FreeCalypso > hg > freecalypso-tools
view loadtools/gtapower.c @ 407:19e5a3e2f9c0
fcup-settime: moved time() retrieval a little closer to the output
A fundamental problem with all simple time transfer tools is that there is
always some delay between the time retrieval on the source system and that
transmitted time being set on the destination, and the resulting time
on the destination system is off by that delay amount. This delay cannot
be fully eliminated when working in a simple environment like ours,
but we should make our best effort to minimize it. In the present case,
moving the atinterf_init() call before the time() retrieval should make
a teensy-tiny improvement.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Sat, 11 Aug 2018 21:52:17 +0000 |
parents | e7502631a0f9 |
children |
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/* * This module is included only when loadtools are being built to run on the * GTA0x application processor (AP). It provides automated modem power * control, i.e., coordinates modem power control with loadtools operations * for convenience. */ #include <sys/types.h> #include <sys/file.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> /* * Check this pathname: it is correct for the kernel version I'm using * on my test GTA02, but it differs for some other kernel versions. */ static char modem_powerctl_pathname[] = "/sys/bus/platform/devices/gta02-pm-gsm.0/power_on"; void set_gta_modem_power_ctrl(boolval) { char strbuf[16]; int len, fd; len = sprintf(strbuf, "%d\n", boolval); fd = open(modem_powerctl_pathname, O_WRONLY); if (fd < 0) { perror(modem_powerctl_pathname); exit(1); } write(fd, strbuf, len); close(fd); } void fork_gta_modem_poweron() { int i; i = fork(); if (i < 0) { perror("fork"); exit(1); } if (i) return; printf("Toggling %s\n", modem_powerctl_pathname); set_gta_modem_power_ctrl(0); usleep(350000); set_gta_modem_power_ctrl(1); exit(0); }