[PATCH v3] extcon: gpio: Add the support for Device tree bindings

[PATCH v3] extcon: gpio: Add the support for Device tree bindings

[Chanwoo Choi]

This patch adds the support for Device tree bindings of extcon-gpio driver.
The extcon-gpio device tree node must include the both 'extcon-id' and
'extcon-gpio' property.

For exmaple:
	usb_cable: extcon-gpio-0 {
		compatible = "extcon-gpio";
		extcon-id = <EXTCON_USB>;
		extcon-gpio = <&gpio6 1 GPIO_ACTIVE_HIGH>;
	}

	ta_cable: extcon-gpio-1 {
		compatible = "extcon-gpio";
		extcon-id = <EXTCON_CHG_USB_DCP>;
		extcon-gpio = <&gpio3 2 GPIO_ACTIVE_LOW>;
		debounce-ms = <50>;	/* 50 millisecond */
		wakeup-source;
	}

	&dwc3_usb {
		extcon = <&usb_cable>;
	};

	&charger {
		extcon = <&ta_cable>;
	};

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
---
Changes from v2:
- Add the more description for 'extcon-id' property in documentation

Changes from v1:
- Create the include/dt-bindings/extcon/extcon.h including the identification
of external connector. These definitions are used in dts file.
- Fix error if CONFIG_OF is disabled.
- Add signed-off tag by Myungjoo Ham

 .../devicetree/bindings/extcon/extcon-gpio.txt     |  43 ++++++++
 drivers/extcon/extcon-gpio.c                       | 116 ++++++++++++++++-----
 include/dt-bindings/extcon/extcon.h                |  47 +++++++++
 include/linux/extcon/extcon-gpio.h                 |   8 +-
 4 files changed, 184 insertions(+), 30 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/extcon/extcon-gpio.txt
 create mode 100644 include/dt-bindings/extcon/extcon.h

diff --git a/Documentation/devicetree/bindings/extcon/extcon-gpio.txt b/Documentation/devicetree/bindings/extcon/extcon-gpio.txt
new file mode 100644
index 000000000000..1e011f9c8536
--- /dev/null
+++ b/Documentation/devicetree/bindings/extcon/extcon-gpio.txt
@@ -0,0 +1,43 @@
+GPIO Extcon device
+
+This is a virtual device used to generate the specific cable states from the
+GPIO pin.
+
+Required properties:
+- compatible: Must be "extcon-gpio".
+- extcon-id: The extcon support the various type of external connector to check
+  whether connector is attached or detached. The each external connector has
+  the unique number to identify it. So this property includes the unique number
+  which indicates the specific external connector. When external connector is
+  attached or detached, GPIO pin detect the changed state. See include/
+  dt-bindings/extcon/extcon.h which defines the unique number for supported
+  external connector from extcon framework.
+- extcon-gpio: GPIO pin to detect the external connector. See gpio binding.
+
+Optional properties:
+- debounce-ms: the debounce dealy for GPIO pin in millisecond.
+- wakeup-source: Boolean, extcon can wake-up the system.
+
+Example: Examples of extcon-gpio node as listed below:
+
+	usb_cable: extcon-gpio-0 {
+		compatible = "extcon-gpio";
+		extcon-id = <EXTCON_USB>;
+		extcon-gpio = <&gpio6 1 GPIO_ACTIVE_HIGH>;
+	}
+
+	ta_cable: extcon-gpio-1 {
+		compatible = "extcon-gpio";
+		extcon-id = <EXTCON_CHG_USB_DCP>;
+		extcon-gpio = <&gpio3 2 GPIO_ACTIVE_LOW>;
+		debounce-ms = <50>;	/* 50 millisecond */
+		wakeup-source;
+	}
+
+	&dwc3_usb {
+		extcon = <&usb_cable>;
+	};
+
+	&charger {
+		extcon = <&ta_cable>;
+	};
diff --git a/drivers/extcon/extcon-gpio.c b/drivers/extcon/extcon-gpio.c
index 279ff8f6637d..69b560d136cd 100644
--- a/drivers/extcon/extcon-gpio.c
+++ b/drivers/extcon/extcon-gpio.c
@@ -1,11 +1,9 @@
 /*
  * extcon_gpio.c - Single-state GPIO extcon driver based on extcon class
  *
- * Copyright (C) 2008 Google, Inc.
- * Author: Mike Lockwood <lockwood@android.com>
- *
- * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon
- * (originally switch class is supported)
+ * Copyright (C) 2015 Chanwoo Choi <cw00.choi@samsung.com>, Samsung Electronics
+ * Copyright (C) 2012 MyungJoo Ham <myungjoo.ham@samsung.com>, Samsung Electronics
+ * Copyright (C) 2008 Mike Lockwood <lockwood@android.com>, Google, Inc.
  *
  * This software is licensed under the terms of the GNU General Public
  * License version 2, as published by the Free Software Foundation, and
@@ -26,12 +24,14 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/property.h>
 #include <linux/slab.h>
 #include <linux/workqueue.h>
 
 struct gpio_extcon_data {
 	struct extcon_dev *edev;
 	int irq;
+	bool irq_wakeup;
 	struct delayed_work work;
 	unsigned long debounce_jiffies;
 
