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0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * mtu3_dr.c - dual role switch and host glue layer
0004  *
0005  * Copyright (C) 2016 MediaTek Inc.
0006  *
0007  * Author: Chunfeng Yun <chunfeng.yun@mediatek.com>
0008  */
0009 
0010 #include "mtu3.h"
0011 #include "mtu3_dr.h"
0012 #include "mtu3_debug.h"
0013 
0014 #define USB2_PORT 2
0015 #define USB3_PORT 3
0016 
0017 static inline struct ssusb_mtk *otg_sx_to_ssusb(struct otg_switch_mtk *otg_sx)
0018 {
0019     return container_of(otg_sx, struct ssusb_mtk, otg_switch);
0020 }
0021 
0022 static void toggle_opstate(struct ssusb_mtk *ssusb)
0023 {
0024     mtu3_setbits(ssusb->mac_base, U3D_DEVICE_CONTROL, DC_SESSION);
0025     mtu3_setbits(ssusb->mac_base, U3D_POWER_MANAGEMENT, SOFT_CONN);
0026 }
0027 
0028 /* only port0 supports dual-role mode */
0029 static int ssusb_port0_switch(struct ssusb_mtk *ssusb,
0030     int version, bool tohost)
0031 {
0032     void __iomem *ibase = ssusb->ippc_base;
0033     u32 value;
0034 
0035     dev_dbg(ssusb->dev, "%s (switch u%d port0 to %s)\n", __func__,
0036         version, tohost ? "host" : "device");
0037 
0038     if (version == USB2_PORT) {
0039         /* 1. power off and disable u2 port0 */
0040         value = mtu3_readl(ibase, SSUSB_U2_CTRL(0));
0041         value |= SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS;
0042         mtu3_writel(ibase, SSUSB_U2_CTRL(0), value);
0043 
0044         /* 2. power on, enable u2 port0 and select its mode */
0045         value = mtu3_readl(ibase, SSUSB_U2_CTRL(0));
0046         value &= ~(SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS);
0047         value = tohost ? (value | SSUSB_U2_PORT_HOST_SEL) :
0048             (value & (~SSUSB_U2_PORT_HOST_SEL));
0049         mtu3_writel(ibase, SSUSB_U2_CTRL(0), value);
0050     } else {
0051         /* 1. power off and disable u3 port0 */
0052         value = mtu3_readl(ibase, SSUSB_U3_CTRL(0));
0053         value |= SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS;
0054         mtu3_writel(ibase, SSUSB_U3_CTRL(0), value);
0055 
0056         /* 2. power on, enable u3 port0 and select its mode */
0057         value = mtu3_readl(ibase, SSUSB_U3_CTRL(0));
0058         value &= ~(SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS);
0059         value = tohost ? (value | SSUSB_U3_PORT_HOST_SEL) :
0060             (value & (~SSUSB_U3_PORT_HOST_SEL));
0061         mtu3_writel(ibase, SSUSB_U3_CTRL(0), value);
0062     }
0063 
0064     return 0;
0065 }
0066 
0067 static void switch_port_to_host(struct ssusb_mtk *ssusb)
0068 {
0069     u32 check_clk = 0;
0070 
0071     dev_dbg(ssusb->dev, "%s\n", __func__);
0072 
0073     ssusb_port0_switch(ssusb, USB2_PORT, true);
0074 
0075     if (ssusb->otg_switch.is_u3_drd) {
0076         ssusb_port0_switch(ssusb, USB3_PORT, true);
0077         check_clk = SSUSB_U3_MAC_RST_B_STS;
0078     }
0079 
0080     ssusb_check_clocks(ssusb, check_clk);
0081 
0082     /* after all clocks are stable */
0083     toggle_opstate(ssusb);
0084 }
0085 
0086 static void switch_port_to_device(struct ssusb_mtk *ssusb)
0087 {
0088     u32 check_clk = 0;
0089 
0090     dev_dbg(ssusb->dev, "%s\n", __func__);
0091 
0092     ssusb_port0_switch(ssusb, USB2_PORT, false);
0093 
0094     if (ssusb->otg_switch.is_u3_drd) {
0095         ssusb_port0_switch(ssusb, USB3_PORT, false);
0096         check_clk = SSUSB_U3_MAC_RST_B_STS;
0097     }
0098 
0099     ssusb_check_clocks(ssusb, check_clk);
0100 }
0101 
0102 int ssusb_set_vbus(struct otg_switch_mtk *otg_sx, int is_on)
0103 {
0104     struct ssusb_mtk *ssusb = otg_sx_to_ssusb(otg_sx);
0105     struct regulator *vbus = otg_sx->vbus;
0106     int ret;
0107 
0108     /* vbus is optional */
0109     if (!vbus)
0110         return 0;
0111 
