and battery.c have been adjusted to reflect that. When drivers hooks into the API, the API calls add_battery() for each battery in the system that passes it a acpi_battery struct. Then, the drivers can use device_create_file() to create new sysfs attributes with that struct and identify the batteries for per-battery attributes. Signed-off-by: Ognjen Galic <smclt30p@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Ognjen Galic
Rafael J. Wysocki
parent
91ab883eb2
commit
fa93854f7a
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@ -33,7 +33,7 @@
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#include <linux/platform_device.h>
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#include <linux/power_supply.h>
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#include <linux/acpi.h>
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#include "battery.h"
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#include <acpi/battery.h>
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#define PREFIX "ACPI: "
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@ -21,8 +21,12 @@
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/init.h>
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#include <linux/types.h>
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#include <linux/jiffies.h>
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@ -42,7 +46,7 @@
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#include <linux/acpi.h>
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#include <linux/power_supply.h>
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#include "battery.h"
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#include <acpi/battery.h>
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#define PREFIX "ACPI: "
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@ -125,6 +129,7 @@ struct acpi_battery {
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struct power_supply_desc bat_desc;
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struct acpi_device *device;
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struct notifier_block pm_nb;
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struct list_head list;
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unsigned long update_time;
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int revision;
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int rate_now;
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@ -630,6 +635,139 @@ static const struct device_attribute alarm_attr = {
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.store = acpi_battery_alarm_store,
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};
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/*
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* The Battery Hooking API
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*
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* This API is used inside other drivers that need to expose
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* platform-specific behaviour within the generic driver in a
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* generic way.
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*
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*/
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static LIST_HEAD(acpi_battery_list);
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static LIST_HEAD(battery_hook_list);
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static DEFINE_MUTEX(hook_mutex);
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void __battery_hook_unregister(struct acpi_battery_hook *hook, int lock)
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{
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struct acpi_battery *battery;
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/*
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* In order to remove a hook, we first need to
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* de-register all the batteries that are registered.
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*/
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if (lock)
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mutex_lock(&hook_mutex);
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list_for_each_entry(battery, &acpi_battery_list, list) {
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hook->remove_battery(battery->bat);
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}
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list_del(&hook->list);
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if (lock)
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mutex_unlock(&hook_mutex);
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pr_info("extension unregistered: %s\n", hook->name);
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}
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void battery_hook_unregister(struct acpi_battery_hook *hook)
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{
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__battery_hook_unregister(hook, 1);
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}
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EXPORT_SYMBOL_GPL(battery_hook_unregister);
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void battery_hook_register(struct acpi_battery_hook *hook)
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{
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struct acpi_battery *battery;
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mutex_lock(&hook_mutex);
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INIT_LIST_HEAD(&hook->list);
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list_add(&hook->list, &battery_hook_list);
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/*
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* Now that the driver is registered, we need
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* to notify the hook that a battery is available
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* for each battery, so that the driver may add
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* its attributes.
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*/
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list_for_each_entry(battery, &acpi_battery_list, list) {
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if (hook->add_battery(battery->bat)) {
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/*
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* If a add-battery returns non-zero,
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* the registration of the extension has failed,
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* and we will not add it to the list of loaded
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* hooks.
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*/
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pr_err("extension failed to load: %s", hook->name);
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__battery_hook_unregister(hook, 0);
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return;
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}
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}
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pr_info("new extension: %s\n", hook->name);
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mutex_unlock(&hook_mutex);
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}
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EXPORT_SYMBOL_GPL(battery_hook_register);
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/*
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* This function gets called right after the battery sysfs
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* attributes have been added, so that the drivers that
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* define custom sysfs attributes can add their own.
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*/
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static void battery_hook_add_battery(struct acpi_battery *battery)
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{
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struct acpi_battery_hook *hook_node;
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mutex_lock(&hook_mutex);
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INIT_LIST_HEAD(&battery->list);
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list_add(&battery->list, &acpi_battery_list);
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/*
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* Since we added a new battery to the list, we need to
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* iterate over the hooks and call add_battery for each
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* hook that was registered. This usually happens
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* when a battery gets hotplugged or initialized
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* during the battery module initialization.
