1 /* 2 * mtu3_dr.c - dual role switch and host glue layer 3 * 4 * Copyright (C) 2016 MediaTek Inc. 5 * 6 * Author: Chunfeng Yun <chunfeng.yun@mediatek.com> 7 * 8 * This software is licensed under the terms of the GNU General Public 9 * License version 2, as published by the Free Software Foundation, and 10 * may be copied, distributed, and modified under those terms. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 */ 18 19 #include <linux/debugfs.h> 20 #include <linux/irq.h> 21 #include <linux/kernel.h> 22 #include <linux/of_device.h> 23 #include <linux/pinctrl/consumer.h> 24 #include <linux/seq_file.h> 25 #include <linux/uaccess.h> 26 27 #include "mtu3.h" 28 #include "mtu3_dr.h" 29 30 #define USB2_PORT 2 31 #define USB3_PORT 3 32 33 enum mtu3_vbus_id_state { 34 MTU3_ID_FLOAT = 1, 35 MTU3_ID_GROUND, 36 MTU3_VBUS_OFF, 37 MTU3_VBUS_VALID, 38 }; 39 40 static void toggle_opstate(struct ssusb_mtk *ssusb) 41 { 42 if (!ssusb->otg_switch.is_u3_drd) { 43 mtu3_setbits(ssusb->mac_base, U3D_DEVICE_CONTROL, DC_SESSION); 44 mtu3_setbits(ssusb->mac_base, U3D_POWER_MANAGEMENT, SOFT_CONN); 45 } 46 } 47 48 /* only port0 supports dual-role mode */ 49 static int ssusb_port0_switch(struct ssusb_mtk *ssusb, 50 int version, bool tohost) 51 { 52 void __iomem *ibase = ssusb->ippc_base; 53 u32 value; 54 55 dev_dbg(ssusb->dev, "%s (switch u%d port0 to %s)\n", __func__, 56 version, tohost ? "host" : "device"); 57 58 if (version == USB2_PORT) { 59 /* 1. power off and disable u2 port0 */ 60 value = mtu3_readl(ibase, SSUSB_U2_CTRL(0)); 61 value |= SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS; 62 mtu3_writel(ibase, SSUSB_U2_CTRL(0), value); 63 64 /* 2. power on, enable u2 port0 and select its mode */ 65 value = mtu3_readl(ibase, SSUSB_U2_CTRL(0)); 66 value &= ~(SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS); 67 value = tohost ? (value | SSUSB_U2_PORT_HOST_SEL) : 68 (value & (~SSUSB_U2_PORT_HOST_SEL)); 69 mtu3_writel(ibase, SSUSB_U2_CTRL(0), value); 70 } else { 71 /* 1. power off and disable u3 port0 */ 72 value = mtu3_readl(ibase, SSUSB_U3_CTRL(0)); 73 value |= SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS; 74 mtu3_writel(ibase, SSUSB_U3_CTRL(0), value); 75 76 /* 2. power on, enable u3 port0 and select its mode */ 77 value = mtu3_readl(ibase, SSUSB_U3_CTRL(0)); 78 value &= ~(SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS); 79 value = tohost ? (value | SSUSB_U3_PORT_HOST_SEL) : 80 (value & (~SSUSB_U3_PORT_HOST_SEL)); 81 mtu3_writel(ibase, SSUSB_U3_CTRL(0), value); 82 } 83 84 return 0; 85 } 86 87 static void switch_port_to_host(struct ssusb_mtk *ssusb) 88 { 89 u32 check_clk = 0; 90 91 dev_dbg(ssusb->dev, "%s\n", __func__); 92 93 ssusb_port0_switch(ssusb, USB2_PORT, true); 94 95 if (ssusb->otg_switch.is_u3_drd) { 96 ssusb_port0_switch(ssusb, USB3_PORT, true); 97 check_clk = SSUSB_U3_MAC_RST_B_STS; 98 } 99 100 ssusb_check_clocks(ssusb, check_clk); 101 102 /* after all clocks are stable */ 103 toggle_opstate(ssusb); 104 } 105 106 static void switch_port_to_device(struct ssusb_mtk *ssusb) 107 { 108 u32 check_clk = 0; 109 110 dev_dbg(ssusb->dev, "%s\n", __func__); 111 112 ssusb_port0_switch(ssusb, USB2_PORT, false); 113 114 if (ssusb->otg_switch.is_u3_drd) { 115 ssusb_port0_switch(ssusb, USB3_PORT, false); 116 check_clk = SSUSB_U3_MAC_RST_B_STS; 117 } 118 119 ssusb_check_clocks(ssusb, check_clk); 120 } 121 122 int ssusb_set_vbus(struct otg_switch_mtk *otg_sx, int is_on) 123 { 124 struct ssusb_mtk *ssusb = 125 container_of(otg_sx, struct ssusb_mtk, otg_switch); 