[PATCH v2 0/3] gpio-charger: add devicetree support

This series adds devicetree support to the gpio-charger and fixes a small
issue with the return value of gpio_get_value.

changes since v1:
- adapt binding example to show how the charger fits into the
  power-supplies structure

Heiko Stuebner (3):
  dt-bindings: document gpio-charger bindings
  power: gpio-charger: add device tree support
  power: gpio-charger: do not use gpio value directly

 .../bindings/power_supply/gpio-charger.txt         | 27 +++++++++
 drivers/power/gpio-charger.c                       | 68 ++++++++++++++++++++--
 2 files changed, 91 insertions(+), 4 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/power_supply/gpio-charger.txt

-- 
1.9.0

From: Heiko Stuebner <redacted>

Some gpio implementations return interesting values for gpio_get_value when
the value is not 0 - as seen on a imx6sl board. Therefore do not use the
value returned from gpio_get_value directly but simply check for 0 or not 0.

Signed-off-by: Heiko Stuebner <redacted>
---
 drivers/power/gpio-charger.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/power/gpio-charger.c b/drivers/power/gpio-charger.c
index 5fe6879..ce99a29 100644
--- a/drivers/power/gpio-charger.c
+++ b/drivers/power/gpio-charger.c

@@ -57,7 +57,7 @@ static int gpio_charger_get_property(struct power_supply *psy,
 
 	switch (psp) {
 	case POWER_SUPPLY_PROP_ONLINE:
-		val->intval = gpio_get_value_cansleep(pdata->gpio);
+		val->intval = gpio_get_value_cansleep(pdata->gpio) ? 1 : 0;
 		val->intval ^= pdata->gpio_active_low;
 		break;
 	default:

-- 
1.9.0

From: Heiko Stuebner <redacted>

Add the ability to parse gpio-charger data from a devicetree node.

Signed-off-by: Heiko Stuebner <redacted>
---
 drivers/power/gpio-charger.c | 66 ++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 63 insertions(+), 3 deletions(-)

diff --git a/drivers/power/gpio-charger.c b/drivers/power/gpio-charger.c
index a0024b2..5fe6879 100644
--- a/drivers/power/gpio-charger.c
+++ b/drivers/power/gpio-charger.c

@@ -22,6 +22,8 @@
 #include <linux/platform_device.h>
 #include <linux/power_supply.h>
 #include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
 
 #include <linux/power/gpio-charger.h>
 

@@ -69,17 +71,68 @@ static enum power_supply_property gpio_charger_properties[] = {
 	POWER_SUPPLY_PROP_ONLINE,
 };
 
+static
+struct gpio_charger_platform_data *gpio_charger_parse_dt(struct device *dev)
+{
+	struct device_node *np = dev->of_node;
+	struct gpio_charger_platform_data *pdata;
+	const char *chargetype;
+	enum of_gpio_flags flags;
+	int ret;
+
+	if (!np)
+		return ERR_PTR(-ENOENT);
+
+	pdata = devm_kzalloc(dev, sizeof(struct gpio_charger_platform_data),
+			     GFP_KERNEL);
+	if (!pdata)
+		return ERR_PTR(-ENOMEM);
+
+	pdata->name = np->name;
+
+	pdata->gpio = of_get_gpio_flags(np, 0, &flags);
+	pdata->gpio_active_low = flags & OF_GPIO_ACTIVE_LOW;
+
+	pdata->type = POWER_SUPPLY_TYPE_UNKNOWN;
+	ret = of_property_read_string(np, "charger-type", &chargetype);
+	if (ret >= 0) {
+		if (!strncmp("unknown", chargetype, 7))
+			pdata->type = POWER_SUPPLY_TYPE_UNKNOWN;
+		else if (!strncmp("battery", chargetype, 7))
+			pdata->type = POWER_SUPPLY_TYPE_BATTERY;
+		else if (!strncmp("ups", chargetype, 3))
+			pdata->type = POWER_SUPPLY_TYPE_UPS;
+		else if (!strncmp("mains", chargetype, 5))
+			pdata->type = POWER_SUPPLY_TYPE_MAINS;
+		else if (!strncmp("usb-sdp", chargetype, 7))
+			pdata->type = POWER_SUPPLY_TYPE_USB;
+		else if (!strncmp("usb-dcp", chargetype, 7))
+			pdata->type = POWER_SUPPLY_TYPE_USB_DCP;
+		else if (!strncmp("usb-cdp", chargetype, 7))
+			pdata->type = POWER_SUPPLY_TYPE_USB_CDP;
+		else if (!strncmp("usb-aca", chargetype, 7))
+			pdata->type = POWER_SUPPLY_TYPE_USB_ACA;
+		else
+			dev_warn(dev, "unknown charger type %s\n", chargetype);
+	}
+
+	return pdata;
+}
+
 static int gpio_charger_probe(struct platform_device *pdev)
 {
-	const struct gpio_charger_platform_data *pdata = pdev->dev.platform_data;
+	struct gpio_charger_platform_data *pdata = pdev->dev.platform_data;
 	struct gpio_charger *gpio_charger;
 	struct power_supply *charger;
 	int ret;
 	int irq;
 
