U-Boot

// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2007
 * Matthias Fuchs, esd gmbh, matthias.fuchs@esd-electronics.com.
 */

/*
 * Epson RX8025 RTC driver.
 */

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

/*---------------------------------------------------------------------*/
#undef DEBUG_RTC

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

#ifndef CONFIG_SYS_I2C_RTC_ADDR
# define CONFIG_SYS_I2C_RTC_ADDR	0x32
#endif

#ifdef CONFIG_DM_RTC
#define DEV_TYPE struct udevice
#else
/* Local udevice */
struct ludevice {
	u8 chip;
};

#define DEV_TYPE struct ludevice

#endif

/*
 * RTC register addresses
 */
#define RTC_SEC_REG_ADDR	0x00
#define RTC_MIN_REG_ADDR	0x01
#define RTC_HR_REG_ADDR		0x02
#define RTC_DAY_REG_ADDR	0x03
#define RTC_DATE_REG_ADDR	0x04
#define RTC_MON_REG_ADDR	0x05
#define RTC_YR_REG_ADDR		0x06

#define RTC_CTL1_REG_ADDR	0x0e
#define RTC_CTL2_REG_ADDR	0x0f

/*
 * Control register 1 bits
 */
#define RTC_CTL1_BIT_2412	0x20

/*
 * Control register 2 bits
 */
#define RTC_CTL2_BIT_PON	0x10
#define RTC_CTL2_BIT_VDET	0x40
#define RTC_CTL2_BIT_XST	0x20
#define RTC_CTL2_BIT_VDSL	0x80

/*
 * Note: the RX8025 I2C RTC requires register
 * reads and write to consist of a single bus
 * cycle. It is not allowed to write the register
 * address in a first cycle that is terminated by
 * a STOP condition. The chips needs a 'restart'
 * sequence (start sequence without a prior stop).
 * This driver has been written for a 4xx board.
 * U-Boot's 4xx i2c driver is currently not capable
 * to generate such cycles to some work arounds
 * are used.
 */

/* static uchar rtc_read (uchar reg); */
#ifdef CONFIG_DM_RTC
/*
 * on mpc85xx based board with DM and offset len 1
 * accessing rtc works fine. May we can drop this ?
 */
#define rtc_read(reg) buf[(reg) & 0xf]
#else
#define rtc_read(reg) buf[((reg) + 1) & 0xf]
#endif

static int rtc_write(DEV_TYPE *dev, uchar reg, uchar val);

/*
 * Get the current time from the RTC
 */
static int rx8025_rtc_get(DEV_TYPE *dev, struct rtc_time *tmp)
{
	int rel = 0;
	uchar sec, min, hour, mday, wday, mon, year, ctl2;
	uchar buf[16];

#ifdef CONFIG_DM_RTC
	if (dm_i2c_read(dev, 0, buf, sizeof(buf))) {
#else
	if (i2c_read(dev->chip, 0, 0, buf, 16)) {
#endif
		printf("Error reading from RTC\n");
		return -EIO;
	}

	sec = rtc_read(RTC_SEC_REG_ADDR);
	min = rtc_read(RTC_MIN_REG_ADDR);
	hour = rtc_read(RTC_HR_REG_ADDR);
	wday = rtc_read(RTC_DAY_REG_ADDR);
	mday = rtc_read(RTC_DATE_REG_ADDR);
	mon = rtc_read(RTC_MON_REG_ADDR);
	year = rtc_read(RTC_YR_REG_ADDR);

	DEBUGR("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
	       "hr: %02x min: %02x sec: %02x\n",
	       year, mon, mday, wday, hour, min, sec);

	/* dump status */
	ctl2 = rtc_read(RTC_CTL2_REG_ADDR);
	if (ctl2 & RTC_CTL2_BIT_PON) {
		printf("RTC: power-on detected\n");
		rel = -1;
	}

	if (ctl2 & RTC_CTL2_BIT_VDET) {
		printf("RTC: voltage drop detected\n");
		rel = -1;
	}

	if (!(ctl2 & RTC_CTL2_BIT_XST)) {
		printf("RTC: oscillator stop detected\n");
		rel = -1;
	}

	tmp->tm_sec  = bcd2bin(sec & 0x7F);
	tmp->tm_min  = bcd2bin(min & 0x7F);
	if (rtc_read(RTC_CTL1_REG_ADDR) & RTC_CTL1_BIT_2412)
		tmp->tm_hour = bcd2bin(hour & 0x3F);
	else
		tmp->tm_hour = bcd2bin(hour & 0x1F) % 12 +
			       ((hour & 0x20) ? 12 : 0);

	tmp->tm_mday = bcd2bin (mday & 0x3F);
	tmp->tm_mon  = bcd2bin (mon & 0x1F);
	tmp->tm_year = bcd2bin (year) + ( bcd2bin (year) >= 70 ? 1900 : 2000);
	tmp->tm_wday = bcd2bin (wday & 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 rel;
}

