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power_supply: Use attribute groups
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This fixes a race between power supply device and initial
attributes creation, plus makes it possible to implement
writable properties.

[Daniel Mack - removed superflous return statement
 and dropped .mode attribute from POWER_SUPPLY_ATTR]

Suggested-by: Greg KH <gregkh@suse.de>
Suggested-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
Tested-by: Daniel Mack <daniel@caiaq.de>
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Anton Vorontsov committed May 19, 2010
1 parent a1e50fd commit 5f487cd
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Showing 4 changed files with 75 additions and 96 deletions.
7 changes: 2 additions & 5 deletions drivers/power/power_supply.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -12,15 +12,12 @@

#ifdef CONFIG_SYSFS

extern int power_supply_create_attrs(struct power_supply *psy);
extern void power_supply_remove_attrs(struct power_supply *psy);
extern void power_supply_init_attrs(struct device_type *dev_type);
extern int power_supply_uevent(struct device *dev, struct kobj_uevent_env *env);

#else

static inline int power_supply_create_attrs(struct power_supply *psy)
{ return 0; }
static inline void power_supply_remove_attrs(struct power_supply *psy) {}
static inline void power_supply_init_attrs(struct device_type *dev_type) {}
#define power_supply_uevent NULL

#endif /* CONFIG_SYSFS */
Expand Down
48 changes: 34 additions & 14 deletions drivers/power/power_supply_core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@
#include <linux/module.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/power_supply.h>
Expand All @@ -22,6 +23,8 @@
struct class *power_supply_class;
EXPORT_SYMBOL_GPL(power_supply_class);

static struct device_type power_supply_dev_type;

static int __power_supply_changed_work(struct device *dev, void *data)
{
struct power_supply *psy = (struct power_supply *)data;
Expand Down Expand Up @@ -144,22 +147,39 @@ struct power_supply *power_supply_get_by_name(char *name)
}
EXPORT_SYMBOL_GPL(power_supply_get_by_name);

static void power_supply_dev_release(struct device *dev)
{
pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
kfree(dev);
}

int power_supply_register(struct device *parent, struct power_supply *psy)
{
int rc = 0;
struct device *dev;
int rc;

psy->dev = device_create(power_supply_class, parent, 0, psy,
"%s", psy->name);
if (IS_ERR(psy->dev)) {
rc = PTR_ERR(psy->dev);
goto dev_create_failed;
}
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev)
return -ENOMEM;

INIT_WORK(&psy->changed_work, power_supply_changed_work);
device_initialize(dev);

rc = power_supply_create_attrs(psy);
dev->class = power_supply_class;
dev->type = &power_supply_dev_type;
dev->parent = parent;
dev->release = power_supply_dev_release;
dev_set_drvdata(dev, psy);
psy->dev = dev;

rc = kobject_set_name(&dev->kobj, "%s", psy->name);
if (rc)
goto kobject_set_name_failed;

rc = device_add(dev);
if (rc)
goto create_attrs_failed;
goto device_add_failed;

INIT_WORK(&psy->changed_work, power_supply_changed_work);

rc = power_supply_create_triggers(psy);
if (rc)
Expand All @@ -170,10 +190,10 @@ int power_supply_register(struct device *parent, struct power_supply *psy)
goto success;

create_triggers_failed:
power_supply_remove_attrs(psy);
create_attrs_failed:
device_unregister(psy->dev);
dev_create_failed:
kobject_set_name_failed:
device_add_failed:
kfree(dev);
success:
return rc;
}
Expand All @@ -183,7 +203,6 @@ void power_supply_unregister(struct power_supply *psy)
{
flush_scheduled_work();
power_supply_remove_triggers(psy);
power_supply_remove_attrs(psy);
device_unregister(psy->dev);
}
EXPORT_SYMBOL_GPL(power_supply_unregister);
Expand All @@ -196,6 +215,7 @@ static int __init power_supply_class_init(void)
return PTR_ERR(power_supply_class);

power_supply_class->dev_uevent = power_supply_uevent;
power_supply_init_attrs(&power_supply_dev_type);

return 0;
}
Expand Down
115 changes: 38 additions & 77 deletions drivers/power/power_supply_sysfs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,7 @@

#define POWER_SUPPLY_ATTR(_name) \
{ \
.attr = { .name = #_name, .mode = 0444 }, \
.attr = { .name = #_name }, \
.show = power_supply_show_property, \
.store = NULL, \
}
Expand All @@ -41,6 +41,9 @@ static struct device_attribute power_supply_attrs[];
static ssize_t power_supply_show_property(struct device *dev,
struct device_attribute *attr,
char *buf) {
static char *type_text[] = {
"Battery", "UPS", "Mains", "USB"
};
static char *status_text[] = {
"Unknown", "Charging", "Discharging", "Not charging", "Full"
};
Expand All @@ -58,12 +61,15 @@ static ssize_t power_supply_show_property(struct device *dev,
static char *capacity_level_text[] = {
"Unknown", "Critical", "Low", "Normal", "High", "Full"
};
ssize_t ret;
ssize_t ret = 0;
struct power_supply *psy = dev_get_drvdata(dev);
const ptrdiff_t off = attr - power_supply_attrs;
union power_supply_propval value;

ret = psy->get_property(psy, off, &value);
if (off == POWER_SUPPLY_PROP_TYPE)
value.intval = psy->type;
else
ret = psy->get_property(psy, off, &value);

if (ret < 0) {
if (ret == -ENODATA)
Expand All @@ -85,6 +91,8 @@ static ssize_t power_supply_show_property(struct device *dev,
return sprintf(buf, "%s\n", technology_text[value.intval]);
else if (off == POWER_SUPPLY_PROP_CAPACITY_LEVEL)
return sprintf(buf, "%s\n", capacity_level_text[value.intval]);
else if (off == POWER_SUPPLY_PROP_TYPE)
return sprintf(buf, "%s\n", type_text[value.intval]);
else if (off >= POWER_SUPPLY_PROP_MODEL_NAME)
return sprintf(buf, "%s\n", value.strval);

