* Copyright (c) 2018 Jason R. Thorpe

/* $NetBSD: tsllux.c,v 1.4 2022/02/12 03:24:35 riastradh Exp $ */

/*-
* Copyright (c) 2018 Jason R. Thorpe
* All rights reserved.
*
* 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.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: tsllux.c,v 1.4 2022/02/12 03:24:35 riastradh Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/conf.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/sysctl.h>

#include <dev/i2c/i2cvar.h>
#include <dev/i2c/tsl256xreg.h>

#include <dev/sysmon/sysmonvar.h>

struct tsllux_softc {
device_t sc_dev;
i2c_tag_t sc_i2c;
i2c_addr_t sc_addr;

uint32_t sc_poweron;

/*
* Locking order is:
* tsllux mutex -> i2c bus
*/
kmutex_t sc_lock;

uint8_t sc_itime;
uint8_t sc_gain;
bool sc_cs_package;
bool sc_auto_gain;

struct sysmon_envsys *sc_sme;
envsys_data_t sc_sensor;

struct sysctllog *sc_sysctllog;
};

#define TSLLUX_F_CS_PACKAGE 0x01

static int tsllux_match(device_t, cfdata_t, void *);
static void tsllux_attach(device_t, device_t, void *);

CFATTACH_DECL_NEW(tsllux, sizeof(struct tsllux_softc),
tsllux_match, tsllux_attach, NULL, NULL);

static const struct device_compatible_entry tsllux_compat_data[] = {
{ .compat = "amstaos,tsl2560" },
{ .compat = "amstaos,tsl2561" },
DEVICE_COMPAT_EOL
};

static int tsllux_read1(struct tsllux_softc *, uint8_t, uint8_t *);
static int tsllux_read2(struct tsllux_softc *, uint8_t, uint16_t *);
static int tsllux_write1(struct tsllux_softc *, uint8_t, uint8_t);
#if 0
static int tsllux_write2(struct tsllux_softc *, uint8_t, uint16_t);
#endif

static void tsllux_sysctl_attach(struct tsllux_softc *);

static int tsllux_poweron(struct tsllux_softc *);
static int tsllux_poweroff(struct tsllux_softc *);

static int tsllux_set_integration_time(struct tsllux_softc *, uint8_t);
static int tsllux_set_gain(struct tsllux_softc *, uint8_t);
static int tsllux_set_autogain(struct tsllux_softc *, bool);

static int tsllux_get_lux(struct tsllux_softc *, uint32_t *,
uint16_t *, uint16_t *);

static void tsllux_sensors_refresh(struct sysmon_envsys *, envsys_data_t *);

static int
tsllux_match(device_t parent, cfdata_t match, void *aux)
{
struct i2c_attach_args *ia = aux;
uint8_t id_reg;
int error, match_result;

if (iic_use_direct_match(ia, match, tsllux_compat_data, &match_result))
return (match_result);

switch (ia->ia_addr) {
case TSL256x_SLAVEADDR_GND:
case TSL256x_SLAVEADDR_FLOAT:
case TSL256x_SLAVEADDR_VDD:
break;

default:
return (0);
}

if (iic_acquire_bus(ia->ia_tag, 0) != 0)
return (0);
error = iic_smbus_read_byte(ia->ia_tag, ia->ia_addr,
TSL256x_REG_ID | COMMAND6x_CMD, &id_reg, 0);
iic_release_bus(ia->ia_tag, 0);

if (error)
return (0);

/* XXX This loses if we have a 2560 rev. 0. */
if (id_reg == 0)
return (I2C_MATCH_ADDRESS_ONLY);

return (I2C_MATCH_ADDRESS_AND_PROBE);
}

static void
tsllux_attach(device_t parent, device_t self, void *aux)
{
struct tsllux_softc *sc = device_private(self);
struct i2c_attach_args *ia = aux;
bool have_i2c;

/* XXX IPL_NONE changes when we support threshold interrupts. */
mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE);

sc->sc_dev = self;
sc->sc_i2c = ia->ia_tag;
sc->sc_addr = ia->ia_addr;

if (device_cfdata(self)->cf_flags & TSLLUX_F_CS_PACKAGE)
sc->sc_cs_package = true;

if (iic_acquire_bus(ia->ia_tag, 0) != 0) {
return;
}

have_i2c = true;

