nut/drivers/megatec.c

/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: t; -*-
 *
 * megatec.c: support for Megatec protocol based UPSes
 *
 * Copyright (C) Carlos Rodrigues <carlos.efr at mail.telepac.pt>
 *
 * megatec.c created on 4/10/2003
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */


/*
 * A document describing the protocol implemented by this driver can be
 * found online at "http://www.networkupstools.org/protocols/megatec.html".
 */


#include "main.h"
#include "serial.h"
#include "megatec.h"

#include <stdio.h>
#include <limits.h>
#include <string.h>
#include <stdlib.h>

#define DRIVER_NAME	"Megatec protocol driver"
#define DRIVER_VERSION	"1.6" /* FIXME: doesn't conform to "X.YZ" */

/* driver description structure */
upsdrv_info_t upsdrv_info = {
	DRIVER_NAME,
	DRIVER_VERSION,
	"Carlos Rodrigues <carlos.efr@mail.telepac.pt>",
	DRV_STABLE,
#ifdef MEGATEC_SUBDRV
	{ &megatec_subdrv_info, NULL }
#else
	{ NULL }
#endif
};

#define ENDCHAR  '\r'
#define IGNCHARS ""

#define RECV_BUFFER_LEN 128
#define FIELD_BUFFER_LEN 16

/* The expected reply lengths */
#define F_CMD_REPLY_LEN  21
#define Q1_CMD_REPLY_LEN 46
#define I_CMD_REPLY_LEN  38

#define IDENT_MAXTRIES   3

#define READ_TIMEOUT 2       /* timeout on read (seconds) */
#define READ_PACE    300000  /* interval to wait between sending a command and reading the response (usec) */

#define MAX_START_DELAY    9999
#define MAX_SHUTDOWN_DELAY 99

/* Maximum length of a string representing these values */
#define MAX_START_DELAY_LEN    4
#define MAX_SHUTDOWN_DELAY_LEN 2

#define MAX_POLL_FAILURES 3

#define N_FLAGS 8

/* The UPS status flags */
#define FL_ON_BATT    0
#define FL_LOW_BATT   1
#define FL_BOOST_TRIM 2
#define FL_FAILED     3
#define FL_UPS_TYPE   4
#define FL_BATT_TEST  5
#define FL_LOAD_OFF   6
#define FL_BEEPER_ON  7  /* bogus on some models */

/* Maximum lengths for the "I" command reply fields */
#define UPS_MFR_CHARS     15
#define UPS_MODEL_CHARS   10
#define UPS_VERSION_CHARS 10

/* Below this value we can safely consider a voltage to be zero */
#define RESIDUAL_VOLTAGE 10.0


/* The values returned by the UPS for an "I" query */
typedef struct {
	char mfr[UPS_MFR_CHARS + 1];
	char model[UPS_MODEL_CHARS + 1];
	char version[UPS_VERSION_CHARS + 1];
} UPSInfo_t;


/* The values returned by the UPS for an "F" query */
typedef struct {
	float volt;
	float current;
	float battvolt;
	float freq;
} FirmwareValues_t;


/* The values returned by the UPS for an "Q1" query */
typedef struct {
	float ivolt;
	float fvolt;
	float ovolt;
	float load;
	float freq;
	float battvolt;
	float temp;
	char flags[N_FLAGS + 1];
} QueryValues_t;


/* Parameters for known battery types */
typedef struct {
	float nominal;  /* battery voltage (nominal) */
	float min;      /* lower bound for a single battery of "nominal" voltage (see "set_battery_params" below) */
	float max;      /* upper bound for a single battery of "nominal" voltage (see "set_battery_params" below) */
	float empty;    /* fully discharged battery */
	float full;     /* fully charged battery */
	float low;      /* low battery (unused) */
} BatteryVolts_t;


