Register with the USB OTG core. Since we don't support
OTG yet we just work as a dual-role device even
if device tree says "otg".

Use extcon framework to get VBUS/ID cable events and
kick the OTG state machine.

Signed-off-by: Roger Quadros <rog...@ti.com>
---
 drivers/usb/dwc3/core.c          | 155 ++++++++++++++++++++++++++++++++++++++-
 drivers/usb/dwc3/core.h          |   6 ++
 drivers/usb/dwc3/platform_data.h |   1 +
 3 files changed, 161 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index ff5773c..a7498e0 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -706,6 +706,133 @@ static int dwc3_core_get_phy(struct dwc3 *dwc)
        return 0;
 }
 
+/* --------------------- Dual-Role management ------------------------------- 
*/
+
+static void dwc3_drd_fsm_sync(struct dwc3 *dwc)
+{
+       int id, vbus;
+
+       /* get ID */
+       id = extcon_get_cable_state(dwc->edev, "USB-HOST");
+       /* Host means ID == 0 */
+       id = !id;
+
+       /* get VBUS */
+       vbus = extcon_get_cable_state(dwc->edev, "USB");
+       dev_dbg(dwc->dev, "id %d vbus %d\n", id, vbus);
+
+       dwc->fsm->id = id;
+       dwc->fsm->vbus = vbus;
+       usb_otg_sync_inputs(dwc->fsm);
+}
+
+static int dwc3_drd_start_host(struct otg_fsm *fsm, int on)
+{
+       struct device *dev = usb_otg_fsm_to_dev(fsm);
+       struct dwc3 *dwc = dev_get_drvdata(dev);
+
+       dev_dbg(dwc->dev, "%s: %d\n", __func__, on);
+       if (on)
+               dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_HOST);
+
+       return 0;
+}
+
+static int dwc3_drd_start_gadget(struct otg_fsm *fsm, int on)
+{
+       struct device *dev = usb_otg_fsm_to_dev(fsm);
+       struct dwc3 *dwc = dev_get_drvdata(dev);
+
+       dev_dbg(dwc->dev, "%s: %d\n", __func__, on);
+       if (on) {
+               dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
+               dwc3_event_buffers_setup(dwc);
+       }
+
+       return 0;
+}
+
+static struct otg_fsm_ops dwc3_drd_ops = {
+       .start_host = dwc3_drd_start_host,
+       .start_gadget = dwc3_drd_start_gadget,
+};
+
+static int dwc3_drd_notifier(struct notifier_block *nb,
+               unsigned long event, void *ptr)
+{
+       struct dwc3 *dwc = container_of(nb, struct dwc3, otg_nb);
+
+       dwc3_drd_fsm_sync(dwc);
+
+       return NOTIFY_DONE;
+}
+
+static int dwc3_drd_init(struct dwc3 *dwc)
+{
+       int ret, id, vbus;
+
+       if (!dwc->edev) {
+               dev_err(dwc->dev, "No extcon device found for OTG mode\n");
+               return -ENODEV;
+       }
+
+       dwc->otg_nb.notifier_call = dwc3_drd_notifier;
+       ret = extcon_register_notifier(dwc->edev, EXTCON_USB, &dwc->otg_nb);
+       if (ret < 0) {
+               dev_err(dwc->dev, "Couldn't register USB cable notifier\n");
+               return -ENODEV;
+       }
+
+       ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
+                                      &dwc->otg_nb);
+       if (ret < 0) {
+               dev_err(dwc->dev, "Couldn't register USB-HOST cable 
notifier\n");
+               ret = -ENODEV;
+               goto extcon_fail;
+       }
+
+       /* sanity check id & vbus states */
+       id = extcon_get_cable_state(dwc->edev, "USB-HOST");
+       vbus = extcon_get_cable_state(dwc->edev, "USB");
+       if (id < 0 || vbus < 0) {
+               dev_err(dwc->dev, "Invalid USB cable state. id %d, vbus %d\n",
+                       id, vbus);
+               ret = -ENODEV;
+               goto fail;
+       }
+
+       /* register parent as DRD device with OTG core */
+       dwc->fsm = usb_otg_register(dwc->dev, &dwc3_drd_ops, true);
+       if (IS_ERR(dwc->fsm)) {
+               ret = PTR_ERR(dwc->fsm);
+               if (ret == -ENOSYS)
+                       dev_err(dwc->dev, "CONFIG_USB_OTG needed for 
dual-role\n");
+               else
+                       dev_err(dwc->dev, "Failed to register with OTG core\n");
+
+               goto fail;
+       }
+
+       dwc3_drd_fsm_sync(dwc);
+
+       return 0;
+fail:
+       extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST, &dwc->otg_nb);
+extcon_fail:
+       extcon_unregister_notifier(dwc->edev, EXTCON_USB, &dwc->otg_nb);
+
+       return ret;
+}
+
+static void dwc3_drd_exit(struct dwc3 *dwc)
+{
+       usb_otg_unregister(dwc->dev);
+       extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST, &dwc->otg_nb);
+       extcon_unregister_notifier(dwc->edev, EXTCON_USB,&dwc->otg_nb);
+}
+
+/* -------------------------------------------------------------------------- 
*/
+
 static int dwc3_core_init_mode(struct dwc3 *dwc)
 {
        struct device *dev = dwc->dev;
@@ -729,13 +856,21 @@ static int dwc3_core_init_mode(struct dwc3 *dwc)
                }
                break;
        case USB_DR_MODE_OTG:
-               dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_OTG);
+               ret = dwc3_drd_init(dwc);
+               if (ret) {
+                       dev_err(dev, "limiting to peripheral only\n");
+                       dwc->dr_mode = USB_DR_MODE_PERIPHERAL;
+                       dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
+                       goto gadget_init;
+               }
+
                ret = dwc3_host_init(dwc);
                if (ret) {
                        dev_err(dev, "failed to initialize host\n");
                        return ret;
                }
 
