drivers/rtc/rtc-rx4581.c - linux/torvalds/linux - Git at Google

 // 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");
	// 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");