/* Known battery types must be in ascending order by "nominal" first, and then by "max". */
static BatteryVolts_t batteries[] = {{ 12.0,  9.0, 16.0,  9.7, 13.7,  0.0 },   /* Mustek PowerMust 600VA Plus (LB unknown) */
                                     { 12.0, 18.0, 30.0, 18.8, 26.8, 22.3 },   /* PowerWalker Line-Interactive VI 1000 */
                                     { 23.5, 18.0, 30.0, 21.3, 27.1, 22.2 },   /* UNITEK ALPHA2600 */
                                     { 24.0, 18.0, 30.0, 19.4, 27.4, 22.2 },   /* Mustek PowerMust 1000VA Plus */
                                     { 36.0,  1.5,  3.0, 1.64, 2.31, 1.88 },   /* Mustek PowerMust 1000VA On-Line */
                                     { 36.0, 30.0, 42.0, 32.5, 41.0,  0.0 },   /* Mecer ME-2000 (LB unknown) */
                                     { 48.0, 38.0, 58.0, 40.0, 54.6, 44.0 },   /* Sven Smart RM2000 */
                                     { 72.0,  1.5,  3.0, 1.74, 2.37, 1.82 },   /* Effekta RM2000MH */
                                     { 96.0,  1.5,  3.0, 1.63, 2.29,  1.8 },   /* Ablerex MS3000RT (LB at 25% charge) */
                                     {  0.0,  0.0,  0.0,  0.0,  0.0,  0.0 }};  /* END OF DATA */

/* Interval between chars on send (usec) */
static int send_pace = 100000;

/* Some models need this */
static char state_dtr = 1;
static char state_rts = 0;

/* Workaround for buggy models */
static char ignore_off = 0;  /* ignore FL_LOAD_OFF if it behaves strangely */

/* Defined in upsdrv_initinfo */
static float battvolt_empty = -1;  /* unknown */
static float battvolt_full = -1;   /* unknown */

/* Battery voltage multiplier (to match the nominal voltage on some models) */
static float battvolt_mult = 1;

/* Minimum and maximum voltage seen on input */
static float ivolt_min = INT_MAX;  /* unknown */
static float ivolt_max = -1;       /* unknown */

/* In minutes: */
static short start_delay = 2;     /* wait at least this amount of time before coming back online */
static short shutdown_delay = 0;  /* wait until going offline */

/* In percentage: */
static float lowbatt = -1;  /* disabled */

static char watchdog_enabled = 0;  /* disabled by default, of course */
static char watchdog_timeout = 1;  /* in minutes */


static char *copy_field(char* dest, char *src, int field_len);
static float get_battery_charge(float battvolt);
static int set_battery_params(float volt_nominal, float volt_now);
static int check_ups(QueryValues_t *status);
static int get_ups_info(UPSInfo_t *info);
static int get_firmware_values(FirmwareValues_t *values);
static int run_query(QueryValues_t *values);

int instcmd(const char *cmdname, const char *extra);
int setvar(const char *varname, const char *val);


/* I know, macros should evaluate their arguments only once */
#define CLAMP(x, min, max) (((x) < (min)) ? (min) : (((x) > (max)) ? (max) : (x)))


static char *copy_field(char* dest, char *src, int field_len)
{
	int i, j;

	/* First we skip the leading spaces... */
	for (i = 0; i < field_len; i++) {
		if (src[i] != ' ') {
			break;
		}
	}

	/* ... then we copy the rest of the field... */
	j = 0;
	while (i < field_len) {
		dest[j] = src[i];

		i++; j++;
	}

	dest[j] = '\0';

	/* ...and finally, remove the trailing spaces. */
	rtrim(dest, ' ');

	return &src[field_len];  /* return the rest of the source buffer */
}


static float get_battery_charge(float battvolt)
{
	float value;

	if (battvolt_empty < 0 || battvolt_full < 0) {
		return -1;
	}

	battvolt = CLAMP(battvolt, battvolt_empty, battvolt_full);
	value = (battvolt - battvolt_empty) / (battvolt_full - battvolt_empty);

	return value * 100;  /* percentage */
}


/*
 * Set the proper limits, depending on the battery voltage,
 * so that the "charge" calculations return meaningful values.
 *
 * This has to be done by looking at the present battery voltage and
 * the nominal voltage because, for example, some 24V models will
 * show a nominal voltage of 24, while others will show a nominal
 * voltage of 12. The present voltage helps telling them apart.
 */
static int set_battery_params(float volt_nominal, float volt_now)
{
	int i = 0;

	while (batteries[i].nominal > 0) {
		if (volt_nominal == batteries[i].nominal) {         /* battery voltage matches... */
			while (volt_nominal == batteries[i].nominal) {  /* ...find the most adequate parameters */
				if (volt_now > batteries[i].min && volt_now < batteries[i].max) {
					battvolt_empty = batteries[i].empty;
					battvolt_full = batteries[i].full;

					upsdebugx(1, "%.1fV battery, interval [%.1fV, %.1fV].", volt_nominal, battvolt_empty, battvolt_full);

					return i;
				}

				i++;

