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.
Tested-by: Kevin Locke <kevin@xxxxxxxxxxxxxxx>
Tested-by: Christoph Böhmwalder <christoph@xxxxxxxxxxxxxx>
Signed-off-by: Ognjen Galic <smclt30p@xxxxxxxxx>
---
drivers/acpi/ac.c | 2 +-
drivers/acpi/battery.c | 139 ++++++++++++++++++++++++++++++++++++++++++++++++-
drivers/acpi/battery.h | 11 ----
drivers/acpi/sbs.c | 2 +-
include/acpi/battery.h | 21 ++++++++
5 files changed, 160 insertions(+), 15 deletions(-)
delete mode 100644 drivers/acpi/battery.h
create mode 100644 include/acpi/battery.h
diff --git a/drivers/acpi/ac.c b/drivers/acpi/ac.c
index 47a7ed5..2d8de2f 100644
--- a/drivers/acpi/ac.c
+++ b/drivers/acpi/ac.c
@@ -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: "
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 13e7b56..2951d07 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -30,6 +30,7 @@
#include <linux/dmi.h>
#include <linux/delay.h>
#include <linux/slab.h>
+#include <linux/list.h>
#include <linux/suspend.h>
#include <asm/unaligned.h>
@@ -42,7 +43,7 @@
#include <linux/acpi.h>
#include <linux/power_supply.h>
-#include "battery.h"
+#include <acpi/battery.h>
#define PREFIX "ACPI: "
@@ -124,6 +125,7 @@ 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;
@@ -626,6 +628,137 @@ 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.
+ *
+ */
+
+LIST_HEAD(acpi_battery_list);
+LIST_HEAD(battery_hook_list);
+
+void battery_hook_unregister(struct acpi_battery_hook *hook)
+{
+
+ struct list_head *position;
+ struct acpi_battery *battery;
+
+ /*
+ * In order to remove a hook, we first need to
+ * de-register all the batteries that are registered.
+ */
+
+ list_for_each(position, &acpi_battery_list) {
+ battery = list_entry(position, struct acpi_battery, list);
+ hook->remove_battery(battery->bat);
+ }
+
+ /* Then, just remove the hook */
+
+ list_del(&hook->list);
+ pr_info("battery: extension unregistered: %s\n", hook->name);
+
+}
+EXPORT_SYMBOL_GPL(battery_hook_unregister);
+
+void battery_hook_register(struct acpi_battery_hook *hook)
+{
+ struct list_head *position;
+ struct acpi_battery *battery;
+
+ 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(position, &acpi_battery_list) {
+ battery = list_entry(position, struct acpi_battery, list);
+ if (hook->add_battery(battery->bat)) {
+
+ /*
+ * If a add-battery returns non-zero,
+ * the registration of the extension has failed,
+ * we will unload it.
+ */
+ pr_err("battery: extension failed to load: %s",
+ hook->name);
+ battery_hook_unregister(hook);
+ return;
+
+ }
+ }
+
+ pr_info("battery: new extension: %s\n", hook->name);
+
+}
+EXPORT_SYMBOL_GPL(battery_hook_register);
+
+static void battery_hook_add_battery(struct acpi_battery *battery)
+{
+
+ /*
+ * 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.
+ */
+
+ struct list_head *position;
+ struct acpi_battery_hook *hook_node;
+
+ 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(position, &battery_hook_list) {
+ hook_node = list_entry(position, struct acpi_battery_hook, 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);
+ pr_err("battery: error in extension, unloading: %s",
+ hook_node->name);
+ }
+ }
+
+}
+
+static void battery_hook_remove_battery(struct acpi_battery *battery)
+{
+ struct list_head *position;
+ struct acpi_battery_hook *hook;
+
+ /*
+ * Before removing the hook, we need to remove all
+ * custom attributes from the battery.
+ */
+ list_for_each(position, &battery_hook_list) {
+ hook = list_entry(position, struct acpi_battery_hook, list);
+ hook->remove_battery(battery->bat);
+ }
+
+ /* Then, just remove the battery from the list */
+
+ list_del(&battery->list);
+
+}
+
static int sysfs_add_battery(struct acpi_battery *battery)
{
struct power_supply_config psy_cfg = { .drv_data = battery, };
@@ -647,6 +780,8 @@ static int sysfs_add_battery(struct acpi_battery *battery)
battery->bat = power_supply_register_no_ws(&battery->device->dev,
&battery->bat_desc, &psy_cfg);
+ battery_hook_add_battery(battery);
