RE: [PATCH] power_supply: Added support for power supply attributesources

[Pallala, Ramakrishna]

Hi Anton,

Following patch needs your attention.

Thanks,
Ram

> From: Pallala, Ramakrishna
> Sent: Monday, June 25, 2012 6:07 PM
> To: linux-kernel@xxxxxxxxxxxxxxx
> Cc: Anton Vorontsov; Anton Vorontsov; Pallala, Ramakrishna
> Subject: [PATCH] power_supply: Added support for power supply attribute
> sources
> 
> On some platforms one driver(or HW chip) may not be able to provide all the
> necessary attributes of the power supply connected to the platform or may
> provide very limited info which can be used by core/primary drivers.
> 
> For example a temperature sensor chip placed near the battery can be used to
> report battery ambient temperature but it does not makes sense to register
> sensor driver with power supply class. Or even a ADC driver or platform driver
> may report power supply properties like voltage/current or charging status but
> registering all those driver with power supply class is not a practical or ideal
> approach.
> 
> This patch adds the generic support to register the drivers as power supply
> attribute(properties) sources and adds an interface to read these attributes from
> power supply class drivers.
> 
> Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@xxxxxxxxx>
> ---
>  Documentation/power/power_supply_class.txt |   30 +++++++++++
>  drivers/power/power_supply_core.c          |   78
> ++++++++++++++++++++++++++++
>  include/linux/power_supply.h               |   28 ++++++++++
>  3 files changed, 136 insertions(+), 0 deletions(-)
> 
> diff --git a/Documentation/power/power_supply_class.txt
> b/Documentation/power/power_supply_class.txt
> index c0f62ae..f8ceb45 100644
> --- a/Documentation/power/power_supply_class.txt
> +++ b/Documentation/power/power_supply_class.txt
> @@ -130,6 +130,36 @@ while battery powers a load)  TIME_TO_FULL - seconds
> left for battery to be considered full (i.e.
>  while battery is charging)
> 
> +Power supply attribute sources
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +On some platforms one driver(or HW chip) may not be able to provide all
> +the necessary attributes of the power supply connected to the platform.
> +
> +For example a temperature sensor chip placed near the battery can be
> +used to report battery ambient temperature but it does not makes sense
> +to register sensor driver with power supply class. Or even a ADC driver
> +or platform driver may report power supply properties like
> +voltage/current or charging status but registering all those driver
> +with power supply class is not a practical or ideal approach.
> +
> +Power supply subsystem provides an interface to register and report
> +about these power supply attributes to the primary driver which is
> +registered with power supply class.
> +
> +Power supply attribute source driver can use the following functions to
> +register/unregister as attributes source.
> +
> +int power_supply_attributes_register(struct device *parent,
> +				struct power_supply_attr_source *psy_attr);
> +
> +void power_supply_attributes_unregister(
> +			struct power_supply_attr_source *psy_attr);
> +
> +Power supply class driver(consumer driver) which needs to get power
> +supply attributes can call the following function.
> +
> +int power_supply_get_external_attr(
> +				struct power_supply_attr_query *query);
> 
>  Battery <-> external power supply interaction
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> diff --git a/drivers/power/power_supply_core.c
> b/drivers/power/power_supply_core.c
> index ff990d2..25c47a3 100644
> --- a/drivers/power/power_supply_core.c
> +++ b/drivers/power/power_supply_core.c
> @@ -14,6 +14,7 @@
>  #include <linux/types.h>
>  #include <linux/init.h>
>  #include <linux/slab.h>
> +#include <linux/list.h>
>  #include <linux/device.h>
>  #include <linux/err.h>
>  #include <linux/power_supply.h>
> @@ -26,6 +27,8 @@ EXPORT_SYMBOL_GPL(power_supply_class);
> 
>  static struct device_type power_supply_dev_type;
> 
> +static LIST_HEAD(list_head_source_attr);
> +
>  static int __power_supply_changed_work(struct device *dev, void *data)  {
>  	struct power_supply *psy = (struct power_supply *)data; @@ -164,6
> +167,34 @@ int power_supply_powers(struct power_supply *psy, struct device
> *dev)  }  EXPORT_SYMBOL_GPL(power_supply_powers);