 	if (!pdata) {
-		dev_err(&pdev->dev, "No platform data\n");
-		return -EINVAL;
+		pdata = gpio_charger_parse_dt(&pdev->dev);
+		if (IS_ERR(pdata)) {
+			dev_err(&pdev->dev, "No platform data\n");
+			return -EINVAL;
+		}
 	}
 
 	if (!gpio_is_valid(pdata->gpio)) {

@@ -189,6 +242,12 @@ static int gpio_charger_resume(struct device *dev)
 static SIMPLE_DEV_PM_OPS(gpio_charger_pm_ops,
 		gpio_charger_suspend, gpio_charger_resume);
 
+static const struct of_device_id gpio_charger_match[] = {
+	{ .compatible = "gpio-charger" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, gpio_charger_match);
+
 static struct platform_driver gpio_charger_driver = {
 	.probe = gpio_charger_probe,
 	.remove = gpio_charger_remove,

@@ -196,6 +255,7 @@ static struct platform_driver gpio_charger_driver = {
 		.name = "gpio-charger",
 		.owner = THIS_MODULE,
 		.pm = &gpio_charger_pm_ops,
+		.of_match_table = of_match_ptr(gpio_charger_match),
 	},
 };
 

-- 
1.9.0

From: Heiko Stuebner <redacted>

This documents the binding for the gpio-charger power-supply.

Signed-off-by: Heiko Stuebner <redacted>
---
 .../bindings/power_supply/gpio-charger.txt         | 27 ++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/power_supply/gpio-charger.txt

diff --git a/Documentation/devicetree/bindings/power_supply/gpio-charger.txt b/Documentation/devicetree/bindings/power_supply/gpio-charger.txt
new file mode 100644
index 0000000..adbb5dc
--- /dev/null
+++ b/Documentation/devicetree/bindings/power_supply/gpio-charger.txt

@@ -0,0 +1,27 @@
+gpio-charger
+
+Required properties :
+ - compatible : "gpio-charger"
+ - gpios : GPIO indicating the charger presence.
+   See GPIO binding in bindings/gpio/gpio.txt .
+ - charger-type : power supply type, one of
+     unknown
+     battery
+     ups
+     mains
+     usb-sdp (USB standard downstream port)
+     usb-dcp (USB dedicated charging port)
+     usb-cdp (USB charging downstream port)
+     usb-aca (USB accessory charger adapter)
+
+Example:
+
+	usb_charger: charger {
+		compatible = "gpio-charger";
+		charger-type = "usb-sdp";
+		gpios = <&gpf0 2 0 0 0>;
+	}
+
+	battery {
+		power-supplies = <&usb_charger>;
+	};

-- 
1.9.0

Heiko

On Sun, Sep 21, 2014 at 1:05 PM, Heiko Stuebner [off-list ref] wrote:

nit: sizeof(*pdata) is smaller / cleaner.

It would be nice to check the gpio for errors here, including handling
the possibility of EPROBE_DEFER.

Do you really need to remove const?  If I remember correctly the const
here is not saying that the variable "pdata" won't change but that the
data pointed to by pdata won't change.  I think that's still the case
(from the perspective of this function).

