[RFC PATCH 0/4] power_supply: Add DT helper function to get power-supply dev from dt

[RFC PATCH 0/4] power_supply: Add DT helper function to get power-supply dev from dt

[Chanwoo Choi]

This patchset add DT helper function to get power-supply device from devicetree.
- of_power_supply_get_dev(struct device *dev, enum power_supply_dev_type type,
			  int index)
Power-supply class provides 'power_supply_get_by_name()' to users who want to
find power-supply device with the name of power-supply device.

If CONFIG_OF is enabled, device drivers which want to get power-supply device
would directly get the power-supply device from devicetree by using of_power_
supply_get_dev(). This function can be used instead of power_supply_get_by_name().

For example,

[After]
	The charger-manager must need the power-supply device of fuelgauge to
	read the battery capacity. The charger-manager dt don't need to consider
	the name of power-supply device for fuelgauge because of only needing
	phandle of fuelgauge power-supply device.

	fuelgauge0: max17047@36 {
		compatible = "maxim,max17047";
		interrupt-parent = <&gpx2>;
		interrputs = <3 2>;
		reg = <0x36>;
	};

	charger-manager@0 {
		compatible = "charger-manager";
		...
		fuel-gauge = <&fuelgauge0>;	/* Need phandle of fuelgauge
						 phandle name is always same. */
		...
	};

[Before]
	Previous way use the name of fuelgauge power-supply device to get
	fuel-gauge device using power_supply_get_by_name(). If change the name
	of fuelgauge device, we have to modify both fuelgauge dt and charger-
	manager dt. The charger-manager has dependency on the name of fuel-gague
	power-supply device.

	max17047@36 {
		compatible = "maxim,max17047";
		interrupt-parent = <&gpx2>;
		interrputs = <3 2>;
		reg = <0x36>;
	};

	charger-manager@0 {
		compatible = "charger-manager";
		...
		cm-fuel-gauge = "max170xx_battery";	/* Need the name of fuel-gauge */
		...
	};


Chanwoo Choi (4):
  power_supply: of: Add an API to get power_supply device from dt node
  charger-manager: Get power_supply device using of_power_supply_get_dev()
  Documentation: dt: charger-manager: Change the way to get fuel-gauge power-supply device
  max17042_battery: Change battery name instead of static name according to device type

 .../bindings/power_supply/charger-manager.txt      |  8 ++-
 drivers/power/Kconfig                              |  4 ++
 drivers/power/Makefile                             |  2 +
 drivers/power/charger-manager.c                    | 22 ++++--
 drivers/power/max17042_battery.c                   |  2 +-
 drivers/power/of_power_supply.c                    | 82 ++++++++++++++++++++++
 include/linux/power/charger-manager.h              |  2 +
 include/linux/power/of_power_supply.h              | 46 ++++++++++++
 8 files changed, 159 insertions(+), 9 deletions(-)
 create mode 100644 drivers/power/of_power_supply.c
 create mode 100644 include/linux/power/of_power_supply.h

-- 
1.8.0

[RFC PATCH 1/4] power_supply: of: Add an API to get power_supply device from dt node

[Chanwoo Choi]

This patch add an API of_power_supply_get_dev() to be used by drivers to
get power_supply device in the case of DT(DeviceTree) node
(this can be used instead of power_supply_get_by_name()).

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
---
 drivers/power/Kconfig                 |  4 ++
 drivers/power/Makefile                |  2 +
 drivers/power/of_power_supply.c       | 82 +++++++++++++++++++++++++++++++++++
 include/linux/power/of_power_supply.h | 46 ++++++++++++++++++++
 4 files changed, 134 insertions(+)
 create mode 100644 drivers/power/of_power_supply.c
 create mode 100644 include/linux/power/of_power_supply.h

diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index ba69751..02240aa 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -8,6 +8,10 @@ menuconfig POWER_SUPPLY
 
 if POWER_SUPPLY
 
+config OF_POWER_SUPPLY
+	def_tristate y
+	depends on OF
+
 config POWER_SUPPLY_DEBUG
 	bool "Power supply debug"
 	help
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index ee54a3e..27d0c9c 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -4,6 +4,8 @@ power_supply-y				:= power_supply_core.o
 power_supply-$(CONFIG_SYSFS)		+= power_supply_sysfs.o
 power_supply-$(CONFIG_LEDS_TRIGGERS)	+= power_supply_leds.o
 
