// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2008
 * Tor Krill, Excito Elektronik i Skåne , tor@excito.com
 *
 * Modelled after the ds1337 driver
 */

/*
 * Date & Time support (no alarms) for Intersil
 * ISL1208 Real Time Clock (RTC).
 */

#include <common.h>
#include <command.h>
#include <dm.h>
#include <rtc.h>
#include <i2c.h>

/*---------------------------------------------------------------------*/
#ifdef DEBUG_RTC
#define DEBUGR(fmt,args...) printf(fmt ,##args)
#else
#define DEBUGR(fmt,args...)
#endif
/*---------------------------------------------------------------------*/

/*
 * RTC register addresses
 */

#define RTC_SEC_REG_ADDR        0x0
#define RTC_MIN_REG_ADDR        0x1
#define RTC_HR_REG_ADDR         0x2
#define RTC_DATE_REG_ADDR       0x3
#define RTC_MON_REG_ADDR        0x4
#define RTC_YR_REG_ADDR         0x5
#define RTC_DAY_REG_ADDR        0x6
#define RTC_STAT_REG_ADDR       0x7
/*
 * RTC control register bits
 */

/*
 * RTC status register bits
 */
#define RTC_STAT_BIT_ARST       0x80    /* AUTO RESET ENABLE BIT */
#define RTC_STAT_BIT_XTOSCB     0x40    /* CRYSTAL OSCILLATOR ENABLE BIT */
#define RTC_STAT_BIT_WRTC       0x10    /* WRITE RTC ENABLE BIT */
#define RTC_STAT_BIT_ALM        0x04    /* ALARM BIT */
#define RTC_STAT_BIT_BAT        0x02    /* BATTERY BIT */
#define RTC_STAT_BIT_RTCF       0x01    /* REAL TIME CLOCK FAIL BIT */

/*
 * Read an RTC register
 */

static int isl1208_rtc_read8(struct udevice *dev, unsigned int reg)
{
        return dm_i2c_reg_read(dev, reg);
}

/*
 * Write an RTC register
 */

static int isl1208_rtc_write8(struct udevice *dev, unsigned int reg, int val)
{
        return dm_i2c_reg_write(dev, reg, val);
}

/*
 * Get the current time from the RTC
 */

static int isl1208_rtc_get(struct udevice *dev, struct rtc_time *tmp)
{
        int ret;
        uchar buf[8], val;

        ret = dm_i2c_read(dev, 0, buf, sizeof(buf));
        if (ret < 0)
                return ret;

        if (buf[RTC_STAT_REG_ADDR] & RTC_STAT_BIT_RTCF) {
                printf ("### Warning: RTC oscillator has stopped\n");
                ret = dm_i2c_read(dev, RTC_STAT_REG_ADDR, &val, sizeof(val));
                if (ret < 0)
                        return ret;

                val = val & ~(RTC_STAT_BIT_BAT | RTC_STAT_BIT_RTCF);
                ret = dm_i2c_write(dev, RTC_STAT_REG_ADDR, &val, sizeof(val));
                if (ret < 0)
                        return ret;
        }

        tmp->tm_sec  = bcd2bin(buf[RTC_SEC_REG_ADDR] & 0x7F);
        tmp->tm_min  = bcd2bin(buf[RTC_MIN_REG_ADDR] & 0x7F);
        tmp->tm_hour = bcd2bin(buf[RTC_HR_REG_ADDR] & 0x3F);
        tmp->tm_mday = bcd2bin(buf[RTC_DATE_REG_ADDR] & 0x3F);
        tmp->tm_mon  = bcd2bin(buf[RTC_MON_REG_ADDR] & 0x1F);
        tmp->tm_year = bcd2bin(buf[RTC_YR_REG_ADDR]) + 2000;
        tmp->tm_wday = bcd2bin(buf[RTC_DAY_REG_ADDR] & 0x07);
        tmp->tm_yday = 0;
        tmp->tm_isdst= 0;

        DEBUGR ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
                tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
                tmp->tm_hour, tmp->tm_min, tmp->tm_sec);

        return 0;
}

/*
 * Set the RTC
 */
static int isl1208_rtc_set(struct udevice *dev, const struct rtc_time *tmp)
{
        int ret;
        uchar val, buf[7];

        DEBUGR ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
                tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
                tmp->tm_hour, tmp->tm_min, tmp->tm_sec);

        if (tmp->tm_year < 2000 || tmp->tm_year > 2099)
                printf("WARNING: year should be between 2000 and 2099!\n");

        /* enable write */
        ret = dm_i2c_read(dev, RTC_STAT_REG_ADDR, &val, sizeof(val));
        if (ret < 0)
                return ret;

        val = val | RTC_STAT_BIT_WRTC;

        ret = dm_i2c_write(dev, RTC_STAT_REG_ADDR, &val, sizeof(val));
        if (ret < 0)
                return ret;

        buf[RTC_YR_REG_ADDR] = bin2bcd(tmp->tm_year % 100);
        buf[RTC_MON_REG_ADDR] = bin2bcd(tmp->tm_mon);
        buf[RTC_DAY_REG_ADDR] = bin2bcd(tmp->tm_wday);
        buf[RTC_DATE_REG_ADDR] = bin2bcd(tmp->tm_mday);
        buf[RTC_HR_REG_ADDR] = bin2bcd(tmp->tm_hour) | 0x80; /* 24h clock */
        buf[RTC_MIN_REG_ADDR] = bin2bcd(tmp->tm_min);
        buf[RTC_SEC_REG_ADDR] = bin2bcd(tmp->tm_sec);

        ret = dm_i2c_write(dev, 0, buf, sizeof(buf));
        if (ret < 0)
                return ret;

        /* disable write */
        ret = dm_i2c_read(dev, RTC_STAT_REG_ADDR, &val, sizeof(val));
        if (ret < 0)
                return ret;

        val = val & ~RTC_STAT_BIT_WRTC;
        ret = dm_i2c_write(dev, RTC_STAT_REG_ADDR, &val, sizeof(val));
        if (ret < 0)
                return ret;

        return 0;
}

static int isl1208_rtc_reset(struct udevice *dev)
{
        return 0;
}

static int isl1208_probe(struct udevice *dev)
{
        i2c_set_chip_flags(dev, DM_I2C_CHIP_RD_ADDRESS |
                           DM_I2C_CHIP_WR_ADDRESS);

        return 0;
}

static const struct rtc_ops isl1208_rtc_ops = {
        .get = isl1208_rtc_get,
        .set = isl1208_rtc_set,
        .reset = isl1208_rtc_reset,
        .read8 = isl1208_rtc_read8,
        .write8 = isl1208_rtc_write8,
};

static const struct udevice_id isl1208_rtc_ids[] = {
        { .compatible = "isil,isl1208" },
        { }
};

U_BOOT_DRIVER(rtc_isl1208) = {
        .name   = "rtc-isl1208",
        .id     = UCLASS_RTC,
        .probe  = isl1208_probe,
        .of_match = isl1208_rtc_ids,
        .ops    = &isl1208_rtc_ops,
};