1 /* $NetBSD: mpl115a.c,v 1.5 2026/10/16 13:42:24 rkujawa Exp $ */ 2 3 /*- 4 * Copyright (c) 2013 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Radoslaw Kujawa. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Freescale MPL115A2 miniature digital barometer driver. 34 * 35 * This driver could be split into bus-independent driver and I2C-specific 36 * attachment, as SPI variant of this chip also exist. 37 */ 38 39 #include <sys/cdefs.h> 40 __KERNEL_RCSID(0, "$NetBSD: mpl115a.c,v 1.5 2026/10/16 13:42:24 rkujawa Exp $"); 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/device.h> 45 #include <sys/kernel.h> 46 #include <sys/mutex.h> 47 48 #include <sys/bus.h> 49 #include <dev/i2c/i2cvar.h> 50 51 #include <dev/sysmon/sysmonvar.h> 52 53 #include <dev/i2c/mpl115areg.h> 54 55 struct mpl115a_softc { 56 device_t sc_dev; 57 58 i2c_tag_t sc_tag; 59 i2c_addr_t sc_addr; 60 61 /* raw coefficients */ 62 int16_t sc_a0; 63 int16_t sc_b1; 64 int16_t sc_b2; 65 int16_t sc_c12; 66 67 /* envsys(4) stuff */ 68 struct sysmon_envsys *sc_sme; 69 envsys_data_t sc_sensor; 70 kmutex_t sc_lock; 71 }; 72 73 74 static int mpl115a_match(device_t, cfdata_t, void *); 75 static void mpl115a_attach(device_t, device_t, void *); 76 77 static uint8_t mpl115a_reg_read_1(struct mpl115a_softc *sc, uint8_t); 78 static void mpl115a_reg_write_1(struct mpl115a_softc *sc, uint8_t, uint8_t); 79 80 static void mpl115a_load_coeffs(struct mpl115a_softc *sc); 81 static uint16_t mpl115a_make_coeff(uint8_t msb, uint8_t lsb); 82 static uint32_t mpl115a_pressure(struct mpl115a_softc *sc); 83 static uint32_t mpl115a_calc(struct mpl115a_softc *sc, uint16_t padc, uint16_t tadc) ; 84 85 static void mpl115a_envsys_register(struct mpl115a_softc *); 86 static void mpl115a_envsys_refresh(struct sysmon_envsys *, envsys_data_t *); 87 88 CFATTACH_DECL_NEW(mpl115a, sizeof (struct mpl115a_softc), 89 mpl115a_match, mpl115a_attach, NULL, NULL); 90 91 static int 92 mpl115a_match(device_t parent, cfdata_t cf, void *aux) 93 { 94 struct i2c_attach_args *ia = aux; 95 96 if (ia->ia_addr == MPL115A_ADDR) 97 return I2C_MATCH_ADDRESS_ONLY; 98 return 0; 99 } 100 101 static void 102 mpl115a_attach(device_t parent, device_t self, void *aux) 103 { 104 struct mpl115a_softc *sc = device_private(self); 105 struct i2c_attach_args *ia = aux; 106 107 sc->sc_dev = self; 108 sc->sc_addr = ia->ia_addr; 109 sc->sc_tag = ia->ia_tag; 110 111 aprint_normal(": Freescale MPL115A2 Pressure Sensor\n"); 112 113 mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE); 114 115 /* Since coefficients do not change load them once. */ 116 mpl115a_load_coeffs(sc); 117 118 mpl115a_envsys_register(sc); 119 } 120 121 /* Construct a coefficients from MSB and LSB bytes. */ 122 static uint16_t 123 mpl115a_make_coeff(uint8_t msb, uint8_t lsb) 124 { 125 uint16_t rv; 126 127 rv = (msb << 8) | lsb; 128 129 #ifdef MPL115A_DEBUG 130 aprint_normal("msb %x, lsb %x, ret val %x\n", msb, lsb, rv); 131 #endif /* MPL115A_DEBUG */ 132 133 return rv; 134 } 135 136 static void 137 mpl115a_load_coeffs(struct mpl115a_softc *sc) 138 { 139 sc->sc_a0 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_A0_MSB), 140 mpl115a_reg_read_1(sc, MPL115A_A0_LSB)); 141 sc->sc_b1 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_B1_MSB), 142 mpl115a_reg_read_1(sc, MPL115A_B1_LSB)); 143 sc->sc_b2 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_B2_MSB), 144 mpl115a_reg_read_1(sc, MPL115A_B2_LSB)); 145 sc->sc_c12 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_C12_MSB), 146 mpl115a_reg_read_1(sc, MPL115A_C12_LSB)); 147 } 148 149 static void 150 mpl115a_reg_write_1(struct mpl115a_softc *sc, uint8_t reg, uint8_t val) 151 { 152 if (iic_acquire_bus(sc->sc_tag, 0) != 0) { 153 aprint_error_dev(sc->sc_dev, "cannot acquire bus for