mirror of
https://github.com/RIOT-OS/RIOT.git
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277 lines
6.3 KiB
C
277 lines
6.3 KiB
C
/*
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* Copyright (C) 2015 PHYTEC Messtechnik GmbH
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*
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*/
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/**
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* @ingroup drivers_tcs37727
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* @{
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*
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* @file
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* @brief Driver for the AMS TCS37727 Color Light-To-Digital Converter
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*
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* @author Felix Siebel <f.siebel@phytec.de>
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* @author Johann Fischer <j.fischer@phytec.de>
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*
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* @}
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*/
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#include <stdint.h>
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#include <stdbool.h>
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#include "periph/i2c.h"
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#include "tcs37727.h"
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#include "tcs37727-internal.h"
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#define ENABLE_DEBUG (0)
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#include "debug.h"
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#define I2C_SPEED I2C_SPEED_FAST
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static int tcs37727_test(tcs37727_t *dev)
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{
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char id;
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i2c_acquire(dev->i2c);
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if (i2c_read_reg(dev->i2c, dev->addr, TCS37727_ID, &id) != 1) {
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i2c_release(dev->i2c);
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return -1;
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}
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i2c_release(dev->i2c);
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if (id != TCS37727_ID_VALUE) {
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return -1;
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}
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return 0;
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}
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int tcs37727_init(tcs37727_t *dev, i2c_t i2c, uint8_t address, int atime_us)
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{
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/* write device descriptor */
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dev->i2c = i2c;
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dev->addr = address;
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dev->initialized = false;
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i2c_acquire(dev->i2c);
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/* initialize the I2C bus */
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if (i2c_init_master(i2c, I2C_SPEED) < 0) {
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i2c_release(dev->i2c);
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return -1;
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}
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i2c_release(dev->i2c);
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if (tcs37727_test(dev)) {
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return -2;
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}
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i2c_acquire(dev->i2c);
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if (i2c_write_reg(dev->i2c, dev->addr, TCS37727_CONTROL,
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TCS37727_CONTROL_AGAIN_4) != 1) {
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i2c_release(dev->i2c);
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return -3;
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}
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dev->again = 4;
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if (i2c_write_reg(dev->i2c, dev->addr, TCS37727_ATIME,
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TCS37727_ATIME_TO_REG(atime_us)) != 1) {
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i2c_release(dev->i2c);
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return -3;
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}
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dev->atime_us = atime_us;
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dev->initialized = true;
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i2c_release(dev->i2c);
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return 0;
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}
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int tcs37727_set_rgbc_active(tcs37727_t *dev)
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{
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uint8_t reg;
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if (dev->initialized == false) {
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return -1;
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}
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i2c_acquire(dev->i2c);
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if (i2c_read_regs(dev->i2c, dev->addr, TCS37727_ENABLE, (char *)®, 1) != 1) {
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i2c_release(dev->i2c);
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return -1;
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}
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reg |= (TCS37727_ENABLE_AEN | TCS37727_ENABLE_PON);
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if (i2c_write_reg(dev->i2c, dev->addr, TCS37727_ENABLE, reg) != 1) {
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i2c_release(dev->i2c);
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return -1;
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}
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i2c_release(dev->i2c);
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return 0;
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}
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int tcs37727_set_rgbc_standby(tcs37727_t *dev)
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{
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uint8_t reg;
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if (dev->initialized == false) {
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return -1;
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}
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i2c_acquire(dev->i2c);
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if (i2c_read_regs(dev->i2c, dev->addr, TCS37727_ENABLE, (char *)®, 1) != 1) {
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i2c_release(dev->i2c);
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return -1;
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}
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reg &= ~TCS37727_ENABLE_AEN;
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if (!(reg & TCS37727_ENABLE_PEN)) {
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reg &= ~TCS37727_ENABLE_PON;
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}
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if (i2c_write_reg(dev->i2c, dev->addr, TCS37727_ENABLE, reg) != 1) {
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i2c_release(dev->i2c);
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return -1;
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}
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i2c_release(dev->i2c);