/* Power on the device and clear any pending interrupts. */
if (tsllux_write1(sc, TSL256x_REG_CONTROL | COMMAND6x_CLEAR,
CONTROL6x_POWER_ON)) {
aprint_error_dev(self, ": unable to power on device\n");
goto out;
}
sc->sc_poweron = 1;

/* Make sure interrupts are disabled. */
if (tsllux_write1(sc, TSL256x_REG_INTERRUPT | COMMAND6x_CLEAR, 0)) {
aprint_error_dev(self, ": unable to disable interrupts\n");
goto out;
}

aprint_naive("\n");
aprint_normal(": TSL256x Light-to-Digital converter%s\n",
sc->sc_cs_package ? " (CS package)" : "");

/* Inititalize timing to reasonable defaults. */
sc->sc_auto_gain = true;
sc->sc_gain = TIMING6x_GAIN_16X;
if (tsllux_set_integration_time(sc, TIMING6x_INTEG_101ms)) {
aprint_error_dev(self, ": unable to set integration time\n");
goto out;
}

tsllux_poweroff(sc);

iic_release_bus(ia->ia_tag, 0);
have_i2c = false;

tsllux_sysctl_attach(sc);

sc->sc_sme = sysmon_envsys_create();
sc->sc_sme->sme_name = device_xname(self);
sc->sc_sme->sme_cookie = sc;
sc->sc_sme->sme_refresh = tsllux_sensors_refresh;

sc->sc_sensor.units = ENVSYS_LUX;
sc->sc_sensor.state = ENVSYS_SINVALID;
snprintf(sc->sc_sensor.desc, sizeof(sc->sc_sensor.desc),
"ambient light");
sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensor);

sysmon_envsys_register(sc->sc_sme);

out:
if (have_i2c) {
if (sc->sc_poweron)
tsllux_poweroff(sc);
iic_release_bus(ia->ia_tag, 0);
}
}

static int
tsllux_sysctl_cs_package(SYSCTLFN_ARGS)
{
struct tsllux_softc *sc;
struct sysctlnode node;
int error;
u_int val;

node = *rnode;
sc = node.sysctl_data;

mutex_enter(&sc->sc_lock);
val = sc->sc_cs_package ? 1 : 0;
node.sysctl_data = &val;
error = sysctl_lookup(SYSCTLFN_CALL(&node));
if (error || newp == NULL) {
mutex_exit(&sc->sc_lock);
return (error);
}

/* CS package indicator is used only in software; no need for I2C. */

sc->sc_cs_package = val ? true : false;
mutex_exit(&sc->sc_lock);

return (error);
}

static int
tsllux_sysctl_autogain(SYSCTLFN_ARGS)
{
struct tsllux_softc *sc;
struct sysctlnode node;
int error;
u_int val;

node = *rnode;
sc = node.sysctl_data;

mutex_enter(&sc->sc_lock);
val = sc->sc_auto_gain ? 1 : 0;
node.sysctl_data = &val;
error = sysctl_lookup(SYSCTLFN_CALL(&node));
if (error || newp == NULL) {
mutex_exit(&sc->sc_lock);
return (error);
}

/* Auto-gain is a software feature; no need for I2C. */

error = tsllux_set_autogain(sc, val ? true : false);
mutex_exit(&sc->sc_lock);

return (error);
}

static int
tsllux_sysctl_gain(SYSCTLFN_ARGS)
{
struct tsllux_softc *sc;
struct sysctlnode node;
int error;
u_int val;
uint8_t new_gain;

node = *rnode;
sc = node.sysctl_data;

mutex_enter(&sc->sc_lock);

switch (sc->sc_gain) {
case TIMING6x_GAIN_1X:
val = 1;
break;

case TIMING6x_GAIN_16X:
val = 16;
break;

default:
val = 1;
break;
}
node.sysctl_data = &val;
error = sysctl_lookup(SYSCTLFN_CALL(&node));
if (error || newp == NULL) {
mutex_exit(&sc->sc_lock);
return (error);
}

switch (val) {
case 1:
new_gain = TIMING6x_GAIN_1X;
break;

case 16:
new_gain = TIMING6x_GAIN_16X;
break;

default:
mutex_exit(&sc->sc_lock);
return (EINVAL);
}

if ((error = iic_acquire_bus(sc->sc_i2c, 0)) != 0) {
mutex_exit(&sc->sc_lock);
return (error);
}

