[PATCH] power-supply: Add function to return system-wide power state

[PATCH] power-supply: Add function to return system-wide power state

[Matthew Garrett]

(resend, I screwed up the Cc)

Certain drivers benefit from knowing whether the system is on ac or 
battery, for instance when determining which backlight registers to 
read. This adds a simple call to determine whether there's an online 
power supply other than any batteries.

Signed-off-by: Matthew Garrett <mjg@redhat.com>

---

The name is a bit odd, but seems to fit in with the existing naming 
scheme.

diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
index cb1ccb4..6a687da 100644
--- a/drivers/power/power_supply_core.c
+++ b/drivers/power/power_supply_core.c
@@ -87,6 +87,31 @@ int power_supply_am_i_supplied(struct power_supply *psy)
 	return error;
 }
 
+static int __power_supply_is_system_supplied(struct device *dev, void *data)
+{
+	union power_supply_propval ret = {0,};
+	struct power_supply *psy = dev_get_drvdata(dev);
+
+	if (psy->type != POWER_SUPPLY_TYPE_BATTERY) {
+		if (psy->get_property(psy,
+				       POWER_SUPPLY_PROP_ONLINE, &ret))
+			return 0;
+		if (ret.intval)
+			return ret.intval;
+	}
+	return 0;
+}
+
+int power_supply_is_system_supplied()
+{
+	int error;
+
+	error = class_for_each_device(power_supply_class, NULL, NULL,
+				      __power_supply_is_system_supplied);
+
+	return error;
+}
+
 int power_supply_register(struct device *parent, struct power_supply *psy)
 {
 	int rc = 0;
@@ -148,6 +173,7 @@ static void __exit power_supply_class_exit(void)
 
 EXPORT_SYMBOL_GPL(power_supply_changed);
 EXPORT_SYMBOL_GPL(power_supply_am_i_supplied);
+EXPORT_SYMBOL_GPL(power_supply_is_system_supplied);
 EXPORT_SYMBOL_GPL(power_supply_register);
 EXPORT_SYMBOL_GPL(power_supply_unregister);
 
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index ea96ead..3e67d0c 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -164,6 +164,7 @@ struct power_supply_info {
 
 extern void power_supply_changed(struct power_supply *psy);
 extern int power_supply_am_i_supplied(struct power_supply *psy);
+extern int power_supply_is_system_supplied(void);
 
 extern int power_supply_register(struct device *parent,
 				 struct power_supply *psy);

-- 
Matthew Garrett | mjg59@srcf.ucam.org

Re: [PATCH] power-supply: Add function to return system-wide power state

[Anton Vorontsov]

On Tue, Aug 26, 2008 at 09:09:59PM +0100, Matthew Garrett wrote:
> (resend, I screwed up the Cc)
> 
> Certain drivers benefit from knowing whether the system is on ac or 
> battery, for instance when determining which backlight registers to 
> read. This adds a simple call to determine whether there's an online 
> power supply other than any batteries.

I like the patch, much thanks!

One comment below.

