linux/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 <[email protected]>
 */

#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 …

struct usb_extcon_info { … };

static const unsigned int usb_extcon_cable[] = …;

/*
 * "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)
{ … }

static irqreturn_t usb_irq_handler(int irq, void *dev_id)
{ … }

static int usb_extcon_probe(struct platform_device *pdev)
{ … }

static void usb_extcon_remove(struct platform_device *pdev)
{ … }

#ifdef CONFIG_PM_SLEEP
static int usb_extcon_suspend(struct device *dev)
{ … }

static int usb_extcon_resume(struct device *dev)
{ … }
#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[] = …;
MODULE_DEVICE_TABLE(of, usb_extcon_dt_match);

static const struct platform_device_id usb_extcon_platform_ids[] = …;
MODULE_DEVICE_TABLE(platform, usb_extcon_platform_ids);

static struct platform_driver usb_extcon_driver = …;

module_platform_driver(…) …;

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;