linux/drivers/usb/mtu3/mtu3_dr.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * mtu3_dr.c - dual role switch and host glue layer
   4 *
   5 * Copyright (C) 2016 MediaTek Inc.
   6 *
   7 * Author: Chunfeng Yun <chunfeng.yun@mediatek.com>
   8 */
   9
  10#include "mtu3.h"
  11#include "mtu3_dr.h"
  12#include "mtu3_debug.h"
  13
  14#define USB2_PORT 2
  15#define USB3_PORT 3
  16
  17static inline struct ssusb_mtk *otg_sx_to_ssusb(struct otg_switch_mtk *otg_sx)
  18{
  19        return container_of(otg_sx, struct ssusb_mtk, otg_switch);
  20}
  21
  22static void toggle_opstate(struct ssusb_mtk *ssusb)
  23{
  24        mtu3_setbits(ssusb->mac_base, U3D_DEVICE_CONTROL, DC_SESSION);
  25        mtu3_setbits(ssusb->mac_base, U3D_POWER_MANAGEMENT, SOFT_CONN);
  26}
  27
  28/* only port0 supports dual-role mode */
  29static int ssusb_port0_switch(struct ssusb_mtk *ssusb,
  30        int version, bool tohost)
  31{
  32        void __iomem *ibase = ssusb->ippc_base;
  33        u32 value;
  34
  35        dev_dbg(ssusb->dev, "%s (switch u%d port0 to %s)\n", __func__,
  36                version, tohost ? "host" : "device");
  37
  38        if (version == USB2_PORT) {
  39                /* 1. power off and disable u2 port0 */
  40                value = mtu3_readl(ibase, SSUSB_U2_CTRL(0));
  41                value |= SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS;
  42                mtu3_writel(ibase, SSUSB_U2_CTRL(0), value);
  43
  44                /* 2. power on, enable u2 port0 and select its mode */
  45                value = mtu3_readl(ibase, SSUSB_U2_CTRL(0));
  46                value &= ~(SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS);
  47                value = tohost ? (value | SSUSB_U2_PORT_HOST_SEL) :
  48                        (value & (~SSUSB_U2_PORT_HOST_SEL));
  49                mtu3_writel(ibase, SSUSB_U2_CTRL(0), value);
  50        } else {
  51                /* 1. power off and disable u3 port0 */
  52                value = mtu3_readl(ibase, SSUSB_U3_CTRL(0));
  53                value |= SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS;
  54                mtu3_writel(ibase, SSUSB_U3_CTRL(0), value);
  55
  56                /* 2. power on, enable u3 port0 and select its mode */
  57                value = mtu3_readl(ibase, SSUSB_U3_CTRL(0));
  58                value &= ~(SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS);
  59                value = tohost ? (value | SSUSB_U3_PORT_HOST_SEL) :
  60                        (value & (~SSUSB_U3_PORT_HOST_SEL));
  61                mtu3_writel(ibase, SSUSB_U3_CTRL(0), value);
  62        }
  63
  64        return 0;
  65}
  66
  67static void switch_port_to_host(struct ssusb_mtk *ssusb)
  68{
  69        u32 check_clk = 0;
  70
  71        dev_dbg(ssusb->dev, "%s\n", __func__);
  72
  73        ssusb_port0_switch(ssusb, USB2_PORT, true);
  74
  75        if (ssusb->otg_switch.is_u3_drd) {
  76                ssusb_port0_switch(ssusb, USB3_PORT, true);
  77                check_clk = SSUSB_U3_MAC_RST_B_STS;
  78        }
  79
  80        ssusb_check_clocks(ssusb, check_clk);
  81
  82        /* after all clocks are stable */
  83        toggle_opstate(ssusb);
  84}
  85
  86static void switch_port_to_device(struct ssusb_mtk *ssusb)
  87{
  88        u32 check_clk = 0;
  89
  90        dev_dbg(ssusb->dev, "%s\n", __func__);
  91
  92        ssusb_port0_switch(ssusb, USB2_PORT, false);
  93
  94        if (ssusb->otg_switch.is_u3_drd) {
  95                ssusb_port0_switch(ssusb, USB3_PORT, false);
  96                check_clk = SSUSB_U3_MAC_RST_B_STS;
  97        }
  98
  99        ssusb_check_clocks(ssusb, check_clk);
 100}
 101
 102int ssusb_set_vbus(struct otg_switch_mtk *otg_sx, int is_on)
 103{
 104        struct ssusb_mtk *ssusb = otg_sx_to_ssusb(otg_sx);
 105        struct regulator *vbus = otg_sx->vbus;
 106        int ret;
 107
 108        /* vbus is optional */
 109        if (!vbus)
 110                return 0;
 111
 112        dev_dbg(ssusb->dev, "%s: turn %s\n", __func__, is_on ? "on" : "off");
