Files
linux/drivers/usb
Feng Mingli f4adf1bc37 usb: dwc_otg_310: pcd: hold wake lock until phy suspended and clk disabled
When begin connecting to PC in device mode, the driver will hold a
wake lock to prevent system from entering deep sleep. If it fails
to connect to PC or doesn't detect the vbus, the driver will suspend
usb phy and disable usb clk, and release the wake lock.

If unlock the wake lock first, system may enter deep sleep before
suspend usb phy and disable usb clk. Then wake up system by pull
out the usb cable, it may cause usb interrupt abnormal.

TEST=rk3126c connect the usb charger into the charging interface,
after the system entered deep sleep, pull out the usb cable with
the following log:

irq 42: nobody cared (try booting with the "irqpoll" option)
CPU: 0 PID: 146 Comm: charger Not tainted 3.10.104 #133
[<c0014088>] unwind_backtrace+0x0/0xe0
[<c00118cc>] show_stack+0x10/0x14
[<c00b0be0>] __report_bad_irq+0x28/0xb8
[<c00b0e68>] note_interrupt+0x138/0x1cc
[<c00aef88>] handle_irq_event_percpu+0x2c0/0x2f4
[<c00aeff8>] handle_irq_event+0x3c/0x5c
[<c00b1a20>] handle_fasteoi_irq+0xbc/0x124
[<c00ae764>] generic_handle_irq+0x20/0x30
[<c000e4cc>] handle_IRQ+0x64/0x8c
[<c000853c>] gic_handle_irq+0x38/0x5c
handlers:
[<c042b3ec>] dwc_otg_common_irq
[<c0438704>] dwc_otg_pcd_irq
[<c03fab48>] usb_hcd_irq
Disabling IRQ #42

Change-Id: Id36717ae68e02226255c1207aeded0bd6fb356cd
Signed-off-by: Feng Mingli <fml@rock-chips.com>
Signed-off-by: William Wu <william.wu@rock-chips.com>
2017-08-11 15:32:23 +08:00
..

To understand all the Linux-USB framework, you'll use these resources:

    * This source code.  This is necessarily an evolving work, and
      includes kerneldoc that should help you get a current overview.
      ("make pdfdocs", and then look at "usb.pdf" for host side and
      "gadget.pdf" for peripheral side.)  Also, Documentation/usb has
      more information.

    * The USB 2.0 specification (from www.usb.org), with supplements
      such as those for USB OTG and the various device classes.
      The USB specification has a good overview chapter, and USB
      peripherals conform to the widely known "Chapter 9".

    * Chip specifications for USB controllers.  Examples include
      host controllers (on PCs, servers, and more); peripheral
      controllers (in devices with Linux firmware, like printers or
      cell phones); and hard-wired peripherals like Ethernet adapters.

    * Specifications for other protocols implemented by USB peripheral
      functions.  Some are vendor-specific; others are vendor-neutral
      but just standardized outside of the www.usb.org team.

Here is a list of what each subdirectory here is, and what is contained in
them.

core/		- This is for the core USB host code, including the
		  usbfs files and the hub class driver ("hub_wq").

host/		- This is for USB host controller drivers.  This
		  includes UHCI, OHCI, EHCI, and others that might
		  be used with more specialized "embedded" systems.

gadget/		- This is for USB peripheral controller drivers and
		  the various gadget drivers which talk to them.


Individual USB driver directories.  A new driver should be added to the
first subdirectory in the list below that it fits into.

image/		- This is for still image drivers, like scanners or
		  digital cameras.
../input/	- This is for any driver that uses the input subsystem,
		  like keyboard, mice, touchscreens, tablets, etc.
../media/	- This is for multimedia drivers, like video cameras,
		  radios, and any other drivers that talk to the v4l
		  subsystem.
../net/		- This is for network drivers.
serial/		- This is for USB to serial drivers.
storage/	- This is for USB mass-storage drivers.
class/		- This is for all USB device drivers that do not fit
		  into any of the above categories, and work for a range
		  of USB Class specified devices. 
misc/		- This is for all USB device drivers that do not fit
		  into any of the above categories.