https://blog.csdn.net/gjy_it/article/details/82223151
8953走的是dwc3-msm.c，8909走的是phy-msm-usb.c
// device 切 host 流程
usbid_change_handler
dwc3_msm_power_set_property_usb
+ POWER_SUPPLY_PROP_USB_OTG
+ queue_delayed_work(mdwc->dwc3_wq, &mdwc->resume_work, 0);
dwc3_resume_work()
--> dwc3_otg_sm_work()
----> OTG_STATE_A_IDLE
----> dwc3_otg_start_host
------> platform_device_add
--------> device_add
----------> bus_probe_device
------------> device_attach
--------------> bus_for_each_drv
----------------> __device_attach
-----------------> driver_probe_device
------------------> platform_drv_probe
--------------------> xhci_plat_probe
xhci_plat_probe
--> usb_add_hcd
----> register_root_hub
------> usb_new_device
--------> usb_enumerate_device
--------> device_add
----------> bus_probe_device
------------> hub_probe
hub_probe
------> hub_configure
--------> hub_activate
----------> hub_init_func2
------------> hub_activate
--------------> kick_hub_wq
//插入usb 鼠标的流程
msm_dwc3_pwr_irq_thread
--> dwc3_pwr_event_handler
----> dwc3_otg_sm_work
------> pm_runtime_resume ---> xhci_resume
xhci_resume
hcd_resume_work //唤醒 root hub用
--> usb_remote_wakeup
----> hub_resume
------> hub_activate
--------> kick_hub_wq
--> hub_irq //普通的 hub 中断
----> kick_hub_wq
//切换到 host 模式和插入 usb 鼠标，都会调用的地方。
kick_hub_wq
--> hub_event
----> port_event
------> hub_port_connect_change
--------> hub_port_connect
----------> usb_new_device