sys/dev/spi/tmp121.c

   1 /* $NetBSD: tmp121.c,v 1.3 2007/11/16 08:00:16 xtraeme Exp $ */
   2
   3 /*-
   4  * Copyright (c) 2006 Urbana-Champaign Independent Media Center.
   5  * Copyright (c) 2006 Garrett D'Amore.
   6  * All rights reserved.
   7  *
   8  * Portions of this code were written by Garrett D'Amore for the
   9  * Champaign-Urbana Community Wireless Network Project.
  10  *
  11  * Redistribution and use in source and binary forms, with or
  12  * without modification, are permitted provided that the following
  13  * conditions are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above
  17  *    copyright notice, this list of conditions and the following
  18  *    disclaimer in the documentation and/or other materials provided
  19  *    with the distribution.
  20  * 3. All advertising materials mentioning features or use of this
  21  *    software must display the following acknowledgements:
  22  *      This product includes software developed by the Urbana-Champaign
  23  *      Independent Media Center.
  24  *      This product includes software developed by Garrett D'Amore.
  25  * 4. Urbana-Champaign Independent Media Center's name and Garrett
  26  *    D'Amore's name may not be used to endorse or promote products
  27  *    derived from this software without specific prior written permission.
  28  *
  29  * THIS SOFTWARE IS PROVIDED BY THE URBANA-CHAMPAIGN INDEPENDENT
  30  * MEDIA CENTER AND GARRETT D'AMORE ``AS IS'' AND ANY EXPRESS OR
  31  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  32  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  33  * ARE DISCLAIMED.  IN NO EVENT SHALL THE URBANA-CHAMPAIGN INDEPENDENT
  34  * MEDIA CENTER OR GARRETT D'AMORE BE LIABLE FOR ANY DIRECT, INDIRECT,
  35  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  36  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  37  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  38  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  40  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  41  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  42  */
  43
  44 #include <sys/cdefs.h>
  45 __KERNEL_RCSID(0, "$NetBSD: tmp121.c,v 1.3 2007/11/16 08:00:16 xtraeme Exp $");
  46
  47 #include <sys/param.h>
  48 #include <sys/systm.h>
  49 #include <sys/device.h>
  50 #include <sys/kernel.h>
  51
  52 #include <dev/sysmon/sysmonvar.h>
  53
  54 #include <dev/spi/spivar.h>
  55
  56 struct tmp121temp_softc {
  57         struct spi_handle *sc_sh;
  58
  59         struct sysmon_envsys *sc_sme;
  60         envsys_data_t sc_sensor;
  61 };
  62
  63 static int      tmp121temp_match(device_t, cfdata_t, void *);
  64 static void     tmp121temp_attach(device_t, device_t, void *);
  65
  66 static void     tmp121temp_refresh(struct sysmon_envsys *, envsys_data_t *);
  67
  68 CFATTACH_DECL_NEW(tmp121temp, sizeof(struct tmp121temp_softc),
  69     tmp121temp_match, tmp121temp_attach, NULL, NULL);
  70
  71 static int
  72 tmp121temp_match(device_t parent, cfdata_t cf, void *aux)
  73 {
  74         struct spi_attach_args *sa = aux;
  75
  76         /* configure for 10MHz */
  77         if (spi_configure(sa->sa_handle, SPI_MODE_0, 1000000))
  78                 return 0;
  79
  80         return 1;
  81 }
  82
  83 static void
  84 tmp121temp_attach(device_t parent, device_t self, void *aux)
  85 {
  86         struct tmp121temp_softc *sc = device_private(self);
  87         struct spi_attach_args *sa = aux;
  88
  89         aprint_naive(": Temperature Sensor\n");
  90         aprint_normal(": TI TMP121 Temperature Sensor\n");
  91
  92         sc->sc_sh = sa->sa_handle;
  93
  94         sc->sc_sme = sysmon_envsys_create();
  95         sc->sc_sensor.units = ENVSYS_STEMP;
  96         strlcpy(sc->sc_sensor.desc, device_xname(self),
  97             sizeof(sc->sc_sensor.desc));
  98         if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensor)) {
  99                 sysmon_envsys_destroy(sc->sc_sme);
 100                 return;
 101         }
 102
 103         sc->sc_sme->sme_name = device_xname(self);
 104         sc->sc_sme->sme_refresh = tmp121temp_refresh;
 105         sc->sc_sme->sme_cookie = sc;
 106
 107         if (sysmon_envsys_register(sc->sc_sme)) {
 108                 aprint_error_dev(self, "unable to register with sysmon\n");
 109                 sysmon_envsys_destroy(sc->sc_sme);
 110         }
 111 }
 112
 113 static void
 114 tmp121temp_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
 115 {
 116         struct tmp121temp_softc *sc = sme->sme_cookie;
 117         uint16_t                reg;
 118         int16_t                 sreg;
 119         int                     val;
 120
 121         if (spi_recv(sc->sc_sh, 2, (uint8_t *)&reg) != 0) {
 122                 edata->state = ENVSYS_SINVALID;
 123                 return;
 124         }
 125
 126         sreg = (int16_t)be16toh(reg);
 127
 128         /*
 129          * convert to uK:
 130          *
 131          * TMP121 bits:
 132          * D15          : sign bit
 133          * D14-D3       : data (D14 is MSB)
 134          * D2-D0        : zero
 135          *
 136          * The data is represented in units of 0.0625 deg C.
 137          */
 138         sreg >>= 3;
 139         val = sreg * 62500 + 273150000;
 140
 141         edata->value_cur = val;
 142         edata->state = ENVSYS_SVALID;
 143 }