+gadget_init:
                ret = dwc3_gadget_init(dwc);
                if (ret) {
                        dev_err(dev, "failed to initialize gadget\n");
@@ -762,6 +897,7 @@ static void dwc3_core_exit_mode(struct dwc3 *dwc)
        case USB_DR_MODE_OTG:
                dwc3_host_exit(dwc);
                dwc3_gadget_exit(dwc);
+               dwc3_drd_exit(dwc);
                break;
        default:
                /* do nothing */
@@ -845,6 +981,16 @@ static int dwc3_probe(struct platform_device *pdev)
        hird_threshold = 12;
 
        if (node) {
+               if (of_property_read_bool(node, "extcon"))
+                       dwc->edev = extcon_get_edev_by_phandle(dev, 0);
+               else if (of_property_read_bool(dev->parent->of_node, "extcon"))
+                       dwc->edev = extcon_get_edev_by_phandle(dev->parent, 0);
+
+               if (IS_ERR(dwc->edev)) {
+                       dev_vdbg(dev, "couldn't get extcon device\n");
+                       return -EPROBE_DEFER;
+               }
+
                dwc->maximum_speed = of_usb_get_maximum_speed(node);
                dwc->has_lpm_erratum = of_property_read_bool(node,
                                "snps,has-lpm-erratum");
@@ -889,6 +1035,13 @@ static int dwc3_probe(struct platform_device *pdev)
                of_property_read_string(node, "snps,hsphy_interface",
                                        &dwc->hsphy_interface);
        } else if (pdata) {
+               if (pdata->extcon) {
+                       dwc->edev = extcon_get_extcon_dev(pdata->extcon);
+                       if (!dwc->edev) {
+                               dev_vdbg(dev, "couldn't get extcon device\n");
+                               return -EPROBE_DEFER;
+                       }
+               }
                dwc->maximum_speed = pdata->maximum_speed;
                dwc->has_lpm_erratum = pdata->has_lpm_erratum;
                if (pdata->lpm_nyet_threshold)
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 0447788..d0fda04 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -31,8 +31,10 @@
 #include <linux/usb/gadget.h>
 #include <linux/usb/otg.h>
 #include <linux/ulpi/interface.h>
+#include <linux/usb/otg-fsm.h>
 
 #include <linux/phy/phy.h>
+#include <linux/extcon.h>
 
 #define DWC3_MSG_MAX   500
 
@@ -753,6 +755,10 @@ struct dwc3 {
 
        struct ulpi             *ulpi;
 
+       struct extcon_dev       *edev;  /* USB cable events ID & VBUS */
+       struct notifier_block   otg_nb; /* notifier for USB cable events */
+       struct otg_fsm          *fsm;
+
        void __iomem            *regs;
        size_t                  regs_size;
 
diff --git a/drivers/usb/dwc3/platform_data.h b/drivers/usb/dwc3/platform_data.h
index d3614ec..b3b245c 100644
--- a/drivers/usb/dwc3/platform_data.h
+++ b/drivers/usb/dwc3/platform_data.h
@@ -47,4 +47,5 @@ struct dwc3_platform_data {
        unsigned tx_de_emphasis:2;
 
        const char *hsphy_interface;
+       const char *extcon;     /* extcon name for USB cable events ID/VBUS */
 };
-- 
2.1.4

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