1 /* $NetBSD: mpl115a.c,v 1.4 2025/06/27 21:36:24 andvar 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 1.4 2025/06/27 21:36:24 andvar 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 #include <sys/endian.h> 48 49 #include <sys/bus.h> 50 #include <dev/i2c/i2cvar.h> 51 52 #include <dev/sysmon/sysmonvar.h> 53 54 #include <dev/i2c/mpl115areg.h> 55 56 #define MPL115A_DEBUG 1 57 58 struct mpl115a_softc { 59 device_t sc_dev; 60 61 i2c_tag_t sc_tag; 62 i2c_addr_t sc_addr; 63 64 /* raw coefficients */ 65 int16_t sc_a0; 66 int16_t sc_b1; 67 int16_t sc_b2; 68 int16_t sc_c12; 69 70 /* envsys(4) stuff */ 71 struct sysmon_envsys *sc_sme; 72 envsys_data_t sc_sensor; 73 kmutex_t sc_lock; 74 }; 75 76 77 static int mpl115a_match(device_t, cfdata_t, void *); 78 static void mpl115a_attach(device_t, device_t, void *); 79 80 static uint8_t mpl115a_reg_read_1(struct mpl115a_softc *sc, uint8_t); 81 static void mpl115a_reg_write_1(struct mpl115a_softc *sc, uint8_t, uint8_t); 82 83 static void mpl115a_load_coeffs(struct mpl115a_softc *sc); 84 static uint16_t mpl115a_make_coeff(uint8_t msb, uint8_t lsb); 85 static uint32_t mpl115a_pressure(struct mpl115a_softc *sc); 86 static uint32_t mpl115a_calc(struct mpl115a_softc *sc, uint16_t padc, uint16_t tadc) ; 87 88 static void mpl115a_envsys_register(struct mpl115a_softc *); 89 static void mpl115a_envsys_refresh(struct sysmon_envsys *, envsys_data_t *); 90 91 CFATTACH_DECL_NEW(mpl115a, sizeof (struct mpl115a_softc), 92 mpl115a_match, mpl115a_attach, NULL, NULL); 93 94 static int 95 mpl115a_match(device_t parent, cfdata_t cf, void *aux) 96 { 97 struct i2c_attach_args *ia = aux; 98 99 if (ia->ia_addr == MPL115A_ADDR) 100 return I2C_MATCH_ADDRESS_ONLY; 101 return 0; 102 } 103 104 static void 105 mpl115a_attach(device_t parent, device_t self, void *aux) 106 { 107 struct mpl115a_softc *sc = device_private(self); 108 struct i2c_attach_args *ia = aux; 109 110 sc->sc_dev = self; 111 sc->sc_addr = ia->ia_addr; 112 sc->sc_tag = ia->ia_tag; 113 114 aprint_normal(": Freescale MPL115A2 Pressure Sensor\n"); 115 116 /* Since coefficients do not change load them once. */ 117 mpl115a_load_coeffs(sc); 118 119 mpl115a_pressure(sc); 120 121 mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE); 122 123 mpl115a_envsys_register(sc); 124 } 125 126 /* Construct a coefficients from MSB and LSB bytes. */ 127 static uint16_t 128 mpl115a_make_coeff(uint8_t msb, uint8_t lsb) 129 { 130 uint16_t rv; 131 132 rv = le16toh((msb << 8) | lsb); 133 134 #ifdef MPL115A_DEBUG 135 aprint_normal("msb %x, lsb %x, ret val %x\n", msb, lsb, rv); 136 #endif /* MPL115A_DEBUG */ 137 138 return rv; 139 } 140 141 static void 142 mpl115a_load_coeffs(struct mpl115a_softc *sc) 143 { 144 sc->sc_a0 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_A0_MSB), 145 mpl115a_reg_read_1(sc, MPL115A_A0_LSB)); 146 sc->sc_b1 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_B1_MSB), 147 mpl115a_reg_read_1(sc, MPL115A_B1_LSB)); 148 sc->sc_b2 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_B2_MSB), 149 mpl115a_reg_read_1(sc, MPL115A_B2_LSB)); 150 sc->sc_c12 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_C12_MSB), 151 mpl115a_reg_read_1(sc, MPL115A_C12_LSB)); 152 } 153 154 static void 155 mpl115a_reg_write_1(struct mpl115a_softc *sc, uint8_t reg, uint8_t val) 156 { 157 if (iic_acquire_bus(sc->sc_tag, 0) != 0) { 158 aprint_error_dev(sc->sc_dev, "cannot acquire bus for write\n"); 159 return; 160 } 161 162 if (iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_addr, ®, 1, 163 &val, 1, 0)) { 164 aprint_error_dev(sc->sc_dev, "cannot execute write\n"); 165 } 166 iic_release_bus(sc->sc_tag, 0); 167 } 168 169 static uint8_t 170 mpl115a_reg_read_1(struct mpl115a_softc *sc, uint8_t reg) 171 { 172 uint8_t