 113
 114        if (is_on) {
 115                ret = regulator_enable(vbus);
 116                if (ret) {
 117                        dev_err(ssusb->dev, "vbus regulator enable failed\n");
 118                        return ret;
 119                }
 120        } else {
 121                regulator_disable(vbus);
 122        }
 123
 124        return 0;
 125}
 126
 127static void ssusb_mode_sw_work(struct work_struct *work)
 128{
 129        struct otg_switch_mtk *otg_sx =
 130                container_of(work, struct otg_switch_mtk, dr_work);
 131        struct ssusb_mtk *ssusb = otg_sx_to_ssusb(otg_sx);
 132        struct mtu3 *mtu = ssusb->u3d;
 133        enum usb_role desired_role = otg_sx->desired_role;
 134        enum usb_role current_role;
 135
 136        current_role = ssusb->is_host ? USB_ROLE_HOST : USB_ROLE_DEVICE;
 137
 138        if (desired_role == USB_ROLE_NONE) {
 139                /* the default mode is host as probe does */
 140                desired_role = USB_ROLE_HOST;
 141                if (otg_sx->default_role == USB_ROLE_DEVICE)
 142                        desired_role = USB_ROLE_DEVICE;
 143        }
 144
 145        if (current_role == desired_role)
 146                return;
 147
 148        dev_dbg(ssusb->dev, "set role : %s\n", usb_role_string(desired_role));
 149        mtu3_dbg_trace(ssusb->dev, "set role : %s", usb_role_string(desired_role));
 150        pm_runtime_get_sync(ssusb->dev);
 151
 152        switch (desired_role) {
 153        case USB_ROLE_HOST:
 154                ssusb_set_force_mode(ssusb, MTU3_DR_FORCE_HOST);
 155                mtu3_stop(mtu);
 156                switch_port_to_host(ssusb);
 157                ssusb_set_vbus(otg_sx, 1);
 158                ssusb->is_host = true;
 159                break;
 160        case USB_ROLE_DEVICE:
 161                ssusb_set_force_mode(ssusb, MTU3_DR_FORCE_DEVICE);
 162                ssusb->is_host = false;
 163                ssusb_set_vbus(otg_sx, 0);
 164                switch_port_to_device(ssusb);
 165                mtu3_start(mtu);
 166                break;
 167        case USB_ROLE_NONE:
 168        default:
 169                dev_err(ssusb->dev, "invalid role\n");
 170        }
 171        pm_runtime_put(ssusb->dev);
 172}
 173
 174static void ssusb_set_mode(struct otg_switch_mtk *otg_sx, enum usb_role role)
 175{
 176        struct ssusb_mtk *ssusb = otg_sx_to_ssusb(otg_sx);
 177
 178        if (ssusb->dr_mode != USB_DR_MODE_OTG)
 179                return;
 180
 181        otg_sx->desired_role = role;
 182        queue_work(system_freezable_wq, &otg_sx->dr_work);
 183}
 184
 185static int ssusb_id_notifier(struct notifier_block *nb,
 186        unsigned long event, void *ptr)
 187{
 188        struct otg_switch_mtk *otg_sx =
 189                container_of(nb, struct otg_switch_mtk, id_nb);
 190
 191        ssusb_set_mode(otg_sx, event ? USB_ROLE_HOST : USB_ROLE_DEVICE);
 192
 193        return NOTIFY_DONE;
 194}
 195
 196static int ssusb_extcon_register(struct otg_switch_mtk *otg_sx)
 197{
 198        struct ssusb_mtk *ssusb = otg_sx_to_ssusb(otg_sx);
 199        struct extcon_dev *edev = otg_sx->edev;
 200        int ret;
 201
 202        /* extcon is optional */
 203        if (!edev)
 204                return 0;
 205
 206        otg_sx->id_nb.notifier_call = ssusb_id_notifier;
 207        ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB_HOST,
 208                                        &otg_sx->id_nb);
 209        if (ret < 0) {
 210                dev_err(ssusb->dev, "failed to register notifier for USB-HOST\n");
 211                return ret;
 212        }
 213
 214        ret = extcon_get_state(edev, EXTCON_USB_HOST);
 215        dev_dbg(ssusb->dev, "EXTCON_USB_HOST: %d\n", ret);
 216
 217        /* default as host, switch to device mode if needed */
 218        if (!ret)
 219                ssusb_set_mode(otg_sx, USB_ROLE_DEVICE);
 220
 221        return 0;
 222}
 223
 224/*
 225 * We provide an interface via debugfs to switch between host and device modes
 226 * depending on user input.
