// SPDX-License-Identifier: GPL-2.0 /* * USB GPIO Based Connection Detection Driver * * Copyright (C) 2019 MediaTek Inc. * * Author: Chunfeng Yun * * Some code borrowed from drivers/extcon/extcon-usb-gpio.c */ #include #include #include #include #include #include #include #include #include #include #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)) { if (PTR_ERR(info->vbus) != -EPROBE_DEFER) 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 "); MODULE_DESCRIPTION("USB GPIO based connection detection driver"); MODULE_LICENSE("GPL v2");