error = tsllux_set_gain(sc, new_gain);
iic_release_bus(sc->sc_i2c, 0);
mutex_exit(&sc->sc_lock);

return (error);
}

static int
tsllux_sysctl_itime(SYSCTLFN_ARGS)
{
struct tsllux_softc *sc;
struct sysctlnode node;
int error;
u_int val;
uint8_t new_itime;

node = *rnode;
sc = node.sysctl_data;

mutex_enter(&sc->sc_lock);

switch (sc->sc_itime) {
case TIMING6x_INTEG_13_7ms:
val = 13;
break;

case TIMING6x_INTEG_101ms:
val = 101;
break;

case TIMING6x_INTEG_402ms:
default:
val = 402;
break;
}
node.sysctl_data = &val;
error = sysctl_lookup(SYSCTLFN_CALL(&node));
if (error || newp == NULL) {
mutex_exit(&sc->sc_lock);
return (error);
}

switch (val) {
case 13:
case 14:
new_itime = TIMING6x_INTEG_13_7ms;
break;

case 101:
new_itime = TIMING6x_INTEG_101ms;
break;

case 402:
new_itime = TIMING6x_INTEG_402ms;
break;

default:
mutex_exit(&sc->sc_lock);
return (EINVAL);
}

if ((error = iic_acquire_bus(sc->sc_i2c, 0)) != 0) {
mutex_exit(&sc->sc_lock);
return (error);
}

error = tsllux_set_integration_time(sc, new_itime);
iic_release_bus(sc->sc_i2c, 0);
mutex_exit(&sc->sc_lock);

return (error);
}

static void
tsllux_sysctl_attach(struct tsllux_softc *sc)
{
struct sysctllog **log = &sc->sc_sysctllog;
const struct sysctlnode *rnode, *cnode;
int error;

error = sysctl_createv(log, 0, NULL, &rnode, CTLFLAG_PERMANENT,
CTLTYPE_NODE, device_xname(sc->sc_dev),
SYSCTL_DESCR("tsl256x control"),
NULL, 0, NULL, 0, CTL_HW, CTL_CREATE, CTL_EOL);
if (error)
return;

error = sysctl_createv(log, 0, &rnode, &cnode,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "cs_package",
SYSCTL_DESCR("sensor in Chipscale (CS) package"),
tsllux_sysctl_cs_package, 0,
(void *)sc, 0, CTL_CREATE, CTL_EOL);
if (error)
return;

error = sysctl_createv(log, 0, &rnode, &cnode,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "auto_gain",
SYSCTL_DESCR("auto-gain algorithm enabled"),
tsllux_sysctl_autogain, 0,
(void *)sc, 0, CTL_CREATE, CTL_EOL);
if (error)
return;

error = sysctl_createv(log, 0, &rnode, &cnode,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "gain",
SYSCTL_DESCR("sensor gain"), tsllux_sysctl_gain, 0,
(void *)sc, 0, CTL_CREATE, CTL_EOL);
if (error)
return;

error = sysctl_createv(log, 0, &rnode, &cnode,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT,
"integration_time",
SYSCTL_DESCR("ADC integration time"), tsllux_sysctl_itime, 0,
(void *)sc, 0, CTL_CREATE, CTL_EOL);
if (error)
return;
}

static void
tsllux_sensors_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
{
struct tsllux_softc *sc = sme->sme_cookie;
uint32_t lux;
int error;

if (edata != &sc->sc_sensor) {
edata->state = ENVSYS_SINVALID;
return;
}

mutex_enter(&sc->sc_lock);

if ((error = iic_acquire_bus(sc->sc_i2c, 0)) == 0) {
error = tsllux_get_lux(sc, &lux, NULL, NULL);
iic_release_bus(sc->sc_i2c, 0);
}

if (error) {
edata->state = ENVSYS_SINVALID;
} else {
edata->value_cur = lux;
edata->state = ENVSYS_SVALID;
}

mutex_exit(&sc->sc_lock);
}

/*
* Allow pending interrupts to be cleared as part of another operation.
*/
#define REGMASK6x (COMMAND6x_REGMASK | COMMAND6x_CLEAR)