> 
> +int power_supply_get_external_attr(struct power_supply_attr_query
> +*query) {
> +	struct list_head *list;
> +	struct power_supply_attr_source *psy_attr;
> +	int ret = -ENODEV;
> +
> +	if (!query || list_empty(&list_head_source_attr))
> +		return -EINVAL;
> +
> +	list_for_each(list, &list_head_source_attr) {
> +		psy_attr = list_entry(list,
> +			struct power_supply_attr_source, attr_pool);
> +
> +		if (psy_attr->type != query->type)
> +			continue;
> +
> +		ret = psy_attr->get_property(psy_attr,
> +				query->property, &query->res);
> +		if (ret < 0)
> +			continue;
> +		else
> +			break;
> +	}
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(power_supply_get_external_attr);
> +
>  static void power_supply_dev_release(struct device *dev)  {
>  	pr_debug("device: '%s': %s\n", dev_name(dev), __func__); @@ -289,6
> +320,53 @@ void power_supply_unregister(struct power_supply *psy)  }
> EXPORT_SYMBOL_GPL(power_supply_unregister);
> 
> +int power_supply_attributes_register(struct device *parent,
> +				struct power_supply_attr_source *psy_attr) {
> +	struct device *dev;
> +	int rc;
> +
> +	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
> +	if (!dev)
> +		return -ENOMEM;
> +
> +	device_initialize(dev);
> +
> +	dev->parent = parent;
> +	dev->release = power_supply_dev_release;
> +	dev_set_drvdata(dev, psy_attr);
> +	psy_attr->dev = dev;
> +
> +	rc = kobject_set_name(&dev->kobj, "%s", psy_attr->name);
> +	if (rc)
> +		goto kobject_set_name_failed;
> +
> +	rc = device_add(dev);
> +	if (rc)
> +		goto device_add_failed;
> +
> +	INIT_LIST_HEAD(&psy_attr->attr_pool);
> +	/* add to the list head */
> +	list_add(&psy_attr->attr_pool, &list_head_source_attr);
> +
> +	goto success;
> +
> +kobject_set_name_failed:
> +device_add_failed:
> +	put_device(dev);
> +success:
> +	return rc;
> +}
> +EXPORT_SYMBOL_GPL(power_supply_attributes_register);
> +
> +void power_supply_attributes_unregister(struct power_supply_attr_source
> +								*psy_attr)
> +{
> +	list_del(&psy_attr->attr_pool);
> +	device_unregister(psy_attr->dev);
> +}
> +EXPORT_SYMBOL_GPL(power_supply_attributes_unregister);
> +
>  static int __init power_supply_class_init(void)  {
>  	power_supply_class = class_create(THIS_MODULE, "power_supply");
> diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h index
> 53f177d..af296c3 100644
> --- a/include/linux/power_supply.h
> +++ b/include/linux/power_supply.h
> @@ -193,6 +193,25 @@ struct power_supply {  #endif  };
> 
> +struct power_supply_attr_query {
> +	enum power_supply_property property;
> +	enum power_supply_type type;
> +	/* variable to store result */
> +	union power_supply_propval res;
> +};
> +
> +struct power_supply_attr_source {
> +	const char *name;
> +	enum power_supply_type type;
> +	int (*get_property)(struct power_supply_attr_source *psy_attr,
> +			    enum power_supply_property psp,
> +			    union power_supply_propval *val);
> +
> +	/* private */
> +	struct device *dev;
> +	struct list_head attr_pool;
> +};
> +
>  /*
>   * This is recommended structure to specify static power supply parameters.
>   * Generic one, parametrizable for different power supplies. Power supply @@ -
> 216,6 +235,8 @@ extern struct power_supply
> *power_supply_get_by_name(char *name);  extern void
> power_supply_changed(struct power_supply *psy);  extern int
> power_supply_am_i_supplied(struct power_supply *psy);  extern int
> power_supply_set_battery_charged(struct power_supply *psy);
> +extern int power_supply_get_external_attr(
> +				struct power_supply_attr_query *query);
> 
>  #ifdef CONFIG_POWER_SUPPLY
>  extern int power_supply_is_system_supplied(void);
> @@ -226,6 +247,13 @@ static inline int power_supply_is_system_supplied(void)
> { return -ENOSYS; }  extern int power_supply_register(struct device *parent,
>  				 struct power_supply *psy);
>  extern void power_supply_unregister(struct power_supply *psy);
> +
> +extern int power_supply_attributes_register(struct device *parent,
> +				struct power_supply_attr_source *psy_attr);
> +
> +extern void power_supply_attributes_unregister(
> +			struct power_supply_attr_source *psy_attr);
> +
>  extern int power_supply_powers(struct power_supply *psy, struct device *dev);
> 
>  /* For APM emulation, think legacy userspace. */
> --
> 1.7.0.4

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