			}

			upsdebugx(1, "%.1fV battery, present voltage (%.1fV) outside of supported intervals.", volt_nominal, volt_now);

			return -1;
		}

		i++;
	}

	upsdebugx(1, "Unsupported battery voltage (%.1fV).", volt_nominal);

	return -1;
}


/*
 * The "status" parameter is left unchanged on failure.
 */
static int check_ups(QueryValues_t *status)
{
	QueryValues_t values;

	if (run_query(&values) < 0) {
		return -1;
	}

	memcpy(status, &values, sizeof(values));

	return 0;
}


static int get_ups_info(UPSInfo_t *info)
{
	char buffer[RECV_BUFFER_LEN];
	char *anchor;
	int ret;

	upsdebugx(2, "Asking for UPS information [I]...");
	ser_flush_io(upsfd);
	ser_send_pace(upsfd, send_pace, "I%c", ENDCHAR);
	usleep(READ_PACE);

	/*
	 * Expected reply: "#UPS_MFR........ UPS_MODEL. UPS_VER...<cr>"
	 */
	ret = ser_get_line(upsfd, buffer, RECV_BUFFER_LEN, ENDCHAR, IGNCHARS, READ_TIMEOUT, 0);

	if (ret < 0) {
		upsdebug_with_errno(2, "I => FAILED");

		return -1;
	}

	if (ret == 0) {
		upsdebugx(2, "I => FAILED [timeout]");

		return -1;
	}

	if (ret < I_CMD_REPLY_LEN) {
		upsdebugx(2, "I => FAILED [short read]");
		upsdebug_hex(3, "I detail", (unsigned char *)buffer, ret);

		return -1;
	}

	if (buffer[0] != '#') {
		upsdebugx(2, "I => FAILED [invalid start character]");
		upsdebug_hex(3, "I detail", (unsigned char *)buffer, ret);

		return -1;
	}

	upsdebugx(2, "I => OK [%s]", buffer);

	memset(info, 0, sizeof(UPSInfo_t));

	/*
	 * Get the manufacturer, model and version fields, skipping
	 * the separator character that sits between them, as well as
	 * the first character (the control character, always a '#').
	 */
	anchor = copy_field(info->mfr, &buffer[1], UPS_MFR_CHARS);
	anchor = copy_field(info->model, anchor + 1, UPS_MODEL_CHARS);
	copy_field(info->version, anchor + 1, UPS_VERSION_CHARS);

	upsdebugx(2, "I VALUES => [%s %s %s]", info->mfr, info->model, info->version);

	return 0;
}


static int get_firmware_values(FirmwareValues_t *values)
{
	char buffer[RECV_BUFFER_LEN];
	char field[FIELD_BUFFER_LEN];
	char *anchor;
	int ret;

	upsdebugx(2, "Asking for UPS power ratings [F]...");
	ser_flush_io(upsfd);
	ser_send_pace(upsfd, send_pace, "F%c", ENDCHAR);
	usleep(READ_PACE);

	/*
	 * Expected reply: "#MMM.M QQQ SS.SS RR.R<cr>"
	 */
	ret = ser_get_line(upsfd, buffer, RECV_BUFFER_LEN, ENDCHAR, IGNCHARS, READ_TIMEOUT, 0);

	if (ret < 0) {
		upsdebug_with_errno(2, "F => FAILED");

		return -1;
	}

	if (ret == 0) {
		upsdebugx(2, "F => FAILED [timeout]");

		return -1;
	}

	if (ret < F_CMD_REPLY_LEN) {
		upsdebugx(2, "F => FAILED [short read]");
		upsdebug_hex(3, "F detail", (unsigned char *)buffer, ret);

		return -1;
	}


	if (buffer[0] != '#') {
		upsdebugx(2, "F => FAILED [invalid start character]");
		upsdebug_hex(3, "F detail", (unsigned char *)buffer, ret);

		return -1;
	}

	upsdebugx(2, "F => OK [%s]", buffer);

	anchor = copy_field(field, &buffer[1], 5);
	values->volt = atof(field);

	anchor = copy_field(field, anchor + 1, 3);
	values->current = atof(field);

	anchor = copy_field(field, anchor + 1, 5);
	values->battvolt = atof(field);

	anchor = copy_field(field, anchor + 1, 4);
	values->freq = atof(field);

	upsdebugx(2, "F VALUES => [%.1f %.1f %.1f %.1f]", values->volt,
	          values->current, values->battvolt, values->freq);

	return 0;
}


static int run_query(QueryValues_t *values)
{
	char buffer[RECV_BUFFER_LEN];
	char field[FIELD_BUFFER_LEN];
	char *anchor;
	int ret;

	upsdebugx(2, "Asking for UPS status [Q1]...");
	ser_flush_io(upsfd);
	ser_send_pace(upsfd, send_pace, "Q1%c", ENDCHAR);
	usleep(READ_PACE);

