/* $NetBSD: mpl115a.c,v 1.3 2019/12/23 14:50:43 thorpej Exp $ */ /*- * Copyright (c) 2013 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Radoslaw Kujawa. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ /* * Freescale MPL115A2 miniature digital barometer driver. * * This driver could be split into bus-indepented driver and I2C-specific * attachment, as SPI variant of this chip also exist. */ #include __KERNEL_RCSID(0, "$NetBSD: mpl115a.c,v 1.3 2019/12/23 14:50:43 thorpej Exp $"); #include #include #include #include #include #include #include #include #include #include #define MPL115A_DEBUG 1 struct mpl115a_softc { device_t sc_dev; i2c_tag_t sc_tag; i2c_addr_t sc_addr; /* raw coefficients */ int16_t sc_a0; int16_t sc_b1; int16_t sc_b2; int16_t sc_c12; /* envsys(4) stuff */ struct sysmon_envsys *sc_sme; envsys_data_t sc_sensor; kmutex_t sc_lock; }; static int mpl115a_match(device_t, cfdata_t, void *); static void mpl115a_attach(device_t, device_t, void *); static uint8_t mpl115a_reg_read_1(struct mpl115a_softc *sc, uint8_t); static void mpl115a_reg_write_1(struct mpl115a_softc *sc, uint8_t, uint8_t); static void mpl115a_load_coeffs(struct mpl115a_softc *sc); static uint16_t mpl115a_make_coeff(uint8_t msb, uint8_t lsb); static uint32_t mpl115a_pressure(struct mpl115a_softc *sc); static uint32_t mpl115a_calc(struct mpl115a_softc *sc, uint16_t padc, uint16_t tadc) ; static void mpl115a_envsys_register(struct mpl115a_softc *); static void mpl115a_envsys_refresh(struct sysmon_envsys *, envsys_data_t *); CFATTACH_DECL_NEW(mpl115a, sizeof (struct mpl115a_softc), mpl115a_match, mpl115a_attach, NULL, NULL); static int mpl115a_match(device_t parent, cfdata_t cf, void *aux) { struct i2c_attach_args *ia = aux; if (ia->ia_addr == MPL115A_ADDR) return I2C_MATCH_ADDRESS_ONLY; return 0; } static void mpl115a_attach(device_t parent, device_t self, void *aux) { struct mpl115a_softc *sc = device_private(self); struct i2c_attach_args *ia = aux; sc->sc_dev = self; sc->sc_addr = ia->ia_addr; sc->sc_tag = ia->ia_tag; aprint_normal(": Freescale MPL115A2 Pressure Sensor\n"); /* Since coefficients do not change load them once. */ mpl115a_load_coeffs(sc); mpl115a_pressure(sc); mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE); mpl115a_envsys_register(sc); } /* Construct a coefficients from MSB and LSB bytes. */ static uint16_t mpl115a_make_coeff(uint8_t msb, uint8_t lsb) { uint16_t rv; rv = le16toh((msb << 8) | lsb); #ifdef MPL115A_DEBUG aprint_normal("msb %x, lsb %x, ret val %x\n", msb, lsb, rv); #endif /* MPL115A_DEBUG */ return rv; } static void mpl115a_load_coeffs(struct mpl115a_softc *sc) { sc->sc_a0 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_A0_MSB), mpl115a_reg_read_1(sc, MPL115A_A0_LSB)); sc->sc_b1 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_B1_MSB), mpl115a_reg_read_1(sc, MPL115A_B1_LSB)); sc->sc_b2 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_B2_MSB), mpl115a_reg_read_1(sc, MPL115A_B2_LSB)); sc->sc_c12 = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_C12_MSB), mpl115a_reg_read_1(sc, MPL115A_C12_LSB)); } static void mpl115a_reg_write_1(struct mpl115a_softc *sc, uint8_t reg, uint8_t val) { if (iic_acquire_bus(sc->sc_tag, 0) != 0) { aprint_error_dev(sc->sc_dev, "cannot acquire bus for write\n"); return; } if (iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_addr, ®, 