@@ -49,7 +49,7 @@ static void gpio_extcon_work(struct work_struct *work)
 	state = gpiod_get_value_cansleep(data->id_gpiod);
 	if (data->pdata->gpio_active_low)
 		state = !state;
-	extcon_set_state(data->edev, state);
+	extcon_set_cable_state_(data->edev, data->pdata->extcon_id, state);
 }
 
 static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
@@ -61,19 +61,50 @@ static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static int gpio_extcon_init(struct device *dev, struct gpio_extcon_data *data)
+static int gpio_extcon_parse_of(struct device *dev,
+				struct gpio_extcon_data *data)
 {
-	struct gpio_extcon_pdata *pdata = data->pdata;
+	struct gpio_extcon_pdata *pdata;
 	int ret;
 
-	ret = devm_gpio_request_one(dev, pdata->gpio, GPIOF_DIR_IN,
-				dev_name(dev));
+	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+
+	ret = device_property_read_u32(dev, "extcon-id", &pdata->extcon_id);
+	if (ret < 0)
+		return -EINVAL;
+
+	data->id_gpiod = devm_gpiod_get(dev, "extcon", GPIOD_IN);
 	if (ret < 0)
 		return ret;
 
-	data->id_gpiod = gpio_to_desc(pdata->gpio);
-	if (!data->id_gpiod)
-		return -EINVAL;
+	data->irq_wakeup = device_property_read_bool(dev, "wakeup-source");
+
+	device_property_read_u32(dev, "debounce-ms", &pdata->debounce);
+
+	pdata->irq_flags = (IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING
+				| IRQF_ONESHOT);
+
+	data->pdata = pdata;
+	return 0;
+}
+
+static int gpio_extcon_init(struct device *dev, struct gpio_extcon_data *data)
+{
+	struct gpio_extcon_pdata *pdata = data->pdata;
+	int ret;
+
+	if (!data->id_gpiod) {
+		ret = devm_gpio_request_one(dev, pdata->gpio, GPIOF_DIR_IN,
+					dev_name(dev));
+		if (ret < 0)
+			return ret;
+
+		data->id_gpiod = gpio_to_desc(pdata->gpio);
+		if (!data->id_gpiod)
+			return -EINVAL;
+	}
 
 	if (pdata->debounce) {
 		ret = gpiod_set_debounce(data->id_gpiod,
@@ -96,16 +127,20 @@ static int gpio_extcon_probe(struct platform_device *pdev)
 	struct gpio_extcon_data *data;
 	int ret;
 
-	if (!pdata)
-		return -EBUSY;
-	if (!pdata->irq_flags || pdata->extcon_id > EXTCON_NONE)
-		return -EINVAL;
-
-	data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_extcon_data),
-				   GFP_KERNEL);
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
-	data->pdata = pdata;
+
+	if (!pdata) {
+		ret = gpio_extcon_parse_of(&pdev->dev, data);
+		if (ret < 0)
+			return ret;
+	} else {
+		data->pdata = pdata;
+	}
+
+	if (!data->pdata->irq_flags || data->pdata->extcon_id == EXTCON_NONE)
+		return -EINVAL;
 
 	/* Initialize the gpio */
 	ret = gpio_extcon_init(&pdev->dev, data);
@@ -113,7 +148,8 @@ static int gpio_extcon_probe(struct platform_device *pdev)
 		return ret;
 
 	/* Allocate the memory of extcon devie and register extcon device */
-	data->edev = devm_extcon_dev_allocate(&pdev->dev, &pdata->extcon_id);
+	data->edev = devm_extcon_dev_allocate(&pdev->dev,
+						&data->pdata->extcon_id);
 	if (IS_ERR(data->edev)) {
 		dev_err(&pdev->dev, "failed to allocate extcon device\n");
 		return -ENOMEM;
@@ -130,7 +166,8 @@ static int gpio_extcon_probe(struct platform_device *pdev)
 	 * is attached or detached.
 	 */
 	ret = devm_request_any_context_irq(&pdev->dev, data->irq,
-					gpio_irq_handler, pdata->irq_flags,
+					gpio_irq_handler,
+					data->pdata->irq_flags,
 					pdev->name, data);
 	if (ret < 0)
 		return ret;
@@ -139,6 +176,8 @@ static int gpio_extcon_probe(struct platform_device *pdev)
 	/* Perform initial detection */
 	gpio_extcon_work(&data->work.work);
 
