/* drivers/rtc/rtc-max6902.c * * Copyright (C) 2006 8D Technologies inc. * Copyright (C) 2004 Compulab Ltd. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * Driver for MAX6902 spi RTC * * Changelog: * * 24-May-2006: Raphael Assenat <raph@8d.com> *                - Major rework *   				Converted to rtc_device and uses the SPI layer. * * ??-???-2005: Someone at Compulab *                - Initial driver creation. */ #include <linux/module.h>#include <linux/version.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>#include <linux/delay.h> #define MAX6902_REG_SECONDS		0x01#define MAX6902_REG_MINUTES		0x03#define MAX6902_REG_HOURS		0x05#define MAX6902_REG_DATE		0x07#define MAX6902_REG_MONTH		0x09#define MAX6902_REG_DAY			0x0B#define MAX6902_REG_YEAR		0x0D#define MAX6902_REG_CONTROL		0x0F#define MAX6902_REG_CENTURY		0x13 #undef MAX6902_DEBUG struct max6902 {	struct rtc_device *rtc;	u8 buf[9]; /* Burst read cmd + 8 registers */	u8 tx_buf[2];	u8 rx_buf[2];}; static void max6902_set_reg(struct device *dev, unsigned char address,				unsigned char data){	struct spi_device *spi = to_spi_device(dev);	unsigned char buf[2]; 	/* MSB must be '0' to write */	buf[0] = address & 0x7f;	buf[1] = data; 	spi_write(spi, buf, 2);} static int max6902_get_reg(struct device *dev, unsigned char address,				unsigned char *data){	struct spi_device *spi = to_spi_device(dev);	struct max6902 *chip = dev_get_drvdata(dev);	struct spi_message message;	struct spi_transfer xfer;	int status; 	if (!data)		return -EINVAL; 	/* Build our spi message */	spi_message_init(&message);	memset(&xfer, 0, sizeof(xfer));	xfer.len = 2;	/* Can tx_buf and rx_buf be equal? The doc in spi.h is not sure... */	xfer.tx_buf = chip->tx_buf;	xfer.rx_buf = chip->rx_buf; 	/* Set MSB to indicate read */	chip->tx_buf[0] = address | 0x80; 	spi_message_add_tail(&xfer, &message); 	/* do the i/o */	status = spi_sync(spi, &message);	if (status == 0)		status = message.status;	else		return status; 	*data = chip->rx_buf[1]; 	return status;} static int max6902_get_datetime(struct device *dev, struct rtc_time *dt){	unsigned char tmp;	int century;	int err;	struct spi_device *spi = to_spi_device(dev);	struct max6902 *chip = dev_get_drvdata(dev);	struct spi_message message;	struct spi_transfer xfer;	int status; 	err = max6902_get_reg(dev, MAX6902_REG_CENTURY, &tmp);	if (err)		return err; 	/* build the message */	spi_message_init(&message);	memset(&xfer, 0, sizeof(xfer));	xfer.len = 1 + 7;	/* Burst read command + 7 registers */	xfer.tx_buf = chip->buf;	xfer.rx_buf = chip->buf;	chip->buf[0] = 0xbf;	/* Burst read */	spi_message_add_tail(&xfer, &message); 	/* do the i/o */	status = spi_sync(spi, &message);	if (status == 0)		status = message.status;	else		return status; 	/* The chip sends data in this order:	 * Seconds, Minutes, Hours, Date, Month, Day, Year */	dt->tm_sec	= BCD2BIN(chip->buf[1]);	dt->tm_min	= BCD2BIN(chip->buf[2]);	dt->tm_hour	= BCD2BIN(chip->buf[3]);	dt->tm_mday	= BCD2BIN(chip->buf[4]);	dt->tm_mon	= BCD2BIN(chip->buf[5]) - 1;	dt->tm_wday	= BCD2BIN(chip->buf[6]);	dt->tm_year = BCD2BIN(chip->buf[7]); 	century = BCD2BIN(tmp) * 100; 	dt->tm_year += century;	dt->tm_year -= 1900; #ifdef MAX6902_DEBUG	printk("\n%s : Read RTC values\n",__FUNCTION__);	printk("tm_hour: %i\n",dt->tm_hour);	printk("tm_min : %i\n",dt->tm_min);	printk("tm_sec : %i\n",dt->tm_sec);	printk("tm_year: %i\n",dt->tm_year);	printk("tm_mon : %i\n",dt->tm_mon);	printk("tm_mday: %i\n",dt->tm_mday);	printk("tm_wday: %i\n",dt->tm_wday);#endif 	return 0;} static int max6902_set_datetime(struct device *dev, struct rtc_time *dt){	dt->tm_year = dt->tm_year+1900; #ifdef MAX6902_DEBUG	printk("\n%s : Setting RTC values\n",__FUNCTION__);	printk("tm_sec : %i\n",dt->tm_sec);	printk("tm_min : %i\n",dt->tm_min);	printk("tm_hour: %i\n",dt->tm_hour);	printk("tm_mday: %i\n",dt->tm_mday);	printk("tm_wday: %i\n",dt->tm_wday);	printk("tm_year: %i\n",dt->tm_year);#endif 	/* Remove write protection */	max6902_set_reg(dev, 0xF, 0); 	max6902_set_reg(dev, 0x01, BIN2BCD(dt->tm_sec));	max6902_set_reg(dev, 0x03, BIN2BCD(dt->tm_min));	max6902_set_reg(dev, 0x05, BIN2BCD(dt->tm_hour)); 	max6902_set_reg(dev, 0x07, BIN2BCD(dt->tm_mday));	max6902_set_reg(dev, 0x09, BIN2BCD(dt->tm_mon+1));	max6902_set_reg(dev, 0x0B, BIN2BCD(dt->tm_wday));	max6902_set_reg(dev, 0x0D, BIN2BCD(dt->tm_year%100));	max6902_set_reg(dev, 0x13, BIN2BCD(dt->tm_year/100)); 	/* Compulab used a delay here. However, the datasheet	 * does not mention a delay being required anywhere... */	/* delay(2000); */ 	/* Write protect */	max6902_set_reg(dev, 0xF, 0x80); 	return 0;} static int max6902_read_time(struct device *dev, struct rtc_time *tm){	return max6902_get_datetime(dev, tm);} static int max6902_set_time(struct device *dev, struct rtc_time *tm){	return max6902_set_datetime(dev, tm);} static const struct rtc_class_ops max6902_rtc_ops = {	.read_time	= max6902_read_time,	.set_time	= max6902_set_time,}; static int __devinit max6902_probe(struct spi_device *spi){	struct rtc_device *rtc;	unsigned char tmp;	struct max6902 *chip;	int res; 	rtc = rtc_device_register("max6902",				&spi->dev, &max6902_rtc_ops, THIS_MODULE);	if (IS_ERR(rtc))		return PTR_ERR(rtc); 	spi->mode = SPI_MODE_3;	spi->bits_per_word = 8;	spi_setup(spi); 	chip = kzalloc(sizeof *chip, GFP_KERNEL);	if (!chip) {		rtc_device_unregister(rtc);		return -ENOMEM;	}	chip->rtc = rtc;	dev_set_drvdata(&spi->dev, chip); 	res = max6902_get_reg(&spi->dev, MAX6902_REG_SECONDS, &tmp);	if (res) {		rtc_device_unregister(rtc);		return res;	} 	return 0;} static int __devexit max6902_remove(struct spi_device *spi){	struct max6902 *chip = platform_get_drvdata(spi);	struct rtc_device *rtc = chip->rtc; 	if (rtc)		rtc_device_unregister(rtc); 	kfree(chip); 	return 0;} static struct spi_driver max6902_driver = {	.driver = {		.name 	= "max6902",		.bus	= &spi_bus_type,		.owner	= THIS_MODULE,	},	.probe 	= max6902_probe,	.remove = __devexit_p(max6902_remove),}; static __init int max6902_init(void){	printk("max6902 spi driver\n");	return spi_register_driver(&max6902_driver);}module_init(max6902_init); static __exit void max6902_exit(void){	spi_unregister_driver(&max6902_driver);}module_exit(max6902_exit); MODULE_DESCRIPTION ("max6902 spi RTC driver");MODULE_AUTHOR ("Raphael Assenat");MODULE_LICENSE ("GPL");