mirror_ubuntu-kernels/drivers/usb
Jon Hunter 203f44c475 usb: phy: tegra: Fix phy suspend for UDC
Commit dfebb5f43a ("usb: chipidea: Add support for Tegra20/30/114/124")
added UDC support for Tegra but with UDC support enabled, is was found
that Tegra30, Tegra114 and Tegra124 would hang on entry to suspend.

The hang occurred during the suspend of the USB PHY when the Tegra PHY
driver attempted to disable the PHY clock. The problem is that before
the Tegra PHY driver is suspended, the chipidea driver already disabled
the PHY clock and when the Tegra PHY driver suspended, it could not read
DEVLC register and caused the device to hang.

The Tegra USB PHY driver is used by both the Tegra EHCI driver and now
the chipidea UDC driver and so simply removing the disabling of the PHY
clock from the USB PHY driver would not work for the Tegra EHCI driver.
Fortunately, the status of the USB PHY clock can be read from the
USB_SUSP_CTRL register and therefore, to workaround this issue, simply
poll the register prior to disabling the clock in USB PHY driver to see
if clock gating has already been initiated. Please note that it can take
a few uS for the clock to disable and so simply reading this status
register once on entry is not sufficient.

Similarly when turning on the PHY clock, it is possible that the clock
is already enabled or in the process of being enabled, and so check for
this when enabling the PHY.

Please note that no issues are seen with Tegra20 because it has a slightly
different PHY to Tegra30/114/124.

Fixes: dfebb5f43a ("usb: chipidea: Add support for Tegra20/30/114/124")
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
2017-10-11 13:13:07 +03:00
..
atm usb: atm: ueagle-atm: constify attribute_group structures. 2017-08-10 11:31:28 -07:00
c67x00 c67x00-hcd: constify hc_driver structures 2017-07-30 07:26:52 -07:00
chipidea usb: chipidea: usb2: check memory allocation failure 2017-08-28 11:44:39 +02:00
class USB: cdc-wdm: ignore -EPIPE from GetEncapsulatedResponse 2017-09-25 10:57:13 +02:00
common usb: common: use of_property_read_bool() 2017-08-28 11:39:31 +02:00
core USB: devio: Don't corrupt user memory 2017-09-25 10:57:13 +02:00
dwc2 usb: dwc2: skip L2 state of hcd if controller work in device mode 2017-08-15 14:18:55 +03:00
dwc3 usb: dwc3: of-simple: Add compatible for Spreadtrum SC9860 platform 2017-09-28 12:41:56 +03:00
early usb/early: Remove trace_printk() callers in xhci-dbc 2017-06-13 10:54:40 +02:00
gadget usb: gadget: udc: atmel: set vbus irqflags explicitly 2017-09-28 12:39:22 +03:00
host Revert "xhci: Limit USB2 port wake support for AMD Promontory hosts" 2017-09-18 17:10:41 +02:00
image USB: microtek: remove unneeded DRIVER_VERSION macro 2017-07-22 15:56:53 +02:00
isp1760 usb: isp1760: compress return logic into one line 2017-07-17 13:13:44 +02:00
misc usb: misc: lvstest: add entry to place port in compliance mode 2017-08-28 11:43:39 +02:00
mon sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
mtu3 usb: changes for v4.14 merge window 2017-08-22 13:16:06 -07:00
musb USB: musb: dsps: add explicit runtime resume at suspend 2017-08-28 10:51:56 +02:00
phy usb: phy: tegra: Fix phy suspend for UDC 2017-10-11 13:13:07 +03:00
renesas_usbhs usb: renesas_usbhs: fix usbhsf_fifo_clear() for RX direction 2017-09-28 12:35:01 +03:00
serial USB: serial: option: simplify 3 D-Link device entries 2017-08-30 09:41:25 +02:00
storage USB: uas: fix bug in handling of alternate settings 2017-09-22 18:29:00 +02:00
typec usb: typec: include linux/device.h in ucsi.h 2017-07-17 13:11:56 +02:00
usbip usbip: vhci-hcd: make vhci_hc_driver const 2017-08-31 18:08:47 +02:00
wusbcore usb: wusbcore: dev-sysfs: constify attribute_group structures. 2017-08-10 11:31:27 -07:00
Kconfig usb: USB Type-C connector class 2017-03-23 13:48:44 +01:00
Makefile USB patches for 4.12-rc1 2017-05-04 18:03:51 -07:00
README
usb-skeleton.c USB: usb-skeleton: refactor endpoint retrieval 2017-03-23 13:54:08 +01:00

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.