126 struct regulator *vbus = otg_sx->vbus; 127 int ret; 128 129 /* vbus is optional */ 130 if (!vbus) 131 return 0; 132 133 dev_dbg(ssusb->dev, "%s: turn %s\n", __func__, is_on ? "on" : "off"); 134 135 if (is_on) { 136 ret = regulator_enable(vbus); 137 if (ret) { 138 dev_err(ssusb->dev, "vbus regulator enable failed\n"); 139 return ret; 140 } 141 } else { 142 regulator_disable(vbus); 143 } 144 145 return 0; 146 } 147 148 /* 149 * switch to host: -> MTU3_VBUS_OFF --> MTU3_ID_GROUND 150 * switch to device: -> MTU3_ID_FLOAT --> MTU3_VBUS_VALID 151 */ 152 static void ssusb_set_mailbox(struct otg_switch_mtk *otg_sx, 153 enum mtu3_vbus_id_state status) 154 { 155 struct ssusb_mtk *ssusb = 156 container_of(otg_sx, struct ssusb_mtk, otg_switch); 157 struct mtu3 *mtu = ssusb->u3d; 158 159 dev_dbg(ssusb->dev, "mailbox state(%d)\n", status); 160 161 switch (status) { 162 case MTU3_ID_GROUND: 163 switch_port_to_host(ssusb); 164 ssusb_set_vbus(otg_sx, 1); 165 ssusb->is_host = true; 166 break; 167 case MTU3_ID_FLOAT: 168 ssusb->is_host = false; 169 ssusb_set_vbus(otg_sx, 0); 170 switch_port_to_device(ssusb); 171 break; 172 case MTU3_VBUS_OFF: 173 mtu3_stop(mtu); 174 pm_relax(ssusb->dev); 175 break; 176 case MTU3_VBUS_VALID: 177 /* avoid suspend when works as device */ 178 pm_stay_awake(ssusb->dev); 179 mtu3_start(mtu); 180 break; 181 default: 182 dev_err(ssusb->dev, "invalid state\n"); 183 } 184 } 185 186 static int ssusb_id_notifier(struct notifier_block *nb, 187 unsigned long event, void *ptr) 188 { 189 struct otg_switch_mtk *otg_sx = 190 container_of(nb, struct otg_switch_mtk, id_nb); 191 192 if (event) 193 ssusb_set_mailbox(otg_sx, MTU3_ID_GROUND); 194 else 195 ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT); 196 197 return NOTIFY_DONE; 198 } 199 200 static int ssusb_vbus_notifier(struct notifier_block *nb, 201 unsigned long event, void *ptr) 202 { 203 struct otg_switch_mtk *otg_sx = 204 container_of(nb, struct otg_switch_mtk, vbus_nb); 205 206 if (event) 207 ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID); 208 else 209 ssusb_set_mailbox(otg_sx, MTU3_VBUS_OFF); 210 211 return NOTIFY_DONE; 212 } 213 214 static int ssusb_extcon_register(struct otg_switch_mtk *otg_sx) 215 { 216 struct ssusb_mtk *ssusb = 217 container_of(otg_sx, struct ssusb_mtk, otg_switch); 218 struct extcon_dev *edev = otg_sx->edev; 219 int ret; 220 221 /* extcon is optional */ 222 if (!edev) 223 return 0; 224 225 otg_sx->vbus_nb.notifier_call = ssusb_vbus_notifier; 226 ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB, 227 &otg_sx->vbus_nb); 228 if (ret < 0) 229 dev_err(ssusb->dev, "failed to register notifier for USB\n"); 230 231 otg_sx->id_nb.notifier_call = ssusb_id_notifier; 232 ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB_HOST, 233 &otg_sx->id_nb); 234 if (ret < 0) 235 dev_err(ssusb->dev, "failed to register notifier for USB-HOST\n"); 236 237 dev_dbg(ssusb->dev, "EXTCON_USB: %d, EXTCON_USB_HOST: %d\n", 238 extcon_get_state(edev, EXTCON_USB), 239 extcon_get_state(edev, EXTCON_USB_HOST)); 240 241 /* default as host, switch to device mode if needed */ 242 if (extcon_get_state(edev, EXTCON_USB_HOST) == false) 243 ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT); 244 if (extcon_get_state(edev, EXTCON_USB) == true) 245 ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID); 246 247 return 0; 248 } 249 250 static void extcon_register_dwork(struct work_struct *work) 251 { 252 struct delayed_work *dwork = to_delayed_work(work); 253 struct otg_switch_mtk *otg_sx = 254 container_of(dwork, struct otg_switch_mtk, extcon_reg_dwork); 255 256 ssusb_extcon_register(otg_sx); 257 } 258 259 /* 260 * We provide an interface via debugfs to switch between host and device modes 261 * depending on user input. 