Annotation of sys/dev/onewire/owtemp.c, Revision 1.1
1.1 ! nbrk 1: /* $OpenBSD: owtemp.c,v 1.8 2007/06/24 05:34:35 dlg Exp $ */
! 2:
! 3: /*
! 4: * Copyright (c) 2006 Alexander Yurchenko <grange@openbsd.org>
! 5: *
! 6: * Permission to use, copy, modify, and distribute this software for any
! 7: * purpose with or without fee is hereby granted, provided that the above
! 8: * copyright notice and this permission notice appear in all copies.
! 9: *
! 10: * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
! 11: * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
! 12: * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
! 13: * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
! 14: * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
! 15: * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
! 16: * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
! 17: */
! 18:
! 19: /*
! 20: * 1-Wire temperature family type device driver.
! 21: */
! 22:
! 23: #include <sys/param.h>
! 24: #include <sys/systm.h>
! 25: #include <sys/device.h>
! 26: #include <sys/kernel.h>
! 27: #include <sys/proc.h>
! 28: #include <sys/rwlock.h>
! 29: #include <sys/sensors.h>
! 30:
! 31: #include <dev/onewire/onewiredevs.h>
! 32: #include <dev/onewire/onewirereg.h>
! 33: #include <dev/onewire/onewirevar.h>
! 34:
! 35: /* Commands */
! 36: #define DS1920_CMD_CONVERT 0x44
! 37: #define DS1920_CMD_READ_SCRATCHPAD 0xbe
! 38:
! 39: /* Scratchpad layout */
! 40: #define DS1920_SP_TEMP_LSB 0
! 41: #define DS1920_SP_TEMP_MSB 1
! 42: #define DS1920_SP_TH 2
! 43: #define DS1920_SP_TL 3
! 44: #define DS1920_SP_COUNT_REMAIN 6
! 45: #define DS1920_SP_COUNT_PERC 7
! 46: #define DS1920_SP_CRC 8
! 47:
! 48: struct owtemp_softc {
! 49: struct device sc_dev;
! 50:
! 51: void * sc_onewire;
! 52: u_int64_t sc_rom;
! 53:
! 54: struct ksensor sc_sensor;
! 55: struct ksensordev sc_sensordev;
! 56: struct sensor_task *sc_sensortask;
! 57: struct rwlock sc_lock;
! 58: };
! 59:
! 60: int owtemp_match(struct device *, void *, void *);
! 61: void owtemp_attach(struct device *, struct device *, void *);
! 62: int owtemp_detach(struct device *, int);
! 63: int owtemp_activate(struct device *, enum devact);
! 64:
! 65: void owtemp_update(void *);
! 66:
! 67: struct cfattach owtemp_ca = {
! 68: sizeof(struct owtemp_softc),
! 69: owtemp_match,
! 70: owtemp_attach,
! 71: owtemp_detach,
! 72: owtemp_activate
! 73: };
! 74:
! 75: struct cfdriver owtemp_cd = {
! 76: NULL, "owtemp", DV_DULL
! 77: };
! 78:
! 79: static const struct onewire_matchfam owtemp_fams[] = {
! 80: { ONEWIRE_FAMILY_DS1920 }
! 81: };
! 82:
! 83: int
! 84: owtemp_match(struct device *parent, void *match, void *aux)
! 85: {
! 86: return (onewire_matchbyfam(aux, owtemp_fams,
! 87: sizeof(owtemp_fams) /sizeof(owtemp_fams[0])));
! 88: }
! 89:
! 90: void
! 91: owtemp_attach(struct device *parent, struct device *self, void *aux)
! 92: {
! 93: struct owtemp_softc *sc = (struct owtemp_softc *)self;
! 94: struct onewire_attach_args *oa = aux;
! 95:
! 96: sc->sc_onewire = oa->oa_onewire;
