ds3231.c

/*
 * Copyright (c) 2020 panrui <https://github.com/Prry/rtt-ds3231>
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2020-03-01     panrui      the first version
 */

#include <rtdevice.h>

#if RT_VER_NUM >= 0x40100
#include <sys/time.h>
#endif /*RT_VER_NUM >= 0x40100*/

#include "ds3231.h"

#ifdef PKG_USING_DS3231

#define DBG_TAG "ds3231"
#define DBG_LVL DBG_LOG
#include <rtdbg.h>

#define     DS3231_ARRD         0x68    /* slave address */

#define     REG_SEC             0x00
#define     REG_MIN             0x01
#define     REG_HOUR            0x02
#define     REG_DAY             0x03
#define     REG_WEEK            0x04
#define     REG_MON             0x05
#define     REG_YEAR            0x06
#define     REG_ALM1_SEC        0x07
#define     REG_ALM1_MIN        0x08
#define     REG_ALM1_HOUR       0x09
#define     REG_ALM1_DAY_DATE   0x0A
#define     REG_ALM2_MIN        0x0B
#define     REG_ALM2_HOUR       0x0C
#define     REG_ALM2_DAY_DATE   0x0D
#define     REG_CONTROL         0x0E
#define     REG_STATUS          0x0F
#define     REG_AGING_OFFSET    0x10
#define     REG_TEMP_MSB        0x11
#define     REG_TEMP_LSB        0x12

#define DS3231_I2C_BUS      "i2c1"      /* i2c linked */
#define DS3231_DEVICE_NAME  "rtc"       /* register device name */

static struct rt_device ds3231_dev; /* ds3231 device */

static unsigned char bcd_to_hex(unsigned char data)
{
    unsigned char temp;

    temp = ((data>>4)*10 + (data&0x0f));
    return temp;
}

static unsigned char hex_to_bcd(unsigned char data)
{
    unsigned char temp;

    temp = (((data/10)<<4) + (data%10));
    return temp;
}

static rt_err_t  ds3231_read_reg(rt_device_t dev, rt_uint8_t reg,rt_uint8_t *data,rt_uint8_t data_size)
{
    struct rt_i2c_msg msg[2];
    struct rt_i2c_bus_device *i2c_bus = RT_NULL;

    RT_ASSERT(dev != RT_NULL);

    i2c_bus = (struct rt_i2c_bus_device*)dev->user_data;
    msg[0].addr  = DS3231_ARRD;
    msg[0].flags = RT_I2C_WR;
    msg[0].len   = 1;
    msg[0].buf   = &reg;
    msg[1].addr  = DS3231_ARRD;
    msg[1].flags = RT_I2C_RD;
    msg[1].len   = data_size;
    msg[1].buf   = data;

    if(rt_i2c_transfer(i2c_bus, msg, 2) == 2)
    {
        return RT_EOK;
    }
    else
    {
        LOG_E("i2c bus read failed!\r\n");
        return -RT_ERROR;
    }
}

static rt_err_t  ds3231_write_reg(rt_device_t dev, rt_uint8_t reg, rt_uint8_t *data, rt_uint8_t data_size)
{
    struct rt_i2c_msg msg[2];
    struct rt_i2c_bus_device *i2c_bus = RT_NULL;

    RT_ASSERT(dev != RT_NULL);

    i2c_bus = (struct rt_i2c_bus_device*)dev->user_data;
    msg[0].addr     = DS3231_ARRD;
    msg[0].flags    = RT_I2C_WR;
    msg[0].len      = 1;
    msg[0].buf      = &reg;
    msg[1].addr     = DS3231_ARRD;
    msg[1].flags    = RT_I2C_WR | RT_I2C_NO_START;
    msg[1].len      = data_size;
    msg[1].buf      = data;
    if(rt_i2c_transfer(i2c_bus, msg, 2) == 2)
    {
        return RT_EOK;
    }
    else
    {
        LOG_E("i2c bus write failed!\r\n");
        return -RT_ERROR;
    }
}

static rt_err_t rt_ds3231_open(rt_device_t dev, rt_uint16_t flag)
{
    if (dev->rx_indicate != RT_NULL)
    {
        /* open interrupt */
    }

    return RT_EOK;
}

static rt_size_t rt_ds3231_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
{
    return RT_EOK;
}

static rt_err_t rt_ds3231_control(rt_device_t dev, int cmd, void *args)
{
    rt_err_t    ret = RT_EOK;
    time_t      *time;
    struct tm   time_temp;
    rt_uint8_t  buff[7];

    RT_ASSERT(dev != RT_NULL);
    rt_memset(&time_temp, 0, sizeof(struct tm));

    switch (cmd)
    {
        /* read time */
        case RT_DEVICE_CTRL_RTC_GET_TIME:
            time = (time_t *)args;
            ret = ds3231_read_reg(dev, REG_SEC,buff,7);
            if(ret == RT_EOK)
            {
                time_temp.tm_year  = bcd_to_hex(buff[6]) + 2000 - 1900;
                time_temp.tm_mon   = bcd_to_hex(buff[5]&0x7f) - 1;
                time_temp.tm_mday  = bcd_to_hex(buff[4]);
                time_temp.tm_hour  = bcd_to_hex(buff[2]);
                time_temp.tm_min   = bcd_to_hex(buff[1]);
                time_temp.tm_sec   = bcd_to_hex(buff[0]);
                *time = mktime(&time_temp);
            }
        break;

