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NETC V4 Timer provides current time with nanosecond resolution, precise periodic pulse, pulse on timeout (alarm), and time capture on external pulse support. And it supports time synchronization as required for IEEE 1588 and IEEE 802.1AS-2020. Inside NETC, ENETC can capture the timestamp of the sent/received packet through the PHC provided by the Timer and record it on the Tx/Rx BD. And through the relevant PHC interfaces provided by the driver, the enetc V4 driver can support PTP time synchronization. In addition, NETC V4 Timer is similar to the QorIQ 1588 timer, but it is not exactly the same. The current ptp-qoriq driver is not compatible with NETC V4 Timer, most of the code cannot be reused, see below reasons. 1. The architecture of ptp-qoriq driver makes the register offset fixed, however, the offsets of all the high registers and low registers of V4 are swapped, and V4 also adds some new registers. so extending ptp-qoriq to make it compatible with V4 Timer is tantamount to completely rewriting ptp-qoriq driver. 2. The usage of some functions is somewhat different from QorIQ timer, such as the setting of TCLK_PERIOD and TMR_ADD, the logic of configuring PPS, etc., so making the driver compatible with V4 Timer will undoubtedly increase the complexity of the code and reduce readability. 3. QorIQ is an expired brand. It is difficult for us to verify whether it works stably on the QorIQ platforms if we refactor the driver, and this will make maintenance difficult, so refactoring the driver obviously does not bring any benefits. Therefore, add this new driver for NETC V4 Timer. Note that the missing features like PEROUT, PPS and EXTTS will be added in subsequent patches. Signed-off-by: Wei Fang <wei.fang@nxp.com> Reviewed-by: Frank Li <Frank.Li@nxp.com> Link: https://patch.msgid.link/20250829050615.1247468-5-wei.fang@nxp.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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 reStructuredText 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.