// SPDX-License-Identifier: GPL-2.0-only/* drivers/rtc/rtc-rx4581.c * * written by Torben Hohn <torbenh@linutronix.de> * * Based on: * drivers/rtc/rtc-max6902.c * * Copyright (C) 2006 8D Technologies inc. * Copyright (C) 2004 Compulab Ltd. * * Driver for MAX6902 spi RTC * * and based on: * drivers/rtc/rtc-rx8581.c * * An I2C driver for the Epson RX8581 RTC * * Author: Martyn Welch <martyn.welch@ge.com> * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc. * * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC) * Copyright 2005-06 Tower Technologies */ #include <linux/module.h>#include <linux/kernel.h>#include <linux/platform_device.h>#include <linux/init.h>#include <linux/rtc.h>#include <linux/spi/spi.h>#include <linux/bcd.h> #define RX4581_REG_SC		0x00 /* Second in BCD */#define RX4581_REG_MN		0x01 /* Minute in BCD */#define RX4581_REG_HR		0x02 /* Hour in BCD */#define RX4581_REG_DW		0x03 /* Day of Week */#define RX4581_REG_DM		0x04 /* Day of Month in BCD */#define RX4581_REG_MO		0x05 /* Month in BCD */#define RX4581_REG_YR		0x06 /* Year in BCD */#define RX4581_REG_RAM		0x07 /* RAM */#define RX4581_REG_AMN		0x08 /* Alarm Min in BCD*/#define RX4581_REG_AHR		0x09 /* Alarm Hour in BCD */#define RX4581_REG_ADM		0x0A#define RX4581_REG_ADW		0x0A#define RX4581_REG_TMR0		0x0B#define RX4581_REG_TMR1		0x0C#define RX4581_REG_EXT		0x0D /* Extension Register */#define RX4581_REG_FLAG		0x0E /* Flag Register */#define RX4581_REG_CTRL		0x0F /* Control Register */  /* Flag Register bit definitions */#define RX4581_FLAG_UF		0x20 /* Update */#define RX4581_FLAG_TF		0x10 /* Timer */#define RX4581_FLAG_AF		0x08 /* Alarm */#define RX4581_FLAG_VLF		0x02 /* Voltage Low */ /* Control Register bit definitions */#define RX4581_CTRL_UIE		0x20 /* Update Interrupt Enable */#define RX4581_CTRL_TIE		0x10 /* Timer Interrupt Enable */#define RX4581_CTRL_AIE		0x08 /* Alarm Interrupt Enable */#define RX4581_CTRL_STOP	0x02 /* STOP bit */#define RX4581_CTRL_RESET	0x01 /* RESET bit */ static int rx4581_set_reg(struct device *dev, unsigned char address,				unsigned char data){	struct spi_device *spi = to_spi_device(dev);	unsigned char buf[2]; 	/* high nibble must be '0' to write */	buf[0] = address & 0x0f;	buf[1] = data; 	return spi_write_then_read(spi, buf, 2, NULL, 0);} static int rx4581_get_reg(struct device *dev, unsigned char address,				unsigned char *data){	struct spi_device *spi = to_spi_device(dev); 	/* Set MSB to indicate read */	*data = address | 0x80; 	return spi_write_then_read(spi, data, 1, data, 1);} /* * In the routines that deal directly with the rx8581 hardware, we use * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. */static int rx4581_get_datetime(struct device *dev, struct rtc_time *tm){	struct spi_device *spi = to_spi_device(dev);	unsigned char date[7];	unsigned char data;	int err; 	/* First we ensure that the "update flag" is not set, we read the	 * time and date then re-read the "update flag". If the update flag	 * has been set, we know that the time has changed during the read so	 * we repeat the whole process again.	 */	err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data);	if (err != 0) {		dev_err(dev, "Unable to read device flags\n");		return -EIO;	} 	do {		/* If update flag set, clear it */		if (data & RX4581_FLAG_UF) {			err = rx4581_set_reg(dev,				RX4581_REG_FLAG, (data & ~RX4581_FLAG_UF));			if (err != 0) {				dev_err(dev, "Unable to write device "					"flags\n");				return -EIO;			}		} 		/* Now read time and date */		date[0] = 0x80;		err = spi_write_then_read(spi, date, 1, date, 7);		if (err < 0) {			dev_err(dev, "Unable to read date\n");			return -EIO;		} 		/* Check flag register */		err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data);		if (err != 0) {			dev_err(dev, "Unable to read device flags\n");			return -EIO;		}	} while (data & RX4581_FLAG_UF); 	if (data & RX4581_FLAG_VLF)		dev_info(dev,			"low voltage detected, date/time is not reliable.