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authorOgnjen Galic <smclt30p@gmail.com>2018-02-07 17:58:13 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-02-22 01:27:13 +0300
commitfa93854f7a7ed63d054405bf3779247d5300edd3 (patch)
treefa4d31fbd9f2946d683a0534b456be3c68b6ad03 /drivers/acpi/battery.c
parent91ab883eb21325ad80f3473633f794c78ac87f51 (diff)
downloadlinux-fa93854f7a7ed63d054405bf3779247d5300edd3.tar.xz
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>
Diffstat (limited to 'drivers/acpi/battery.c')
-rw-r--r--drivers/acpi/battery.c147
1 files changed, 144 insertions, 3 deletions
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 7128488a3a72..f14a2bb1f7cd 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -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);