1.. SPDX-License-Identifier: GPL-2.0 2 3======================================= 4stmmac (synopsys dwmac) devlink support 5======================================= 6 7This document describes the devlink features implemented by the ``stmmac`` 8device driver. 9 10Parameters 11========== 12 13The ``stmmac`` driver implements the following driver-specific parameters. 14 15.. list-table:: Driver-specific parameters implemented 16 :widths: 5 5 5 85 17 18 * - Name 19 - Type 20 - Mode 21 - Description 22 * - ``phc_coarse_adj`` 23 - Boolean 24 - runtime 25 - Enable the Coarse timestamping mode, as defined in the DWMAC TRM. 26 A detailed explanation of this timestamping mode can be found in the 27 Socfpga Functionnal Description [1]. 28 29 In Coarse mode, the ptp clock is expected to be fed by a high-precision 30 clock that is externally adjusted, and the subsecond increment used for 31 timestamping is set to 1/ptp_clock_rate. 32 33 In Fine mode (i.e. Coarse mode == false), the ptp clock frequency is 34 continuously adjusted, but the subsecond increment is set to 35 2/ptp_clock_rate. 36 37 Coarse mode is suitable for PTP Grand Master operation. If unsure, leave 38 the parameter to False. 39 40 [1] https://www.intel.com/content/www/us/en/docs/programmable/683126/21-2/functional-description-of-the-emac.html 41