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PTP hardware block can be configured to utilize the external clock. Also the current ptp timestamp can be captured when external trigger is applied on a gpio pin. These features are required in scenarios like connecting a external timing device to the chip for time synchronization. The timing device provides the clock and trigger(PPS signal) to the PTP block. This patch does the following: 1. configures PTP block to use external clock frequency and timestamp capture on external event. 2. sends PTP_REQ_EXTTS events to kernel ptp phc susbsytem with captured timestamps 3. aligns PPS edge to adjusted ptp clock in the ptp device by setting the PPS_THRESH to the reminder of the last timestamp value captured by external PPS Signed-off-by: Yi Guo <yig@marvell.com> Signed-off-by: Hariprasad Kelam <hkelam@marvell.com> Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com> Signed-off-by: Sunil Goutham <sgoutham@marvell.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.