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ANDROID: power_supply: Add a helper function to retrieve psy array from phandle

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power_supply_get_by_phandle retrieves power_supply object based on
phandle. However, when multiple power_supply objects are registered
by the same parent device the first power_supply object's reference
is returned. This returned power_supply object's reference varies
according to probe order. Add a helper to return all the power_supply
object's reference.

The caller has to provide the power_supply pointer array.
-EOVERFLOW is returned when the size of the array is not enough to
pass back all the power_supply objects.

Patch was sent to mainline linux, however, was deemed incomplete due
to lack of mainline user.

Link: https://lore.kernel.org/linux-pm/20200407211243.247362-1-badhri@google.com/T/
Bug: 161416774
Bug: 167486462
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Change-Id: I6d9c52edb4472e73fc2d3c8eb32a41bec8bbde2a
This commit is contained in:
Badhri Jagan Sridharan
2020-09-01 21:16:09 -07:00
committed by Alistair Delva
parent 2bd29a1007
commit dea1a925f6
2 changed files with 87 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

78
drivers/power/supply/power_supply_core.c
View File

@@ -32,6 +32,13 @@ EXPORT_SYMBOL_GPL(power_supply_notifier);
static struct device_type power_supply_dev_type;
struct match_device_node_array_param {
struct device_node *parent_of_node;
struct power_supply **psy;
ssize_t psy_size;
ssize_t psy_count;
};
#define POWER_SUPPLY_DEFERRED_REGISTER_TIME msecs_to_jiffies(10)
static bool __power_supply_is_supplied_by(struct power_supply *supplier,
@@ -522,6 +529,77 @@ struct power_supply *power_supply_get_by_phandle(struct device_node *np,
}
EXPORT_SYMBOL_GPL(power_supply_get_by_phandle);
static int power_supply_match_device_node_array(struct device *dev,
void *data)
{
struct match_device_node_array_param *param =
(struct match_device_node_array_param *)data;
struct power_supply **psy = param->psy;
ssize_t size = param->psy_size;
ssize_t *count = &param->psy_count;
if (!dev->parent || dev->parent->of_node != param->parent_of_node)
return 0;
if (*count >= size)
return -EOVERFLOW;
psy[*count] = dev_get_drvdata(dev);
atomic_inc(&psy[*count]->use_cnt);
(*count)++;
return 0;
}
/**
* power_supply_get_by_phandle_array() - Similar to
* power_supply_get_by_phandle but returns an array of power supply
* objects which are associated with the phandle.
* @np: Pointer to device node holding phandle property.
* @property: Name of property holding a power supply name.
* @psy: Array of power_supply pointers provided by the client which is
* filled by power_supply_get_by_phandle_array.
* @size: size of power_supply pointer array.
*
* If power supply was found, it increases reference count for the
* internal power supply's device. The user should power_supply_put()
* after usage.
*
* Return: On success returns the number of power supply objects filled
* in the @psy array.
* -EOVERFLOW when size of @psy array is not suffice.
* -EINVAL when @psy is NULL or @size is 0.
* -ENODEV when matching device_node is not found.
*/
int power_supply_get_by_phandle_array(struct device_node *np,
const char *property,
struct power_supply **psy,
ssize_t size)
{
struct device_node *power_supply_np;
int ret;
struct match_device_node_array_param param;
if (!psy || !size)
return -EINVAL;
power_supply_np = of_parse_phandle(np, property, 0);
if (!power_supply_np)
return -ENODEV;
param.parent_of_node = power_supply_np;
param.psy = psy;
param.psy_size = size;
param.psy_count = 0;
ret = class_for_each_device(power_supply_class, NULL, &param,
power_supply_match_device_node_array);
of_node_put(power_supply_np);
return param.psy_count;
}
EXPORT_SYMBOL_GPL(power_supply_get_by_phandle_array);
static void devm_power_supply_put(struct device *dev, void *res)
{
struct power_supply **psy = res;

9
include/linux/power_supply.h
View File

@@ -379,12 +379,21 @@ extern void power_supply_put(struct power_supply *psy);
#ifdef CONFIG_OF
extern struct power_supply *power_supply_get_by_phandle(struct device_node *np,
const char *property);
extern int power_supply_get_by_phandle_array(struct device_node *np,
const char *property,
struct power_supply **psy,
ssize_t size);
extern struct power_supply *devm_power_supply_get_by_phandle(
struct device *dev, const char *property);
#else /* !CONFIG_OF */
static inline struct power_supply *
power_supply_get_by_phandle(struct device_node *np, const char *property)
{ return NULL; }
static int power_supply_get_by_phandle_array(struct device_node *np,
const char *property,
struct power_supply **psy,
int size)
{ return 0; }
static inline struct power_supply *
devm_power_supply_get_by_phandle(struct device *dev, const char *property)
{ return NULL; }