| .. SPDX-License-Identifier: GPL-2.0 | |
| ======================================= | |
| 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. | |
| .. list-table:: Driver-specific parameters implemented | |
| :widths: 5 5 5 85 | |
| * - Name | |
| - Type | |
| - Mode | |
| - Description | |
| * - ``phc_coarse_adj`` | |
| - Boolean | |
| - runtime | |
| - Enable the Coarse timestamping mode, as defined in the DWMAC TRM. | |
| A detailed explanation of this timestamping mode can be found in the | |
| Socfpga Functional Description [1]. | |
| In Coarse mode, the ptp clock is expected to be fed by a high-precision | |
| clock that is externally adjusted, and 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 | |
| continuously adjusted, 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. | |
| [1] https://www.intel.com/content/www/us/en/docs/programmable/683126/21-2/functional-description-of-the-emac.html |