+obj-$(CONFIG_OF_POWER_SUPPLY)	+= of_power_supply.o
+
 obj-$(CONFIG_POWER_SUPPLY)	+= power_supply.o
 obj-$(CONFIG_GENERIC_ADC_BATTERY)	+= generic-adc-battery.o
 
diff --git a/drivers/power/of_power_supply.c b/drivers/power/of_power_supply.c
new file mode 100644
index 0000000..25d93a1
--- /dev/null
+++ b/drivers/power/of_power_supply.c
@@ -0,0 +1,82 @@
+/*
+ * OF helpers for Power supply class
+ *
+ * Copyright (C) 2014 Samsung Electronics
+ * Chanwoo Choi <cw00.choi@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/power_supply.h>
+#include <linux/power/of_power_supply.h>
+
+/*
+ * of_power_supply_get_dev - Get the power_supply device from devicetree
+ * @dev - instance to the given device
+ * @index - index into list of power_supply
+ *
+ * return the instance of power_supply device
+ */
+struct power_supply *of_power_supply_get_dev(struct device *dev,
+					     enum power_supply_dev_type type,
+					     int index)
+{
+	struct power_supply *power_supply_dev;
+	struct device_node *node;
+	const char *name;
+	union __parent_dev {
+		struct platform_device *platform;
+		struct i2c_client *i2c;
+	} parent_dev;
+
+	if (!dev->of_node) {
+		dev_dbg(dev, "device does not have a device node entry\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (type >= POWER_SUPPLY_DEV_END || type <= POWER_SUPPLY_DEV_UNKNOWN) {
+		dev_dbg(dev, "unknown power_supply device : %d\n", type);
+		return ERR_PTR(-EINVAL);
+	}
+
+	node = of_parse_phandle(dev->of_node, power_supply_dev_list[type],
+				index);
+	if (!node) {
+		dev_dbg(dev, "failed to get phandle in %s node\n",
+			dev->of_node->full_name);
+		return ERR_PTR(-ENODEV);
+	}
+
+	parent_dev.platform = of_find_device_by_node(node);
+	if (parent_dev.platform) {
+		name = dev_name(&parent_dev.platform->dev);
+		goto success;
+	}
+
+	parent_dev.i2c = of_find_i2c_device_by_node(node);
+	if (parent_dev.i2c) {
+		name = parent_dev.i2c->name;
+		goto success;
+	}
+
+	return ERR_PTR(-ENODEV);
+
+success:
+	power_supply_dev = power_supply_get_by_name(name);
+	if (!power_supply_dev) {
+		dev_dbg(dev, "unable to get power supply device : %s\n", name);
+		return ERR_PTR(-ENODEV);
+	}
+
+	return power_supply_dev;
+}
+EXPORT_SYMBOL_GPL(of_power_supply_get_dev);
diff --git a/include/linux/power/of_power_supply.h b/include/linux/power/of_power_supply.h
new file mode 100644
index 0000000..cfd4874
--- /dev/null
+++ b/include/linux/power/of_power_supply.h
@@ -0,0 +1,46 @@
+/*
+ * OF helpers for Power supply class
+ *
+ * Copyright (C) 2014 Samsung Electronics
+ * Chanwoo Choi <cw00.choi@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef __LINUX_OF_POWER_SUPPLY_H
+#define __LINUX_OF_POWER_SUPPLY_H
+
+#include <linux/err.h>
+
+enum power_supply_dev_type {
+	POWER_SUPPLY_DEV_UNKNOWN = 0,
+	POWER_SUPPLY_DEV_FUELGAUGE,
+	POWER_SUPPLY_DEV_CHARGER,
+
+	POWER_SUPPLY_DEV_END,
+};
+
+static const char * const power_supply_dev_list[] = {
+	[POWER_SUPPLY_DEV_UNKNOWN]	= "unknown",
+	[POWER_SUPPLY_DEV_FUELGAUGE]	= "fuelgauge",
+	[POWER_SUPPLY_DEV_CHARGER]	= "charger",
+};
+
+#if IS_ENABLED(CONFIG_OF_POWER_SUPPLY)
+extern struct power_supply
+	*of_power_supply_get_dev(struct device *dev,
+				 enum power_supply_dev_type type,
+				 int index);
+#else
+static inline struct power_supply
+	*of_power_supply_get_dev(struct device *dev,
+				 enum power_supply_dev_type type,
+				 int index)
+{
+	return ERR_PTR(-ENOSYS);
+}
+#endif /* CONFIG_OF_POWER_SUPPLY */
+#endif /* __LINUX_OF_POWER_SUPPLY_H */
-- 
1.8.0