! 97: sc->sc_rom = oa->oa_rom;
! 98:
! 99: /* Initialize sensor */
! 100: strlcpy(sc->sc_sensordev.xname, sc->sc_dev.dv_xname,
! 101: sizeof(sc->sc_sensordev.xname));
! 102: sc->sc_sensor.type = SENSOR_TEMP;
! 103:
! 104: sc->sc_sensortask = sensor_task_register(sc, owtemp_update, 5);
! 105: if (sc->sc_sensortask == NULL) {
! 106: printf(": unable to register update task\n");
! 107: return;
! 108: }
! 109: sensor_attach(&sc->sc_sensordev, &sc->sc_sensor);
! 110: sensordev_install(&sc->sc_sensordev);
! 111:
! 112: rw_init(&sc->sc_lock, sc->sc_dev.dv_xname);
! 113: printf("\n");
! 114: }
! 115:
! 116: int
! 117: owtemp_detach(struct device *self, int flags)
! 118: {
! 119: struct owtemp_softc *sc = (struct owtemp_softc *)self;
! 120:
! 121: rw_enter_write(&sc->sc_lock);
! 122: sensordev_deinstall(&sc->sc_sensordev);
! 123: if (sc->sc_sensortask != NULL)
! 124: sensor_task_unregister(sc->sc_sensortask);
! 125: rw_exit_write(&sc->sc_lock);
! 126:
! 127: return (0);
! 128: }
! 129:
! 130: int
! 131: owtemp_activate(struct device *self, enum devact act)
! 132: {
! 133: return (0);
! 134: }
! 135:
! 136: void
! 137: owtemp_update(void *arg)
! 138: {
! 139: struct owtemp_softc *sc = arg;
! 140: u_int8_t data[9];
! 141: u_int16_t temp;
! 142: int count_perc, count_remain, val;
! 143:
! 144: rw_enter_write(&sc->sc_lock);
! 145: onewire_lock(sc->sc_onewire, 0);
! 146: if (onewire_reset(sc->sc_onewire) != 0)
! 147: goto done;
! 148: onewire_matchrom(sc->sc_onewire, sc->sc_rom);
! 149:
! 150: /*
! 151: * Start temperature conversion. The conversion takes up to 750ms.
! 152: * After sending the command, the data line must be held high for
! 153: * at least 750ms to provide power during the conversion process.
! 154: * As such, no other activity may take place on the 1-Wire bus for
! 155: * at least this period.
! 156: */
! 157: onewire_write_byte(sc->sc_onewire, DS1920_CMD_CONVERT);
! 158: tsleep(sc, PRIBIO, "owtemp", hz);
! 159:
! 160: if (onewire_reset(sc->sc_onewire) != 0)
! 161: goto done;
! 162: onewire_matchrom(sc->sc_onewire, sc->sc_rom);
! 163:
! 164: /*
! 165: * The result of the temperature measurement is placed in the
! 166: * first two bytes of the scratchpad.
! 167: */
! 168: onewire_write_byte(sc->sc_onewire, DS1920_CMD_READ_SCRATCHPAD);
! 169: onewire_read_block(sc->sc_onewire, data, 9);
! 170: if (onewire_crc(data, 8) == data[DS1920_SP_CRC]) {
! 171: temp = data[DS1920_SP_TEMP_MSB] << 8 |
! 172: data[DS1920_SP_TEMP_LSB];
! 173: count_perc = data[DS1920_SP_COUNT_PERC];
! 174: count_remain = data[DS1920_SP_COUNT_REMAIN];
! 175:
! 176: if (count_perc != 0) {
! 177: /* High resolution algorithm */
! 178: temp &= ~0x0001;
! 179: val = temp * 500000 - 250000 +
! 180: ((count_perc - count_remain) * 1000000) /
! 181: count_perc;
! 182: } else {
! 183: val = temp * 500000;
! 184: }
! 185: sc->sc_sensor.value = 273150000 + val;
! 186: }
! 187:
! 188: done:
! 189: onewire_unlock(sc->sc_onewire);
! 190: rw_exit_write(&sc->sc_lock);
! 191: }
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