	/*
	 * Expected reply: "(MMM.M NNN.N PPP.P QQQ RR.R S.SS TT.T b7b6b5b4b3b2b1b0<cr>"
	 */
	ret = ser_get_line(upsfd, buffer, RECV_BUFFER_LEN, ENDCHAR, IGNCHARS, READ_TIMEOUT, 0);

	if (ret < 0) {
		upsdebug_with_errno(2, "Q1 => FAILED");

		return -1;
	}

	if (ret == 0) {
		upsdebugx(2, "Q1 => FAILED [timeout]");

		return -1;
	}

	if (ret < Q1_CMD_REPLY_LEN) {
		upsdebugx(2, "Q1 => FAILED [short read]");
		upsdebug_hex(3, "Q1 detail", (unsigned char *)buffer, ret);

		return -1;
	}

	if (buffer[0] != '(') {
		upsdebugx(2, "Q1 => FAILED [invalid start character]");
		upsdebug_hex(3, "Q1 detail", (unsigned char *)buffer, ret);

		return -1;
	}

	upsdebugx(2, "Q1 => OK [%s]", buffer);

	anchor = copy_field(field, &buffer[1], 5);
	values->ivolt = atof(field);

	anchor = copy_field(field, anchor + 1, 5);
	values->fvolt = atof(field);

	anchor = copy_field(field, anchor + 1, 5);
	values->ovolt = atof(field);

	anchor = copy_field(field, anchor + 1, 3);
	values->load = atof(field);

	anchor = copy_field(field, anchor + 1, 4);
	values->freq = atof(field);

	anchor = copy_field(field, anchor + 1, 4);
	values->battvolt = atof(field);

	anchor = copy_field(field, anchor + 1, 4);
	values->temp = atof(field);

	anchor = copy_field(values->flags, anchor + 1, N_FLAGS);

	if (strlen(values->flags) < N_FLAGS) {
		upsdebugx(2, "Q1 => FAILED [flags error]");
		return -1;
	}

	upsdebugx(2, "Q1 VALUES => [%.1f %.1f %.1f %.1f %.1f %.1f %.1f %s]",
	          values->ivolt, values->fvolt, values->ovolt, values->load,
	          values->freq, values->battvolt, values->temp, values->flags);

	return 0;
}


void upsdrv_initinfo(void)
{
	int i;
	FirmwareValues_t values;
	QueryValues_t status;
	UPSInfo_t info;

	/*
	 * Some models apparently time-out with the default send pace, so we must
	 * allow the user to override it if needed be. The configuration parameter
	 * is specified in milliseconds for the user's benefit.
	 */
	if (getval("sendpace")) {
		upsdebugx(2, "Default command send pace is %d usec.", send_pace);
		upsdebugx(2, "Parameter [sendpace]: [%s]", getval("sendpace"));

		/* Having 1 second as the upper-bound is an arbitrary choice... */
		send_pace = CLAMP(atoi(getval("sendpace")), 1, 1000) * 1000;

		upslogx(LOG_NOTICE, "Command send pace changed to %d usec.", send_pace);
	}

	/*
	 * UPS detection sequence.
	 */
	upsdebugx(1, "Starting UPS detection process...");

	/* Some models seem to need this. We'll just discard the ouput for now... */
	get_ups_info(&info);

	/* Check for a compatible UPS... */
	for (i = 0; i < IDENT_MAXTRIES; i++) {
		if (check_ups(&status) == 0) {
			break;
		}
	}

	if (i == IDENT_MAXTRIES) {
		fatalx(EXIT_FAILURE, "Megatec protocol UPS not detected.");
	}

	dstate_setinfo("ups.type", status.flags[FL_UPS_TYPE] == '1' ? "standby" : "online");

	upsdebugx(1, "Cancelling any pending shutdown or battery test.");
	ser_send_pace(upsfd, send_pace, "C%c", ENDCHAR);

