/*      $NetBSD: mpl115a.c,v 1.4 2025/06/27 21:36:24 andvar 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-independent driver and I2C-specific
* attachment, as SPI variant of this chip also exist.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: mpl115a.c,v 1.4 2025/06/27 21:36:24 andvar 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, 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, &reg, 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);
}

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