Commit 541332a1 authored by Roger Quadros's avatar Roger Quadros Committed by Chanwoo Choi
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extcon: usb-gpio: Add VBUS detection support 



Driver can now work with both ID and VBUS pins or either one of
them.

There can be the following 3 cases

1) Both ID and VBUS GPIOs are available:

ID = LOW -> USB_HOST active, USB inactive
ID = HIGH -> USB_HOST inactive, USB state is same as VBUS.

2) Only ID GPIO is available:

ID = LOW -> USB_HOST active, USB inactive
ID = HIGH -> USB_HOST inactive, USB active

3) Only VBUS GPIO is available:

VBUS = LOW -> USB_HOST inactive, USB inactive
VBUS = HIGH -> USB_HOST inactive, USB active

Signed-off-by: default avatarRoger Quadros <rogerq@ti.com>
Reviewed-by: default avatarPeter Chen <peter.chen@nxp.com>
Signed-off-by: default avatarChanwoo Choi <cw00.choi@samsung.com>
parent a25f0944

Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt

+3 −0
Original line number Diff line number Diff line
@@ -5,7 +5,10 @@ connected to a GPIO pin. 


Required properties:

- compatible: Should be "linux,extcon-usb-gpio"



Either one of id-gpio or vbus-gpio must be present. Both can be present as well.

- id-gpio: gpio for USB ID pin. See gpio binding.

- vbus-gpio: gpio for USB VBUS pin.



Example: Examples of extcon-usb-gpio node in dra7-evm.dts as listed below:

	extcon_usb1 {

drivers/extcon/extcon-usb-gpio.c

+129 −40
Original line number Diff line number Diff line
@@ -24,7 +24,6 @@ 
#include <linux/module.h>

#include <linux/of_gpio.h>

#include <linux/platform_device.h>

#include <linux/pm_wakeirq.h>

#include <linux/slab.h>

#include <linux/workqueue.h>

#include <linux/acpi.h>
@@ -36,7 +35,9 @@ struct usb_extcon_info { 
	struct extcon_dev *edev;



	struct gpio_desc *id_gpiod;

	struct gpio_desc *vbus_gpiod;

	int id_irq;

	int vbus_irq;



	unsigned long debounce_jiffies;

	struct delayed_work wq_detcable;
@@ -48,31 +49,47 @@ static const unsigned int usb_extcon_cable[] = { 
	EXTCON_NONE,

};



/*

 * "USB" = VBUS and "USB-HOST" = !ID, so we have:

 * Both "USB" and "USB-HOST" can't be set as active at the

 * same time so if "USB-HOST" is active (i.e. ID is 0)  we keep "USB" inactive

 * even if VBUS is on.

 *

 *  State              |    ID   |   VBUS

 * ----------------------------------------

 *  [1] USB            |    H    |    H

 *  [2] none           |    H    |    L

 *  [3] USB-HOST       |    L    |    H

 *  [4] USB-HOST       |    L    |    L

 *

 * In case we have only one of these signals:

 * - VBUS only - we want to distinguish between [1] and [2], so ID is always 1.

 * - ID only - we want to distinguish between [1] and [4], so VBUS = ID.

*/

static void usb_extcon_detect_cable(struct work_struct *work)

{

	int id;

	int id, vbus;

	struct usb_extcon_info *info = container_of(to_delayed_work(work),

						    struct usb_extcon_info,

						    wq_detcable);



	/* check ID and update cable state */

	id = gpiod_get_value_cansleep(info->id_gpiod);

	if (id) {

		/*

		 * ID = 1 means USB HOST cable detached.

		 * As we don't have event for USB peripheral cable attached,

		 * we simulate USB peripheral attach here.

		 */

	/* check ID and VBUS and update cable state */

	id = info->id_gpiod ?

		gpiod_get_value_cansleep(info->id_gpiod) : 1;

	vbus = info->vbus_gpiod ?

		gpiod_get_value_cansleep(info->vbus_gpiod) : id;



	/* at first we clean states which are no longer active */

	if (id)

		extcon_set_state_sync(info->edev, EXTCON_USB_HOST, false);

		extcon_set_state_sync(info->edev, EXTCON_USB, true);

	} else {

		/*

		 * ID = 0 means USB HOST cable attached.

		 * As we don't have event for USB peripheral cable detached,

		 * we simulate USB peripheral detach here.