Expand Down Expand Up @@ -132,67 +140,50 @@ static struct device_attribute power_supply_attrs[] = {
POWER_SUPPLY_ATTR(time_to_empty_avg),
POWER_SUPPLY_ATTR(time_to_full_now),
POWER_SUPPLY_ATTR(time_to_full_avg),
POWER_SUPPLY_ATTR(type),
/* Properties of type `const char *' */
POWER_SUPPLY_ATTR(model_name),
POWER_SUPPLY_ATTR(manufacturer),
POWER_SUPPLY_ATTR(serial_number),
};

static ssize_t power_supply_show_static_attrs(struct device *dev,
struct device_attribute *attr,
char *buf) {
static char *type_text[] = { "Battery", "UPS", "Mains", "USB" };
struct power_supply *psy = dev_get_drvdata(dev);

return sprintf(buf, "%s\n", type_text[psy->type]);
}

static struct device_attribute power_supply_static_attrs[] = {
__ATTR(type, 0444, power_supply_show_static_attrs, NULL),
};
static struct attribute *
__power_supply_attrs[ARRAY_SIZE(power_supply_attrs) + 1];

int power_supply_create_attrs(struct power_supply *psy)
static mode_t power_supply_attr_is_visible(struct kobject *kobj,
struct attribute *attr,
int attrno)
{
int rc = 0;
int i, j;

for (i = 0; i < ARRAY_SIZE(power_supply_static_attrs); i++) {
rc = device_create_file(psy->dev,
&power_supply_static_attrs[i]);
if (rc)
goto statics_failed;
}
struct device *dev = container_of(kobj, struct device, kobj);
struct power_supply *psy = dev_get_drvdata(dev);
int i;

for (j = 0; j < psy->num_properties; j++) {
rc = device_create_file(psy->dev,
&power_supply_attrs[psy->properties[j]]);
if (rc)
goto dynamics_failed;
for (i = 0; i < psy->num_properties; i++) {
if (psy->properties[i] == attrno)
return 0444;
}

goto succeed;

dynamics_failed:
while (j--)
device_remove_file(psy->dev,
&power_supply_attrs[psy->properties[j]]);
statics_failed:
while (i--)
device_remove_file(psy->dev, &power_supply_static_attrs[i]);
succeed:
return rc;
return 0;
}

void power_supply_remove_attrs(struct power_supply *psy)
static struct attribute_group power_supply_attr_group = {
.attrs = __power_supply_attrs,
.is_visible = power_supply_attr_is_visible,
};

static const struct attribute_group *power_supply_attr_groups[] = {
&power_supply_attr_group,
NULL,
};

void power_supply_init_attrs(struct device_type *dev_type)
{
int i;

for (i = 0; i < ARRAY_SIZE(power_supply_static_attrs); i++)
device_remove_file(psy->dev, &power_supply_static_attrs[i]);
dev_type->groups = power_supply_attr_groups;

for (i = 0; i < psy->num_properties; i++)
device_remove_file(psy->dev,
&power_supply_attrs[psy->properties[i]]);
for (i = 0; i < ARRAY_SIZE(power_supply_attrs); i++)
__power_supply_attrs[i] = &power_supply_attrs[i].attr;
}

static char *kstruprdup(const char *str, gfp_t gfp)
Expand Down Expand Up @@ -236,36 +227,6 @@ int power_supply_uevent(struct device *dev, struct kobj_uevent_env *env)
if (!prop_buf)
return -ENOMEM;

for (j = 0; j < ARRAY_SIZE(power_supply_static_attrs); j++) {
struct device_attribute *attr;
char *line;

attr = &power_supply_static_attrs[j];

ret = power_supply_show_static_attrs(dev, attr, prop_buf);
if (ret < 0)
goto out;

line = strchr(prop_buf, '\n');
if (line)
*line = 0;

attrname = kstruprdup(attr->attr.name, GFP_KERNEL);
if (!attrname) {
ret = -ENOMEM;
goto out;
}

dev_dbg(dev, "Static prop %s=%s\n", attrname, prop_buf);

ret = add_uevent_var(env, "POWER_SUPPLY_%s=%s", attrname, prop_buf);
kfree(attrname);
if (ret)
goto out;
}

dev_dbg(dev, "%zd dynamic props\n", psy->num_properties);

for (j = 0; j < psy->num_properties; j++) {
struct device_attribute *attr;
char *line;
Expand Down
1 change: 1 addition & 0 deletions include/linux/power_supply.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -114,6 +114,7 @@ enum power_supply_property {
POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
POWER_SUPPLY_PROP_TIME_TO_FULL_NOW,
POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
POWER_SUPPLY_PROP_TYPE, /* use power_supply.type instead */
/* Properties of type `const char *' */
POWER_SUPPLY_PROP_MODEL_NAME,
POWER_SUPPLY_PROP_MANUFACTURER,
Expand Down

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