mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-04-13 09:49:06 +08:00
82363cf2ee
There is a regression in the upcoming v3.16-rc1, that is caused by a problem that has been around for a while but now finally hangs the system. The bootcrawl looks like this: pinctrl-nomadik soc:pinctrl: pin GPIO256_AF28 already requested by a03e0000.usb_per5; cannot claim for musb-hdrc.0.auto pinctrl-nomadik soc:pinctrl: pin-256 (musb-hdrc.0.auto) status -22 pinctrl-nomadik soc:pinctrl: could not request pin 256 (GPIO256_AF28) from group usb_a_1 on device pinctrl-nomadik musb-hdrc musb-hdrc.0.auto: Error applying setting, reverse things back HS USB OTG: no transceiver configured musb-hdrc musb-hdrc.0.auto: musb_init_controller failed with status -517 platform musb-hdrc.0.auto: Driver musb-hdrc requests probe deferral (...) The ux500 MUSB driver propagates the OF node to the dynamically created musb-hdrc device, which is incorrect as it makes the OF core believe there are two devices spun from the very same DT node, which confuses other parts of the device core, notably the pin control subsystem, which will try to apply all the pin control settings also to the HDRC device as it gets instantiated. (The OMAP2430 for example, does not set the of_node member.) Cc: <stable@vger.kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Acked-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Felipe Balbi <balbi@ti.com>
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 ("khubd").
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.