262 * This is useful in special cases, such as uses TYPE-A receptacle but also 263 * wants to support dual-role mode. 264 * It generates cable state changes by pulling up/down IDPIN and 265 * notifies driver to switch mode by "extcon-usb-gpio". 266 * NOTE: when use MICRO receptacle, should not enable this interface. 267 */ 268 static void ssusb_mode_manual_switch(struct ssusb_mtk *ssusb, int to_host) 269 { 270 struct otg_switch_mtk *otg_sx = &ssusb->otg_switch; 271 272 if (to_host) 273 pinctrl_select_state(otg_sx->id_pinctrl, otg_sx->id_ground); 274 else 275 pinctrl_select_state(otg_sx->id_pinctrl, otg_sx->id_float); 276 } 277 278 279 static int ssusb_mode_show(struct seq_file *sf, void *unused) 280 { 281 struct ssusb_mtk *ssusb = sf->private; 282 283 seq_printf(sf, "current mode: %s(%s drd)\n(echo device/host)\n", 284 ssusb->is_host ? "host" : "device", 285 ssusb->otg_switch.manual_drd_enabled ? "manual" : "auto"); 286 287 return 0; 288 } 289 290 static int ssusb_mode_open(struct inode *inode, struct file *file) 291 { 292 return single_open(file, ssusb_mode_show, inode->i_private); 293 } 294 295 static ssize_t ssusb_mode_write(struct file *file, 296 const char __user *ubuf, size_t count, loff_t *ppos) 297 { 298 struct seq_file *sf = file->private_data; 299 struct ssusb_mtk *ssusb = sf->private; 300 char buf[16]; 301 302 if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count))) 303 return -EFAULT; 304 305 if (!strncmp(buf, "host", 4) && !ssusb->is_host) { 306 ssusb_mode_manual_switch(ssusb, 1); 307 } else if (!strncmp(buf, "device", 6) && ssusb->is_host) { 308 ssusb_mode_manual_switch(ssusb, 0); 309 } else { 310 dev_err(ssusb->dev, "wrong or duplicated setting\n"); 311 return -EINVAL; 312 } 313 314 return count; 315 } 316 317 static const struct file_operations ssusb_mode_fops = { 318 .open = ssusb_mode_open, 319 .write = ssusb_mode_write, 320 .read = seq_read, 321 .llseek = seq_lseek, 322 .release = single_release, 323 }; 324 325 static void ssusb_debugfs_init(struct ssusb_mtk *ssusb) 326 { 327 struct dentry *root; 328 struct dentry *file; 329 330 root = debugfs_create_dir(dev_name(ssusb->dev), usb_debug_root); 331 if (IS_ERR_OR_NULL(root)) { 332 if (!root) 333 dev_err(ssusb->dev, "create debugfs root failed\n"); 334 return; 335 } 336 ssusb->dbgfs_root = root; 337 338 file = debugfs_create_file("mode", S_IRUGO | S_IWUSR, root, 339 ssusb, &ssusb_mode_fops); 340 if (!file) 341 dev_dbg(ssusb->dev, "create debugfs mode failed\n"); 342 } 343 344 static void ssusb_debugfs_exit(struct ssusb_mtk *ssusb) 345 { 346 debugfs_remove_recursive(ssusb->dbgfs_root); 347 } 348 349 int ssusb_otg_switch_init(struct ssusb_mtk *ssusb) 350 { 351 struct otg_switch_mtk *otg_sx = &ssusb->otg_switch; 352 353 INIT_DELAYED_WORK(&otg_sx->extcon_reg_dwork, extcon_register_dwork); 354 355 if (otg_sx->manual_drd_enabled) 356 ssusb_debugfs_init(ssusb); 357 358 /* It is enough to delay 1s for waiting for host initialization */ 359 schedule_delayed_work(&otg_sx->extcon_reg_dwork, HZ); 360 361 return 0; 362 } 363 364 void ssusb_otg_switch_exit(struct ssusb_mtk *ssusb) 365 { 366 struct otg_switch_mtk *otg_sx = &ssusb->otg_switch; 367 368 cancel_delayed_work(&otg_sx->extcon_reg_dwork); 369 370 if (otg_sx->manual_drd_enabled) 371 ssusb_debugfs_exit(ssusb); 372 } 373