mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-12-30 01:18:30 -05:00
d8c80bb3b5
Adding phy calibration sequence for USB 3.0 DRD PHY present on Exynos5420/5800 systems. This calibration facilitates setting certain PHY parameters viz. the Loss-of-Signal (LOS) Detector Threshold Level, as well as Tx-Vboost-Level for Super-Speed operations. Additionally we also set proper time to wait for RxDetect measurement, for desired PHY reference clock, so as to solve issue with enumeration of few USB 3.0 devices, like Samsung SUM-TSB16S 3.0 USB drive on the controller. We are using CR_port for this purpose to send required data to override the LOS values. On testing with USB 3.0 devices on USB 3.0 port present on SMDK5420, and peach-pit boards should see following message: usb 2-1: new SuperSpeed USB device number 2 using xhci-hcd and without this patch, should see below shown message: usb 1-1: new high-speed USB device number 2 using xhci-hcd [Also removed unnecessary extra lines in the register macro definitions] Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com> [adapted to use phy_calibrate as entry point] Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com> Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com> Signed-off-by: Kishon Vijay Abraham I <kishon@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 ("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.