Commit 4602f3bf authored by Chunfeng Yun's avatar Chunfeng Yun Committed by Greg Kroah-Hartman
Browse files

usb: common: add USB GPIO based connection detection driver 



Due to the requirement of usb-connector.txt binding, the old way
using extcon to support USB Dual-Role switch is now deprecated
when use Type-B connector.
This patch introduces a USB GPIO based connection detection driver,
used to support Type-B connector which typically uses an input GPIO
to detect USB ID pin, and try to replace the function provided
by the extcon-usb-gpio driver

Signed-off-by: default avatarChunfeng Yun <chunfeng.yun@mediatek.com>
Tested-by: default avatarNagarjuna Kristam <nkristam@nvidia.com>
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/1567070558-29417-11-git-send-email-chunfeng.yun@mediatek.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 12b591bc

drivers/usb/common/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -36,3 +36,16 @@ config USB_ULPI_BUS 
	  To compile this driver as a module, choose M here: the module will

	  be called ulpi.



config USB_CONN_GPIO

	tristate "USB GPIO Based Connection Detection Driver"

	depends on GPIOLIB

	select USB_ROLE_SWITCH

	help

	  The driver supports USB role switch between host and device via GPIO

	  based USB cable detection, used typically if an input GPIO is used

	  to detect USB ID pin, and another input GPIO may be also used to detect

	  Vbus pin at the same time, it also can be used to enable/disable

	  device if an input GPIO is only used to detect Vbus pin.



	  To compile the driver as a module, choose M here: the module will

	  be called usb-conn-gpio.ko

drivers/usb/common/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -8,5 +8,6 @@ usb-common-y += common.o 
usb-common-$(CONFIG_TRACING)	  += debug.o

usb-common-$(CONFIG_USB_LED_TRIG) += led.o



obj-$(CONFIG_USB_CONN_GPIO)	+= usb-conn-gpio.o

obj-$(CONFIG_USB_OTG_FSM) += usb-otg-fsm.o

obj-$(CONFIG_USB_ULPI_BUS)	+= ulpi.o

drivers/usb/common/usb-conn-gpio.c

0 → 100644
+284 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * USB GPIO Based Connection Detection Driver

 *

 * Copyright (C) 2019 MediaTek Inc.

 *

 * Author: Chunfeng Yun <chunfeng.yun@mediatek.com>

 *

 * Some code borrowed from drivers/extcon/extcon-usb-gpio.c

 */



#include <linux/device.h>

#include <linux/gpio/consumer.h>

#include <linux/interrupt.h>

#include <linux/irq.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/pinctrl/consumer.h>

#include <linux/platform_device.h>

#include <linux/regulator/consumer.h>

#include <linux/usb/role.h>



#define USB_GPIO_DEB_MS		20	/* ms */

#define USB_GPIO_DEB_US		((USB_GPIO_DEB_MS) * 1000)	/* us */



#define USB_CONN_IRQF	\

	(IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT)



struct usb_conn_info {

	struct device *dev;

	struct usb_role_switch *role_sw;

	enum usb_role last_role;

	struct regulator *vbus;

	struct delayed_work dw_det;

	unsigned long debounce_jiffies;



	struct gpio_desc *id_gpiod;

	struct gpio_desc *vbus_gpiod;

	int id_irq;

	int vbus_irq;

};



/**

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

 * Both "DEVICE" and "HOST" can't be set as active at the same time

 * so if "HOST" is active (i.e. ID is 0)  we keep "DEVICE" inactive

 * even if VBUS is on.

 *

 *  Role          |   ID  |  VBUS

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

 *  [1] DEVICE    |   H   |   H

 *  [2] NONE      |   H   |   L

 *  [3] HOST      |   L   |   H

 *  [4] 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_conn_detect_cable(struct work_struct *work)

{

	struct usb_conn_info *info;

	enum usb_role role;

	int id, vbus, ret;



	info = container_of(to_delayed_work(work),

			    struct usb_conn_info, dw_det);



	/* check ID and VBUS */

	id = info->id_gpiod ?

		gpiod_get_value_cansleep(info->id_gpiod) : 1;

	vbus = info->vbus_gpiod ?

		gpiod_get_value_cansleep(info->vbus_gpiod) : id;



	if (!id)

		role = USB_ROLE_HOST;

	else if (vbus)

		role = USB_ROLE_DEVICE;

	else

		role = USB_ROLE_NONE;



	dev_dbg(info->dev, "role %d/%d, gpios: id %d, vbus %d\n",

		info->last_role, role, id, vbus);



	if (info->last_role == role) {

		dev_warn(info->dev, "repeated role: %d\n", role);

		return;

	}



	if (info->last_role == USB_ROLE_HOST)

		regulator_disable(info->vbus);



	ret = usb_role_switch_set_role(info->role_sw, role);

	if (ret)

		dev_err(info->dev, "failed to set role: %d\n", ret);



	if (role == USB_ROLE_HOST) {

		ret = regulator_enable(info->vbus);

		if (ret)

			dev_err(info->dev, "enable vbus regulator failed\n");