\n"); 	dev_dbg(dev,		"%s: raw data is sec=%02x, min=%02x, hr=%02x, "		"wday=%02x, mday=%02x, mon=%02x, year=%02x\n",		__func__,		date[0], date[1], date[2], date[3], date[4], date[5], date[6]); 	tm->tm_sec = bcd2bin(date[RX4581_REG_SC] & 0x7F);	tm->tm_min = bcd2bin(date[RX4581_REG_MN] & 0x7F);	tm->tm_hour = bcd2bin(date[RX4581_REG_HR] & 0x3F); /* rtc hr 0-23 */	tm->tm_wday = ilog2(date[RX4581_REG_DW] & 0x7F);	tm->tm_mday = bcd2bin(date[RX4581_REG_DM] & 0x3F);	tm->tm_mon = bcd2bin(date[RX4581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */	tm->tm_year = bcd2bin(date[RX4581_REG_YR]);	if (tm->tm_year < 70)		tm->tm_year += 100;	/* assume we are in 1970...2069 */  	dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "		"mday=%d, mon=%d, year=%d, wday=%d\n",		__func__,		tm->tm_sec, tm->tm_min, tm->tm_hour,		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 	return 0;} static int rx4581_set_datetime(struct device *dev, struct rtc_time *tm){	struct spi_device *spi = to_spi_device(dev);	int err;	unsigned char buf[8], data; 	dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "		"mday=%d, mon=%d, year=%d, wday=%d\n",		__func__,		tm->tm_sec, tm->tm_min, tm->tm_hour,		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 	buf[0] = 0x00;	/* hours, minutes and seconds */	buf[RX4581_REG_SC+1] = bin2bcd(tm->tm_sec);	buf[RX4581_REG_MN+1] = bin2bcd(tm->tm_min);	buf[RX4581_REG_HR+1] = bin2bcd(tm->tm_hour); 	buf[RX4581_REG_DM+1] = bin2bcd(tm->tm_mday); 	/* month, 1 - 12 */	buf[RX4581_REG_MO+1] = bin2bcd(tm->tm_mon + 1); 	/* year and century */	buf[RX4581_REG_YR+1] = bin2bcd(tm->tm_year % 100);	buf[RX4581_REG_DW+1] = (0x1 << tm->tm_wday); 	/* Stop the clock */	err = rx4581_get_reg(dev, RX4581_REG_CTRL, &data);	if (err != 0) {		dev_err(dev, "Unable to read control register\n");		return -EIO;	} 	err = rx4581_set_reg(dev, RX4581_REG_CTRL,		(data | RX4581_CTRL_STOP));	if (err != 0) {		dev_err(dev, "Unable to write control register\n");		return -EIO;	} 	/* write register's data */	err = spi_write_then_read(spi, buf, 8, NULL, 0);	if (err != 0) {		dev_err(dev, "Unable to write to date registers\n");		return -EIO;	} 	/* get VLF and clear it */	err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data);	if (err != 0) {		dev_err(dev, "Unable to read flag register\n");		return -EIO;	} 	err = rx4581_set_reg(dev, RX4581_REG_FLAG,		(data & ~(RX4581_FLAG_VLF)));	if (err != 0) {		dev_err(dev, "Unable to write flag register\n");		return -EIO;	} 	/* Restart the clock */	err = rx4581_get_reg(dev, RX4581_REG_CTRL, &data);	if (err != 0) {		dev_err(dev, "Unable to read control register\n");		return -EIO;	} 	err = rx4581_set_reg(dev, RX4581_REG_CTRL,		(data & ~(RX4581_CTRL_STOP)));	if (err != 0) {		dev_err(dev, "Unable to write control register\n");		return -EIO;	} 	return 0;} static const struct rtc_class_ops rx4581_rtc_ops = {	.read_time	= rx4581_get_datetime,	.set_time	= rx4581_set_datetime,}; static int rx4581_probe(struct spi_device *spi){	struct rtc_device *rtc;	unsigned char tmp;	int res; 	res = rx4581_get_reg(&spi->dev, RX4581_REG_SC, &tmp);	if (res != 0)		return res; 	rtc = devm_rtc_device_register(&spi->dev, "rx4581",				&rx4581_rtc_ops, THIS_MODULE);	if (IS_ERR(rtc))		return PTR_ERR(rtc); 	spi_set_drvdata(spi, rtc);	return 0;} static const struct spi_device_id rx4581_id[] = {	{ "rx4581", 0 },	{ }};MODULE_DEVICE_TABLE(spi, rx4581_id); static struct spi_driver rx4581_driver = {	.driver = {		.name	= "rtc-rx4581",	},	.probe	= rx4581_probe,	.id_table = rx4581_id,}; module_spi_driver(rx4581_driver); MODULE_DESCRIPTION("rx4581 spi RTC driver");MODULE_AUTHOR("Torben Hohn");MODULE_LICENSE("GPL");MODULE_ALIAS("spi:rtc-rx4581");