	/*
	 * Try to identify the UPS.
	 */
	if (get_ups_info(&info) >= 0) {
		char model[UPS_MODEL_CHARS + UPS_VERSION_CHARS + 2];
		snprintf(model, sizeof(model), "%s %s", info.model, info.version);

		dstate_setinfo("ups.mfr", "%s", getval("mfr") ? getval("mfr") : info.mfr);
		dstate_setinfo("ups.model", "%s", getval("model") ? getval("model") : model);

		upslogx(LOG_INFO, "Megatec protocol UPS detected [%s %s %s].", info.mfr, info.model, info.version);
	} else {
		dstate_setinfo("ups.mfr", "%s", getval("mfr") ? getval("mfr") : "unknown");
		dstate_setinfo("ups.model", "%s", getval("model") ? getval("model") : "unknown");

		upslogx(LOG_INFO, "Megatec protocol UPS detected.");
	}

	dstate_setinfo("ups.serial", "%s", getval("serial") ? getval("serial") : "unknown");

	/*
	 * Workaround for buggy models.
	 */
	ignore_off = testvar("ignoreoff");

	if (status.flags[FL_LOAD_OFF] == '1' && status.load > 0.01 && !ignore_off) {
		ignore_off = 1;
		upslogx(LOG_INFO, "The UPS reports OFF status but appears to be ON. Parameter \"ignoreoff\" set automatically.");
	}
	upsdebugx(2, "Parameter [ignoreoff]: [%s]", (ignore_off ? "true" : "false"));

	/*
	 * Set battery-related values.
	 */
	if (get_firmware_values(&values) >= 0) {
		dstate_setinfo("battery.voltage.nominal", "%.1f", values.battvolt);
		dstate_setinfo("input.voltage.nominal", "%.1f", values.volt);
		dstate_setinfo("input.frequency.nominal", "%.1f", values.freq);

		if (set_battery_params(values.battvolt, status.battvolt) < 0) {
			upslogx(LOG_NOTICE, "This UPS has an unsupported combination of battery voltage/number of batteries.");
		}
	}

	if (getval("battvoltmult")) {
		upsdebugx(2, "Parameter [battvoltmult]: [%s]", getval("battvoltmult"));

		/* Having SHRT_MAX as the upper-bound is an arbitrary choice... */
		battvolt_mult = CLAMP(atof(getval("battvoltmult")), 1, SHRT_MAX);

		upslogx(LOG_NOTICE, "The battery voltage reported by the UPS will be multiplied by %.1f.", battvolt_mult);
	}

	if (getval("battvolts")) {
		upsdebugx(2, "Parameter [battvolts]: [%s]", getval("battvolts"));

		if (sscanf(getval("battvolts"), "%f:%f", &battvolt_empty, &battvolt_full) != 2) {
			fatalx(EXIT_FAILURE, "Error in \"battvolts\" parameter.");
		}

		upslogx(LOG_NOTICE, "Overriding battery voltage interval [%.1fV, %.1fV].", battvolt_empty, battvolt_full);
	}

	if (battvolt_empty < 0 || battvolt_full < 0) {
		upslogx(LOG_NOTICE, "Cannot calculate charge percentage for this UPS.");
	}

	if (getval("lowbatt")) {
		if (battvolt_empty < 0 || battvolt_full < 0) {
			upslogx(LOG_NOTICE, "Ignoring \"lowbatt\" parameter.");
		} else {
			lowbatt = CLAMP(atof(getval("lowbatt")), 0, 100);
		}
	}

	/*
	 * Set the restart and shutdown delays.
	 */
	if (getval("ondelay")) {
		start_delay = CLAMP(atoi(getval("ondelay")), 0, MAX_START_DELAY);
	}

	if (getval("offdelay")) {
		shutdown_delay = CLAMP(atoi(getval("offdelay")), 0, MAX_SHUTDOWN_DELAY);
	}

	dstate_setinfo("ups.delay.start", "%d", start_delay);
	dstate_setinfo("ups.delay.shutdown", "%d", shutdown_delay);

	/*
	 * Register the available instant commands.
	 */
	dstate_addcmd("test.battery.start.deep");
	dstate_addcmd("test.battery.start");
	dstate_addcmd("test.battery.stop");
	dstate_addcmd("shutdown.return");
	dstate_addcmd("shutdown.stayoff");
	dstate_addcmd("shutdown.stop");
	dstate_addcmd("load.on");
	dstate_addcmd("load.off");
	dstate_addcmd("reset.input.minmax");
	dstate_addcmd("reset.watchdog");
	dstate_addcmd("beeper.toggle");

	upsh.instcmd = instcmd;
	upsh.setvar = setvar;

	upsdebugx(1, "Done setting up the UPS.");
}


void upsdrv_updateinfo(void)
{
	QueryValues_t query;
	float charge;
	static int poll_fail = 0;

