/* $NetBSD: mpl115a.c,v 1.2 2018/06/16 21:22:13 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 <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: mpl115a.c,v 1.2 2018/06/16 21:22:13 thorpej Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/kernel.h>
#include <sys/mutex.h>
#include <sys/endian.h>
#include <sys/bus.h>
#include <dev/i2c/i2cvar.h>
#include <dev/sysmon/sysmonvar.h>
#include <dev/i2c/mpl115areg.h>
#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, I2C_F_POLL) != 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, I2C_F_POLL)) {
aprint_error_dev(sc->sc_dev, "cannot execute write\n");
}
iic_release_bus(sc->sc_tag, I2C_F_POLL);
}
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, I2C_F_POLL) != 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, I2C_F_POLL)) {
aprint_error_dev(sc->sc_dev, "cannot execute read\n");
iic_release_bus(sc->sc_tag, I2C_F_POLL);
return 0;
}
iic_release_bus(sc->sc_tag, I2C_F_POLL);
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);
}