 227 * This is useful in special cases, such as uses TYPE-A receptacle but also
 228 * wants to support dual-role mode.
 229 */
 230void ssusb_mode_switch(struct ssusb_mtk *ssusb, int to_host)
 231{
 232        struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 233
 234        ssusb_set_mode(otg_sx, to_host ? USB_ROLE_HOST : USB_ROLE_DEVICE);
 235}
 236
 237void ssusb_set_force_mode(struct ssusb_mtk *ssusb,
 238                          enum mtu3_dr_force_mode mode)
 239{
 240        u32 value;
 241
 242        value = mtu3_readl(ssusb->ippc_base, SSUSB_U2_CTRL(0));
 243        switch (mode) {
 244        case MTU3_DR_FORCE_DEVICE:
 245                value |= SSUSB_U2_PORT_FORCE_IDDIG | SSUSB_U2_PORT_RG_IDDIG;
 246                break;
 247        case MTU3_DR_FORCE_HOST:
 248                value |= SSUSB_U2_PORT_FORCE_IDDIG;
 249                value &= ~SSUSB_U2_PORT_RG_IDDIG;
 250                break;
 251        case MTU3_DR_FORCE_NONE:
 252                value &= ~(SSUSB_U2_PORT_FORCE_IDDIG | SSUSB_U2_PORT_RG_IDDIG);
 253                break;
 254        default:
 255                return;
 256        }
 257        mtu3_writel(ssusb->ippc_base, SSUSB_U2_CTRL(0), value);
 258}
 259
 260static int ssusb_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
 261{
 262        struct ssusb_mtk *ssusb = usb_role_switch_get_drvdata(sw);
 263        struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 264
 265        ssusb_set_mode(otg_sx, role);
 266
 267        return 0;
 268}
 269
 270static enum usb_role ssusb_role_sw_get(struct usb_role_switch *sw)
 271{
 272        struct ssusb_mtk *ssusb = usb_role_switch_get_drvdata(sw);
 273
 274        return ssusb->is_host ? USB_ROLE_HOST : USB_ROLE_DEVICE;
 275}
 276
 277static int ssusb_role_sw_register(struct otg_switch_mtk *otg_sx)
 278{
 279        struct usb_role_switch_desc role_sx_desc = { 0 };
 280        struct ssusb_mtk *ssusb = otg_sx_to_ssusb(otg_sx);
 281        struct device *dev = ssusb->dev;
 282        enum usb_dr_mode mode;
 283
 284        if (!otg_sx->role_sw_used)
 285                return 0;
 286
 287        mode = usb_get_role_switch_default_mode(dev);
 288        if (mode == USB_DR_MODE_PERIPHERAL)
 289                otg_sx->default_role = USB_ROLE_DEVICE;
 290        else
 291                otg_sx->default_role = USB_ROLE_HOST;
 292
 293        role_sx_desc.set = ssusb_role_sw_set;
 294        role_sx_desc.get = ssusb_role_sw_get;
 295        role_sx_desc.fwnode = dev_fwnode(dev);
 296        role_sx_desc.driver_data = ssusb;
 297        otg_sx->role_sw = usb_role_switch_register(dev, &role_sx_desc);
 298        if (IS_ERR(otg_sx->role_sw))
 299                return PTR_ERR(otg_sx->role_sw);
 300
 301        ssusb_set_mode(otg_sx, otg_sx->default_role);
 302
 303        return 0;
 304}
 305
 306int ssusb_otg_switch_init(struct ssusb_mtk *ssusb)
 307{
 308        struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 309        int ret = 0;
 310
 311        INIT_WORK(&otg_sx->dr_work, ssusb_mode_sw_work);
 312
 313        if (otg_sx->manual_drd_enabled)
 314                ssusb_dr_debugfs_init(ssusb);
 315        else if (otg_sx->role_sw_used)
 316                ret = ssusb_role_sw_register(otg_sx);
 317        else
 318                ret = ssusb_extcon_register(otg_sx);
 319
 320        return ret;
 321}
 322
 323void ssusb_otg_switch_exit(struct ssusb_mtk *ssusb)
 324{
 325        struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 326
 327        cancel_work_sync(&otg_sx->dr_work);
 328        usb_role_switch_unregister(otg_sx->role_sw);
 329}
 330