1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * USB GPIO Based Connection Detection Driver 4 * 5 * Copyright (C) 2019 MediaTek Inc. 6 * 7 * Author: Chunfeng Yun <chunfeng.yun@mediatek.com> 8 * 9 * Some code borrowed from drivers/extcon/extcon-usb-gpio.c 10 */ 11 12 #include <linux/device.h> 13 #include <linux/gpio/consumer.h> 14 #include <linux/interrupt.h> 15 #include <linux/irq.h> 16 #include <linux/module.h> 17 #include <linux/of.h> 18 #include <linux/pinctrl/consumer.h> 19 #include <linux/platform_device.h> 20 #include <linux/regulator/consumer.h> 21 #include <linux/usb/role.h> 22 23 #define USB_GPIO_DEB_MS 20 /* ms */ 24 #define USB_GPIO_DEB_US ((USB_GPIO_DEB_MS) * 1000) /* us */ 25 26 #define USB_CONN_IRQF \ 27 (IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT) 28 29 struct usb_conn_info { 30 struct device *dev; 31 struct usb_role_switch *role_sw; 32 enum usb_role last_role; 33 struct regulator *vbus; 34 struct delayed_work dw_det; 35 unsigned long debounce_jiffies; 36 37 struct gpio_desc *id_gpiod; 38 struct gpio_desc *vbus_gpiod; 39 int id_irq; 40 int vbus_irq; 41 }; 42 43 /** 44 * "DEVICE" = VBUS and "HOST" = !ID, so we have: 45 * Both "DEVICE" and "HOST" can't be set as active at the same time 46 * so if "HOST" is active (i.e. ID is 0) we keep "DEVICE" inactive 47 * even if VBUS is on. 48 * 49 * Role | ID | VBUS 50 * ------------------------------------ 51 * [1] DEVICE | H | H 52 * [2] NONE | H | L 53 * [3] HOST | L | H 54 * [4] HOST | L | L 55 * 56 * In case we have only one of these signals: 57 * - VBUS only - we want to distinguish between [1] and [2], so ID is always 1 58 * - ID only - we want to distinguish between [1] and [4], so VBUS = ID 59 */ 60 static void usb_conn_detect_cable(struct work_struct *work) 61 { 62 struct usb_conn_info *info; 63 enum usb_role role; 64 int id, vbus, ret; 65 66 info = container_of(to_delayed_work(work), 67 struct usb_conn_info, dw_det); 68 69 /* check ID and VBUS */ 70 id = info->id_gpiod ? 71 gpiod_get_value_cansleep(info->id_gpiod) : 1; 72 vbus = info->vbus_gpiod ? 73 gpiod_get_value_cansleep(info->vbus_gpiod) : id; 74 75 if (!id) 76 role = USB_ROLE_HOST; 77 else if (vbus) 78 role = USB_ROLE_DEVICE; 79 else 80 role = USB_ROLE_NONE; 81 82 dev_dbg(info->dev, "role %d/%d, gpios: id %d, vbus %d\n", 83 info->last_role, role, id, vbus); 84 85 if (info->last_role == role) { 86 dev_warn(info->dev, "repeated role: %d\n", role); 87 return; 88 } 89 90 if (info->last_role == USB_ROLE_HOST) 91 regulator_disable(info->vbus); 92 93 ret = usb_role_switch_set_role(info->role_sw, role); 94 if (ret) 95 dev_err(info->dev, "failed to set role: %d\n", ret); 96 97 if (role == USB_ROLE_HOST) { 98 ret = regulator_enable(info->vbus); 99 if (ret) 100 dev_err(info->dev, "enable vbus regulator failed\n"); 101 } 102 103 info->last_role = role; 104 105 dev_dbg(info->dev, "vbus regulator is %s\n", 106 regulator_is_enabled(info->vbus) ? "enabled" : "disabled"); 107 } 108 109 static void usb_conn_queue_dwork(struct usb_conn_info *info, 110 unsigned long delay) 111 { 112 queue_delayed_work(system_power_efficient_wq, &info->dw_det, delay); 113 } 114 115 static irqreturn_t usb_conn_isr(int irq, void *dev_id) 116 { 117 struct usb_conn_info *info = dev_id; 118 119 usb_conn_queue_dwork(info, info->debounce_jiffies); 120 121 return IRQ_HANDLED; 122 } 123 124 static int usb_conn_probe(struct platform_device *pdev) 125 { 126 struct device *dev = &pdev->dev; 127 struct usb_conn_info *info; 128 int ret = 0; 129 130 info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL); 131 if (!info) 132 return -ENOMEM; 133 134 info->dev = dev; 135 info->id_gpiod = devm_gpiod_get_optional(dev, "id", GPIOD_IN); 136 if (IS_ERR(info->id_gpiod)) 137 return PTR_ERR(info->id_gpiod); 138 139 info->vbus_gpiod = devm_gpiod_get_optional(dev, "vbus", GPIOD_IN); 