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

// SPDX-License-Identifier: GPL-2.0
/*
 * USB GPIO Based Connection Detection Driver
 *
 * Copyright (C) 2019 MediaTek Inc.
 *
 * Author: Chunfeng Yun <[email protected]>
 *
 * 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/power_supply.h>
#include <linux/regulator/consumer.h>
#include <linux/usb/role.h>

#define USB_GPIO_DEB_MS …
#define USB_GPIO_DEB_US …

#define USB_CONN_IRQF …

struct usb_conn_info { … };

/*
 * "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)
{ … }

static void usb_conn_queue_dwork(struct usb_conn_info *info,
				 unsigned long delay)
{ … }

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

static enum power_supply_property usb_charger_properties[] = …;

static int usb_charger_get_property(struct power_supply *psy,
				    enum power_supply_property psp,
				    union power_supply_propval *val)
{ … }

static int usb_conn_psy_register(struct usb_conn_info *info)
{ … }

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

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

static int __maybe_unused usb_conn_suspend(struct device *dev)
{ … }

static int __maybe_unused usb_conn_resume(struct device *dev)
{ … }

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[] = …;
MODULE_DEVICE_TABLE(of, usb_conn_dt_match);

static struct platform_driver usb_conn_driver = …;

module_platform_driver(…) …;

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