static int
tsllux_read1(struct tsllux_softc *sc, uint8_t reg, uint8_t *valp)
{
reg = (reg & REGMASK6x) | COMMAND6x_CMD;
return (iic_smbus_read_byte(sc->sc_i2c, sc->sc_addr, reg, valp, 0));
}

static int
tsllux_read2(struct tsllux_softc *sc, uint8_t reg, uint16_t *valp)
{
reg = (reg & REGMASK6x) | COMMAND6x_CMD | COMMAND6x_WORD;
return (iic_smbus_read_word(sc->sc_i2c, sc->sc_addr, reg, valp, 0));
}

static int
tsllux_write1(struct tsllux_softc *sc, uint8_t reg, uint8_t val)
{
reg = (reg & REGMASK6x) | COMMAND6x_CMD;
return (iic_smbus_write_byte(sc->sc_i2c, sc->sc_addr, reg, val, 0));
}

#if 0
static int
tsllux_write2(struct tsllux_softc *sc, uint8_t reg, uint16_t val)
{
reg = (reg & REGMASK6x) | COMMAND6x_CMD | COMMAND6x_WORD;
return (iic_smbus_write_word(sc->sc_i2c, sc->sc_addr, reg, val, 0));
}
#endif

#undef REGMASK

static int
tsllux_poweron(struct tsllux_softc *sc)
{
int error;

if (sc->sc_poweron++ == 0) {
uint8_t val;

error = tsllux_write1(sc, TSL256x_REG_CONTROL,
CONTROL6x_POWER_ON);
if (error)
return (error);

error = tsllux_read1(sc, TSL256x_REG_CONTROL, &val);
if (error)
return (error);

if (val != CONTROL6x_POWER_ON) {
aprint_error_dev(sc->sc_dev,
"failed to power on sensor\n");
return (EIO);
}
}
return (0);
}

static int
tsllux_poweroff(struct tsllux_softc *sc)
{
if (sc->sc_poweron && --sc->sc_poweron == 0)
return (tsllux_write1(sc, TSL256x_REG_CONTROL,
CONTROL6x_POWER_OFF));
return (0);
}

static int
tsllux_set_integration_time(struct tsllux_softc *sc, uint8_t time)
{
int error;

switch (time) {
case TIMING6x_INTEG_13_7ms:
case TIMING6x_INTEG_101ms:
case TIMING6x_INTEG_402ms:
break;

default:
return (EINVAL);
}

if ((error = tsllux_poweron(sc)) != 0)
return (error);

if ((error = tsllux_write1(sc, TSL256x_REG_TIMING,
time | sc->sc_gain)) != 0)
goto out;

sc->sc_itime = time;

out:
(void) tsllux_poweroff(sc);
return (error);
}

static int
tsllux_set_gain0(struct tsllux_softc *sc, uint8_t gain)
{
int error;

if ((error = tsllux_write1(sc, TSL256x_REG_TIMING,
sc->sc_itime | gain)) != 0)
return (error);

sc->sc_gain = gain;
return (0);
}

static int
tsllux_set_gain(struct tsllux_softc *sc, uint8_t gain)
{
int error;

switch (gain) {
case TIMING6x_GAIN_1X:
case TIMING6x_GAIN_16X:
break;

default:
return (EINVAL);
}

if ((error = tsllux_poweron(sc)) != 0)
return (error);

if ((error = tsllux_set_gain0(sc, gain)) != 0)
goto out;

sc->sc_auto_gain = false;

out:
(void) tsllux_poweroff(sc);
return (error);
}

static int
tsllux_set_autogain(struct tsllux_softc *sc, bool use_autogain)
{

sc->sc_auto_gain = use_autogain;
return (0);
}

static int
tsllux_wait_for_adcs(struct tsllux_softc *sc)
{
int ms;

switch (sc->sc_itime) {
case TIMING6x_INTEG_13_7ms:
/* Wait 15ms for 13.7ms integration */
ms = 15;
break;

case TIMING6x_INTEG_101ms:
/* Wait 120ms for 101ms integration */
ms = 120;
break;

case TIMING6x_INTEG_402ms:
default:
/* Wait 450ms for 402ms integration */
ms = 450;
break;
}

if (ms < hztoms(1)) {
/* Just busy-wait if we want to wait for less than 1 tick. */
delay(ms * 1000);
} else {
/* Round up one tick for the case where we sleep. */
(void) kpause("tslluxwait", false, mstohz(ms) + 1, NULL);
}