[RFC PATCH 2/4] charger-manager: Get power_supply device using of_power_supply_get_dev()

[Chanwoo Choi]

This patch use of_power_supply_get_dev() dt funtion to get power_supply device
instead of legacy method. This patch get direclty the instance of power supply
device from dt.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>
---
---
 drivers/power/charger-manager.c       | 22 ++++++++++++++++------
 include/linux/power/charger-manager.h |  2 ++
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/power/charger-manager.c b/drivers/power/charger-manager.c
index 9e4dab4..a5bb9ae 100644
--- a/drivers/power/charger-manager.c
+++ b/drivers/power/charger-manager.c
@@ -23,6 +23,7 @@
 #include <linux/workqueue.h>
 #include <linux/platform_device.h>
 #include <linux/power/charger-manager.h>
+#include <linux/power/of_power_supply.h>
 #include <linux/regulator/consumer.h>
 #include <linux/sysfs.h>
 #include <linux/of.h>
@@ -1584,7 +1585,12 @@ static struct charger_desc *of_cm_parse_desc(struct device *dev)
 		}
 	}
 
-	of_property_read_string(np, "cm-fuel-gauge", &desc->psy_fuel_gauge);
+	desc->fuel_gauge = of_power_supply_get_dev(dev,
+						POWER_SUPPLY_DEV_FUELGAUGE, 0);
+	if (IS_ERR_OR_NULL(desc->fuel_gauge)) {
+		dev_err(dev, "Failed to get device instance of fuel-gague\n");
+		return ERR_PTR(-ENODEV);
+	}
 
 	of_property_read_string(np, "cm-thermal-zone", &desc->thermal_zone);
 
@@ -1739,11 +1745,15 @@ static int charger_manager_probe(struct platform_device *pdev)
 		}
 	}
 
-	cm->fuel_gauge = power_supply_get_by_name(desc->psy_fuel_gauge);
-	if (!cm->fuel_gauge) {
-		dev_err(&pdev->dev, "Cannot find power supply \"%s\"\n",
-			desc->psy_fuel_gauge);
-		return -ENODEV;
+	if (desc->fuel_gauge) {
+		cm->fuel_gauge = desc->fuel_gauge;
+	} else {
+		cm->fuel_gauge = power_supply_get_by_name(desc->psy_fuel_gauge);
+		if (!cm->fuel_gauge) {
+			dev_err(&pdev->dev, "Cannot find power supply \"%s\"\n",
+					desc->psy_fuel_gauge);
+			return -ENODEV;
+		}
 	}
 
 	if (desc->polling_interval_ms == 0 ||
diff --git a/include/linux/power/charger-manager.h b/include/linux/power/charger-manager.h
index 07e7945..92cc47a 100644
--- a/include/linux/power/charger-manager.h
+++ b/include/linux/power/charger-manager.h
@@ -175,6 +175,7 @@ struct charger_regulator {
  * @num_charger_regulator: the number of entries in charger_regulators
  * @charger_regulators: array of charger regulators
  * @psy_fuel_gauge: the name of power-supply for fuel gauge
+ * @fuel_gauge: power_supply device for fuel gauge
  * @thermal_zone : the name of thermal zone for battery
  * @temp_min : Minimum battery temperature for charging.
  * @temp_max : Maximum battery temperature for charging.
@@ -210,6 +211,7 @@ struct charger_desc {
 	struct charger_regulator *charger_regulators;
 
 	const char *psy_fuel_gauge;
+	struct power_supply *fuel_gauge;
 
 	const char *thermal_zone;
 
-- 
1.8.0

[RFC PATCH 3/4] Documentation: dt: charger-manager: Change the way to get fuel-gauge power-supply device

[Chanwoo Choi]