> Signed-off-by: Matthew Garrett <mjg@redhat.com>
> 
> ---
> 
> The name is a bit odd, but seems to fit in with the existing naming 
> scheme.
> 
> diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
> index cb1ccb4..6a687da 100644
> --- a/drivers/power/power_supply_core.c
> +++ b/drivers/power/power_supply_core.c
> @@ -87,6 +87,31 @@ int power_supply_am_i_supplied(struct power_supply *psy)
>  	return error;
>  }
>  
> +static int __power_supply_is_system_supplied(struct device *dev, void *data)
> +{
> +	union power_supply_propval ret = {0,};
> +	struct power_supply *psy = dev_get_drvdata(dev);
> +
> +	if (psy->type != POWER_SUPPLY_TYPE_BATTERY) {
> +		if (psy->get_property(psy,
> +				       POWER_SUPPLY_PROP_ONLINE, &ret))
> +			return 0;
> +		if (ret.intval)
> +			return ret.intval;
> +	}
> +	return 0;
> +}
> +
> +int power_supply_is_system_supplied()
> +{
> +	int error;
> +
> +	error = class_for_each_device(power_supply_class, NULL, NULL,
> +				      __power_supply_is_system_supplied);
> +
> +	return error;
> +}
> +
>  int power_supply_register(struct device *parent, struct power_supply *psy)
>  {
>  	int rc = 0;
> @@ -148,6 +173,7 @@ static void __exit power_supply_class_exit(void)
>  
>  EXPORT_SYMBOL_GPL(power_supply_changed);
>  EXPORT_SYMBOL_GPL(power_supply_am_i_supplied);
> +EXPORT_SYMBOL_GPL(power_supply_is_system_supplied);
>  EXPORT_SYMBOL_GPL(power_supply_register);
>  EXPORT_SYMBOL_GPL(power_supply_unregister);
>  
> diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
> index ea96ead..3e67d0c 100644
> --- a/include/linux/power_supply.h
> +++ b/include/linux/power_supply.h
> @@ -164,6 +164,7 @@ struct power_supply_info {
>  
>  extern void power_supply_changed(struct power_supply *psy);
>  extern int power_supply_am_i_supplied(struct power_supply *psy);
> +extern int power_supply_is_system_supplied(void);

May I suggest adding
static int power_supply_is_system_supplied(void) { return -ENOSYS; }
in case of !CONFIG_POWER_SUPPLY? This way drivers may not strictly
depend on power supply class.

And "if (power_supply_is_system_supplied())" will assume that we're
always supplied, which good assumption, I think.

Thanks,

-- 
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2

Re: [PATCH] power-supply: Add function to return system-wide power state

[Matthew Garrett]

Something like this?

diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
index cb1ccb4..6a687da 100644
--- a/drivers/power/power_supply_core.c
+++ b/drivers/power/power_supply_core.c
@@ -87,6 +87,31 @@ int power_supply_am_i_supplied(struct power_supply *psy)
 	return error;
 }
 
+static int __power_supply_is_system_supplied(struct device *dev, void *data)
+{
+	union power_supply_propval ret = {0,};
+	struct power_supply *psy = dev_get_drvdata(dev);
+
+	if (psy->type != POWER_SUPPLY_TYPE_BATTERY) {
+		if (psy->get_property(psy,
+				       POWER_SUPPLY_PROP_ONLINE, &ret))
+			return 0;
+		if (ret.intval)
+			return ret.intval;
+	}
+	return 0;
+}
+
+int power_supply_is_system_supplied()
+{
+	int error;
+
+	error = class_for_each_device(power_supply_class, NULL, NULL,
+				      __power_supply_is_system_supplied);
+
+	return error;
+}
+
 int power_supply_register(struct device *parent, struct power_supply *psy)
 {
 	int rc = 0;
@@ -148,6 +173,7 @@ static void __exit power_supply_class_exit(void)
 
 EXPORT_SYMBOL_GPL(power_supply_changed);
 EXPORT_SYMBOL_GPL(power_supply_am_i_supplied);
+EXPORT_SYMBOL_GPL(power_supply_is_system_supplied);
 EXPORT_SYMBOL_GPL(power_supply_register);
 EXPORT_SYMBOL_GPL(power_supply_unregister);
 
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index ea96ead..304df22 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -164,11 +164,16 @@ struct power_supply_info {
 
 extern void power_supply_changed(struct power_supply *psy);
 extern int power_supply_am_i_supplied(struct power_supply *psy);
-
 extern int power_supply_register(struct device *parent,
 				 struct power_supply *psy);
 extern void power_supply_unregister(struct power_supply *psy);
 
+#ifdef CONFIG_POWER_SUPPLY
+extern int power_supply_is_system_supplied(void);
+#else
+static int power_supply_is_system_supplied(void) { return -ENOSYS; }
+#endif
+
 /* For APM emulation, think legacy userspace. */
 extern struct class *power_supply_class;
 


-- 
Matthew Garrett | mjg59@srcf.ucam.org

Re: [PATCH] power-supply: Add function to return system-wide power state

[Anton Vorontsov]

On Tue, Aug 26, 2008 at 09:33:27PM +0100, Matthew Garrett wrote:
> Something like this?