return (0);
}

static int
tsllux_read_adcs(struct tsllux_softc *sc, uint16_t *adc0valp,
uint16_t *adc1valp)
{
int error;

if ((error = tsllux_read2(sc, TSL256x_REG_DATA0LOW, adc0valp)) == 0)
error = tsllux_read2(sc, TSL256x_REG_DATA1LOW, adc1valp);

return (error);
}

/*
* The following code is partially derived from Adafruit's TSL2561
* driver for Arduino (which was in turn derived from the data sheet),
* which carries this notice:
*
* @file Adafruit_TSL2561_U.cpp
*
* @mainpage Adafruit TSL2561 Light/Lux sensor driver
*
* @section intro_sec Introduction
*
* This is the documentation for Adafruit's TSL2561 driver for the
* Arduino platform. It is designed specifically to work with the
* Adafruit TSL2561 breakout: http://www.adafruit.com/products/439
*
* These sensors use I2C to communicate, 2 pins (SCL+SDA) are required
* to interface with the breakout.
*
* Adafruit invests time and resources providing this open source code,
* please support Adafruit and open-source hardware by purchasing
* products from Adafruit!
*
* @section dependencies Dependencies
*
* This library depends on <a href="https://github.com/adafruit/Adafruit_Sensor">
* Adafruit_Sensor</a> being present on your system. Please make sure you have
* installed the latest version before using this library.
*
* @section author Author
*
* Written by Kevin "KTOWN" Townsend for Adafruit Industries.
*
* @section license License
*
* BSD license, all text here must be included in any redistribution.
*
* @section HISTORY
*
* v2.0 - Rewrote driver for Adafruit_Sensor and Auto-Gain support, and
* added lux clipping check (returns 0 lux on sensor saturation)
* v1.0 - First release (previously TSL2561)
*/

static int
tsllux_read_sensors(struct tsllux_softc *sc, uint16_t *adc0p, uint16_t *adc1p)
{
int error;

if ((error = tsllux_poweron(sc)) != 0)
return (error);

if ((error = tsllux_wait_for_adcs(sc)) != 0)
goto out;

error = tsllux_read_adcs(sc, adc0p, adc1p);

out:
(void) tsllux_poweroff(sc);
return (error);
}

/*
* Auto-gain thresholds:
*/
#define TSL2561_AGC_THI_13MS (4850) /* Max value at Ti 13ms = 5047 */
#define TSL2561_AGC_TLO_13MS (100) /* Min value at Ti 13ms = 100 */
#define TSL2561_AGC_THI_101MS (36000) /* Max value at Ti 101ms = 37177 */
#define TSL2561_AGC_TLO_101MS (200) /* Min value at Ti 101ms = 200 */
#define TSL2561_AGC_THI_402MS (63000) /* Max value at Ti 402ms = 65535 */
#define TSL2561_AGC_TLO_402MS (500) /* Min value at Ti 402ms = 500 */

static int
tsllux_get_sensor_data(struct tsllux_softc *sc, uint16_t *broadband,
uint16_t *ir)
{
int error = 0;
uint16_t adc0, adc1;
bool did_adjust_gain, valid;
uint16_t hi, lo;

if (sc->sc_auto_gain == false) {
error = tsllux_read_sensors(sc, &adc0, &adc1);
goto out;
}

/* Set the hi / lo threshold based on current integration time. */
switch (sc->sc_itime) {
case TIMING6x_INTEG_13_7ms:
hi = TSL2561_AGC_THI_13MS;
lo = TSL2561_AGC_TLO_13MS;
break;

case TIMING6x_INTEG_101ms:
hi = TSL2561_AGC_THI_101MS;
lo = TSL2561_AGC_TLO_101MS;
break;

case TIMING6x_INTEG_402ms:
default:
hi = TSL2561_AGC_THI_402MS;
lo = TSL2561_AGC_TLO_402MS;
}

