Various drivers, mostly in platform/x86 extend the ACPI battery driver
with additional sysfs attributes to implement more UAPIs than are
exposed through ACPI by using various side-channels, like WMI,
nonstandard ACPI or EC communication.
While the created sysfs attributes look similar to the attributes
provided by the powersupply core, there are various deficiencies:
* They don't show up in uevent payload.
* They can't be queried with the standard in-kernel APIs.
* They don't work with triggers.
* The extending driver has to reimplement all of the parsing,
formatting and sysfs display logic.
* Writing a extension driver is completely different from writing a
normal power supply driver.
This extension API avoids all of these issues.
An extension is just a "struct power_supply_ext" with the same kind of
callbacks as in a normal "struct power_supply_desc".
The API is meant to be used via battery_hook_register(), the same way as
the current extensions.
Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
---
drivers/power/supply/power_supply.h | 14 +++
drivers/power/supply/power_supply_core.c | 159 ++++++++++++++++++++++++++++--
drivers/power/supply/power_supply_sysfs.c | 26 ++++-
include/linux/power_supply.h | 32 ++++++
4 files changed, 221 insertions(+), 10 deletions(-)
diff --git a/drivers/power/supply/power_supply.h b/drivers/power/supply/power_supply.h
index 5dabbd895538003096b62d03fdd0201b82b090e6..4c3e602c416cec556173a8eb1a3114c13ded71b7 100644
--- a/drivers/power/supply/power_supply.h
+++ b/drivers/power/supply/power_supply.h
@@ -9,6 +9,8 @@
* Modified: 2004, Oct Szabolcs Gyurko
*/
+#include <linux/lockdep.h>
+
struct device;
struct device_type;
struct power_supply;
@@ -17,6 +19,18 @@ extern int power_supply_property_is_writeable(struct power_supply *psy,
enum power_supply_property psp);
extern bool power_supply_has_property(struct power_supply *psy,
enum power_supply_property psp);
+extern bool power_supply_ext_has_property(const struct power_supply_ext *ext,
+ enum power_supply_property psp);
+
+struct power_supply_ext_registration {
+ struct list_head list_head;
+ const struct power_supply_ext *ext;
+ void *data;
+};
+
+#define power_supply_for_each_extension(pos, psy) \
+ lockdep_assert_held(&(psy)->extensions_sem); \
+ list_for_each_entry(pos, &(psy)->extensions, list_head)
#ifdef CONFIG_SYSFS
diff --git a/drivers/power/supply/power_supply_core.c b/drivers/power/supply/power_supply_core.c
index 502b07468b93dfb7f5a6c2092588d931a7d015f2..72d9205130d2ec9b7b401eddb7461a58e0be49e5 100644
--- a/drivers/power/supply/power_supply_core.c
+++ b/drivers/power/supply/power_supply_core.c
@@ -81,6 +81,7 @@ static int __power_supply_changed_work(struct device *dev, void *data)
static void power_supply_changed_work(struct work_struct *work)
{
+ int ret;
unsigned long flags;
struct power_supply *psy = container_of(work, struct power_supply,
changed_work);
@@ -88,6 +89,16 @@ static void power_supply_changed_work(struct work_struct *work)
dev_dbg(&psy->dev, "%s\n", __func__);
spin_lock_irqsave(&psy->changed_lock, flags);
+
+ if (unlikely(psy->update_groups)) {
+ psy->update_groups = false;
+ spin_unlock_irqrestore(&psy->changed_lock, flags);
+ ret = sysfs_update_groups(&psy->dev.kobj, power_supply_dev_type.groups);
+ if (ret)
+ dev_warn(&psy->dev, "failed to update sysfs groups: %pe\n", ERR_PTR(ret));
+ spin_lock_irqsave(&psy->changed_lock, flags);
+ }
+
/*
* Check 'changed' here to avoid issues due to race between
* power_supply_changed() and this routine. In worst case
@@ -1196,15 +1207,34 @@ static bool psy_desc_has_property(const struct power_supply_desc *psy_desc,
return found;
}
+bool power_supply_ext_has_property(const struct power_supply_ext *psy_ext,
+ enum power_supply_property psp)
+{
+ int i;
+
+ for (i = 0; i < psy_ext->num_properties; i++)
+ if (psy_ext->properties[i] == psp)
+ return true;
+
+ return false;
+}
+
bool power_supply_has_property(struct power_supply *psy,
enum power_supply_property psp)
{
+ struct power_supply_ext_registration *reg;
+
if (psy_desc_has_property(psy->desc, psp))
return true;
if (power_supply_battery_info_has_prop(psy->battery_info, psp))
return true;
+ power_supply_for_each_extension(reg, psy) {
+ if (power_supply_ext_has_property(reg->ext, psp))
+ return true;
+ }
+
return false;
}
@@ -1212,12 +1242,21 @@ int power_supply_get_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
{
+ struct power_supply_ext_registration *reg;
+
if (atomic_read(&psy->use_cnt) <= 0) {
if (!psy->initialized)
return -EAGAIN;
return -ENODEV;
