lm75.c revision 1.18
1 /* $NetBSD: lm75.c,v 1.18 2008/04/04 10:11:01 xtraeme Exp $ */ 2 3 /* 4 * Copyright (c) 2003 Wasabi Systems, Inc. 5 * All rights reserved. 6 * 7 * Written by Jason R. Thorpe for Wasabi Systems, Inc. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed for the NetBSD Project by 20 * Wasabi Systems, Inc. 21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse 22 * or promote products derived from this software without specific prior 23 * written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC 29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 * POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38 #include <sys/cdefs.h> 39 __KERNEL_RCSID(0, "$NetBSD: lm75.c,v 1.18 2008/04/04 10:11:01 xtraeme Exp $"); 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/device.h> 44 #include <sys/kernel.h> 45 46 #include <dev/sysmon/sysmonvar.h> 47 48 #include <dev/i2c/i2cvar.h> 49 #include <dev/i2c/lm75reg.h> 50 51 struct lmtemp_softc { 52 i2c_tag_t sc_tag; 53 int sc_address; 54 55 struct sysmon_envsys *sc_sme; 56 envsys_data_t sc_sensor; 57 58 uint32_t (*sc_lmtemp_decode)(const uint8_t *); 59 }; 60 61 static int lmtemp_match(device_t, cfdata_t, void *); 62 static void lmtemp_attach(device_t, device_t, void *); 63 64 CFATTACH_DECL_NEW(lmtemp, sizeof(struct lmtemp_softc), 65 lmtemp_match, lmtemp_attach, NULL, NULL); 66 67 static void lmtemp_refresh(struct sysmon_envsys *, envsys_data_t *); 68 69 static int lmtemp_config_write(struct lmtemp_softc *, uint8_t); 70 static uint32_t lmtemp_decode_lm75(const uint8_t *); 71 static uint32_t lmtemp_decode_ds75(const uint8_t *); 72 static uint32_t lmtemp_decode_lm77(const uint8_t *); 73 74 enum { 75 lmtemp_lm75 = 0, 76 lmtemp_ds75, 77 lmtemp_lm77, 78 }; 79 static const struct { 80 int lmtemp_type; 81 const char *lmtemp_name; 82 int lmtemp_addrmask; 83 int lmtemp_addr; 84 uint32_t (*lmtemp_decode)(const uint8_t *); 85 } lmtemptbl[] = { 86 { lmtemp_lm75, "LM75", 87 LM75_ADDRMASK, LM75_ADDR, lmtemp_decode_lm75 }, 88 { lmtemp_ds75, "DS75", 89 LM75_ADDRMASK, LM75_ADDR, lmtemp_decode_ds75 }, 90 { lmtemp_lm77, "LM77", 91 LM77_ADDRMASK, LM77_ADDR, lmtemp_decode_lm77 }, 92 93 { -1, NULL, 94 0, 0, NULL } 95 }; 96 97 static int 98 lmtemp_match(device_t parent, cfdata_t cf, void *aux) 99 { 100 struct i2c_attach_args *ia = aux; 101 int i; 102 103 for (i = 0; lmtemptbl[i].lmtemp_type != -1 ; i++) 104 if (lmtemptbl[i].lmtemp_type == cf->cf_flags) 105 break; 106 if (lmtemptbl[i].lmtemp_type == -1) 107 return 0; 108 109 if ((ia->ia_addr & lmtemptbl[i].lmtemp_addrmask) == 110 lmtemptbl[i].lmtemp_addr) 111 return 1; 112 113 return 0; 114 } 115 116 static void 117 lmtemp_attach(device_t parent, device_t self, void *aux) 118 { 119 struct lmtemp_softc *sc = device_private(self); 120 struct i2c_attach_args *ia = aux; 121 int i; 122 123 for (i = 0; lmtemptbl[i].lmtemp_type != -1 ; i++) 124 if (lmtemptbl[i].lmtemp_type == 125 device_cfdata(self)->cf_flags) 126 break; 127 128 sc->sc_tag = ia->ia_tag; 129 sc->sc_address = ia->ia_addr; 130 131 aprint_naive(": Temperature Sensor\n"); 132 aprint_normal(": %s Temperature Sensor\n", lmtemptbl[i].lmtemp_name); 133 134 /* Set the configuration of the LM75 to defaults. */ 135 iic_acquire_bus(sc->sc_tag, I2C_F_POLL); 136 if (lmtemp_config_write(sc, 0) != 0) { 137 aprint_error_dev(self, "unable to write config register\n"); 138 iic_release_bus(sc->sc_tag, I2C_F_POLL); 139 return; 140 } 141 iic_release_bus(sc->sc_tag, I2C_F_POLL); 142 143 sc->sc_sme = sysmon_envsys_create(); 144 /* Initialize