Commit fa93854f authored by Ognjen Galic's avatar Ognjen Galic Committed by Rafael J. Wysocki

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: default avatarOgnjen Galic <smclt30p@gmail.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 91ab883e
......@@ -33,7 +33,7 @@
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/acpi.h>
#include "battery.h"
#include <acpi/battery.h>
#define PREFIX "ACPI: "
......
......@@ -21,8 +21,12 @@
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/jiffies.h>
......@@ -42,7 +46,7 @@
#include <linux/acpi.h>
#include <linux/power_supply.h>
#include "battery.h"
#include <acpi/battery.h>
#define PREFIX "ACPI: "
......@@ -125,6 +129,7 @@ struct acpi_battery {
struct power_supply_desc bat_desc;
struct acpi_device *device;
struct notifier_block pm_nb;
struct list_head list;
unsigned long update_time;
int revision;
int rate_now;
......@@ -630,6 +635,139 @@ static const struct device_attribute alarm_attr = {
.store = acpi_battery_alarm_store,
};
/*
* The Battery Hooking API
*
* This API is used inside other drivers that need to expose
* platform-specific behaviour within the generic driver in a
* generic way.
*
*/
static LIST_HEAD(acpi_battery_list);
static LIST_HEAD(battery_hook_list);
static DEFINE_MUTEX(hook_mutex);
void __battery_hook_unregister(struct acpi_battery_hook *hook, int lock)
{
struct acpi_battery *battery;
/*
* In order to remove a hook, we first need to
* de-register all the batteries that are registered.
*/
if (lock)
mutex_lock(&hook_mutex);
list_for_each_entry(battery, &acpi_battery_list, list) {
hook->remove_battery(battery->bat);
}
list_del(&hook->list);
if (lock)
mutex_unlock(&hook_mutex);
pr_info("extension unregistered: %s\n", hook->name);
}
void battery_hook_unregister(struct acpi_battery_hook *hook)
{
__battery_hook_unregister(hook, 1);
}
EXPORT_SYMBOL_GPL(battery_hook_unregister);
void battery_hook_register(struct acpi_battery_hook *hook)
{
struct acpi_battery *battery;
mutex_lock(&hook_mutex);
INIT_LIST_HEAD(&hook->list);
list_add(&hook->list, &battery_hook_list);
/*
* Now that the driver is registered, we need
* to notify the hook that a battery is available
* for each battery, so that the driver may add
* its attributes.
*/
list_for_each_entry(battery, &acpi_battery_list, list) {
if (hook->add_battery(battery->bat)) {
/*
* If a add-battery returns non-zero,
* the registration of the extension has failed,
* and we will not add it to the list of loaded
* hooks.
*/
pr_err("extension failed to load: %s", hook->name);
__battery_hook_unregister(hook, 0);
return;
}
}
pr_info("new extension: %s\n", hook->name);
mutex_unlock(&hook_mutex);
}
EXPORT_SYMBOL_GPL(battery_hook_register);
/*
* This function gets called right after the battery sysfs
* attributes have been added, so that the drivers that
* define custom sysfs attributes can add their own.
*/
static void battery_hook_add_battery(struct acpi_battery *battery)
{
struct acpi_battery_hook *hook_node;
mutex_lock(&hook_mutex);
INIT_LIST_HEAD(&battery->list);
list_add(&battery->list, &acpi_battery_list);
/*
* Since we added a new battery to the list, we need to
* iterate over the hooks and call add_battery for each
* hook that was registered. This usually happens
* when a battery gets hotplugged or initialized
* during the battery module initialization.
*/
list_for_each_entry(hook_node, &battery_hook_list, list) {
if (hook_node->add_battery(battery->bat)) {
/*
* The notification of the extensions has failed, to
* prevent further errors we will unload the extension.
*/
__battery_hook_unregister(hook_node, 0);
pr_err("error in extension, unloading: %s",
hook_node->name);
}
}
mutex_unlock(&hook_mutex);
}
static void battery_hook_remove_battery(struct acpi_battery *battery)
{
struct acpi_battery_hook *hook;
mutex_lock(&hook_mutex);
/*
* Before removing the hook, we need to remove all
* custom attributes from the battery.
*/
list_for_each_entry(hook, &battery_hook_list, list) {
hook->remove_battery(battery->bat);
}
/* Then, just remove the battery from the list */
list_del(&battery->list);
mutex_unlock(&hook_mutex);
}
static void __exit battery_hook_exit(void)
{
struct acpi_battery_hook *hook;
struct acpi_battery_hook *ptr;
/*
* At this point, the acpi_bus_unregister_driver()
* has called remove for all batteries. We just
* need to remove the hooks.
*/
list_for_each_entry_safe(hook, ptr, &battery_hook_list, list) {
__battery_hook_unregister(hook, 1);
}
mutex_destroy(&hook_mutex);
}
static int sysfs_add_battery(struct acpi_battery *battery)
{
struct power_supply_config psy_cfg = { .drv_data = battery, };
......@@ -657,6 +795,7 @@ static int sysfs_add_battery(struct acpi_battery *battery)
battery->bat = NULL;
return result;
}
battery_hook_add_battery(battery);
return device_create_file(&battery->bat->dev, &alarm_attr);
}
......@@ -667,7 +806,7 @@ static void sysfs_remove_battery(struct acpi_battery *battery)
mutex_unlock(&battery->sysfs_lock);
return;
}
battery_hook_remove_battery(battery);
device_remove_file(&battery->bat->dev, &alarm_attr);
power_supply_unregister(battery->bat);
battery->bat = NULL;
......@@ -1399,8 +1538,10 @@ static int __init acpi_battery_init(void)
static void __exit acpi_battery_exit(void)
{
async_synchronize_cookie(async_cookie + 1);
if (battery_driver_registered)
if (battery_driver_registered) {
acpi_bus_unregister_driver(&acpi_battery_driver);
battery_hook_exit();
}
#ifdef CONFIG_ACPI_PROCFS_POWER
if (acpi_battery_dir)
acpi_unlock_battery_dir(acpi_battery_dir);
......
......@@ -32,9 +32,9 @@
#include <linux/delay.h>
#include <linux/power_supply.h>
#include <linux/platform_data/x86/apple.h>
#include <acpi/battery.h>
#include "sbshc.h"
#include "battery.h"
#define PREFIX "ACPI: "
......
......@@ -8,4 +8,14 @@
#define ACPI_BATTERY_NOTIFY_INFO 0x81
#define ACPI_BATTERY_NOTIFY_THRESHOLD 0x82
struct acpi_battery_hook {
const char *name;
int (*add_battery)(struct power_supply *battery);
int (*remove_battery)(struct power_supply *battery);
struct list_head list;
};
void battery_hook_register(struct acpi_battery_hook *hook);
void battery_hook_unregister(struct acpi_battery_hook *hook);
#endif
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