/*
 * Set the RTC
 */
static int rx8025_rtc_set(DEV_TYPE *dev, const struct rtc_time *tmp)
{
	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 < 1970 || tmp->tm_year > 2069)
		printf("WARNING: year should be between 1970 and 2069!\n");

	if (rtc_write(dev, RTC_YR_REG_ADDR, bin2bcd(tmp->tm_year % 100)))
		return -EIO;

	if (rtc_write(dev, RTC_MON_REG_ADDR, bin2bcd(tmp->tm_mon)))
		return -EIO;

	if (rtc_write(dev, RTC_DAY_REG_ADDR, bin2bcd(tmp->tm_wday)))
		return -EIO;

	if (rtc_write(dev, RTC_DATE_REG_ADDR, bin2bcd(tmp->tm_mday)))
		return -EIO;

	if (rtc_write(dev, RTC_HR_REG_ADDR, bin2bcd(tmp->tm_hour)))
		return -EIO;

	if (rtc_write(dev, RTC_MIN_REG_ADDR, bin2bcd(tmp->tm_min)))
		return -EIO;

	if (rtc_write(dev, RTC_SEC_REG_ADDR, bin2bcd(tmp->tm_sec)))
		return -EIO;

	return rtc_write(dev, RTC_CTL1_REG_ADDR, RTC_CTL1_BIT_2412);
}

/*
 * Reset the RTC
 */
static int rx8025_rtc_reset(DEV_TYPE *dev)
{
	uchar buf[16];
	uchar ctl2;

#ifdef CONFIG_DM_RTC
	if (dm_i2c_read(dev, 0, buf, sizeof(buf))) {
#else
	if (i2c_read(dev->chip, 0, 0, buf, 16)) {
#endif
		printf("Error reading from RTC\n");
		return -EIO;
	}

	ctl2 = rtc_read(RTC_CTL2_REG_ADDR);
	ctl2 &= ~(RTC_CTL2_BIT_PON | RTC_CTL2_BIT_VDET);
	ctl2 |= RTC_CTL2_BIT_XST | RTC_CTL2_BIT_VDSL;

	return rtc_write(dev, RTC_CTL2_REG_ADDR, ctl2);
}

/*
 * Helper functions
 */
static int rtc_write(DEV_TYPE *dev, uchar reg, uchar val)
{
	uchar buf[2];
	buf[0] = reg << 4;
	buf[1] = val;

#ifdef CONFIG_DM_RTC
	if (dm_i2c_write(dev, 0, buf, 2)) {
#else
	if (i2c_write(dev->chip, 0, 0, buf, 2) != 0) {
#endif
		printf("Error writing to RTC\n");
		return -EIO;
	}

	return 0;
}

#ifdef CONFIG_DM_RTC
static int rx8025_probe(struct udevice *dev)
{
	uchar buf[16];
	int ret = 0;

	if (i2c_get_chip_offset_len(dev) != 1)
		ret = i2c_set_chip_offset_len(dev, 1);

	if (ret)
		return ret;

	return dm_i2c_read(dev, 0, buf, sizeof(buf));
}

static const struct rtc_ops rx8025_rtc_ops = {
	.get = rx8025_rtc_get,
	.set = rx8025_rtc_set,
	.reset = rx8025_rtc_reset,
};

static const struct udevice_id rx8025_rtc_ids[] = {
	{ .compatible = "epson,rx8025" },
	{ }
};

U_BOOT_DRIVER(rx8010sj_rtc) = {
	.name	  = "rx8025_rtc",
	.id	      = UCLASS_RTC,
	.probe    = rx8025_probe,
	.of_match = rx8025_rtc_ids,
	.ops	  = &rx8025_rtc_ops,
};
#else
int rtc_get(struct rtc_time *tm)
{
	struct ludevice dev = {
		.chip = CONFIG_SYS_I2C_RTC_ADDR,
	};

	return rx8025_rtc_get(&dev, tm);
}

int rtc_set(struct rtc_time *tm)
{
	struct ludevice dev = {
		.chip = CONFIG_SYS_I2C_RTC_ADDR,
	};

	return rx8025_rtc_set(&dev, tm);
}

void rtc_reset(void)
{
	struct ludevice dev = {
		.chip = CONFIG_SYS_I2C_RTC_ADDR,
	};

	rx8025_rtc_reset(&dev);
}
#endif