Yup, except that I forgot 'inline' in my example. ;-) I'll add it
before applying, thanks!

> diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
> index cb1ccb4..6a687da 100644
> --- a/drivers/power/power_supply_core.c
> +++ b/drivers/power/power_supply_core.c
> @@ -87,6 +87,31 @@ int power_supply_am_i_supplied(struct power_supply *psy)
>  	return error;
>  }
>  
> +static int __power_supply_is_system_supplied(struct device *dev, void *data)
> +{
> +	union power_supply_propval ret = {0,};
> +	struct power_supply *psy = dev_get_drvdata(dev);
> +
> +	if (psy->type != POWER_SUPPLY_TYPE_BATTERY) {
> +		if (psy->get_property(psy,
> +				       POWER_SUPPLY_PROP_ONLINE, &ret))
> +			return 0;
> +		if (ret.intval)
> +			return ret.intval;
> +	}
> +	return 0;
> +}
> +
> +int power_supply_is_system_supplied()
> +{
> +	int error;
> +
> +	error = class_for_each_device(power_supply_class, NULL, NULL,
> +				      __power_supply_is_system_supplied);
> +
> +	return error;
> +}
> +
>  int power_supply_register(struct device *parent, struct power_supply *psy)
>  {
>  	int rc = 0;
> @@ -148,6 +173,7 @@ static void __exit power_supply_class_exit(void)
>  
>  EXPORT_SYMBOL_GPL(power_supply_changed);
>  EXPORT_SYMBOL_GPL(power_supply_am_i_supplied);
> +EXPORT_SYMBOL_GPL(power_supply_is_system_supplied);
>  EXPORT_SYMBOL_GPL(power_supply_register);
>  EXPORT_SYMBOL_GPL(power_supply_unregister);
>  
> diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
> index ea96ead..304df22 100644
> --- a/include/linux/power_supply.h
> +++ b/include/linux/power_supply.h
> @@ -164,11 +164,16 @@ struct power_supply_info {
>  
>  extern void power_supply_changed(struct power_supply *psy);
>  extern int power_supply_am_i_supplied(struct power_supply *psy);
> -
>  extern int power_supply_register(struct device *parent,
>  				 struct power_supply *psy);
>  extern void power_supply_unregister(struct power_supply *psy);
>  
> +#ifdef CONFIG_POWER_SUPPLY
> +extern int power_supply_is_system_supplied(void);
> +#else
> +static int power_supply_is_system_supplied(void) { return -ENOSYS; }
> +#endif
> +
>  /* For APM emulation, think legacy userspace. */
>  extern struct class *power_supply_class;

-- 
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2

Re: [PATCH] power-supply: Add function to return system-wide power state

[Anton Vorontsov]

On Tue, Aug 26, 2008 at 09:33:27PM +0100, Matthew Garrett wrote:
> Something like this?

I just applied it to battery-2.6.git with the following changes:

[...]
> +int power_supply_is_system_supplied()

-()
+(void)

[...]
> +#ifdef CONFIG_POWER_SUPPLY

Added || defined(CONFIG_POWER_SUPPLY_MODULE)

> +extern int power_supply_is_system_supplied(void);
> +#else
> +static int power_supply_is_system_supplied(void) { return -ENOSYS; }

Added inline keyword, otherwise gcc might warn about defined but
not used function.


Please test battery-2.6.git tree (or simply next `-next` tree ;-)
if everything is okay.

Thanks again!

-- 
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2