1, &val, 1, 0)) { aprint_error_dev(sc->sc_dev, "cannot execute write\n"); } iic_release_bus(sc->sc_tag, 0); } static uint8_t mpl115a_reg_read_1(struct mpl115a_softc *sc, uint8_t reg) { uint8_t rv, wbuf[2]; if (iic_acquire_bus(sc->sc_tag, 0) != 0) { #ifdef MPL115A_DEBUG aprint_error_dev(sc->sc_dev, "cannot acquire bus for read\n"); #endif /* MPL115A_DEBUG */ return 0; } wbuf[0] = reg; if (iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr, wbuf, 1, &rv, 1, 0)) { iic_release_bus(sc->sc_tag, 0); aprint_error_dev(sc->sc_dev, "cannot execute read\n"); return 0; } iic_release_bus(sc->sc_tag, 0); return rv; } /* Get pressure in pascals. */ static uint32_t mpl115a_pressure(struct mpl115a_softc *sc) { uint32_t rv; uint16_t padc, tadc; rv = 0; mpl115a_reg_write_1(sc, MPL115A_CONVERT, 1); delay(20); /* even 3 should be enough */ padc = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_PADC_MSB), mpl115a_reg_read_1(sc, MPL115A_PADC_LSB)); /* XXX, this fails */ padc = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_PADC_MSB), mpl115a_reg_read_1(sc, MPL115A_PADC_LSB)); tadc = mpl115a_make_coeff(mpl115a_reg_read_1(sc, MPL115A_TADC_MSB), mpl115a_reg_read_1(sc, MPL115A_TADC_LSB)); #ifdef MPL115A_DEBUG aprint_normal_dev(sc->sc_dev, "padc %x, tadc %x\n", padc, tadc); #endif /* MPL115A_DEBUG */ rv = mpl115a_calc(sc, padc, tadc); #ifdef MPL115A_DEBUG aprint_normal_dev(sc->sc_dev, "%d Pa\n", rv); #endif /* MPL115A_DEBUG */ return rv; } /* The following calculation routine was suggested by Matt Thomas. */ static uint32_t mpl115a_calc(struct mpl115a_softc *sc, uint16_t padc, uint16_t tadc) { int32_t fp_a0, fp_b1, fp_b2, fp_c12, fp_padc, fp_tadc; int32_t c12x2, a1, a1x2, y1, a2x2, pcomp; uint32_t pre_kpa1, pre_kpa2, pa; /* convert coefficients to common fixed point format */ fp_a0 = sc->sc_a0 << 13; /* 12.3 -> 15.16 */ fp_b1 = sc->sc_b1 << 3; /* 2.13 -> 15.16 */ fp_b2 = sc->sc_b2 << 2; /* 1.14 -> 15.16 */ fp_c12 = sc->sc_c12 >> 2; /* 0.22 */ fp_padc = padc >> 6; fp_tadc = tadc >> 6; c12x2 = (fp_c12 * fp_tadc + 0x3f) >> 6; a1 = fp_b1 + c12x2; a1x2 = a1 * fp_padc; y1 = fp_a0 + a1x2; a2x2 = fp_b2 * fp_tadc; pcomp = y1 + a2x2; /* pre_kpa has 16 fractional digits so it's accurate to 1/65536 kPa */ pre_kpa1 = pcomp * (115 - 50); pre_kpa2 = pre_kpa1 / 1023 + (50 << 16); /* but the real accuracy of the sensor is around +/- 1 kPa... */ pa = ((pre_kpa2 + 32768) >> 16) * 1000; return pa; } static void mpl115a_envsys_register(struct mpl115a_softc *sc) { sc->sc_sme = sysmon_envsys_create(); strlcpy(sc->sc_sensor.desc, "Absolute pressure", sizeof(sc->sc_sensor.desc)); /* sc->sc_sensor.units = ENVSYS_SPRESSURE; */ sc->sc_sensor.units = ENVSYS_INTEGER; sc->sc_sensor.state = ENVSYS_SINVALID; if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensor)) { aprint_error_dev(sc->sc_dev, "error attaching sensor\n"); return; } sc->sc_sme->sme_name = device_xname(sc->sc_dev); sc->sc_sme->sme_cookie = sc; sc->sc_sme->sme_refresh = mpl115a_envsys_refresh; if (sysmon_envsys_register(sc->sc_sme)) { aprint_error_dev(sc->sc_dev, "unable to register in sysmon\n"); sysmon_envsys_destroy(sc->sc_sme); } } static void mpl115a_envsys_refresh(struct sysmon_envsys *sme, envsys_data_t *edata) { struct mpl115a_softc *sc = sme->sme_cookie; mutex_enter(&sc->sc_lock); edata->value_cur = mpl115a_pressure(sc); edata->state = ENVSYS_SVALID; mutex_exit(&sc->sc_lock); }