rv, wbuf[2]; 173 174 if (iic_acquire_bus(sc->sc_tag, 0) != 0) { 175 #ifdef MPL115A_DEBUG 176 aprint_error_dev(sc->sc_dev, "cannot acquire bus for read\n"); 177 #endif /* MPL115A_DEBUG */ 178 return 0; 179 } 180 181 wbuf[0] = reg; 182 183 if (iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr, wbuf, 184 1, &rv, 1, 0)) { 185 iic_release_bus(sc->sc_tag, 0); 186 aprint_error_dev(sc->sc_dev, "cannot execute read\n"); 187 return 0; 188 } 189 iic_release_bus(sc->sc_tag, 0); 190 191 return rv; 192 } 193 194 195 196 /* Get pressure in pascals. */ 197 static uint32_t 198 mpl115a_pressure(struct mpl115a_softc *sc) 199 { 200 uint32_t rv; 201 202 uint16_t padc, tadc; 203 204 rv = 0; 205 206 mpl115a_reg_write_1(sc, MPL115A_CONVERT, 1); 207 delay(20); /* even 3 should be enough */ 208 209 padc = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_PADC_MSB), 210 mpl115a_reg_read_1(sc, MPL115A_PADC_LSB)); /* XXX, this fails */ 211 padc = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_PADC_MSB), 212 mpl115a_reg_read_1(sc, MPL115A_PADC_LSB)); 213 214 tadc = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_TADC_MSB), 215 mpl115a_reg_read_1(sc, MPL115A_TADC_LSB)); 216 217 #ifdef MPL115A_DEBUG 218 aprint_normal_dev(sc->sc_dev, "padc %x, tadc %x\n", padc, tadc); 219 #endif /* MPL115A_DEBUG */ 220 221 rv = mpl115a_calc(sc, padc, tadc); 222 223 #ifdef MPL115A_DEBUG 224 aprint_normal_dev(sc->sc_dev, "%d Pa\n", rv); 225 #endif /* MPL115A_DEBUG */ 226 227 return rv; 228 } 229 230 /* The following calculation routine was suggested by Matt Thomas. */ 231 static uint32_t 232 mpl115a_calc(struct mpl115a_softc *sc, uint16_t padc, uint16_t tadc) 233 { 234 int32_t fp_a0, fp_b1, fp_b2, fp_c12, fp_padc, fp_tadc; 235 int32_t c12x2, a1, a1x2, y1, a2x2, pcomp; 236 uint32_t pre_kpa1, pre_kpa2, pa; 237 238 /* convert coefficients to common fixed point format */ 239 fp_a0 = sc->sc_a0 << 13; /* 12.3 -> 15.16 */ 240 fp_b1 = sc->sc_b1 << 3; /* 2.13 -> 15.16 */ 241 fp_b2 = sc->sc_b2 << 2; /* 1.14 -> 15.16 */ 242 fp_c12 = sc->sc_c12 >> 2; /* 0.22 */ 243 244 fp_padc = padc >> 6; 245 fp_tadc = tadc >> 6; 246 247 c12x2 = (fp_c12 * fp_tadc + 0x3f) >> 6; 248 a1 = fp_b1 + c12x2; 249 a1x2 = a1 * fp_padc; 250 y1 = fp_a0 + a1x2; 251 a2x2 = fp_b2 * fp_tadc; 252 pcomp = y1 + a2x2; 253 254 /* pre_kpa has 16 fractional digits so it's accurate to 1/65536 kPa */ 255 pre_kpa1 = pcomp * (115 - 50); 256 pre_kpa2 = pre_kpa1 / 1023 + (50 << 16); 257 258 /* but the real accuracy of the sensor is around +/- 1 kPa... */ 259 pa = ((pre_kpa2 + 32768) >> 16) * 1000; 260 261 return pa; 262 } 263 264 static void 265 mpl115a_envsys_register(struct mpl115a_softc *sc) 266 { 267 sc->sc_sme = sysmon_envsys_create(); 268 269 strlcpy(sc->sc_sensor.desc, "Absolute pressure", 270 sizeof(sc->sc_sensor.desc)); 271 /* sc->sc_sensor.units = ENVSYS_SPRESSURE; */ 272 sc->sc_sensor.units = ENVSYS_INTEGER; 273 sc->sc_sensor.state = ENVSYS_SINVALID; 274 275 if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensor)) { 276 aprint_error_dev(sc->sc_dev, 277 "error attaching sensor\n"); 278 return; 279 } 280 281 sc->sc_sme->sme_name = device_xname(sc->sc_dev); 282 sc->sc_sme->sme_cookie = sc; 283 sc->sc_sme->sme_refresh = mpl115a_envsys_refresh; 284 285 if (sysmon_envsys_register(sc->sc_sme)) { 286 aprint_error_dev(sc->sc_dev, "unable to register in sysmon\n"); 287 sysmon_envsys_destroy(sc->sc_sme); 288 } 289 } 290 291 static void 292 mpl115a_envsys_refresh(struct sysmon_envsys *sme, envsys_data_t *edata) 293 { 294 struct mpl115a_softc *sc = sme->sme_cookie; 295 296 mutex_enter(&sc->sc_lock); 297 298 edata->value_cur = mpl115a_pressure(sc); 299 edata->state = ENVSYS_SVALID; 300 301 mutex_exit(&sc->sc_lock); 302 } 303 304
Indexes created Sun Sep 21 20:09:37 GMT 2025