/* Read data and adjust the gain until we have a valid range. */
for (valid = false, did_adjust_gain = false; valid == false; ) {
if ((error = tsllux_read_sensors(sc, &adc0, &adc1)) != 0)
goto out;

if (did_adjust_gain == false) {
if (adc0 < lo && sc->sc_gain == TIMING6x_GAIN_1X) {
/* Increase the gain and try again. */
if ((error =
tsllux_set_gain0(sc,
TIMING6x_GAIN_16X)) != 0)
goto out;
did_adjust_gain = true;
} else if (adc0 > hi &&
sc->sc_gain == TIMING6x_GAIN_16X) {
/* Decrease the gain and try again. */
if ((error =
tsllux_set_gain0(sc,
TIMING6x_GAIN_1X)) != 0)
goto out;
did_adjust_gain = true;
} else {
/*
* Reading is either valid or we're already
* at the chip's limits.
*/
valid = true;
}
} else {
/*
* If we've already adjust the gain once, just
* return the new results. This avoids endless
* loops where a value is at one extre pre-gain
* and at the other extreme post-gain.
*/
valid = true;
}
}

out:
if (error == 0) {
if (broadband != NULL)
*broadband = adc0;
if (ir != NULL)
*ir = adc1;
}
return (error);
}

/*
* Clipping thresholds:
*/
#define TSL2561_CLIPPING_13MS (4900)
#define TSL2561_CLIPPING_101MS (37000)
#define TSL2561_CLIPPING_402MS (65000)

/*
* Scaling factors:
*/
#define TSL2561_LUX_LUXSCALE (14) /* Scale by 2^14 */
#define TSL2561_LUX_RATIOSCALE (9) /* Scale ratio by 2^9 */
#define TSL2561_LUX_CHSCALE (10) /* Scale channel values by 2^10 */
#define TSL2561_LUX_CHSCALE_TINT0 (0x7517) /* 322/11 * 2^TSL2561_LUX_CHSCALE */
#define TSL2561_LUX_CHSCALE_TINT1 (0x0FE7) /* 322/81 * 2^TSL2561_LUX_CHSCALE */

/*
* Lux factors (the datasheet explains how these magic constants
* are used):
*/
/* T, FN and CL package values */
#define TSL2561_LUX_K1T (0x0040) /* 0.125 * 2^RATIO_SCALE */
#define TSL2561_LUX_B1T (0x01f2) /* 0.0304 * 2^LUX_SCALE */
#define TSL2561_LUX_M1T (0x01be) /* 0.0272 * 2^LUX_SCALE */
#define TSL2561_LUX_K2T (0x0080) /* 0.250 * 2^RATIO_SCALE */
#define TSL2561_LUX_B2T (0x0214) /* 0.0325 * 2^LUX_SCALE */
#define TSL2561_LUX_M2T (0x02d1) /* 0.0440 * 2^LUX_SCALE */
#define TSL2561_LUX_K3T (0x00c0) /* 0.375 * 2^RATIO_SCALE */
#define TSL2561_LUX_B3T (0x023f) /* 0.0351 * 2^LUX_SCALE */
#define TSL2561_LUX_M3T (0x037b) /* 0.0544 * 2^LUX_SCALE */
#define TSL2561_LUX_K4T (0x0100) /* 0.50 * 2^RATIO_SCALE */
#define TSL2561_LUX_B4T (0x0270) /* 0.0381 * 2^LUX_SCALE */
#define TSL2561_LUX_M4T (0x03fe) /* 0.0624 * 2^LUX_SCALE */
#define TSL2561_LUX_K5T (0x0138) /* 0.61 * 2^RATIO_SCALE */
#define TSL2561_LUX_B5T (0x016f) /* 0.0224 * 2^LUX_SCALE */
#define TSL2561_LUX_M5T (0x01fc) /* 0.0310 * 2^LUX_SCALE */
#define TSL2561_LUX_K6T (0x019a) /* 0.80 * 2^RATIO_SCALE */
#define TSL2561_LUX_B6T (0x00d2) /* 0.0128 * 2^LUX_SCALE */
#define TSL2561_LUX_M6T (0x00fb) /* 0.0153 * 2^LUX_SCALE */
#define TSL2561_LUX_K7T (0x029a) /* 1.3 * 2^RATIO_SCALE */
#define TSL2561_LUX_B7T (0x0018) /* 0.00146 * 2^LUX_SCALE */
#define TSL2561_LUX_M7T (0x0012) /* 0.00112 * 2^LUX_SCALE */
#define TSL2561_LUX_K8T (0x029a) /* 1.3 * 2^RATIO_SCALE */
#define TSL2561_LUX_B8T (0x0000) /* 0.000 * 2^LUX_SCALE */
#define TSL2561_LUX_M8T (0x0000) /* 0.000 * 2^LUX_SCALE */