Probably should pass back the error code since it might be
EPROBE_DEFER.  ...and <sigh> I guess you need the special case of
"don't print if it's EPROBE_DEFER".  I almost wish we had a helper
function for that.  ;)

Given that you don't have any #ifdefs with "CONFIG_OF", I think
gpio_charger_match will always exist.  It seems like you should remove
the of_match_ptr or add some #ifdefs.  I can't quite keep up with what
the currently suggested best practice is here, though.

-Doug

Heiko,

On Sun, Sep 21, 2014 at 1:05 PM, Heiko Stuebner [off-list ref] wrote:

There is a common practice about using "!!" for this.  AKA:
"val->intval = !!gpio_get_value_cansleep(pdata->gpio);".

                val->intval ^= pdata->gpio_active_low;

It seems like while you're at it you could also fix
"pdata->gpio_active_low" to have the "!!", just to be safe.

...if you don't fix this, perhaps you should fix your last patch to
add a "!!", like:

  pdata->gpio_active_low = !!(flags & OF_GPIO_ACTIVE_LOW);

...technically OF_GPIO_ACTIVE_LOW is 0x1 so it's not a bug, but...

Heiko,

On Sun, Sep 21, 2014 at 1:05 PM, Heiko Stuebner [off-list ref] wrote:

From: Heiko Stuebner <redacted>

This documents the binding for the gpio-charger power-supply.

Signed-off-by: Heiko Stuebner <redacted>
---
 .../bindings/power_supply/gpio-charger.txt         | 27 ++++++++++++++++++++++
 1 file changed, 27 insertions(+)

It is not an area I'm an expert on, but this seems pretty reasonable to me.

Reviewed-by: Doug Anderson <dianders@chromium.org>

Am Montag, 22. September 2014, 09:48:33 schrieb Doug Anderson:

quoted

@@ -196,6 +255,7 @@ static struct platform_driver gpio_charger_driver = {

                .name = "gpio-charger",
                .owner = THIS_MODULE,
                .pm = &gpio_charger_pm_ops,

+               .of_match_table = of_match_ptr(gpio_charger_match),

Given that you don't have any #ifdefs with "CONFIG_OF", I think
gpio_charger_match will always exist.  It seems like you should remove
the of_match_ptr or add some #ifdefs.  I can't quite keep up with what
the currently suggested best practice is here, though.

I've kept the of_match_ptr in v3. The dt parsing functions (of_read_foo,...) 
define stubs for the !CONFIG_OF case which we use here in this case and 
of_match_ptr is also defined differently for both OF and !OF, so it feels like 
it should be there ;-)


Heiko

Heiko,

On Tue, Sep 23, 2014 at 5:03 AM, Heiko Stübner [off-list ref] wrote:

Am Montag, 22. September 2014, 09:48:33 schrieb Doug Anderson:

quoted

quoted

@@ -196,6 +255,7 @@ static struct platform_driver gpio_charger_driver = {

                .name = "gpio-charger",
                .owner = THIS_MODULE,
                .pm = &gpio_charger_pm_ops,

+               .of_match_table = of_match_ptr(gpio_charger_match),

Given that you don't have any #ifdefs with "CONFIG_OF", I think
gpio_charger_match will always exist.  It seems like you should remove
the of_match_ptr or add some #ifdefs.  I can't quite keep up with what
the currently suggested best practice is here, though.

I've kept the of_match_ptr in v3. The dt parsing functions (of_read_foo,...)
define stubs for the !CONFIG_OF case which we use here in this case and
of_match_ptr is also defined differently for both OF and !OF, so it feels like
it should be there ;-)

...I was thinking you'd get a compile-time warning about
gpio_charger_match not being used.  ...but I can't seem to trigger it
with my compiler settings.  In any case, I'm fairly certain that in
the !CONFIG_OF case (plus non-module case) that "gpio_charger_match"
will be defined but not used in your code.

I was under the impression that of_match_ptr was defined differently
for OF and !OF so that you could use it in the case where the
structure itself (gpio_charger_match) had #ifdefs around it...
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html