+	device_init_wakeup(&pdev->dev, data->irq_wakeup);
+
 	return 0;
 }
 
@@ -152,11 +191,23 @@ static int gpio_extcon_remove(struct platform_device *pdev)
 }
 
 #ifdef CONFIG_PM_SLEEP
+static int gpio_extcon_suspend(struct device *dev)
+{
+	struct gpio_extcon_data *data = dev_get_drvdata(dev);
+
+	if (data->irq_wakeup)
+		enable_irq_wake(data->irq);
+
+	return 0;
+}
+
 static int gpio_extcon_resume(struct device *dev)
 {
-	struct gpio_extcon_data *data;
+	struct gpio_extcon_data *data = dev_get_drvdata(dev);
+
+	if (data->irq_wakeup)
+		disable_irq_wake(data->irq);
 
-	data = dev_get_drvdata(dev);
 	if (data->pdata->check_on_resume)
 		queue_delayed_work(system_power_efficient_wq,
 			&data->work, data->debounce_jiffies);
@@ -165,7 +216,18 @@ static int gpio_extcon_resume(struct device *dev)
 }
 #endif
 
-static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume);
+#if defined(CONFIG_OF)
+static const struct of_device_id gpio_extcon_of_match[] = {
+	{ .compatible = "extcon-gpio", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, gpio_extcon_of_match);
+#else
+#define gpio_extcon_of_match	NULL
+#endif
+
+static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops,
+			gpio_extcon_suspend, gpio_extcon_resume);
 
 static struct platform_driver gpio_extcon_driver = {
 	.probe		= gpio_extcon_probe,
@@ -173,11 +235,13 @@ static struct platform_driver gpio_extcon_driver = {
 	.driver		= {
 		.name	= "extcon-gpio",
 		.pm	= &gpio_extcon_pm_ops,
+		.of_match_table = gpio_extcon_of_match,
 	},
 };
 
 module_platform_driver(gpio_extcon_driver);
 
+MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
 MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
 MODULE_DESCRIPTION("GPIO extcon driver");
 MODULE_LICENSE("GPL");
diff --git a/include/dt-bindings/extcon/extcon.h b/include/dt-bindings/extcon/extcon.h
new file mode 100644
index 000000000000..dbba5886cc8c
--- /dev/null
+++ b/include/dt-bindings/extcon/extcon.h
@@ -0,0 +1,47 @@
+/*
+ * This header provides constants for most extcon bindings.
+ *
+ * Most extcon bindings include the unique identification format.
+ * In most cases, the unique id format uses the standard values/macro
+ * defined in this header.
+ */
+
+#ifndef _DT_BINDINGS_EXTCON_EXTCON_H
+#define _DT_BINDINGS_EXTCON_EXTCON_H
+
+/* USB external connector */
+#define EXTCON_USB		1
+#define EXTCON_USB_HOST		2
+
+/* Charging external connector */
+#define EXTCON_CHG_USB_SDP	5	/* Standard Downstream Port */
+#define EXTCON_CHG_USB_DCP	6	/* Dedicated Charging Port */
+#define EXTCON_CHG_USB_CDP	7	/* Charging Downstream Port */
+#define EXTCON_CHG_USB_ACA	8	/* Accessory Charger Adapter */
+#define EXTCON_CHG_USB_FAST	9
+#define EXTCON_CHG_USB_SLOW	10
+
+/* Jack external connector */
+#define EXTCON_JACK_MICROPHONE	20
+#define EXTCON_JACK_HEADPHONE	21
+#define EXTCON_JACK_LINE_IN	22
+#define EXTCON_JACK_LINE_OUT	23
+#define EXTCON_JACK_VIDEO_IN	24
+#define EXTCON_JACK_VIDEO_OUT	25
+#define EXTCON_JACK_SPDIF_IN	26	/* Sony Philips Digital InterFace */
+#define EXTCON_JACK_SPDIF_OUT	27
+
+/* Display external connector */
+#define EXTCON_DISP_HDMI	40	/* High-Definition Multimedia Interface */
+#define EXTCON_DISP_MHL		41	/* Mobile High-Definition Link */
+#define EXTCON_DISP_DVI		42	/* Digital Visual Interface */
+#define EXTCON_DISP_VGA		43	/* Video Graphics Array */
+
+/* Miscellaneous external connector */
+#define EXTCON_DOCK		60
+#define EXTCON_JIG		61
+#define EXTCON_MECHANICAL	62
+
+#define EXTCON_NUM		63
+
+#endif /* _DT_BINDINGS_EXTCON_EXTCON_H */
diff --git a/include/linux/extcon/extcon-gpio.h b/include/linux/extcon/extcon-gpio.h
index 7cacafb78b09..416c2adad7fb 100644
--- a/include/linux/extcon/extcon-gpio.h
+++ b/include/linux/extcon/extcon-gpio.h
@@ -1,8 +1,8 @@
 /*
  * Single-state GPIO extcon driver based on extcon class
  *
- * Copyright (C) 2012 Samsung Electronics
- * Author: MyungJoo Ham <myungjoo.ham@samsung.com>
+ * Copyright (C) 2015 Chanwoo Choi <cw00.choi@samsung.com>, Samsung Electronics
+ * Copyright (C) 2012 MyungJoo Ham <myungjoo.ham@samsung.com>, Samsung Electronics
  *
  * based on switch class driver
  * Copyright (C) 2008 Google, Inc.
@@ -35,10 +35,10 @@
  *			while resuming from sleep.
  */
 struct gpio_extcon_pdata {
-	unsigned int extcon_id;
+	u32 extcon_id;
 	unsigned gpio;
 	bool gpio_active_low;
-	unsigned long debounce;
+	u32 debounce;
 	unsigned long irq_flags;
 