This patch use the phandle of fuel-gauge device instead of the name of fuel-gauge
device to get fuel-gauge device directly from dt.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>
---
 .../devicetree/bindings/power_supply/charger-manager.txt          | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/power_supply/charger-manager.txt b/Documentation/devicetree/bindings/power_supply/charger-manager.txt
index 2b33750..ceebd66 100644
--- a/Documentation/devicetree/bindings/power_supply/charger-manager.txt
+++ b/Documentation/devicetree/bindings/power_supply/charger-manager.txt
@@ -6,7 +6,7 @@ Required properties :
  - <>-supply : for regulator consumer
  - cm-num-chargers : number of chargers
  - cm-chargers : name of chargers
- - cm-fuel-gauge : name of battery fuel gauge
+ - fuelgauge : phandle of fuelgauge power-supply device
  - subnode <regulator> :
 	- cm-regulator-name : name of charger regulator
 	- subnode <cable> :
@@ -30,6 +30,10 @@ Optional properties :
  - cm-dis/charging-max = limits of charging duration
 
 Example :
+	fuelgauge0: max17047@36 {
+		compatible = "maxim,max17047";
+	};
+
 	charger-manager@0 {
 		compatible = "charger-manager";
 		chg-reg-supply = <&charger_regulator>;
@@ -48,7 +52,7 @@ Example :
 		cm-num-chargers = <3>;
 		cm-chargers = "charger0", "charger1", "charger2";
 
-		cm-fuel-gauge = "fuelgauge0";
+		fuelgauge = <&fuelgauge0>;
 
 		cm-thermal-zone = "thermal_zone.1"
 		/* in deci centigrade */
-- 
1.8.0

[RFC PATCH 4/4] max17042_battery: Change battery name instead of static name according to device type

[Chanwoo Choi]

This patch use device name to make power_supply path according to device type:

[Before]
In case of max17042/max17047/max17050,
- /sys/class/power_supply/max170xx_battery

[After]
In case of max17042,
- /sys/class/power_supply/max17042
In case of max17047,
- /sys/class/power_supply/max17047
In case of max17050,
- /sys/class/power_supply/max17050

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
---
 drivers/power/max17042_battery.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/power/max17042_battery.c b/drivers/power/max17042_battery.c
index 66da691..cba6def 100644
--- a/drivers/power/max17042_battery.c
+++ b/drivers/power/max17042_battery.c
@@ -707,7 +707,7 @@ static int max17042_probe(struct i2c_client *client,
 		return -EIO;
 	}
 
-	chip->battery.name		= "max170xx_battery";
+	chip->battery.name		= client->name;
 	chip->battery.type		= POWER_SUPPLY_TYPE_BATTERY;
 	chip->battery.get_property	= max17042_get_property;
 	chip->battery.properties	= max17042_battery_props;
-- 
1.8.0

Re: [RFC PATCH 0/4] power_supply: Add DT helper function to get power-supply dev from dt

[sre]

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Hi,

On Mon, Mar 17, 2014 at 09:43:43PM +0900, Chanwoo Choi wrote:
> This patchset add DT helper function to get power-supply device from devicetree.
> - of_power_supply_get_dev(struct device *dev, enum power_supply_dev_type type,
> 			  int index)
> Power-supply class provides 'power_supply_get_by_name()' to users who want to
> find power-supply device with the name of power-supply device.
> 
> If CONFIG_OF is enabled, device drivers which want to get power-supply device
> would directly get the power-supply device from devicetree by using of_power_
> supply_get_dev(). This function can be used instead of power_supply_get_by_name().
> 
> For example,
> [...]

include/linux/power_supply.h provides the following function already:

struct power_supply *
power_supply_get_by_phandle(struct device_node *np, const char *property);

-- Sebastian

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Re: [RFC PATCH 0/4] power_supply: Add DT helper function to get power-supply dev from dt

[Chanwoo Choi]

Hi,

On 03/18/2014 09:38 AM, sre@ring0.de wrote:
> Hi,
> 
> On Mon, Mar 17, 2014 at 09:43:43PM +0900, Chanwoo Choi wrote:
>> This patchset add DT helper function to get power-supply device from devicetree.
>> - of_power_supply_get_dev(struct device *dev, enum power_supply_dev_type type,
>> 			  int index)
>> Power-supply class provides 'power_supply_get_by_name()' to users who want to
>> find power-supply device with the name of power-supply device.
>>
>> If CONFIG_OF is enabled, device drivers which want to get power-supply device
>> would directly get the power-supply device from devicetree by using of_power_
>> supply_get_dev(). This function can be used instead of power_supply_get_by_name().
>>
>> For example,
>> [...]
> 
> include/linux/power_supply.h provides the following function already:
> 
> struct power_supply *
> power_supply_get_by_phandle(struct device_node *np, const char *property);
> 

OK, thanks for your reply.