        /* set time */
        case RT_DEVICE_CTRL_RTC_SET_TIME:
        {
            struct tm *time_new;

            time = (time_t *)args;
            time_new = localtime(time);
            buff[6] = hex_to_bcd(time_new->tm_year + 1900 - 2000);
            buff[5] = hex_to_bcd(time_new->tm_mon + 1);
            buff[4] = hex_to_bcd(time_new->tm_mday);
            buff[3] = hex_to_bcd(time_new->tm_wday+1);
            buff[2] = hex_to_bcd(time_new->tm_hour);
            buff[1] = hex_to_bcd(time_new->tm_min);
            buff[0] = hex_to_bcd(time_new->tm_sec);
            ret = ds3231_write_reg(dev, REG_SEC, buff, 7);
        }
        break;
    #ifdef RT_USING_ALARM
        /* get alarm time */
        case RT_DEVICE_CTRL_RTC_GET_ALARM:
        {
            struct rt_rtc_wkalarm *alm_time;

            ret = ds3231_read_reg(dev, REG_ALM1_SEC, buff, 4);
            if(ret == RT_EOK)
            {
                alm_time = (struct rt_rtc_wkalarm *)args;
                alm_time->tm_hour  = bcd_to_hex(buff[2]);
                alm_time->tm_min   = bcd_to_hex(buff[1]);
                alm_time->tm_sec   = bcd_to_hex(buff[0]);
            }
        }
        break;

        /* set alarm time */
        case RT_DEVICE_CTRL_RTC_SET_ALARM:
        {
            struct rt_rtc_wkalarm *alm_time;

            alm_time = (struct rt_rtc_wkalarm *)args;
            buff[3] = 0x80; /* enable, alarm when hours, minutes, and seconds match */
            buff[2] = hex_to_bcd(alm_time->tm_hour);
            buff[1] = hex_to_bcd(alm_time->tm_min);
            buff[0] = hex_to_bcd(alm_time->tm_sec);
            ret = ds3231_write_reg(dev, REG_ALM1_SEC, buff, 4);
        }
        break;
    #endif
        default:
        break;
    }
    return ret;
}

float ds3231_get_temperature(void)
{
    rt_int8_t buff[2];
    float temp = 0.0f;

    ds3231_read_reg(&ds3231_dev, REG_TEMP_MSB, (rt_uint8_t*)buff, 2);
    if(buff[0]&0x80)
    {/* negative temperature */
        temp = buff[0];
        temp -= (buff[1]>>6)*0.25;  /* 0.25C resolution */
    }
    else
    {/* positive temperature */
        temp = buff[0];
        temp += ((buff[1]>>6)&0x03)*0.25;
    }

    return temp;
}

int rt_hw_ds3231_init(void)
{
    struct rt_i2c_bus_device *i2c_device;
    uint8_t data;

    i2c_device = rt_i2c_bus_device_find(DS3231_I2C_BUS);
    if (i2c_device == RT_NULL)
    {
        LOG_E("i2c bus device %s not found!\r\n", DS3231_I2C_BUS);
        return -RT_ERROR;
    }

    /* register rtc device */
    ds3231_dev.type         = RT_Device_Class_RTC;
    ds3231_dev.init         = RT_NULL;
    ds3231_dev.open         = rt_ds3231_open;
    ds3231_dev.close        = RT_NULL;
    ds3231_dev.read         = rt_ds3231_read;
    ds3231_dev.write        = RT_NULL;
    ds3231_dev.control      = rt_ds3231_control;
    ds3231_dev.user_data    = (void*)i2c_device;    /* save i2cbus */;
    rt_device_register(&ds3231_dev, DS3231_DEVICE_NAME, RT_DEVICE_FLAG_RDWR);

    /* init ds3231 */
    data = 0x04;    /* close clock out */
    ds3231_write_reg(&ds3231_dev, REG_CONTROL, &data, 1);
    LOG_D("the rtc of ds3231 init succeed!");

    return 0;
}
INIT_DEVICE_EXPORT(rt_hw_ds3231_init);

#ifdef RT_USING_FINSH
#include <finsh.h>

void list_ds31_temp(void)
{
    float temp = 0.0f;

    temp = ds3231_get_temperature();

    rt_kprintf("ds3231 temperature: [%d.%dC] \n", (int)temp, (int)(temp * 10) % 10);
}
FINSH_FUNCTION_EXPORT(list_ds31_temp, list ds3231 temperature.)
#endif /* RT_USING_FINSH */

#if defined(RT_USING_FINSH) && defined(FINSH_USING_MSH)
MSH_CMD_EXPORT(list_ds31_temp, list ds3231 temperature.);
#endif /* RT_USING_FINSH & FINSH_USING_MSH */

#endif /* PKG_USING_DS3231 */