/* $OpenBSD: owtemp.c,v 1.1 2006/03/04 16:27:03 grange Exp $ */ /* * Copyright (c) 2006 Alexander Yurchenko * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ /* * 1-Wire temperature family type device driver. */ #include #include #include #include #include #include #include #include #include #define DS1920_CMD_CONVERT 0x44 #define DS1920_CMD_READ_SCRATCHPAD 0xbe struct owtemp_softc { struct device sc_dev; void * sc_onewire; u_int64_t sc_rom; struct sensor sc_sensor; int sc_dying; }; int owtemp_match(struct device *, void *, void *); void owtemp_attach(struct device *, struct device *, void *); int owtemp_detach(struct device *, int); int owtemp_activate(struct device *, enum devact); void owtemp_update(void *); struct cfattach owtemp_ca = { sizeof(struct owtemp_softc), owtemp_match, owtemp_attach, owtemp_detach, owtemp_activate }; struct cfdriver owtemp_cd = { NULL, "owtemp", DV_DULL }; static const struct onewire_matchfam owtemp_fams[] = { { ONEWIRE_FAMILY_DS1920 } }; int owtemp_match(struct device *parent, void *match, void *aux) { return (onewire_matchbyfam(aux, owtemp_fams, sizeof(owtemp_fams) /sizeof(owtemp_fams[0]))); } void owtemp_attach(struct device *parent, struct device *self, void *aux) { struct owtemp_softc *sc = (struct owtemp_softc *)self; struct onewire_attach_args *oa = aux; sc->sc_onewire = oa->oa_onewire; sc->sc_rom = oa->oa_rom; /* Initialize sensor */ strlcpy(sc->sc_sensor.device, sc->sc_dev.dv_xname, sizeof(sc->sc_sensor.device)); sc->sc_sensor.type = SENSOR_TEMP; strlcpy(sc->sc_sensor.desc, "Temp", sizeof(sc->sc_sensor.desc)); if (sensor_task_register(sc, owtemp_update, 5)) { printf(": unable to register update task\n"); return; } sensor_add(&sc->sc_sensor); printf("\n"); } int owtemp_detach(struct device *self, int flags) { struct owtemp_softc *sc = (struct owtemp_softc *)self; sensor_del(&sc->sc_sensor); sensor_task_unregister(sc); return (0); } int owtemp_activate(struct device *self, enum devact act) { struct owtemp_softc *sc = (struct owtemp_softc *)self; switch (act) { case DVACT_ACTIVATE: return (EOPNOTSUPP); case DVACT_DEACTIVATE: sc->sc_dying = 1; break; } return (0); } void owtemp_update(void *arg) { struct owtemp_softc *sc = arg; u_int8_t data[9]; onewire_lock(sc->sc_onewire, 0); if (onewire_reset(sc->sc_onewire) != 0) goto done; onewire_matchrom(sc->sc_onewire, sc->sc_rom); /* * Start temperature conversion. The conversion takes up to 750ms. * After sending the command, the data line must be held high for * at least 750ms to provide power during the conversion process. * As such, no other activity may take place on the 1-Wire bus for * at least this period. */ onewire_write_byte(sc->sc_onewire, DS1920_CMD_CONVERT); tsleep(sc, PRIBIO, "owtemp", hz); if (onewire_reset(sc->sc_onewire) != 0) goto done; onewire_matchrom(sc->sc_onewire, sc->sc_rom); /* * The result of the temperature measurement is placed in the * first two bytes of the scratchpad. */ onewire_write_byte(sc->sc_onewire, DS1920_CMD_READ_SCRATCHPAD); onewire_read_block(sc->sc_onewire, data, 9); if (onewire_crc(data, 8) == data[8]) { sc->sc_sensor.value = 273150000 + (int)((u_int16_t)data[1] << 8 | data[0]) * 500000; } done: onewire_unlock(sc->sc_onewire); }