ltr329/ltr329.c

/*
 * File:        ltr329.c
 * Description: Library for the Lite-On Optical Sensor LTR-329ALS-01
 * Author:      David Zaitlik
 * Date:        2022-05-22
 *
 *
 * Copyright (c) 2024 Veles Labs s.r.o.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 */

#include "ltr329.h"

static int8_t ltr329_read_register (ltr329_cmd_t register_addr, uint8_t *register_data );
static int8_t ltr329_write_register (ltr329_cmd_t register_addr, uint8_t register_data);

/*
 * Functions to be implemented by user
 */

/* I2C */
int8_t ltr329_i2c_transmit(uint8_t address, uint8_t *buffer, int len) __attribute__((weak));
int8_t ltr329_i2c_receive(uint8_t address, uint8_t *buffer, int len) __attribute__((weak)); 
/* Interrupts */
int8_t ltr329_disable_interrupts(void) __attribute__((weak));
int8_t ltr329_enable_interrupts(void) __attribute__((weak));
/* delay function */
void delay_ms(int delay_ms) __attribute__((weak));

static int8_t ltr329_read_register (ltr329_cmd_t register_addr, uint8_t *register_data )
{
	uint8_t tx_buffer[1];
	uint8_t rx_buffer[1];
	int result;

	// start measurement
	tx_buffer[0] = register_addr;
	/* disable interrupts to prevent modbus/i2c conflict */
	ltr329_disable_interrupts();
	result = ltr329_i2c_transmit(LTR329_I2C_ADDRESS<<1, tx_buffer, 1);
	ltr329_enable_interrupts();
	if (result != I2C_OK) {
		return LTR329_ERROR;
	}
	delay_ms(10); /* 10 ms should be enough */
	/* read out */
	ltr329_disable_interrupts();
	result = ltr329_i2c_receive(LTR329_I2C_ADDRESS<<1, rx_buffer, 1);
	ltr329_enable_interrupts();
	if (result != I2C_OK) {
		return LTR329_ERROR;
	}

	*register_data = rx_buffer[0];
	return LTR329_OK;
}

static int8_t ltr329_write_register (ltr329_cmd_t register_addr, uint8_t register_data)
{
	uint8_t tx_buffer[2];
	int result;

	// start measurement
	tx_buffer[0] = register_addr;
	tx_buffer[1] = register_data;
	/* disable interrupts to prevent modbus/i2c conflict */
	ltr329_disable_interrupts();
	result = ltr329_i2c_transmit(LTR329_I2C_ADDRESS<<1, tx_buffer, 2);
	ltr329_enable_interrupts();
	if (result != I2C_OK) {
		return LTR329_ERROR;
	}
	return LTR329_OK;
}

int8_t ltr329_write_settings (ltr329_gain_t gain, ltr329_als_mode_t mode, ltr329_integration_time_t integ_time, ltr329_measurement_rate_t meas_rate)
{
	int8_t result;
	/* Write Gain and ALS Mode */
	result = ltr329_write_register(LTR329_ALS_CONTR, (gain | mode));
	if (result != LTR329_OK)
	{
		return LTR329_ERROR;
	}
	/* Write Integration Time and Measurement Rate */

	result = ltr329_write_register(LTR329_ALS_MEAS_RATE, (integ_time | meas_rate));
	if (result != LTR329_OK)
	{
		return LTR329_ERROR;
	}
	return LTR329_OK;
}

int8_t ltr329_read_settings (ltr329_gain_t *gain, ltr329_als_mode_t *mode, ltr329_integration_time_t *integ_time, ltr329_measurement_rate_t *meas_rate)
{
	int8_t result;
	uint8_t control_register_data;
	uint8_t rate_register_data;

	result = ltr329_read_register(LTR329_ALS_CONTR, &control_register_data);
	if (result != LTR329_OK)
	{
		return LTR329_ERROR;
	}

	result = ltr329_read_register(LTR329_ALS_MEAS_RATE, &rate_register_data);
	if (result != LTR329_OK)
	{
		return LTR329_ERROR;
	}

	uint8_t control_register_gain_mask = 0b00011100;
	uint8_t control_register_mode_mask = 0b00000001;
	uint8_t rate_register_int_time_mask = 0b00111000;
	uint8_t rate_register_rate_mask = 0b00000111;

	/* Return Registers Values */
	/* TODO: This might not be safe */
	*gain = control_register_data & control_register_gain_mask;
	*mode = control_register_data & control_register_mode_mask;
	*integ_time = rate_register_data & rate_register_int_time_mask;
	*meas_rate = rate_register_data & rate_register_rate_mask;

	return LTR329_OK;
}

int8_t ltr329_sw_reset( void )
{
	int8_t result;
	/* Write Gain and ALS Mode */
	result = ltr329_write_register(LTR329_ALS_CONTR, 0b00000010);
	if (result != LTR329_OK)
	{
		return LTR329_ERROR;
	}
	return LTR329_OK;
}

int8_t ltr329_measure (uint16_t *data_ch0, uint16_t *data_ch1)
{
	uint8_t ch0_l, ch0_h, ch1_l, ch1_h;
	int result;
	result = ltr329_read_register(LTR329_ALS_DATA_CH0_0, &ch0_l);
	if (result != LTR329_OK)
	{
		return LTR329_ERROR;
	}
	result = ltr329_read_register(LTR329_ALS_DATA_CH0_1, &ch0_h);
	if (result != LTR329_OK)
	{
		return LTR329_ERROR;
	}
	result = ltr329_read_register(LTR329_ALS_DATA_CH1_0, &ch1_l);
	if (result != LTR329_OK)
	{
		return LTR329_ERROR;
	}
	result = ltr329_read_register(LTR329_ALS_DATA_CH1_1, &ch1_h);
	if (result != LTR329_OK)
	{
		return LTR329_ERROR;
	}

	*data_ch0 = (ch0_h << 8) + ch0_l;
	*data_ch1 = (ch1_h << 8) + ch1_l;
	return LTR329_OK;
}

int8_t ltr329_read_status_register(uint8_t *data_valid, uint8_t *new_data, ltr329_gain_t *gain)
{
	int8_t result;
	uint8_t status_register_data;
	result = ltr329_read_register(LTR329_ALS_STATUS, &status_register_data);
	if (result != LTR329_OK)
	{
		return LTR329_ERROR;
	}

	/* Check data valid */
	uint8_t data_invalid_mask = 0b10000000;
	if ((status_register_data & data_invalid_mask) == data_invalid_mask)
	{
		*data_valid = 0;
	} else
	{
		*data_valid = 1;
	}

	/* Check if there is new data */
	uint8_t data_status_mask = 0b00000100;
	if ((status_register_data & data_status_mask) == data_status_mask)
	{
		*new_data = 1;
	} else
	{
		*new_data = 0;
	}

	/* Check Gain */
	/* TODO: This might not be safe */
	uint8_t gain_mask = 0b01110000;
	*gain = status_register_data & gain_mask;

	return LTR329_OK;
}

int8_t ltr329_read_device_info (uint8_t *manufacturer_id, uint8_t *part_id)
{
	int8_t result;
	result = ltr329_read_register(LTR329_MANUFAC_ID, manufacturer_id);
	if (result != LTR329_OK)
	{
		return LTR329_ERROR;
	}
	result = ltr329_read_register(LTR329_PART_ID, part_id);
	if (result != LTR329_OK)
	{
		return LTR329_ERROR;
	}
	return LTR329_OK;
}