Dear all,
Ignore this patchset. I'll re-send new patchset using power_supply_get_by_phandle().

Best Regards,
Chanwoo Choi

Re: [RFC PATCH 0/4] power_supply: Add DT helper function to get power-supply dev from dt

[Chanwoo Choi]

Hi Sebastian,

On 03/18/2014 09:38 AM, sre@ring0.de wrote:
> Hi,
> 
> On Mon, Mar 17, 2014 at 09:43:43PM +0900, Chanwoo Choi wrote:
>> This patchset add DT helper function to get power-supply device from devicetree.
>> - of_power_supply_get_dev(struct device *dev, enum power_supply_dev_type type,
>> 			  int index)
>> Power-supply class provides 'power_supply_get_by_name()' to users who want to
>> find power-supply device with the name of power-supply device.
>>
>> If CONFIG_OF is enabled, device drivers which want to get power-supply device
>> would directly get the power-supply device from devicetree by using of_power_
>> supply_get_dev(). This function can be used instead of power_supply_get_by_name().
>>
>> For example,
>> [...]
> 
> include/linux/power_supply.h provides the following function already:
> 
> struct power_supply *
> power_supply_get_by_phandle(struct device_node *np, const char *property);
> 

I checked power_supply_get_by_phandle().
But power_supply_get_by_phandle() is different from of_power_supply_get_dev()

So, I expalin the difference between "power_supply_get_by_phandle()" and "of_power_supply_get_dev()".

Existing "power_supply_get_by_phandle()"
- Need correct the name of power_supply property.
some device driver using power_supply_get_by_phandle() has the dependecy of 
the name of power_supply property.

If the name of power_supply property is modified,
have to modify some device driver using power_supply_get_by_phandle().

But,
Proposed "of_power_supply_get_dev()"
- of_power_supply_get_dev() has not dependency of specific name.
of_power_supply_get_dev() only need device type of power_supply device among following device type:
	"fuelgague"
	"charger"
	we can do addtional device type of power_supply device.

If some device driver use of_poewr_supply_get_dev(),
don't need to consider the name of power_supply device.	

Thanks,
Chanwoo Choi

Re: [RFC PATCH 0/4] power_supply: Add DT helper function to get power-supply dev from dt

[sre]

[-- Attachment #1: Type: text/plain, Size: 2140 bytes --]

Hi Chanwoo,

On Tue, Mar 18, 2014 at 03:06:00PM +0900, Chanwoo Choi wrote:
> I checked power_supply_get_by_phandle().
> But power_supply_get_by_phandle() is different from of_power_supply_get_dev()
> 
> So, I expalin the difference between "power_supply_get_by_phandle()" and "of_power_supply_get_dev()".
> 
> Existing "power_supply_get_by_phandle()"
> - Need correct the name of power_supply property.
> some device driver using power_supply_get_by_phandle() has the dependecy of 
> the name of power_supply property.
> 
> If the name of power_supply property is modified,
> have to modify some device driver using power_supply_get_by_phandle().

The property names are part of the DT ABI, which is not supposed to
be stable.

> But,
> Proposed "of_power_supply_get_dev()"
> - of_power_supply_get_dev() has not dependency of specific name.
> of_power_supply_get_dev() only need device type of power_supply device among following device type:
> 	"fuelgague"
> 	"charger"
> 	we can do addtional device type of power_supply device.
> 
> If some device driver use of_poewr_supply_get_dev(),
> don't need to consider the name of power_supply device.	
 
You don't need to consider the name of the power_supply device for
power_supply_get_by_phandle either. You only need to consider the
property name, which references the power_supply device. You can
have a look at drivers/power/bq2415x_charger.c, which makes use
of this function:

power_supply_get_by_phandle(np, "ti,usb-charger-detection");

A corresponding DT node can be found in arch/arm/boot/dts/omap3-n900.dts:

bq24150a: bq24150a@6b {
    /* ... */

    ti,usb-charger-detection = <&isp1704>;
}

As you can see the property name has nothing to do with any
names from the referenced node. Apart from that the node name
is also needed by your proposed of_power_supply_get_dev. The
difference is, that you hardcoded it to be either "fuelgauge"
or "charger". The following two calls should return the same
node:

of_power_supply_get_dev(dev, POWER_SUPPLY_DEV_FUELGAUGE, 0);
of_power_supply_get_dev(dev, "fuelgauge");

-- Sebastian

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