	if (run_query(&query) < 0) {
		/*
		 * Query wasn't successful (we got some weird
		 * response), however we won't fatalx(EXIT_FAILURE, ) as this
		 * happens sometimes when the ups is offline.
		 *
		 * Some fault tolerance is good, we just assume
		 * that the UPS is just taking a nap. ;)
		 */
		poll_fail++;
		upsdebugx(2, "Poll failure [%d].", poll_fail);
		ser_comm_fail("No status from UPS.");

		if (poll_fail >= MAX_POLL_FAILURES) {
			upsdebugx(2, "Too many poll failures, data is stale.");
			dstate_datastale();
		}

		return;
	}

	poll_fail = 0;
	ser_comm_good();

	dstate_setinfo("input.voltage", "%.1f", query.ivolt);
	dstate_setinfo("input.voltage.fault", "%.1f", query.fvolt);
	dstate_setinfo("output.voltage", "%.1f", query.ovolt);
	dstate_setinfo("ups.load", "%.1f", query.load);
	dstate_setinfo("input.frequency", "%.1f", query.freq);

	/*
	 * The battery voltage multiplier should only be applied to battery.voltage
	 * in order not to break the charge calculation (that uses the 'raw' value
	 * that is reported by the UPS).
	 */
	dstate_setinfo("battery.voltage", "%.2f", battvolt_mult * query.battvolt);

	if (query.temp > 0.01) {
		dstate_setinfo("ups.temperature", "%.1f", query.temp);
	}

	charge = get_battery_charge(query.battvolt);
	if (charge >= 0) {
		dstate_setinfo("battery.charge", "%.1f", charge);

		upsdebugx(2, "Calculated battery charge: %.1f%%", charge);
	}

	dstate_setinfo("ups.beeper.status", query.flags[FL_BEEPER_ON] == '1' ? "enabled" : "disabled");

	status_init();

	/*
	 * Some models, when OFF, never change to on-battery status when
	 * line power is unavailable. To get around this, we also look at
	 * the input voltage level here.
	 */
	if (query.flags[FL_ON_BATT] == '1' || query.ivolt < RESIDUAL_VOLTAGE) {
		status_set("OB");
	} else {
		status_set("OL");

		if (query.flags[FL_BOOST_TRIM] == '1') {
			if (query.ivolt < query.ovolt) {
				status_set("BOOST");
			} else if (query.ivolt > query.ovolt) {
				status_set("TRIM");
			} else {
				status_set("BYPASS");
			}
		}

		/* Update minimum and maximum input voltage levels too */
		if (query.ivolt < ivolt_min) {
			ivolt_min = query.ivolt;
		}

		if (query.ivolt > ivolt_max) {
			ivolt_max = query.ivolt;
		}

		dstate_setinfo("input.voltage.minimum", "%.1f", ivolt_min);
		dstate_setinfo("input.voltage.maximum", "%.1f", ivolt_max);
	}

	/*
	 * If "lowbatt > 0", it becomes a "soft" low battery level
	 * and the hardware flag "FL_LOW_BATT" is always ignored.
	 */
	if ((lowbatt <= 0 && query.flags[FL_LOW_BATT] == '1') ||
	    (lowbatt > 0 && charge < lowbatt)) {
		status_set("LB");
	}

	if (query.flags[FL_BATT_TEST] == '1') {
		status_set("CAL");
	}

	if (query.flags[FL_LOAD_OFF] == '1' && !ignore_off) {
		status_set("OFF");
	}

	alarm_init();

	if (query.flags[FL_FAILED] == '1') {
		alarm_set("Internal UPS fault!");
	}

	alarm_commit();

	status_commit();

	dstate_dataok();
}


void upsdrv_shutdown(void)
{
	int s_wait = getval("offdelay") ? CLAMP(atoi(getval("offdelay")), 0, MAX_SHUTDOWN_DELAY) : shutdown_delay;
	int r_wait = getval("ondelay") ? CLAMP(atoi(getval("ondelay")), 0, MAX_START_DELAY) : start_delay;

	upslogx(LOG_INFO, "Shutting down UPS.");

	ser_send_pace(upsfd, send_pace, "C%c", ENDCHAR);
	ser_send_pace(upsfd, send_pace, "S%02dR%04d%c", s_wait, r_wait, ENDCHAR);
}


int instcmd(const char *cmdname, const char *extra)
{
	char buffer[RECV_BUFFER_LEN];

