stmmac (synopsys dwmac) devlink support

This document describes the devlink features implemented by the stmmac device driver.

Parameters

The stmmac driver implements the following driver-specific parameters.

Driver-specific parameters implemented

Name	Type	Mode	Description
ts_coarse	Boolean	runtime	Enable the Coarse timestamping mode. In Coarse mode, the ptp clock is expected to be updated through an external PPS input, but the subsecond increment used for timestamping is set to 1/ptp_clock_rate. In Fine mode (i.e. Coarse mode == false), the ptp clock frequency is adjusted more frequently, but the subsecond increment is set to 2/ptp_clock_rate. Coarse mode is suitable for PTP Grand Master operation. If unsure, leave the parameter to False.