140 if (IS_ERR(info->vbus_gpiod)) 141 return PTR_ERR(info->vbus_gpiod); 142 143 if (!info->id_gpiod && !info->vbus_gpiod) { 144 dev_err(dev, "failed to get gpios\n"); 145 return -ENODEV; 146 } 147 148 if (info->id_gpiod) 149 ret = gpiod_set_debounce(info->id_gpiod, USB_GPIO_DEB_US); 150 if (!ret && info->vbus_gpiod) 151 ret = gpiod_set_debounce(info->vbus_gpiod, USB_GPIO_DEB_US); 152 if (ret < 0) 153 info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEB_MS); 154 155 INIT_DELAYED_WORK(&info->dw_det, usb_conn_detect_cable); 156 157 info->vbus = devm_regulator_get(dev, "vbus"); 158 if (IS_ERR(info->vbus)) { 159 if (PTR_ERR(info->vbus) != -EPROBE_DEFER) 160 dev_err(dev, "failed to get vbus\n"); 161 return PTR_ERR(info->vbus); 162 } 163 164 info->role_sw = usb_role_switch_get(dev); 165 if (IS_ERR(info->role_sw)) { 166 if (PTR_ERR(info->role_sw) != -EPROBE_DEFER) 167 dev_err(dev, "failed to get role switch\n"); 168 169 return PTR_ERR(info->role_sw); 170 } 171 172 if (info->id_gpiod) { 173 info->id_irq = gpiod_to_irq(info->id_gpiod); 174 if (info->id_irq < 0) { 175 dev_err(dev, "failed to get ID IRQ\n"); 176 ret = info->id_irq; 177 goto put_role_sw; 178 } 179 180 ret = devm_request_threaded_irq(dev, info->id_irq, NULL, 181 usb_conn_isr, USB_CONN_IRQF, 182 pdev->name, info); 183 if (ret < 0) { 184 dev_err(dev, "failed to request ID IRQ\n"); 185 goto put_role_sw; 186 } 187 } 188 189 if (info->vbus_gpiod) { 190 info->vbus_irq = gpiod_to_irq(info->vbus_gpiod); 191 if (info->vbus_irq < 0) { 192 dev_err(dev, "failed to get VBUS IRQ\n"); 193 ret = info->vbus_irq; 194 goto put_role_sw; 195 } 196 197 ret = devm_request_threaded_irq(dev, info->vbus_irq, NULL, 198 usb_conn_isr, USB_CONN_IRQF, 199 pdev->name, info); 200 if (ret < 0) { 201 dev_err(dev, "failed to request VBUS IRQ\n"); 202 goto put_role_sw; 203 } 204 } 205 206 platform_set_drvdata(pdev, info); 207 208 /* Perform initial detection */ 209 usb_conn_queue_dwork(info, 0); 210 211 return 0; 212 213 put_role_sw: 214 usb_role_switch_put(info->role_sw); 215 return ret; 216 } 217 218 static int usb_conn_remove(struct platform_device *pdev) 219 { 220 struct usb_conn_info *info = platform_get_drvdata(pdev); 221 222 cancel_delayed_work_sync(&info->dw_det); 223 224 if (info->last_role == USB_ROLE_HOST) 225 regulator_disable(info->vbus); 226 227 usb_role_switch_put(info->role_sw); 228 229 return 0; 230 } 231 232 static int __maybe_unused usb_conn_suspend(struct device *dev) 233 { 234 struct usb_conn_info *info = dev_get_drvdata(dev); 235 236 if (info->id_gpiod) 237 disable_irq(info->id_irq); 238 if (info->vbus_gpiod) 239 disable_irq(info->vbus_irq); 240 241 pinctrl_pm_select_sleep_state(dev); 242 243 return 0; 244 } 245 246 static int __maybe_unused usb_conn_resume(struct device *dev) 247 { 248 struct usb_conn_info *info = dev_get_drvdata(dev); 249 250 pinctrl_pm_select_default_state(dev); 251 252 if (info->id_gpiod) 253 enable_irq(info->id_irq); 254 if (info->vbus_gpiod) 255 enable_irq(info->vbus_irq); 256 257 usb_conn_queue_dwork(info, 0); 258 259 return 0; 260 } 261 262 static SIMPLE_DEV_PM_OPS(usb_conn_pm_ops, 263 usb_conn_suspend, usb_conn_resume); 264 265 static const struct of_device_id usb_conn_dt_match[] = { 266 { .compatible = "gpio-usb-b-connector", }, 267 { } 268 }; 269 MODULE_DEVICE_TABLE(of, usb_conn_dt_match); 270 271 static struct platform_driver usb_conn_driver = { 272 .probe = usb_conn_probe, 273 .remove = usb_conn_remove, 274 .driver = { 275 .name = "usb-conn-gpio", 276 .pm = &usb_conn_pm_ops, 277 .of_match_table = usb_conn_dt_match, 278 }, 279 }; 280 281 module_platform_driver(usb_conn_driver); 282 283 MODULE_AUTHOR("Chunfeng Yun <chunfeng.yun@mediatek.com>"); 284 MODULE_DESCRIPTION("USB GPIO based connection detection driver"); 285 MODULE_LICENSE("GPL v2"); 286