0112     dev_dbg(ssusb->dev, "%s: turn %s\n", __func__, is_on ? "on" : "off");
0113 
0114     if (is_on) {
0115         ret = regulator_enable(vbus);
0116         if (ret) {
0117             dev_err(ssusb->dev, "vbus regulator enable failed\n");
0118             return ret;
0119         }
0120     } else {
0121         regulator_disable(vbus);
0122     }
0123 
0124     return 0;
0125 }
0126 
0127 static void ssusb_mode_sw_work(struct work_struct *work)
0128 {
0129     struct otg_switch_mtk *otg_sx =
0130         container_of(work, struct otg_switch_mtk, dr_work);
0131     struct ssusb_mtk *ssusb = otg_sx_to_ssusb(otg_sx);
0132     struct mtu3 *mtu = ssusb->u3d;
0133     enum usb_role desired_role = otg_sx->desired_role;
0134     enum usb_role current_role;
0135 
0136     current_role = ssusb->is_host ? USB_ROLE_HOST : USB_ROLE_DEVICE;
0137 
0138     if (desired_role == USB_ROLE_NONE) {
0139         /* the default mode is host as probe does */
0140         desired_role = USB_ROLE_HOST;
0141         if (otg_sx->default_role == USB_ROLE_DEVICE)
0142             desired_role = USB_ROLE_DEVICE;
0143     }
0144 
0145     if (current_role == desired_role)
0146         return;
0147 
0148     dev_dbg(ssusb->dev, "set role : %s\n", usb_role_string(desired_role));
0149     mtu3_dbg_trace(ssusb->dev, "set role : %s", usb_role_string(desired_role));
0150     pm_runtime_get_sync(ssusb->dev);
0151 
0152     switch (desired_role) {
0153     case USB_ROLE_HOST:
0154         ssusb_set_force_mode(ssusb, MTU3_DR_FORCE_HOST);
0155         mtu3_stop(mtu);
0156         switch_port_to_host(ssusb);
0157         ssusb_set_vbus(otg_sx, 1);
0158         ssusb->is_host = true;
0159         break;
0160     case USB_ROLE_DEVICE:
0161         ssusb_set_force_mode(ssusb, MTU3_DR_FORCE_DEVICE);
0162         ssusb->is_host = false;
0163         ssusb_set_vbus(otg_sx, 0);
0164         switch_port_to_device(ssusb);
0165         mtu3_start(mtu);
0166         break;
0167     case USB_ROLE_NONE:
0168     default:
0169         dev_err(ssusb->dev, "invalid role\n");
0170     }
0171     pm_runtime_put(ssusb->dev);
0172 }
0173 
0174 static void ssusb_set_mode(struct otg_switch_mtk *otg_sx, enum usb_role role)
0175 {
0176     struct ssusb_mtk *ssusb = otg_sx_to_ssusb(otg_sx);
0177 
0178     if (ssusb->dr_mode != USB_DR_MODE_OTG)
0179         return;
0180 
0181     otg_sx->desired_role = role;
0182     queue_work(system_freezable_wq, &otg_sx->dr_work);
0183 }
0184 
0185 static int ssusb_id_notifier(struct notifier_block *nb,
0186     unsigned long event, void *ptr)
0187 {
0188     struct otg_switch_mtk *otg_sx =
0189         container_of(nb, struct otg_switch_mtk, id_nb);
0190 
0191     ssusb_set_mode(otg_sx, event ? USB_ROLE_HOST : USB_ROLE_DEVICE);
0192 
0193     return NOTIFY_DONE;
0194 }
0195 
0196 static int ssusb_extcon_register(struct otg_switch_mtk *otg_sx)
0197 {
0198     struct ssusb_mtk *ssusb = otg_sx_to_ssusb(otg_sx);
0199     struct extcon_dev *edev = otg_sx->edev;
0200     int ret;
0201 
0202     /* extcon is optional */
0203     if (!edev)
0204         return 0;
0205 
0206     otg_sx->id_nb.notifier_call = ssusb_id_notifier;
0207     ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB_HOST,
0208                     &otg_sx->id_nb);
0209     if (ret < 0) {
0210         dev_err(ssusb->dev, "failed to register notifier for USB-HOST\n");
0211         return ret;
0212     }
0213 
0214     ret = extcon_get_state(edev, EXTCON_USB_HOST);
0215     dev_dbg(ssusb->dev, "EXTCON_USB_HOST: %d\n", ret);
0216 
0217     /* default as host, switch to device mode if needed */
0218     if (!ret)
0219         ssusb_set_mode(otg_sx, USB_ROLE_DEVICE);
0220 
0221     return 0;
0222 }
0223 
0224 /*
0225  * We provide an interface via debugfs to switch between host and device modes
0226  * depending on user input.
