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tmp121.c revision 1.3 
      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 device sc_dev;
     58 
     59 	struct spi_handle *sc_sh;
     60 
     61 	struct sysmon_envsys *sc_sme;
     62 	envsys_data_t sc_sensor;
     63 };
     64 
     65 static int tmp121temp_match(struct device *, struct cfdata *, void *);
     66 static void tmp121temp_attach(struct device *, struct device *, void *);
     67 
     68 static void tmp121temp_refresh(struct sysmon_envsys *, envsys_data_t *);
     69 
     70 CFATTACH_DECL(tmp121temp, sizeof(struct tmp121temp_softc),
     71     tmp121temp_match, tmp121temp_attach, NULL, NULL);
     72 
     73 static int
     74 tmp121temp_match(struct device *parent, struct cfdata *cf, void *aux)
     75 {
     76 	struct spi_attach_args *sa = aux;
     77 
     78 	/* configure for 10MHz */
     79 	if (spi_configure(sa->sa_handle, SPI_MODE_0, 1000000))
     80 		return 0;
     81 
     82 	return 1;
     83 }
     84 
     85 static void
     86 tmp121temp_attach(struct device *parent, struct device *self, void *aux)
     87 {
     88 	struct tmp121temp_softc *sc = device_private(self);
     89 	struct spi_attach_args *sa = aux;
     90 
     91 	aprint_naive(": Temperature Sensor\n");
     92 	aprint_normal(": TI TMP121 Temperature Sensor\n");
     93 
     94 	sc->sc_sh = sa->sa_handle;
     95 
     96 	sc->sc_sme = sysmon_envsys_create();
     97 	sc->sc_sensor.units = ENVSYS_STEMP;
     98 	strlcpy(sc->sc_sensor.desc, device_xname(self),
     99 	    sizeof(sc->sc_sensor.desc));
    100 	if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensor)) {
    101 		sysmon_envsys_destroy(sc->sc_sme);
    102 		return;
    103 	}
    104 
    105 	sc->sc_sme->sme_name = device_xname(self);
    106 	sc->sc_sme->sme_refresh = tmp121temp_refresh;
    107 	sc->sc_sme->sme_cookie = sc;
    108 
    109 	if (sysmon_envsys_register(sc->sc_sme)) {
    110 		aprint_error("%s: unable to register with sysmon\n",
    111 		    device_xname(self));
    112 		sysmon_envsys_destroy(sc->sc_sme);
    113 	}
    114 }
    115 
    116 static void
    117 tmp121temp_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
    118 {
    119 	struct tmp121temp_softc *sc = sme->sme_cookie;
    120 	uint16_t		reg;
    121 	int16_t			sreg;
    122 	int			val;
    123 
    124 	if (spi_recv(sc->sc_sh, 2, (uint8_t *)&reg) != 0) {
    125 		edata->state = ENVSYS_SINVALID;
    126 		return;
    127 	}
    128 
    129 	sreg = (int16_t)be16toh(reg);
    130 
    131 	/*
    132 	 * convert to uK:
    133 	 *
    134 	 * TMP121 bits:
    135 	 * D15		: sign bit
    136 	 * D14-D3	: data (D14 is MSB)
    137 	 * D2-D0	: zero
    138 	 *
    139 	 * The data is represented in units of 0.0625 deg C.
    140 	 */
    141 	sreg >>= 3;
    142 	val = sreg * 62500 + 273150000;
    143 
    144 	edata->value_cur = val;
    145 	edata->state = ENVSYS_SVALID;
    146 }
    147