root/drivers/extcon/extcon-usb-gpio.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * drivers/extcon/extcon-usb-gpio.c - USB GPIO extcon driver
 *
 * Copyright (C) 2015 Texas Instruments Incorporated - https://www.ti.com
 * Author: Roger Quadros <rogerq@ti.com>
 */

#include <linux/extcon-provider.h>
#include <linux/gpio/consumer.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/pinctrl/consumer.h>
#include <linux/mod_devicetable.h>

#define USB_GPIO_DEBOUNCE_MS    20      /* ms */

struct usb_extcon_info {
        struct device *dev;
        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;
};

static const unsigned int usb_extcon_cable[] = {
        EXTCON_USB,
        EXTCON_USB_HOST,
        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, vbus;
        struct usb_extcon_info *info = container_of(to_delayed_work(work),
                                                    struct usb_extcon_info,
                                                    wq_detcable);

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        /* at first we clean states which are no longer active */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

static irqreturn_t usb_irq_handler(int irq, void *dev_id)
{
        struct usb_extcon_info *info = dev_id;

        queue_delayed_work(system_power_efficient_wq, &info->wq_detcable,
                           info->debounce_jiffies);

        return IRQ_HANDLED;
}

static int usb_extcon_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
        struct usb_extcon_info *info;
        int ret;

        if (!np)
                return -EINVAL;

        info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
        if (!info)
                return -ENOMEM;

        info->dev = dev;
        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");
                return -ENOMEM;
        }

        ret = devm_extcon_dev_register(dev, info->edev);
        if (ret < 0) {
                dev_err(dev, "failed to register extcon device\n");
                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");
                        return info->id_irq;
                }

                ret = devm_request_threaded_irq(dev, info->id_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 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_set_wakeup_capable(&pdev->dev, true);

        /* Perform initial detection */
        usb_extcon_detect_cable(&info->wq_detcable.work);

        return 0;
}

static void usb_extcon_remove(struct platform_device *pdev)
{
        struct usb_extcon_info *info = platform_get_drvdata(pdev);

        cancel_delayed_work_sync(&info->wq_detcable);
        device_init_wakeup(&pdev->dev, false);
}

#ifdef CONFIG_PM_SLEEP
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;
                        }
                }
        }

        if (!device_may_wakeup(dev))
                pinctrl_pm_select_sleep_state(dev);

        return ret;
}

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))
                pinctrl_pm_select_default_state(dev);

        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;
                        }
                }
        }

        queue_delayed_work(system_power_efficient_wq,
                           &info->wq_detcable, 0);

        return ret;
}
#endif

static SIMPLE_DEV_PM_OPS(usb_extcon_pm_ops,
                         usb_extcon_suspend, usb_extcon_resume);

static const struct of_device_id usb_extcon_dt_match[] = {
        { .compatible = "linux,extcon-usb-gpio", },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, usb_extcon_dt_match);

static const struct platform_device_id usb_extcon_platform_ids[] = {
        { .name = "extcon-usb-gpio", },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(platform, usb_extcon_platform_ids);

static struct platform_driver usb_extcon_driver = {
        .probe          = usb_extcon_probe,
        .remove         = usb_extcon_remove,
        .driver         = {
                .name   = "extcon-usb-gpio",
                .pm     = &usb_extcon_pm_ops,
                .of_match_table = usb_extcon_dt_match,
        },
        .id_table = usb_extcon_platform_ids,
};

module_platform_driver(usb_extcon_driver);

MODULE_AUTHOR("Roger Quadros <rogerq@ti.com>");
MODULE_DESCRIPTION("USB GPIO extcon driver");
MODULE_LICENSE("GPL v2");