 	bool check_on_resume;
-- 
1.9.1

Re: [PATCH v3] extcon: gpio: Add the support for Device tree bindings

[Rob Herring]

On Tue, Oct 20, 2015 at 11:37 PM, Chanwoo Choi <cw00.choi@samsung.com> wrote:
> This patch adds the support for Device tree bindings of extcon-gpio driver.
> The extcon-gpio device tree node must include the both 'extcon-id' and
> 'extcon-gpio' property.

I think this is too tied to the Linux driver. Instead, think about
what the connector contains. I think you should define a usb connector
node and compatible (e.g. usb-connector or usb-ab-connector). This
probably needs to distinguish the connector type as well especially
with TypeC coming.

>
> For exmaple:
>         usb_cable: extcon-gpio-0 {
>                 compatible = "extcon-gpio";
>                 extcon-id = <EXTCON_USB>;
>                 extcon-gpio = <&gpio6 1 GPIO_ACTIVE_HIGH>;

This tied to a Vbus detect circuit?

So "vbus-detect-gpios" in the connector node.

For host side (or OTG host mode), you may also need a vbus-supply
regulator property. OTG will also need an id-gpios for ID pin.

>         }
>
>         ta_cable: extcon-gpio-1 {

This is all the same connector as above?

>                 compatible = "extcon-gpio";
>                 extcon-id = <EXTCON_CHG_USB_DCP>;
>                 extcon-gpio = <&gpio3 2 GPIO_ACTIVE_LOW>;

This is just detecting D+ and D- are both pulled high?

So "dcp-detect-gpios" in the connector node.

>                 debounce-ms = <50>;     /* 50 millisecond */
>                 wakeup-source;

wakeup-source implies an interrupt as I read Sudeep's series. Either
gpios need to be allowed or these need to be defined as interrupts.

>         }
>
>         &dwc3_usb {
>                 extcon = <&usb_cable>;
>         };
>
>         &charger {
>                 extcon = <&ta_cable>;

Not sure what to do with this. Both can point to a single connector
node I think.

Rob

Re: [PATCH v3] extcon: gpio: Add the support for Device tree bindings

[Chanwoo Choi]

Hi Rob,

First of all, thanks for your review.

On 2015년 10월 22일 07:35, Rob Herring wrote:
> On Tue, Oct 20, 2015 at 11:37 PM, Chanwoo Choi <cw00.choi-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org> wrote:
>> This patch adds the support for Device tree bindings of extcon-gpio driver.
>> The extcon-gpio device tree node must include the both 'extcon-id' and
>> 'extcon-gpio' property.
> 
> I think this is too tied to the Linux driver. Instead, think about
> what the connector contains. I think you should define a usb connector
> node and compatible (e.g. usb-connector or usb-ab-connector). This

The Extcon framework support the various external connector.
You mean that extcon-gpio.c should have the separate compatible
for each external connector?