		 */

	if (!vbus)

		extcon_set_state_sync(info->edev, EXTCON_USB, false);



	if (!id) {

		extcon_set_state_sync(info->edev, EXTCON_USB_HOST, true);

	} else {

		if (vbus)

			extcon_set_state_sync(info->edev, EXTCON_USB, true);

	}

}
@@ -101,12 +118,21 @@ static int usb_extcon_probe(struct platform_device *pdev) 
		return -ENOMEM;



	info->dev = dev;

	info->id_gpiod = devm_gpiod_get(&pdev->dev, "id", GPIOD_IN);

	if (IS_ERR(info->id_gpiod)) {

		dev_err(dev, "failed to get ID GPIO\n");

		return PTR_ERR(info->id_gpiod);

	info->id_gpiod = devm_gpiod_get_optional(&pdev->dev, "id", GPIOD_IN);

	info->vbus_gpiod = devm_gpiod_get_optional(&pdev->dev, "vbus",

						   GPIOD_IN);



	if (!info->id_gpiod && !info->vbus_gpiod) {

		dev_err(dev, "failed to get gpios\n");

		return -ENODEV;

	}



	if (IS_ERR(info->id_gpiod))

		return PTR_ERR(info->id_gpiod);



	if (IS_ERR(info->vbus_gpiod))

		return PTR_ERR(info->vbus_gpiod);



	info->edev = devm_extcon_dev_allocate(dev, usb_extcon_cable);

	if (IS_ERR(info->edev)) {

		dev_err(dev, "failed to allocate extcon device\n");
@@ -119,13 +145,19 @@ static int usb_extcon_probe(struct platform_device *pdev) 
		return ret;

	}



	if (info->id_gpiod)

		ret = gpiod_set_debounce(info->id_gpiod,

					 USB_GPIO_DEBOUNCE_MS * 1000);

	if (!ret && info->vbus_gpiod)

		ret = gpiod_set_debounce(info->vbus_gpiod,

					 USB_GPIO_DEBOUNCE_MS * 1000);



	if (ret < 0)

		info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEBOUNCE_MS);



	INIT_DELAYED_WORK(&info->wq_detcable, usb_extcon_detect_cable);



	if (info->id_gpiod) {

		info->id_irq = gpiod_to_irq(info->id_gpiod);

		if (info->id_irq < 0) {

			dev_err(dev, "failed to get ID IRQ\n");
@@ -141,10 +173,28 @@ static int usb_extcon_probe(struct platform_device *pdev) 
			dev_err(dev, "failed to request handler for ID IRQ\n");

			return ret;

		}

	}



	if (info->vbus_gpiod) {

		info->vbus_irq = gpiod_to_irq(info->vbus_gpiod);

		if (info->vbus_irq < 0) {

			dev_err(dev, "failed to get VBUS IRQ\n");

			return info->vbus_irq;

		}



		ret = devm_request_threaded_irq(dev, info->vbus_irq, NULL,

						usb_irq_handler,

						IRQF_TRIGGER_RISING |

						IRQF_TRIGGER_FALLING | IRQF_ONESHOT,

						pdev->name, info);

		if (ret < 0) {

			dev_err(dev, "failed to request handler for VBUS IRQ\n");

			return ret;

		}

	}



	platform_set_drvdata(pdev, info);

	device_init_wakeup(dev, true);

	dev_pm_set_wake_irq(dev, info->id_irq);



	/* Perform initial detection */

	usb_extcon_detect_cable(&info->wq_detcable.work);
@@ -157,8 +207,6 @@ static int usb_extcon_remove(struct platform_device *pdev) 
	struct usb_extcon_info *info = platform_get_drvdata(pdev);



	cancel_delayed_work_sync(&info->wq_detcable);



	dev_pm_clear_wake_irq(&pdev->dev);

	device_init_wakeup(&pdev->dev, false);



	return 0;
@@ -170,12 +218,32 @@ static int usb_extcon_suspend(struct device *dev) 
	struct usb_extcon_info *info = dev_get_drvdata(dev);

	int ret = 0;



	if (device_may_wakeup(dev)) {

		if (info->id_gpiod) {

			ret = enable_irq_wake(info->id_irq);

			if (ret)

				return ret;

		}

		if (info->vbus_gpiod) {

			ret = enable_irq_wake(info->vbus_irq);

			if (ret) {

				if (info->id_gpiod)

					disable_irq_wake(info->id_irq);



				return ret;

			}

		}

	}



	/*

	 * We don't want to process any IRQs after this point

	 * as GPIOs used behind I2C subsystem might not be

	 * accessible until resume completes. So disable IRQ.

	 */

	if (info->id_gpiod)

		disable_irq(info->id_irq);

	if (info->vbus_gpiod)

		disable_irq(info->vbus_irq);



	return ret;

}
@@ -185,7 +253,28 @@ static int usb_extcon_resume(struct device *dev) 
	struct usb_extcon_info *info = dev_get_drvdata(dev);

	int ret = 0;



	if (device_may_wakeup(dev)) {

		if (info->id_gpiod) {

			ret = disable_irq_wake(info->id_irq);

			if (ret)

				return ret;

		}

		if (info->vbus_gpiod) {

			ret = disable_irq_wake(info->vbus_irq);

			if (ret) {

				if (info->id_gpiod)

					enable_irq_wake(info->id_irq);



				return ret;

			}

		}

	}



	if (info->id_gpiod)

		enable_irq(info->id_irq);

	if (info->vbus_gpiod)

		enable_irq(info->vbus_irq);



	if (!device_may_wakeup(dev))

		queue_delayed_work(system_power_efficient_wq,

				   &info->wq_detcable, 0);

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