usb: chipidea: add one errata for revision 2.40a

The first two patches add identification register API's. These can be used to get controller's revision.

The third patch implements an errata for revision 2.40a. Not sure which other SOCs implement this version of the Chipidea core but this fixes the usb client issue observed on Vybrids. The patch was tested on a Toradex Colibri VF61 module with the 3.18 kernel. iperf tests ran for three hours plus, with these patches applied have found the USB client connection to be now reliable.

This patchset is based off on Shawn Guo's for-next branch
https://git.kernel.org/cgit/linux/kernel/git/shawnguo/linux.git/tree/?h=for-next

The credit for the patches and fix goes to Matthieu Castet and Peter Chen. First two patches are by Peter Chen and the third patch which fixed the bug we observed was reported by Matthieu Castet.

The discussion of the problem and the relevant testing details can be found at this link: http://www.spinics.net/lists/linux-usb/msg118544.html

The first version of this patchset originally send by Peter Chen can be found at this link: http://www.spinics.net/lists/linux-usb/msg118753.html

Comments for review are welcome :).
Note: I am going on a vacation so will not be able to reply or do any further tests till Monday. Will attend and take care of any comments/requests for further changes/testing from Tuesday. Apologize for the delay in advance.

Sanchayan Maity (3):
usb: chipidea: Add identification registers access APIs
usb: chipidea: Add chipidea revision information
usb: chipidea: Add errata for revision 2.40a

 drivers/usb/chipidea/bits.h |   10 ++++++++
 drivers/usb/chipidea/ci.h   |   53 +++++++++++++++++++++++++++++++++++++++++++
 drivers/usb/chipidea/core.c |   23 +++++++++++++++++--
 drivers/usb/chipidea/udc.c  |   20 ++++++++++++++++
 4 files changed, 104 insertions(+), 2 deletions(-)

1.7.9.5