For example,
static const struct of_device_id gpio_extcon_of_match[] = {
	{
		.compatible = "extcon-usb",	/* USB connector */
		.data = EXTCON_USB_DATA,
	}, {
		.compatible = "extcon-chg-sdp",	/* SDP charger connector */
		.data = EXTCON_CHG_SDP_DATA,
	}, {
		.compatible = "extcon-chg-dcp",	/* DCP charger connector */
		.data = EXTCON_CHG_DCP_DATA,
	}, {
		.compatible = "extcon-jack-microphone", /* Microphone jack connector */
		.data = EXTCON_JACK_MICROPHONE_DATA,
	}, {
		.compatible = "extcon-disp-hdmi", /* HDMI connector*/
		.data = EXTCON_DISP_HDMI_DATA,
	},
	......

};

static struct platform_driver extcon_gpio_driver = {
	.probe	= gpio_extcon_probe,
	.remove	= gpio_extcon_remove,
	.driver	= {
		.name = "extcon-gpio",
		.of_match_table = gpio_extcon_of_match,
	},
};

> probably needs to distinguish the connector type as well especially
> with TypeC coming.

You're right. Currently Extcon framework don't support the setting of connector type
(e.g., USB Type A, Type B, Mini-A, Type-C ...)
I'm planing to add the extcon core API to support the connector type.

> 
>>
>> For exmaple:
>>         usb_cable: extcon-gpio-0 {
>>                 compatible = "extcon-gpio";
>>                 extcon-id = <EXTCON_USB>;
>>                 extcon-gpio = <&gpio6 1 GPIO_ACTIVE_HIGH>;
> 
> This tied to a Vbus detect circuit?
> 
> So "vbus-detect-gpios" in the connector node.

If extcon-gpio.c driver support the multiple comaptible for each external connector,
this driver will support the separate property name for gpio to get it from devicetree.

> 
> For host side (or OTG host mode), you may also need a vbus-supply
> regulator property. OTG will also need an id-gpios for ID pin.

There is already drivers/extcon/extcon-usb-gpio.c driver for USB with GPIO.
[1] https://lkml.org/lkml/2015/2/2/187

> 
>>         }
>>
>>         ta_cable: extcon-gpio-1 {
> 
> This is all the same connector as above?
> 
>>                 compatible = "extcon-gpio";
>>                 extcon-id = <EXTCON_CHG_USB_DCP>;
>>                 extcon-gpio = <&gpio3 2 GPIO_ACTIVE_LOW>;
> 
> This is just detecting D+ and D- are both pulled high?

The extcon-gpio.c might be used to detect the external connector by using only GPIO
which has not correlation to both D+  and D-. This GPIO pin is just used to detect
the state whether external connector is attached or detached.

> 
> So "dcp-detect-gpios" in the connector node.

ditto.

> 
>>                 debounce-ms = <50>;     /* 50 millisecond */
>>                 wakeup-source;
> 
> wakeup-source implies an interrupt as I read Sudeep's series. Either
> gpios need to be allowed or these need to be defined as interrupts.

You are right. I'm going to consider it and modify this driver with more proper method.

> 
>>         }
>>
>>         &dwc3_usb {
>>                 extcon = <&usb_cable>;
>>         };
>>
>>         &charger {
>>                 extcon = <&ta_cable>;
> 
> Not sure what to do with this. Both can point to a single connector
> node I think.

There are both extcon provider driver and client driver.

The extcon provider driver provide client driver to get whether cable state is attached
or detached. And then client driver is waiting the notification from extcon provider driver.
Before waiting the notification from extcon providier driver, the client driver should get
the instance of specific extcon provider driver to register the notifier chain.

When getting the instance of specific extcon provider in device tree,
the client driver use the extcon_get_edev_by_phandle() function which
parses the phandle name of 'extcon'.

The latest Linux kernel includes the example[1][2] in arch/arm/boot/dts/omap5-cm-t54.dts

[1] http://www.spinics.net/lists/linux-omap/msg105074.html
- ARM: dts: sbc-t54: add support for sbc-t54 with cm-t54
[2] ARM: dts: cm-t54: setup omap_dwc3
- http://www.spinics.net/lists/linux-omap/msg111174.html

For example 
&i2c1 {
	......
	palmas: palmas@48 {
		extcon_usb3: palmas_usb {
			compatible = "ti,plamas-usb-vid";
			ti,enable-vbus-detection;
			ti,enable-id-detection;
			ti,wakeup;
		};
		......
	};
	......
};

&usb3 {
	extcon = <&extcon_usb3>;
	vbus-supply = <...>;
};

Regards,
Chanwoo Choi
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