RIOT/drivers/isl29125/isl29125.c

/*
 * Copyright 2015 Ludwig Knüpfer
 *
 * This file is subject to the terms and conditions of the GNU Lesser
 * General Public License v2.1. See the file LICENSE in the top level
 * directory for more details.
 */

/**
 * @ingroup     driver_isl29125
 * @{
 *
 * @file
 * @brief       Device driver implementation for the ISL29125 RGB light sensor
 *
 * @author      Ludwig Knüpfer <ludwig.knuepfer@fu-berlin.de>
 *
 * @}
 */

#include <stdint.h>

#include "isl29125.h"
#include "isl29125-internal.h"
#include "periph/i2c.h"
#include "periph/gpio.h"
#include "color.h"

#define ENABLE_DEBUG    (0)
#include "debug.h"

/***********************************************************************
 * public API implementation
 **********************************************************************/

int isl29125_init(isl29125_t *dev, i2c_t i2c, gpio_t gpio,
                  isl29125_mode_t mode, isl29125_range_t range,
                  isl29125_resolution_t resolution)
{
    DEBUG("isl29125_init\n");

    /* initialize device descriptor */
    dev->i2c = i2c;
    dev->res = resolution;
    dev->range = range;
    dev->gpio = gpio;

    /* configuration 1: operation mode, range, resolution */
    char conf1 = 0x00;
    conf1 |= mode;
    conf1 |= range;
    conf1 |= resolution;
    conf1 |= ISL29125_CON1_SYNCOFF; /* TODO: implement SYNC mode configuration */

    /* TODO: implement configuration 2: infrared compensation configuration */

    /* TODO: implement configuration 3: interrupt mode configuration */

    /* acquire exclusive access to the bus */
    DEBUG("isl29125_init: i2c_acquire\n");
    (void) i2c_acquire(dev->i2c);

    /* initialize the I2C bus */
    DEBUG("isl29125_init: i2c_init_master\n");
    (void) i2c_init_master(i2c, I2C_SPEED_NORMAL);

    /* verify the device ID */
    DEBUG("isl29125_init: i2c_read_reg\n");
    char reg_id;
    int ret = i2c_read_reg(dev->i2c, ISL29125_I2C_ADDRESS, ISL29125_REG_ID, &reg_id);
    if ((reg_id == ISL29125_ID) && (ret == 1)) {
        DEBUG("isl29125_init: ID successfully verified\n");
    }
    else {
        DEBUG("isl29125_init: ID could not be verified, ret: %i\n", ret);
        (void) i2c_release(dev->i2c);
        return -1;
    }

    /* configure and enable the sensor */
    DEBUG("isl29125_init: i2c_write_reg(ISL29125_REG_RESET)\n");
    (void) i2c_write_reg(dev->i2c, ISL29125_I2C_ADDRESS, ISL29125_REG_RESET, ISL29125_CMD_RESET);

    DEBUG("isl29125_init: i2c_write_reg(ISL29125_REG_CONF1)\n");
    (void) i2c_write_reg(dev->i2c, ISL29125_I2C_ADDRESS, ISL29125_REG_CONF1, conf1);

    /* release the I2C bus */
    DEBUG("isl29125_init: i2c_release\n");
    (void) i2c_release(dev->i2c);

    DEBUG("isl29125_init: success\n");
    return 0;
}

void isl29125_read_rgb_lux(isl29125_t *dev, isl29125_rgb_t *dest)
{
    /* acquire exclusive access to the bus */
    (void) i2c_acquire(dev->i2c);

    /* read values */
    char bytes[6];
    (void) i2c_read_regs(dev->i2c, ISL29125_I2C_ADDRESS, ISL29125_REG_GDLB, bytes, 6);

    /* release the I2C bus */
    (void) i2c_release(dev->i2c);

    /* possibly shift by 4 to normalize 12 to 16 bit */
    int resfactor = (dev->res == ISL29125_RESOLUTION_12) ? 4 : 0;
    /* parse and normalize readings */
    uint16_t green = (bytes[0] | (bytes[1] << 8)) << resfactor;
    uint16_t red   = (bytes[2] | (bytes[3] << 8)) << resfactor;
    uint16_t blue  = (bytes[4] | (bytes[5] << 8)) << resfactor;

    DEBUG("isl29125_read_rgb: adjusted, unconverted readings: (%5i / %5i / %5i) \n", red, green, blue);

    /* convert readings to lux */
    float luxfactor = (dev->range == ISL29125_RANGE_10K) ? 10000.0 / 65535.0 : 375.0 / 65535.0;
    dest->red = red * luxfactor;
    dest->green = green * luxfactor;
    dest->blue = blue * luxfactor;
}

void isl29125_read_rgb_color(isl29125_t *dev, color_rgb_t *dest)
{
    /* acquire exclusive access to the bus */
    (void) i2c_acquire(dev->i2c);

    /* read values */
    char bytes[6];
    (void) i2c_read_regs(dev->i2c, ISL29125_I2C_ADDRESS, ISL29125_REG_GDLB, bytes, 6);

    /* release the I2C bus */
    (void) i2c_release(dev->i2c);

    /* factor normalize 12 or 16 bit to 8 bit */
    int normfactor = (dev->res == ISL29125_RESOLUTION_12) ? 4 : 8;
    /* parse and normalize readings */
    dest->g = (bytes[0] | (bytes[1] << 8)) >> normfactor;
    dest->r = (bytes[2] | (bytes[3] << 8)) >> normfactor;
    dest->b = (bytes[4] | (bytes[5] << 8)) >> normfactor;
}

void isl29125_set_mode(isl29125_t *dev, isl29125_mode_t mode)
{
    char conf1;

    (void) i2c_acquire(dev->i2c);

    (void) i2c_read_reg(dev->i2c, ISL29125_I2C_ADDRESS, ISL29125_REG_CONF1, &conf1);
    conf1 &= ~ISL29125_CON1_MASK_MODE;
    conf1 |= mode;
    (void) i2c_write_reg(dev->i2c, ISL29125_I2C_ADDRESS, ISL29125_REG_CONF1, conf1);

    (void) i2c_release(dev->i2c);
}