/* CS package values */
#define TSL2561_LUX_K1C (0x0043) /* 0.130 * 2^RATIO_SCALE */
#define TSL2561_LUX_B1C (0x0204) /* 0.0315 * 2^LUX_SCALE */
#define TSL2561_LUX_M1C (0x01ad) /* 0.0262 * 2^LUX_SCALE */
#define TSL2561_LUX_K2C (0x0085) /* 0.260 * 2^RATIO_SCALE */
#define TSL2561_LUX_B2C (0x0228) /* 0.0337 * 2^LUX_SCALE */
#define TSL2561_LUX_M2C (0x02c1) /* 0.0430 * 2^LUX_SCALE */
#define TSL2561_LUX_K3C (0x00c8) /* 0.390 * 2^RATIO_SCALE */
#define TSL2561_LUX_B3C (0x0253) /* 0.0363 * 2^LUX_SCALE */
#define TSL2561_LUX_M3C (0x0363) /* 0.0529 * 2^LUX_SCALE */
#define TSL2561_LUX_K4C (0x010a) /* 0.520 * 2^RATIO_SCALE */
#define TSL2561_LUX_B4C (0x0282) /* 0.0392 * 2^LUX_SCALE */
#define TSL2561_LUX_M4C (0x03df) /* 0.0605 * 2^LUX_SCALE */
#define TSL2561_LUX_K5C (0x014d) /* 0.65 * 2^RATIO_SCALE */
#define TSL2561_LUX_B5C (0x0177) /* 0.0229 * 2^LUX_SCALE */
#define TSL2561_LUX_M5C (0x01dd) /* 0.0291 * 2^LUX_SCALE */
#define TSL2561_LUX_K6C (0x019a) /* 0.80 * 2^RATIO_SCALE */
#define TSL2561_LUX_B6C (0x0101) /* 0.0157 * 2^LUX_SCALE */
#define TSL2561_LUX_M6C (0x0127) /* 0.0180 * 2^LUX_SCALE */
#define TSL2561_LUX_K7C (0x029a) /* 1.3 * 2^RATIO_SCALE */
#define TSL2561_LUX_B7C (0x0037) /* 0.00338 * 2^LUX_SCALE */
#define TSL2561_LUX_M7C (0x002b) /* 0.00260 * 2^LUX_SCALE */
#define TSL2561_LUX_K8C (0x029a) /* 1.3 * 2^RATIO_SCALE */
#define TSL2561_LUX_B8C (0x0000) /* 0.000 * 2^LUX_SCALE */
#define TSL2561_LUX_M8C (0x0000) /* 0.000 * 2^LUX_SCALE */

struct lux_factor_table_entry {
uint16_t k;
uint16_t b;
uint16_t m;
};

static const struct lux_factor_table_entry lux_factor_table[] = {
{ TSL2561_LUX_K1T, TSL2561_LUX_B1T, TSL2561_LUX_M1T },
{ TSL2561_LUX_K2T, TSL2561_LUX_B2T, TSL2561_LUX_M2T },
{ TSL2561_LUX_K3T, TSL2561_LUX_B3T, TSL2561_LUX_M3T },
{ TSL2561_LUX_K4T, TSL2561_LUX_B4T, TSL2561_LUX_M4T },
{ TSL2561_LUX_K5T, TSL2561_LUX_B5T, TSL2561_LUX_M5T },
{ TSL2561_LUX_K6T, TSL2561_LUX_B6T, TSL2561_LUX_M6T },
{ TSL2561_LUX_K7T, TSL2561_LUX_B7T, TSL2561_LUX_M7T },
{ TSL2561_LUX_K8T, TSL2561_LUX_B8T, TSL2561_LUX_M8T },
};
static const int lux_factor_table_last_entry =
(sizeof(lux_factor_table) / sizeof(lux_factor_table[0])) - 1;