0227  * This is useful in special cases, such as uses TYPE-A receptacle but also
0228  * wants to support dual-role mode.
0229  */
0230 void ssusb_mode_switch(struct ssusb_mtk *ssusb, int to_host)
0231 {
0232     struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
0233 
0234     ssusb_set_mode(otg_sx, to_host ? USB_ROLE_HOST : USB_ROLE_DEVICE);
0235 }
0236 
0237 void ssusb_set_force_mode(struct ssusb_mtk *ssusb,
0238               enum mtu3_dr_force_mode mode)
0239 {
0240     u32 value;
0241 
0242     value = mtu3_readl(ssusb->ippc_base, SSUSB_U2_CTRL(0));
0243     switch (mode) {
0244     case MTU3_DR_FORCE_DEVICE:
0245         value |= SSUSB_U2_PORT_FORCE_IDDIG | SSUSB_U2_PORT_RG_IDDIG;
0246         break;
0247     case MTU3_DR_FORCE_HOST:
0248         value |= SSUSB_U2_PORT_FORCE_IDDIG;
0249         value &= ~SSUSB_U2_PORT_RG_IDDIG;
0250         break;
0251     case MTU3_DR_FORCE_NONE:
0252         value &= ~(SSUSB_U2_PORT_FORCE_IDDIG | SSUSB_U2_PORT_RG_IDDIG);
0253         break;
0254     default:
0255         return;
0256     }
0257     mtu3_writel(ssusb->ippc_base, SSUSB_U2_CTRL(0), value);
0258 }
0259 
0260 static int ssusb_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
0261 {
0262     struct ssusb_mtk *ssusb = usb_role_switch_get_drvdata(sw);
0263     struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
0264 
0265     ssusb_set_mode(otg_sx, role);
0266 
0267     return 0;
0268 }
0269 
0270 static enum usb_role ssusb_role_sw_get(struct usb_role_switch *sw)
0271 {
0272     struct ssusb_mtk *ssusb = usb_role_switch_get_drvdata(sw);
0273 
0274     return ssusb->is_host ? USB_ROLE_HOST : USB_ROLE_DEVICE;
0275 }
0276 
0277 static int ssusb_role_sw_register(struct otg_switch_mtk *otg_sx)
0278 {
0279     struct usb_role_switch_desc role_sx_desc = { 0 };
0280     struct ssusb_mtk *ssusb = otg_sx_to_ssusb(otg_sx);
0281     struct device *dev = ssusb->dev;
0282     enum usb_dr_mode mode;
0283 
0284     if (!otg_sx->role_sw_used)
0285         return 0;
0286 
0287     mode = usb_get_role_switch_default_mode(dev);
0288     if (mode == USB_DR_MODE_PERIPHERAL)
0289         otg_sx->default_role = USB_ROLE_DEVICE;
0290     else
0291         otg_sx->default_role = USB_ROLE_HOST;
0292 
0293     role_sx_desc.set = ssusb_role_sw_set;
0294     role_sx_desc.get = ssusb_role_sw_get;
0295     role_sx_desc.fwnode = dev_fwnode(dev);
0296     role_sx_desc.driver_data = ssusb;
0297     otg_sx->role_sw = usb_role_switch_register(dev, &role_sx_desc);
0298     if (IS_ERR(otg_sx->role_sw))
0299         return PTR_ERR(otg_sx->role_sw);
0300 
0301     ssusb_set_mode(otg_sx, otg_sx->default_role);
0302 
0303     return 0;
0304 }
0305 
0306 int ssusb_otg_switch_init(struct ssusb_mtk *ssusb)
0307 {
0308     struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
0309     int ret = 0;
0310 
0311     INIT_WORK(&otg_sx->dr_work, ssusb_mode_sw_work);
0312 
0313     if (otg_sx->manual_drd_enabled)
0314         ssusb_dr_debugfs_init(ssusb);
0315     else if (otg_sx->role_sw_used)
0316         ret = ssusb_role_sw_register(otg_sx);
0317     else
0318         ret = ssusb_extcon_register(otg_sx);
0319 
0320     return ret;
0321 }
0322 
0323 void ssusb_otg_switch_exit(struct ssusb_mtk *ssusb)
0324 {
0325     struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
0326 
0327     cancel_work_sync(&otg_sx->dr_work);
0328     usb_role_switch_unregister(otg_sx->role_sw);
0329 }
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