	}



	info->last_role = role;



	dev_dbg(info->dev, "vbus regulator is %s\n",

		regulator_is_enabled(info->vbus) ? "enabled" : "disabled");

}



static void usb_conn_queue_dwork(struct usb_conn_info *info,

				 unsigned long delay)

{

	queue_delayed_work(system_power_efficient_wq, &info->dw_det, delay);

}



static irqreturn_t usb_conn_isr(int irq, void *dev_id)

{

	struct usb_conn_info *info = dev_id;



	usb_conn_queue_dwork(info, info->debounce_jiffies);



	return IRQ_HANDLED;

}



static int usb_conn_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct usb_conn_info *info;

	int ret = 0;



	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);

	if (!info)

		return -ENOMEM;



	info->dev = dev;

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

	if (IS_ERR(info->id_gpiod))

		return PTR_ERR(info->id_gpiod);



	info->vbus_gpiod = devm_gpiod_get_optional(dev, "vbus", GPIOD_IN);

	if (IS_ERR(info->vbus_gpiod))

		return PTR_ERR(info->vbus_gpiod);



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

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

		return -ENODEV;

	}



	if (info->id_gpiod)

		ret = gpiod_set_debounce(info->id_gpiod, USB_GPIO_DEB_US);

	if (!ret && info->vbus_gpiod)

		ret = gpiod_set_debounce(info->vbus_gpiod, USB_GPIO_DEB_US);

	if (ret < 0)

		info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEB_MS);



	INIT_DELAYED_WORK(&info->dw_det, usb_conn_detect_cable);



	info->vbus = devm_regulator_get(dev, "vbus");

	if (IS_ERR(info->vbus)) {

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

		return PTR_ERR(info->vbus);

	}



	info->role_sw = usb_role_switch_get(dev);

	if (IS_ERR(info->role_sw)) {

		if (PTR_ERR(info->role_sw) != -EPROBE_DEFER)

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



		return PTR_ERR(info->role_sw);

	}



	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");

			ret = info->id_irq;

			goto put_role_sw;

		}



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

						usb_conn_isr, USB_CONN_IRQF,

						pdev->name, info);

		if (ret < 0) {

			dev_err(dev, "failed to request ID IRQ\n");

			goto put_role_sw;

		}

	}



	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");

			ret = info->vbus_irq;

			goto put_role_sw;

		}



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

						usb_conn_isr, USB_CONN_IRQF,

						pdev->name, info);

		if (ret < 0) {

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

			goto put_role_sw;

		}

	}



	platform_set_drvdata(pdev, info);



	/* Perform initial detection */

	usb_conn_queue_dwork(info, 0);



	return 0;



put_role_sw:

	usb_role_switch_put(info->role_sw);

	return ret;

}



static int usb_conn_remove(struct platform_device *pdev)

{

	struct usb_conn_info *info = platform_get_drvdata(pdev);



	cancel_delayed_work_sync(&info->dw_det);



	if (info->last_role == USB_ROLE_HOST)

		regulator_disable(info->vbus);



	usb_role_switch_put(info->role_sw);



	return 0;

}



static int __maybe_unused usb_conn_suspend(struct device *dev)

{

	struct usb_conn_info *info = dev_get_drvdata(dev);



	if (info->id_gpiod)

		disable_irq(info->id_irq);

	if (info->vbus_gpiod)

		disable_irq(info->vbus_irq);



	pinctrl_pm_select_sleep_state(dev);



	return 0;

}



static int __maybe_unused usb_conn_resume(struct device *dev)

{

	struct usb_conn_info *info = dev_get_drvdata(dev);



	pinctrl_pm_select_default_state(dev);



	if (info->id_gpiod)

		enable_irq(info->id_irq);

	if (info->vbus_gpiod)

		enable_irq(info->vbus_irq);



	usb_conn_queue_dwork(info, 0);



	return 0;

}



static SIMPLE_DEV_PM_OPS(usb_conn_pm_ops,

			 usb_conn_suspend, usb_conn_resume);



static const struct of_device_id usb_conn_dt_match[] = {

	{ .compatible = "gpio-usb-b-connector", },

	{ }

};

MODULE_DEVICE_TABLE(of, usb_conn_dt_match);



static struct platform_driver usb_conn_driver = {

	.probe		= usb_conn_probe,

	.remove		= usb_conn_remove,

	.driver		= {

		.name	= "usb-conn-gpio",

		.pm	= &usb_conn_pm_ops,

		.of_match_table = usb_conn_dt_match,

	},

};



module_platform_driver(usb_conn_driver);



MODULE_AUTHOR("Chunfeng Yun <chunfeng.yun@mediatek.com>");

MODULE_DESCRIPTION("USB GPIO based connection detection driver");

MODULE_LICENSE("GPL v2");

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