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120 lines
2.9 KiB
C
120 lines
2.9 KiB
C
/*
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* Copyright (C) 2014 Freie Universität Berlin
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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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* @ingroup drivers_isl29020
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* @{
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*
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* @file
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* @brief Device driver implementation for the ISL29020 light sensor
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*
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* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
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* @author Peter Kietzmann <peter.kietzmann@haw-hamburg.de>
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*
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* @}
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*/
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#include "isl29020.h"
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#include "isl29020-internal.h"
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#include "periph/i2c.h"
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#define ENABLE_DEBUG 0
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#include "debug.h"
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#define DEV_I2C (dev->params.i2c)
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#define DEV_ADDR (dev->params.addr)
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#define DEV_RANGE (dev->params.range)
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#define DEV_MODE (dev->params.mode)
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int isl29020_init(isl29020_t *dev, const isl29020_params_t *params)
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{
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dev->params = *params;
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int res;
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uint8_t tmp;
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/* initialize device descriptor */
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dev->lux_fac = (float)((1 << (10 + (2 * DEV_RANGE))) - 1) / 0xffff;
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/* acquire exclusive access to the bus */
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i2c_acquire(DEV_I2C);
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/* configure and enable the sensor */
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tmp = (ISL29020_CMD_EN | ISL29020_CMD_MODE |
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ISL29020_RES_INT_16 | DEV_RANGE | (DEV_MODE << 5));
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res = i2c_write_reg(DEV_I2C, DEV_ADDR, ISL29020_REG_CMD, tmp, 0);
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/* release the bus for other threads */
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i2c_release(DEV_I2C);
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if (res < 0) {
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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 isl29020_read(const isl29020_t *dev)
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{
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uint8_t low, high;
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uint16_t res;
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int ret;
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i2c_acquire(DEV_I2C);
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/* read lighting value */
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ret = i2c_read_reg(DEV_I2C, DEV_ADDR, ISL29020_REG_LDATA, &low, 0);
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ret += i2c_read_reg(DEV_I2C, DEV_ADDR, ISL29020_REG_HDATA, &high, 0);
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i2c_release(DEV_I2C);
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if (ret < 0) {
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return -1;
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}
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res = (high << 8) | low;
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DEBUG("ISL29020: Raw value: %i - high: %i, low: %i\n", res, high, low);
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/* calculate and return the actual lux value */
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return (int)(dev->lux_fac * res);
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}
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int isl29020_enable(const isl29020_t *dev)
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{
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int res;
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uint8_t tmp;
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i2c_acquire(DEV_I2C);
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res = i2c_read_reg(DEV_I2C, DEV_ADDR, ISL29020_REG_CMD, &tmp, 0);
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if (res < 0) {
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i2c_release(DEV_I2C);
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return -1;
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}
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tmp |= ISL29020_CMD_EN;
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res = i2c_write_reg(DEV_I2C, DEV_ADDR, ISL29020_REG_CMD, tmp, 0);
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if (res < 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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return 0;
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}
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int isl29020_disable(const isl29020_t *dev)
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{
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int res;
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uint8_t tmp;
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i2c_acquire(DEV_I2C);
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res = i2c_read_reg(DEV_I2C, DEV_ADDR, ISL29020_REG_CMD, &tmp, 0);
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if (res < 0) {
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i2c_release(DEV_I2C);
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return -1;
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}
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tmp &= ~(ISL29020_CMD_EN);
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res = i2c_write_reg(DEV_I2C, DEV_ADDR, ISL29020_REG_CMD, tmp, 0);
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if (res < 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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return 0;
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}
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