18c2ecf20Sopenharmony_ci# SPDX-License-Identifier: GPL-2.0-only 28c2ecf20Sopenharmony_ci# 38c2ecf20Sopenharmony_ci# PPS support configuration 48c2ecf20Sopenharmony_ci# 58c2ecf20Sopenharmony_ci 68c2ecf20Sopenharmony_cimenuconfig PPS 78c2ecf20Sopenharmony_ci tristate "PPS support" 88c2ecf20Sopenharmony_ci help 98c2ecf20Sopenharmony_ci PPS (Pulse Per Second) is a special pulse provided by some GPS 108c2ecf20Sopenharmony_ci antennae. Userland can use it to get a high-precision time 118c2ecf20Sopenharmony_ci reference. 128c2ecf20Sopenharmony_ci 138c2ecf20Sopenharmony_ci Some antennae's PPS signals are connected with the CD (Carrier 148c2ecf20Sopenharmony_ci Detect) pin of the serial line they use to communicate with the 158c2ecf20Sopenharmony_ci host. In this case use the SERIAL_LINE client support. 168c2ecf20Sopenharmony_ci 178c2ecf20Sopenharmony_ci Some antennae's PPS signals are connected with some special host 188c2ecf20Sopenharmony_ci inputs so you have to enable the corresponding client support. 198c2ecf20Sopenharmony_ci 208c2ecf20Sopenharmony_ci To compile this driver as a module, choose M here: the module 218c2ecf20Sopenharmony_ci will be called pps_core.ko. 228c2ecf20Sopenharmony_ci 238c2ecf20Sopenharmony_ciif PPS 248c2ecf20Sopenharmony_ci 258c2ecf20Sopenharmony_ciconfig PPS_DEBUG 268c2ecf20Sopenharmony_ci bool "PPS debugging messages" 278c2ecf20Sopenharmony_ci help 288c2ecf20Sopenharmony_ci Say Y here if you want the PPS support to produce a bunch of debug 298c2ecf20Sopenharmony_ci messages to the system log. Select this if you are having a 308c2ecf20Sopenharmony_ci problem with PPS support and want to see more of what is going on. 318c2ecf20Sopenharmony_ci 328c2ecf20Sopenharmony_ciconfig NTP_PPS 338c2ecf20Sopenharmony_ci bool "PPS kernel consumer support" 348c2ecf20Sopenharmony_ci depends on !NO_HZ_COMMON 358c2ecf20Sopenharmony_ci help 368c2ecf20Sopenharmony_ci This option adds support for direct in-kernel time 378c2ecf20Sopenharmony_ci synchronization using an external PPS signal. 388c2ecf20Sopenharmony_ci 398c2ecf20Sopenharmony_ci It doesn't work on tickless systems at the moment. 408c2ecf20Sopenharmony_ci 418c2ecf20Sopenharmony_cisource "drivers/pps/clients/Kconfig" 428c2ecf20Sopenharmony_ci 438c2ecf20Sopenharmony_cisource "drivers/pps/generators/Kconfig" 448c2ecf20Sopenharmony_ci 458c2ecf20Sopenharmony_ciendif # PPS 46