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return 0;
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}
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static uint8_t tcs37727_trim_gain(tcs37727_t *dev, int rawc)
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{
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uint8_t reg_again = 0;
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int val_again = dev->again;
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if (dev->initialized == false) {
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return -1;
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}
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if (rawc < TCS37727_AG_THRESHOLD_LOW) {
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switch (val_again) {
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case 1:
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reg_again = TCS37727_CONTROL_AGAIN_4;
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val_again = 4;
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break;
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case 4:
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reg_again = TCS37727_CONTROL_AGAIN_16;
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val_again = 16;
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break;
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case 16:
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reg_again = TCS37727_CONTROL_AGAIN_60;
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val_again = 60;
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break;
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case 60:
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default:
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return -1;
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}
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}
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else if (rawc > TCS37727_AG_THRESHOLD_HIGH) {
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switch (val_again) {
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case 60:
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reg_again = TCS37727_CONTROL_AGAIN_16;
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val_again = 16;
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break;
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case 16:
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reg_again = TCS37727_CONTROL_AGAIN_4;
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val_again = 4;
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break;
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case 4:
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reg_again = TCS37727_CONTROL_AGAIN_1;
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val_again = 1;
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break;
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case 1:
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default:
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return -1;
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}
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}
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else {
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return 0;
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}
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i2c_acquire(dev->i2c);
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uint8_t reg = 0;
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if (i2c_read_reg(dev->i2c, dev->addr, TCS37727_CONTROL, (char *)®) != 1) {
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i2c_release(dev->i2c);
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return -2;
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}
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reg &= ~TCS37727_CONTROL_AGAIN_MASK;
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reg |= reg_again;
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if (i2c_write_reg(dev->i2c, dev->addr, TCS37727_CONTROL, reg) != 1) {
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i2c_release(dev->i2c);
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return -2;
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}
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i2c_release(dev->i2c);
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dev->again = val_again;
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return 0;
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}
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int tcs37727_read(tcs37727_t *dev, tcs37727_data_t *data)
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{
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char buf[8];
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if (dev->initialized == false) {
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return -1;
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}
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i2c_acquire(dev->i2c);
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if (i2c_read_regs(dev->i2c, dev->addr,
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(TCS37727_INC_TRANS | TCS37727_CDATA), buf, 8) != 8) {
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i2c_release(dev->i2c);
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return -1;
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}
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i2c_release(dev->i2c);
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int32_t tmpc = ((uint16_t)buf[1] << 8) | buf[0];
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int32_t tmpr = ((uint16_t)buf[3] << 8) | buf[2];
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int32_t tmpg = ((uint16_t)buf[5] << 8) | buf[4];
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int32_t tmpb = ((uint16_t)buf[7] << 8) | buf[6];
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DEBUG("rawr: %"PRIi32" rawg %"PRIi32" rawb %"PRIi32" rawc %"PRIi32"\n",
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tmpr, tmpg, tmpb, tmpc);
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/* Remove IR component as described in the DN40. */
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int32_t ir = (tmpr + tmpg + tmpb - tmpc) >> 1;
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tmpr -= ir;
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tmpg -= ir;
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tmpb -= ir;
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/* Color temperature calculation as described in the DN40. */
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int32_t ct = (CT_COEF_IF * tmpb) / tmpr + CT_OFFSET_IF;
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/* Lux calculation as described in the DN40. */
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int32_t gi = R_COEF_IF * tmpr + G_COEF_IF * tmpg + B_COEF_IF * tmpb;
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/* TODO: add Glass Attenuation Factor GA compensation */
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int32_t cpl = (dev->atime_us * dev->again) / DGF_IF;
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int32_t lux = gi / cpl;
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/* Autogain */
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tcs37727_trim_gain(dev, tmpc);
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data->red = (tmpr < 0) ? 0 : (tmpr * 1000) / cpl;
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data->green = (tmpg < 0) ? 0 : (tmpg * 1000) / cpl;
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data->blue = (tmpb < 0) ? 0 : (tmpb * 1000) / cpl;
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data->clear = (tmpb < 0) ? 0 : (tmpc * 1000) / cpl;
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data->lux = (lux < 0) ? 0 : lux;
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data->ct = (ct < 0) ? 0 : ct;
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return 0;
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}
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