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*/
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list_for_each_entry(hook_node, &battery_hook_list, list) {
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if (hook_node->add_battery(battery->bat)) {
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/*
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* The notification of the extensions has failed, to
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* prevent further errors we will unload the extension.
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*/
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__battery_hook_unregister(hook_node, 0);
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pr_err("error in extension, unloading: %s",
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hook_node->name);
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}
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}
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mutex_unlock(&hook_mutex);
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}
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static void battery_hook_remove_battery(struct acpi_battery *battery)
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{
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struct acpi_battery_hook *hook;
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mutex_lock(&hook_mutex);
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/*
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* Before removing the hook, we need to remove all
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* custom attributes from the battery.
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*/
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list_for_each_entry(hook, &battery_hook_list, list) {
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hook->remove_battery(battery->bat);
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}
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/* Then, just remove the battery from the list */
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list_del(&battery->list);
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mutex_unlock(&hook_mutex);
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}
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static void __exit battery_hook_exit(void)
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{
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struct acpi_battery_hook *hook;
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struct acpi_battery_hook *ptr;
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/*
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* At this point, the acpi_bus_unregister_driver()
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* has called remove for all batteries. We just
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* need to remove the hooks.
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*/
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list_for_each_entry_safe(hook, ptr, &battery_hook_list, list) {
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__battery_hook_unregister(hook, 1);
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}
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mutex_destroy(&hook_mutex);
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}
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static int sysfs_add_battery(struct acpi_battery *battery)
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{
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struct power_supply_config psy_cfg = { .drv_data = battery, };
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@ -657,6 +795,7 @@ static int sysfs_add_battery(struct acpi_battery *battery)
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battery->bat = NULL;
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return result;
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}
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battery_hook_add_battery(battery);
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return device_create_file(&battery->bat->dev, &alarm_attr);
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}
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@ -667,7 +806,7 @@ static void sysfs_remove_battery(struct acpi_battery *battery)
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mutex_unlock(&battery->sysfs_lock);
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return;
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}
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battery_hook_remove_battery(battery);
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device_remove_file(&battery->bat->dev, &alarm_attr);
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power_supply_unregister(battery->bat);
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battery->bat = NULL;
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@ -1399,8 +1538,10 @@ static int __init acpi_battery_init(void)
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static void __exit acpi_battery_exit(void)
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{
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async_synchronize_cookie(async_cookie + 1);
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if (battery_driver_registered)
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if (battery_driver_registered) {
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acpi_bus_unregister_driver(&acpi_battery_driver);
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battery_hook_exit();
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}
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#ifdef CONFIG_ACPI_PROCFS_POWER
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if (acpi_battery_dir)
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acpi_unlock_battery_dir(acpi_battery_dir);
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@ -1,11 +0,0 @@
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ACPI_BATTERY_H
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#define __ACPI_BATTERY_H
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#define ACPI_BATTERY_CLASS "battery"
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#define ACPI_BATTERY_NOTIFY_STATUS 0x80
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#define ACPI_BATTERY_NOTIFY_INFO 0x81
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#define ACPI_BATTERY_NOTIFY_THRESHOLD 0x82
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#endif
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@ -32,9 +32,9 @@
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#include <linux/delay.h>
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#include <linux/power_supply.h>
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#include <linux/platform_data/x86/apple.h>
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#include <acpi/battery.h>
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#include "sbshc.h"
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#include "battery.h"
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#define PREFIX "ACPI: "
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@ -0,0 +1,21 @@
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ACPI_BATTERY_H
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#define __ACPI_BATTERY_H
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#define ACPI_BATTERY_CLASS "battery"
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#define ACPI_BATTERY_NOTIFY_STATUS 0x80
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#define ACPI_BATTERY_NOTIFY_INFO 0x81
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#define ACPI_BATTERY_NOTIFY_THRESHOLD 0x82
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struct acpi_battery_hook {
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const char *name;
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int (*add_battery)(struct power_supply *battery);
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int (*remove_battery)(struct power_supply *battery);
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struct list_head list;
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};
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void battery_hook_register(struct acpi_battery_hook *hook);
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void battery_hook_unregister(struct acpi_battery_hook *hook);
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#endif
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