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);
}