	/*
	 * Some commands are always supported by every UPS implementing
	 * the megatec protocol, but others may or may not be supported.
	 * Unsupported commands are echoed back without ENDCHAR.
	 */

	if (strcasecmp(cmdname, "test.battery.start.deep") == 0) {
		ser_flush_io(upsfd);
		ser_send_pace(upsfd, send_pace, "TL%c", ENDCHAR);
		usleep(READ_PACE);

		if (ser_get_line(upsfd, buffer, 2 + 1, '\0', IGNCHARS, READ_TIMEOUT, 0) > 0) {
			upslogx(LOG_NOTICE, "test.battery.start.deep not supported by UPS hardware.");
		} else {
			upslogx(LOG_INFO, "Deep battery test started.");
		}

		return STAT_INSTCMD_HANDLED;
	}

	if (strcasecmp(cmdname, "test.battery.start") == 0) {
		ser_flush_io(upsfd);
		ser_send_pace(upsfd, send_pace, "T%c", ENDCHAR);
		usleep(READ_PACE);

		if (ser_get_line(upsfd, buffer, 1 + 1, '\0', IGNCHARS, READ_TIMEOUT, 0) > 0) {
			upslogx(LOG_NOTICE, "test.battery.start not supported by UPS hardware.");
		} else {
			upslogx(LOG_INFO, "Battery test started.");
		}

		return STAT_INSTCMD_HANDLED;
	}

	if (strcasecmp(cmdname, "test.battery.stop") == 0) {
		ser_flush_io(upsfd);
		ser_send_pace(upsfd, send_pace, "CT%c", ENDCHAR);
		usleep(READ_PACE);

		if (ser_get_line(upsfd, buffer, 2 + 1, '\0', IGNCHARS, READ_TIMEOUT, 0) > 0) {
			upslogx(LOG_NOTICE, "test.battery.stop not supported by UPS hardware.");
		} else {
			upslogx(LOG_INFO, "Battery test stopped.");
		}

		return STAT_INSTCMD_HANDLED;
	}

	if (strcasecmp(cmdname, "shutdown.return") == 0) {
		ser_send_pace(upsfd, send_pace, "C%c", ENDCHAR);
		watchdog_enabled = 0;

		ser_send_pace(upsfd, send_pace, "S%02dR%04d%c", shutdown_delay, start_delay, ENDCHAR);

		upslogx(LOG_INFO, "Shutdown (return) initiated.");

		return STAT_INSTCMD_HANDLED;
	}

	if (strcasecmp(cmdname, "shutdown.stayoff") == 0) {
		ser_send_pace(upsfd, send_pace, "C%c", ENDCHAR);
		watchdog_enabled = 0;

		ser_flush_io(upsfd);
		ser_send_pace(upsfd, send_pace, "S%02d%c", shutdown_delay, ENDCHAR);
		usleep(READ_PACE);

		if (ser_get_line(upsfd, buffer, 3 + 1, '\0', IGNCHARS, READ_TIMEOUT, 0) > 0) {
			ser_send_pace(upsfd, send_pace, "S%02dR9999%c", shutdown_delay, ENDCHAR);
			upslogx(LOG_NOTICE, "UPS refuses to turn the load off indefinitely. Will turn off for 9999 minutes instead.");
		}

		upslogx(LOG_INFO, "Shutdown (stayoff) initiated.");

		return STAT_INSTCMD_HANDLED;
	}

	if (strcasecmp(cmdname, "shutdown.stop") == 0) {
		ser_send_pace(upsfd, send_pace, "C%c", ENDCHAR);
		watchdog_enabled = 0;

		upslogx(LOG_INFO, "Shutdown canceled.");

		return STAT_INSTCMD_HANDLED;
	}

	if (strcasecmp(cmdname, "load.on") == 0) {
		ser_send_pace(upsfd, send_pace, "C%c", ENDCHAR);
		watchdog_enabled = 0;

		upslogx(LOG_INFO, "Turning the load on.");

		return STAT_INSTCMD_HANDLED;
	}

	if (strcasecmp(cmdname, "load.off") == 0) {
		ser_send_pace(upsfd, send_pace, "C%c", ENDCHAR);
		watchdog_enabled = 0;

		ser_flush_io(upsfd);
		ser_send_pace(upsfd, send_pace, "S00%c", ENDCHAR);
		usleep(READ_PACE);

		if (ser_get_line(upsfd, buffer, 3 + 1, '\0', IGNCHARS, READ_TIMEOUT, 0) > 0) {
			ser_send_pace(upsfd, send_pace, "S00R9999%c", ENDCHAR);
			upslogx(LOG_NOTICE, "UPS refuses to turn the load off indefinitely. Will turn off for 9999 minutes instead.");
		}