static const struct lux_factor_table_entry lux_factor_table_cs_package[] = {
{ TSL2561_LUX_K1C, TSL2561_LUX_B1C, TSL2561_LUX_M1C },
{ TSL2561_LUX_K2C, TSL2561_LUX_B2C, TSL2561_LUX_M2C },
{ TSL2561_LUX_K3C, TSL2561_LUX_B3C, TSL2561_LUX_M3C },
{ TSL2561_LUX_K4C, TSL2561_LUX_B4C, TSL2561_LUX_M4C },
{ TSL2561_LUX_K5C, TSL2561_LUX_B5C, TSL2561_LUX_M5C },
{ TSL2561_LUX_K6C, TSL2561_LUX_B6C, TSL2561_LUX_M6C },
{ TSL2561_LUX_K7C, TSL2561_LUX_B7C, TSL2561_LUX_M7C },
{ TSL2561_LUX_K8C, TSL2561_LUX_B8C, TSL2561_LUX_M8C },
};
static const int lux_factor_table_cs_package_last_entry =
(sizeof(lux_factor_table_cs_package) /
sizeof(lux_factor_table_cs_package[0])) - 1;

static int
tsllux_get_lux(struct tsllux_softc *sc, uint32_t *luxp,
uint16_t *raw_broadband, uint16_t *raw_ir)
{
uint32_t channel0, channel1, scale, ratio, lux = 0;
uint16_t broadband, ir;
uint16_t clip_threshold;
const struct lux_factor_table_entry *table;
int idx, last_entry, error;
int32_t temp;

if ((error = tsllux_get_sensor_data(sc, &broadband, &ir)) != 0)
return (error);

if (luxp == NULL) {
/*
* Caller doesn't want the calculated Lux value, so
* don't bother calculating it. Maybe they just want
* the raw sensor data?
*/
goto out;
}

/*
* Check to see if the sensor is saturated. If so,
* just return a "max brightness" value.
*/
switch (sc->sc_itime) {
case TIMING6x_INTEG_13_7ms:
clip_threshold = TSL2561_CLIPPING_13MS;
break;

case TIMING6x_INTEG_101ms:
clip_threshold = TSL2561_CLIPPING_101MS;
break;

case TIMING6x_INTEG_402ms:
default:
clip_threshold = TSL2561_CLIPPING_402MS;
break;
}

if (broadband > clip_threshold || ir > clip_threshold) {
lux = 65536;
goto out;
}

/* Get correct scale factor based on integration time. */
switch (sc->sc_itime) {
case TIMING6x_INTEG_13_7ms:
scale = TSL2561_LUX_CHSCALE_TINT0;
break;

case TIMING6x_INTEG_101ms:
scale = TSL2561_LUX_CHSCALE_TINT1;
break;

case TIMING6x_INTEG_402ms:
default:
scale = (1 << TSL2561_LUX_CHSCALE);
}

/* Scale for gain. */
if (sc->sc_gain == TIMING6x_GAIN_1X)
scale <<= 4;

/* Scale the channel values. */
channel0 = ((uint32_t)broadband * scale) >> TSL2561_LUX_CHSCALE;
channel1 = ((uint32_t)ir * scale) >> TSL2561_LUX_CHSCALE;

/* Find the ratio of the channel values (ir / broadband) */
if (channel0 != 0)
ratio = (channel1 << (TSL2561_LUX_RATIOSCALE + 1)) / channel0;
else
ratio = 0;

/* Round the ratio value. */
ratio = (ratio + 1) >> 1;

if (sc->sc_cs_package) {
table = lux_factor_table_cs_package;
last_entry = lux_factor_table_cs_package_last_entry;
} else {
table = lux_factor_table;
last_entry = lux_factor_table_last_entry;
}

/*
* The table is arranged such that we compare <= against
* the key, and if all else fails, we use the last entry.
* The pseudo-code in the data sheet shows what's going on.
*/
for (idx = 0; idx < last_entry; idx++) {
if (ratio <= table[idx].k)
break;
}

temp = ((channel0 * table[idx].b) - (channel1 * table[idx].m));

/* Do not allow negative Lux value. */
if (temp < 0)
temp = 0;

/* Round lsb (2^(LUX_SCALE-1)) */
temp += (1 << (TSL2561_LUX_LUXSCALE-1));

/* Strip off fractional portion */
lux = temp >> TSL2561_LUX_LUXSCALE;

out:
if (error == 0) {
if (luxp != NULL)
*luxp = lux;
if (raw_broadband != NULL)
*raw_broadband = broadband;
if (raw_ir != NULL)
*raw_ir = ir;
}
return (error);
}