write\n"); 154 return; 155 } 156 157 if (iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_addr, ®, 1, 158 &val, 1, 0)) { 159 aprint_error_dev(sc->sc_dev, "cannot execute write\n"); 160 } 161 iic_release_bus(sc->sc_tag, 0); 162 } 163 164 static uint8_t 165 mpl115a_reg_read_1(struct mpl115a_softc *sc, uint8_t reg) 166 { 167 uint8_t rv, wbuf[2]; 168 169 if (iic_acquire_bus(sc->sc_tag, 0) != 0) { 170 #ifdef MPL115A_DEBUG 171 aprint_error_dev(sc->sc_dev, "cannot acquire bus for read\n"); 172 #endif /* MPL115A_DEBUG */ 173 return 0; 174 } 175 176 wbuf[0] = reg; 177 178 if (iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr, wbuf, 179 1, &rv, 1, 0)) { 180 iic_release_bus(sc->sc_tag, 0); 181 aprint_error_dev(sc->sc_dev, "cannot execute read\n"); 182 return 0; 183 } 184 iic_release_bus(sc->sc_tag, 0); 185 186 return rv; 187 } 188 189 190 191 /* Get pressure in pascals. */ 192 static uint32_t 193 mpl115a_pressure(struct mpl115a_softc *sc) 194 { 195 uint32_t rv; 196 197 uint16_t padc, tadc; 198 199 rv = 0; 200 201 mpl115a_reg_write_1(sc, MPL115A_CONVERT, 0); 202 delay(MPL115A_CONVERT_US); 203 204 padc = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_PADC_MSB), 205 mpl115a_reg_read_1(sc, MPL115A_PADC_LSB)); 206 207 tadc = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_TADC_MSB), 208 mpl115a_reg_read_1(sc, MPL115A_TADC_LSB)); 209 210 #ifdef MPL115A_DEBUG 211 aprint_normal_dev(sc->sc_dev, "padc %x, tadc %x\n", padc, tadc); 212 #endif /* MPL115A_DEBUG */ 213 214 rv = mpl115a_calc(sc, padc, tadc); 215 216 #ifdef MPL115A_DEBUG 217 aprint_normal_dev(sc->sc_dev, "%d Pa\n", rv); 218 #endif /* MPL115A_DEBUG */ 219 220 return rv; 221 } 222 223 /* The following calculation routine was suggested by Matt Thomas. */ 224 static uint32_t 225 mpl115a_calc(struct mpl115a_softc *sc, uint16_t padc, uint16_t tadc) 226 { 227 int32_t fp_a0, fp_b1, fp_b2, fp_c12, fp_padc, fp_tadc; 228 int64_t pre_kpa; 229 int32_t c12x2, a1, a1x2, y1, a2x2, pcomp; 230 231 /* convert coefficients to common fixed point format */ 232 fp_a0 = sc->sc_a0 << 13; /* 12.3 -> 15.16 */ 233 fp_b1 = sc->sc_b1 << 3; /* 2.13 -> 15.16 */ 234 fp_b2 = sc->sc_b2 << 2; /* 1.14 -> 15.16 */ 235 fp_c12 = sc->sc_c12 >> 2; /* 0.22 */ 236 237 fp_padc = padc >> 6; 238 fp_tadc = tadc >> 6; 239 240 c12x2 = (fp_c12 * fp_tadc + 0x3f) >> 6; 241 a1 = fp_b1 + c12x2; 242 a1x2 = a1 * fp_padc; 243 y1 = fp_a0 + a1x2; 244 a2x2 = fp_b2 * fp_tadc; 245 pcomp = y1 + a2x2; 246 247 /* pre_kpa has 16 fractional digits so it's accurate to 1/65536 kPa */ 248 pre_kpa = (int64_t)pcomp * (115 - 50) / 1023 + (50 << 16); 249 250 return (pre_kpa * 1000 + 32768) >> 16; 251 } 252 253 static void 254 mpl115a_envsys_register(struct mpl115a_softc *sc) 255 { 256 sc->sc_sme = sysmon_envsys_create(); 257 258 strlcpy(sc->sc_sensor.desc, "Absolute pressure", 259 sizeof(sc->sc_sensor.desc)); 260 sc->sc_sensor.units = ENVSYS_PRESSURE; 261 sc->sc_sensor.state = ENVSYS_SINVALID; 262 263 if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensor)) { 264 aprint_error_dev(sc->sc_dev, 265 "error attaching sensor\n"); 266 return; 267 } 268 269 sc->sc_sme->sme_name = device_xname(sc->sc_dev); 270 sc->sc_sme->sme_cookie = sc; 271 sc->sc_sme->sme_refresh = mpl115a_envsys_refresh; 272 273 if (sysmon_envsys_register(sc->sc_sme)) { 274 aprint_error_dev(sc->sc_dev, "unable to register in sysmon\n"); 275 sysmon_envsys_destroy(sc->sc_sme); 276 } 277 } 278 279 static void 280 mpl115a_envsys_refresh(struct sysmon_envsys *sme, envsys_data_t *edata) 281 { 282 struct mpl115a_softc *sc = sme->sme_cookie; 283 284 mutex_enter(&sc->sc_lock); 285 286 edata->value_cur = mpl115a_pressure(sc) * 100; 287 edata->state = ENVSYS_SVALID; 288 289 mutex_exit(&sc->sc_lock); 290 } 291 292
Indexes created Sun Oct 25 00:26:45 UTC 2026