}
+ scoped_guard(rwsem_read, &psy->extensions_sem) {
+ power_supply_for_each_extension(reg, psy) {
+ if (power_supply_ext_has_property(reg->ext, psp))
+ return reg->ext->get_property(psy, reg->ext, reg->data, psp, val);
+ }
+ }
+
if (psy_desc_has_property(psy->desc, psp))
return psy->desc->get_property(psy, psp, val);
else if (power_supply_battery_info_has_prop(psy->battery_info, psp))
@@ -1231,7 +1270,24 @@ int power_supply_set_property(struct power_supply *psy,
enum power_supply_property psp,
const union power_supply_propval *val)
{
- if (atomic_read(&psy->use_cnt) <= 0 || !psy->desc->set_property)
+ struct power_supply_ext_registration *reg;
+
+ if (atomic_read(&psy->use_cnt) <= 0)
+ return -ENODEV;
+
+ scoped_guard(rwsem_read, &psy->extensions_sem) {
+ power_supply_for_each_extension(reg, psy) {
+ if (power_supply_ext_has_property(reg->ext, psp)) {
+ if (reg->ext->set_property)
+ return reg->ext->set_property(psy, reg->ext, reg->data,
+ psp, val);
+ else
+ return -ENODEV;
+ }
+ }
+ }
+
+ if (!psy->desc->set_property)
return -ENODEV;
return psy->desc->set_property(psy, psp, val);
@@ -1241,7 +1297,22 @@ EXPORT_SYMBOL_GPL(power_supply_set_property);
int power_supply_property_is_writeable(struct power_supply *psy,
enum power_supply_property psp)
{
- return psy->desc->property_is_writeable && psy->desc->property_is_writeable(psy, psp);
+ struct power_supply_ext_registration *reg;
+
+ power_supply_for_each_extension(reg, psy) {
+ if (power_supply_ext_has_property(reg->ext, psp)) {
+ if (reg->ext->property_is_writeable)
+ return reg->ext->property_is_writeable(psy, reg->ext,
+ reg->data, psp);
+ else
+ return -ENODEV;
+ }
+ }
+
+ if (!psy->desc->property_is_writeable)
+ return -ENODEV;
+
+ return psy->desc->property_is_writeable(psy, psp);
}
void power_supply_external_power_changed(struct power_supply *psy)
@@ -1260,6 +1331,73 @@ int power_supply_powers(struct power_supply *psy, struct device *dev)
}
EXPORT_SYMBOL_GPL(power_supply_powers);
+static int power_supply_update_sysfs_and_hwmon(struct power_supply *psy)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&psy->changed_lock, flags);
+ psy->update_groups = true;
+ spin_unlock_irqrestore(&psy->changed_lock, flags);
+
+ power_supply_changed(psy);
+
+ power_supply_remove_hwmon_sysfs(psy);
+ return power_supply_add_hwmon_sysfs(psy);
+}
+
+int power_supply_register_extension(struct power_supply *psy, const struct power_supply_ext *ext,
+ void *data)
+{
+ struct power_supply_ext_registration *reg;
+ size_t i;
+ int ret;
+
+ if (!psy || !ext || !ext->properties || !ext->num_properties)
+ return -EINVAL;
+
+ guard(rwsem_write)(&psy->extensions_sem);
+
+ for (i = 0; i < ext->num_properties; i++)
+ if (power_supply_has_property(psy, ext->properties[i]))
+ return -EEXIST;
+
+ reg = kmalloc(sizeof(*reg), GFP_KERNEL);
+ if (!reg)
+ return -ENOMEM;
+
+ reg->ext = ext;
+ reg->data = data;
+ list_add(®->list_head, &psy->extensions);
+
+ ret = power_supply_update_sysfs_and_hwmon(psy);
+ if (ret) {
+ list_del(®->list_head);
+ kfree(reg);
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(power_supply_register_extension);
+
+void power_supply_unregister_extension(struct power_supply *psy, const struct power_supply_ext *ext)
+{
+ struct power_supply_ext_registration *reg;
+
+ guard(rwsem_write)(&psy->extensions_sem);
+
+ power_supply_for_each_extension(reg, psy) {
+ if (reg->ext == ext) {
+ list_del(®->list_head);
+ kfree(reg);
+ power_supply_update_sysfs_and_hwmon(psy);
+ return;
+ }
+ }
+
+ dev_warn(&psy->dev, "Trying to unregister invalid extension");
+}
+EXPORT_SYMBOL_GPL(power_supply_unregister_extension);
+
static void power_supply_dev_release(struct device *dev)
{
struct power_supply *psy = to_power_supply(dev);
@@ -1414,6 +1552,9 @@ __power_supply_register(struct device *parent,
}
spin_lock_init(&psy->changed_lock);
+ init_rwsem(&psy->extensions_sem);
+ INIT_LIST_HEAD(&psy->extensions);
+
rc = device_add(dev);
if (rc)
goto device_add_failed;
@@ -1426,13 +1567,15 @@ __power_supply_register(struct device *parent,
if (rc)
goto register_thermal_failed;
- rc = power_supply_create_triggers(psy);
- if (rc)
- goto create_triggers_failed;
+ scoped_guard(rwsem_read, &psy->extensions_sem) {
+ rc = power_supply_create_triggers(psy);
+ if (rc)
+ goto create_triggers_failed;
- rc = power_supply_add_hwmon_sysfs(psy);
- if (rc)
- goto add_hwmon_sysfs_failed;
+ rc = power_supply_add_hwmon_sysfs(psy);
+ if (rc)
+ goto add_hwmon_sysfs_failed;
+ }
/*
* Update use_cnt after any uevents (most notably from device_add()).
diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c
index 99bfe1f03eb8326d38c4e2831c9670313b42e425..927ddb9d83bb7259809ba695cb9398d1ad654b46 100644
--- a/drivers/power/supply/power_supply_sysfs.c
+++ b/drivers/power/supply/power_supply_sysfs.c
@@ -268,6 +268,27 @@ static ssize_t power_supply_show_enum_with_available(
return count;
}
+static ssize_t power_supply_show_charge_behaviour(struct device *dev,
+ struct power_supply *psy,
+ union power_supply_propval *value,
+ char *buf)
+{
+ struct power_supply_ext_registration *reg;
+
+ scoped_guard(rwsem_read, &psy->extensions_sem) {
+ power_supply_for_each_extension(reg, psy) {
+ if (power_supply_ext_has_property(reg->ext,
+ POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR))
+ return power_supply_charge_behaviour_show(dev,
+ reg->ext->charge_behaviours,
+ value->intval, buf);
+ }
+ }
+
+ return power_supply_charge_behaviour_show(dev, psy->desc->charge_behaviours,
+ value->intval, buf);
+}
+
static ssize_t power_supply_format_property(struct device *dev,
bool uevent,
struct device_attribute *attr,
@@ -307,8 +328,7 @@ static ssize_t power_supply_format_property(struct device *dev,
case POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR:
if (uevent) /* no possible values in uevents */
goto default_format;
- ret = power_supply_charge_behaviour_show(dev, psy->desc->charge_behaviours,
- value.intval, buf);
+ ret = power_supply_show_charge_behaviour(dev, psy, &value, buf);
break;
case POWER_SUPPLY_PROP_MODEL_NAME ... POWER_SUPPLY_PROP_SERIAL_NUMBER:
ret = sysfs_emit(buf, "%s\n", value.strval);
@@ -385,6 +405,8 @@ static umode_t power_supply_attr_is_visible(struct kobject *kobj,
if (attrno == POWER_SUPPLY_PROP_TYPE)
return mode;
+ guard(rwsem_read)(&psy->extensions_sem);
+
if (power_supply_has_property(psy, attrno)) {
if (power_supply_property_is_writeable(psy, attrno) > 0)
mode |= S_IWUSR;
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index b98106e1a90f34bce5129317a099f363248342b9..016e44cb3eb5eb7ace01a032661f65a5d81a522f 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -15,6 +15,8 @@
#include <linux/device.h>
#include <linux/workqueue.h>
#include <linux/leds.h>
+#include <linux/rwsem.h>
+#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/notifier.h>
@@ -281,6 +283,27 @@ struct power_supply_desc {
int use_for_apm;
};
+struct power_supply_ext {
+ u8 charge_behaviours;
+ const enum power_supply_property *properties;
+ size_t num_properties;
+
+ int (*get_property)(struct power_supply *psy,
+ const struct power_supply_ext *ext,
+ void *data,
+ enum power_supply_property psp,
+ union power_supply_propval *val);
+ int (*set_property)(struct power_supply *psy,
+ const struct power_supply_ext *ext,
+ void *data,
+ enum power_supply_property psp,
+ const union power_supply_propval *val);
+ int (*property_is_writeable)(struct power_supply *psy,
+ const struct power_supply_ext *ext,
+ void *data,
+ enum power_supply_property psp);
+};
+
struct power_supply {
const struct power_supply_desc *desc;
@@ -300,10 +323,13 @@ struct power_supply {
struct delayed_work deferred_register_work;
spinlock_t changed_lock;
bool changed;
+ bool update_groups;
bool initialized;
bool removing;
atomic_t use_cnt;
struct power_supply_battery_info *battery_info;
+ struct rw_semaphore extensions_sem; /* protects "extensions" */
+ struct list_head extensions;
#ifdef CONFIG_THERMAL
struct thermal_zone_device *tzd;
struct thermal_cooling_device *tcd;
@@ -878,6 +904,12 @@ devm_power_supply_register(struct device *parent,
extern void power_supply_unregister(struct power_supply *psy);
extern int power_supply_powers(struct power_supply *psy, struct device *dev);
+extern int power_supply_register_extension(struct power_supply *psy,
+ const struct power_supply_ext *ext,
+ void *data);
+extern void power_supply_unregister_extension(struct power_supply *psy,
+ const struct power_supply_ext *ext);
+
#define to_power_supply(device) container_of(device, struct power_supply, dev)
extern void *power_supply_get_drvdata(struct power_supply *psy);
--
2.47.1