sensor data. */ 145 sc->sc_sensor.units = ENVSYS_STEMP; 146 (void)strlcpy(sc->sc_sensor.desc, device_xname(self), 147 sizeof(sc->sc_sensor.desc)); 148 if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensor)) { 149 sysmon_envsys_destroy(sc->sc_sme); 150 return; 151 } 152 153 sc->sc_lmtemp_decode = lmtemptbl[i].lmtemp_decode; 154 155 /* Hook into system monitor. */ 156 sc->sc_sme->sme_name = device_xname(self); 157 sc->sc_sme->sme_cookie = sc; 158 sc->sc_sme->sme_refresh = lmtemp_refresh; 159 160 if (sysmon_envsys_register(sc->sc_sme)) { 161 aprint_error_dev(self, "unable to register with sysmon\n"); 162 sysmon_envsys_destroy(sc->sc_sme); 163 } 164 } 165 166 static int 167 lmtemp_config_write(struct lmtemp_softc *sc, uint8_t val) 168 { 169 uint8_t cmdbuf[2]; 170 171 cmdbuf[0] = LM75_REG_CONFIG; 172 cmdbuf[1] = val; 173 174 return iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, 175 sc->sc_address, cmdbuf, 1, &cmdbuf[1], 1, I2C_F_POLL); 176 } 177 178 static int 179 lmtemp_temp_read(struct lmtemp_softc *sc, uint8_t which, uint32_t *valp) 180 { 181 int error; 182 uint8_t cmdbuf[1]; 183 uint8_t buf[LM75_TEMP_LEN]; 184 185 cmdbuf[0] = which; 186 187 error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, 188 sc->sc_address, cmdbuf, 1, buf, LM75_TEMP_LEN, 0); 189 if (error) 190 return error; 191 192 *valp = sc->sc_lmtemp_decode(buf); 193 return 0; 194 } 195 196 static void 197 lmtemp_refresh_sensor_data(struct lmtemp_softc *sc) 198 { 199 uint32_t val; 200 int error; 201 202 error = lmtemp_temp_read(sc, LM75_REG_TEMP, &val); 203 if (error) { 204 #if 0 205 printf("%s: unable to read temperature, error = %d\n", 206 sc->sc_dev.dv_xname, error); 207 #endif 208 sc->sc_sensor.state = ENVSYS_SINVALID; 209 return; 210 } 211 212 sc->sc_sensor.value_cur = val; 213 sc->sc_sensor.state = ENVSYS_SVALID; 214 } 215 216 static void 217 lmtemp_refresh(struct sysmon_envsys *sme, envsys_data_t *edata) 218 { 219 struct lmtemp_softc *sc = sme->sme_cookie; 220 221 iic_acquire_bus(sc->sc_tag, 0); /* also locks our instance */ 222 lmtemp_refresh_sensor_data(sc); 223 iic_release_bus(sc->sc_tag, 0); /* also unlocks our instance */ 224 } 225 226 static uint32_t 227 lmtemp_decode_lm75(const uint8_t *buf) 228 { 229 int neg, temp; 230 uint32_t val; 231 232 if (buf[0] & 1) { 233 /* Below 0C */ 234 temp = ~buf[1] + 1; 235 neg = 1; 236 } else { 237 temp = buf[1]; 238 neg = 0; 239 } 240 241 /* Temp is given in 1/2 deg. C, we convert to uK. */ 242 val = ((neg ? -temp : temp) / 2) * 1000000 + 273150000; 243 if (temp & 1) { 244 if (neg) 245 val -= 500000; 246 else 247 val += 500000; 248 } 249 250 return val; 251 } 252 253 static uint32_t 254 lmtemp_decode_ds75(const uint8_t *buf) 255 { 256 int temp; 257 258 /* 259 * Sign-extend the MSB byte, and add in the fractions of a 260 * degree contained in the LSB (precision 1/16th DegC). 261 */ 262 temp = (int8_t)buf[0]; 263 temp = (temp << 4) | ((buf[1] >> 4) & 0xf); 264 265 /* 266 * Conversion to uK is simple. 267 */ 268 return (temp * 62500 + 273150000); 269 } 270 271 static uint32_t 272 lmtemp_decode_lm77(const uint8_t *buf) 273 { 274 int temp; 275 uint32_t val; 276 277 /* 278 * Describe each bits of temperature registers on LM77. 279 * D15 - D12: Sign 280 * D11 - D3 : Bit8(MSB) - Bit0 281 */ 282 temp = (int8_t)buf[0]; 283 temp = (temp << 5) | ((buf[1] >> 3) & 0x1f); 284 285 /* Temp is given in 1/2 deg. C, we convert to uK. */ 286 val = temp * 500000 + 273150000; 287 288 return val; 289 } 290 291
Indexes created Thu Oct 02 07:10:07 GMT 2025