diff options
Diffstat (limited to 'sys/dev/onewire/owtemp.c')
| -rw-r--r-- | sys/dev/onewire/owtemp.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/sys/dev/onewire/owtemp.c b/sys/dev/onewire/owtemp.c new file mode 100644 index 00000000000..1fd5b673881 --- /dev/null +++ b/sys/dev/onewire/owtemp.c @@ -0,0 +1,167 @@ +/* $OpenBSD: owtemp.c,v 1.1 2006/03/04 16:27:03 grange Exp $ */ + +/* + * Copyright (c) 2006 Alexander Yurchenko <grange@openbsd.org> + * + * 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 <sys/param.h> +#include <sys/systm.h> +#include <sys/device.h> +#include <sys/kernel.h> +#include <sys/proc.h> +#include <sys/sensors.h> + +#include <dev/onewire/onewiredevs.h> +#include <dev/onewire/onewirereg.h> +#include <dev/onewire/onewirevar.h> + +#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); +} |