		upslogx(LOG_INFO, "Turning the load off.");

		return STAT_INSTCMD_HANDLED;
	}

	if (strcasecmp(cmdname, "reset.input.minmax") == 0) {
		ivolt_min = INT_MAX;
		ivolt_max = -1;

		dstate_setinfo("input.voltage.minimum", "%.1f", ivolt_min);
		dstate_setinfo("input.voltage.maximum", "%.1f", ivolt_max);

		upslogx(LOG_INFO, "Resetting minimum and maximum input voltage values.");

		return STAT_INSTCMD_HANDLED;
	}

	if (strcasecmp(cmdname, "reset.watchdog") == 0) {
		ser_send_pace(upsfd, send_pace, "C%c", ENDCHAR);
		ser_send_pace(upsfd, send_pace, "S%02dR0001%c", watchdog_timeout, ENDCHAR);

		if (watchdog_enabled) {
			upsdebugx(2, "Resetting the UPS watchdog.");
		} else {
			watchdog_enabled = 1;
			upslogx(LOG_INFO, "UPS watchdog started.");
		}

		return STAT_INSTCMD_HANDLED;
	}

	if (strcasecmp(cmdname, "beeper.toggle") == 0) {
		ser_flush_io(upsfd);
		ser_send_pace(upsfd, send_pace, "Q%c", ENDCHAR);
		usleep(READ_PACE);

		if (ser_get_line(upsfd, buffer, 1 + 1, '\0', IGNCHARS, READ_TIMEOUT, 0) > 0) {
			upslogx(LOG_NOTICE, "beeper.toggle not supported by UPS hardware.");
		} else {
			upslogx(LOG_INFO, "Toggling UPS beeper.");
		}

		return STAT_INSTCMD_HANDLED;
	}

	upslogx(LOG_NOTICE, "instcmd: unknown command [%s]", cmdname);

	return STAT_INSTCMD_UNKNOWN;
}


int setvar(const char *varname, const char *val)
{
	return STAT_SET_UNKNOWN;
}


void upsdrv_help(void)
{
}


void upsdrv_makevartable(void)
{
	addvar(VAR_VALUE, "mfr", "Manufacturer name");
	addvar(VAR_VALUE, "model", "Model name");
	addvar(VAR_VALUE, "serial", "UPS serial number");
	addvar(VAR_VALUE, "lowbatt", "Low battery level (%)");
	addvar(VAR_VALUE, "ondelay", "Min. delay before UPS startup (minutes)");
	addvar(VAR_VALUE, "offdelay", "Delay before UPS shutdown (minutes)");
	addvar(VAR_VALUE, "battvolts", "Battery voltages (empty:full)");
	addvar(VAR_VALUE, "battvoltmult", "Battery voltage multiplier");
	addvar(VAR_FLAG , "ignoreoff", "Ignore the OFF status from the UPS");
	addvar(VAR_VALUE, "sendpace", "Interval between command chars (msec)");
	addvar(VAR_VALUE, "dtr", "Serial DTR line state (0/1)");
	addvar(VAR_VALUE, "rts", "Serial RTS line state (0/1)");

	megatec_subdrv_makevartable();
}


void upsdrv_initups(void)
{
	upsfd = ser_open(device_path);
	ser_set_speed(upsfd, device_path, B2400);

	if (getval("dtr")) {
		upsdebugx(2, "Parameter [dtr]: [%s]", getval("dtr"));

		if (strcmp(getval("dtr"), "0") != 0 && strcmp(getval("dtr"), "1") != 0) {
			fatalx(EXIT_FAILURE, "Error in \"dtr\" parameter.");
		}

		state_dtr = atoi(getval("dtr"));
	}

	if (getval("rts")) {
		upsdebugx(2, "Parameter [rts]: [%s]", getval("rts"));

		if (strcmp(getval("rts"), "0") != 0 && strcmp(getval("rts"), "1") != 0) {
			fatalx(EXIT_FAILURE, "Error in \"rts\" parameter.");
		}

		state_rts = atoi(getval("rts"));
	}

	upsdebugx(2, "DTR=%d, RTS=%d", state_dtr, state_rts);

	ser_set_dtr(upsfd, state_dtr);
	ser_set_rts(upsfd, state_rts);
}


void upsdrv_cleanup(void)
{
	ser_set_dtr(upsfd, 0);
	ser_close(upsfd, device_path);
}


/* EOF - megatec.c */