/* * ST M48T86 / Dallas DS12887 RTC driver * Copyright (c) 2006 Tower Technologies * * Author: Alessandro Zummo <a.zummo@towertech.it> * * 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. * * This drivers only supports the clock running in BCD and 24H mode. * If it will be ever adapted to binary and 12H mode, care must be taken * to not introduce bugs. */ #include <linux/module.h> #include <linux/rtc.h> #include <linux/platform_device.h> #include <linux/platform_data/rtc-m48t86.h> #include <linux/bcd.h> #define M48T86_REG_SEC 0x00 #define M48T86_REG_SECALRM 0x01 #define M48T86_REG_MIN 0x02 #define M48T86_REG_MINALRM 0x03 #define M48T86_REG_HOUR 0x04 #define M48T86_REG_HOURALRM 0x05 #define M48T86_REG_DOW 0x06 /* 1 = sunday */ #define M48T86_REG_DOM 0x07 #define M48T86_REG_MONTH 0x08 /* 1 - 12 */ #define M48T86_REG_YEAR 0x09 /* 0 - 99 */ #define M48T86_REG_A 0x0A #define M48T86_REG_B 0x0B #define M48T86_REG_C 0x0C #define M48T86_REG_D 0x0D #define M48T86_REG_B_H24 (1 << 1) #define M48T86_REG_B_DM (1 << 2) #define M48T86_REG_B_SET (1 << 7) #define M48T86_REG_D_VRT (1 << 7) static int m48t86_rtc_read_time(struct device *dev, struct rtc_time *tm) { unsigned char reg; struct platform_device *pdev = to_platform_device(dev); struct m48t86_ops *ops = dev_get_platdata(&pdev->dev); reg = ops->readbyte(M48T86_REG_B); if (reg & M48T86_REG_B_DM) { /* data (binary) mode */ tm->tm_sec = ops->readbyte(M48T86_REG_SEC); tm->tm_min = ops->readbyte(M48T86_REG_MIN); tm->tm_hour = ops->readbyte(M48T86_REG_HOUR) & 0x3F; tm->tm_mday = ops->readbyte(M48T86_REG_DOM); /* tm_mon is 0-11 */ tm->tm_mon = ops->readbyte(M48T86_REG_MONTH) - 1; tm->tm_year = ops->readbyte(M48T86_REG_YEAR) + 100; tm->tm_wday = ops->readbyte(M48T86_REG_DOW); } else { /* bcd mode */ tm->tm_sec = bcd2bin(ops->readbyte(M48T86_REG_SEC)); tm->tm_min = bcd2bin(ops->readbyte(M48T86_REG_MIN)); tm->tm_hour = bcd2bin(ops->readbyte(M48T86_REG_HOUR) & 0x3F); tm->tm_mday = bcd2bin(ops->readbyte(M48T86_REG_DOM)); /* tm_mon is 0-11 */ tm->tm_mon = bcd2bin(ops->readbyte(M48T86_REG_MONTH)) - 1; tm->tm_year = bcd2bin(ops->readbyte(M48T86_REG_YEAR)) + 100; tm->tm_wday = bcd2bin(ops->readbyte(M48T86_REG_DOW)); } /* correct the hour if the clock is in 12h mode */ if (!(reg & M48T86_REG_B_H24)) if (ops->readbyte(M48T86_REG_HOUR) & 0x80) tm->tm_hour += 12; return rtc_valid_tm(tm); } static int m48t86_rtc_set_time(struct device *dev, struct rtc_time *tm) { unsigned char reg; struct platform_device *pdev = to_platform_device(dev); struct m48t86_ops *ops = dev_get_platdata(&pdev->dev); reg = ops->readbyte(M48T86_REG_B); /* update flag and 24h mode */ reg |= M48T86_REG_B_SET | M48T86_REG_B_H24; ops->writebyte(reg, M48T86_REG_B); if (reg & M48T86_REG_B_DM) { /* data (binary) mode */ ops->writebyte(tm->tm_sec, M48T86_REG_SEC); ops->writebyte(tm->tm_min, M48T86_REG_MIN); ops->writebyte(tm->tm_hour, M48T86_REG_HOUR); ops->writebyte(tm->tm_mday, M48T86_REG_DOM); ops->writebyte(tm->tm_mon + 1, M48T86_REG_MONTH); ops->writebyte(tm->tm_year % 100, M48T86_REG_YEAR); ops->writebyte(tm->tm_wday, M48T86_REG_DOW); } else { /* bcd mode */ ops->writebyte(bin2bcd(tm->tm_sec), M48T86_REG_SEC); ops->writebyte(bin2bcd(tm->tm_min), M48T86_REG_MIN); ops->writebyte(bin2bcd(tm->tm_hour), M48T86_REG_HOUR); ops->writebyte(bin2bcd(tm->tm_mday), M48T86_REG_DOM); ops->writebyte(bin2bcd(tm->tm_mon + 1), M48T86_REG_MONTH); ops->writebyte(bin2bcd(tm->tm_year % 100), M48T86_REG_YEAR); ops->writebyte(bin2bcd(tm->tm_wday), M48T86_REG_DOW); } /* update ended */ reg &= ~M48T86_REG_B_SET; ops->writebyte(reg, M48T86_REG_B); return 0; } static int m48t86_rtc_proc(struct device *dev, struct seq_file *seq) { unsigned char reg; struct platform_device *pdev = to_platform_device(dev); struct m48t86_ops *ops = dev_get_platdata(&pdev->dev); reg = ops->readbyte(M48T86_REG_B); seq_printf(seq, "mode\t\t: %s\n", (reg & M48T86_REG_B_DM) ? "binary" : "bcd"); reg = ops->readbyte(M48T86_REG_D); seq_printf(seq, "battery\t\t: %s\n", (reg & M48T86_REG_D_VRT) ? "ok" : "exhausted"); return 0; } static const struct rtc_class_ops m48t86_rtc_ops = { .read_time = m48t86_rtc_read_time, .set_time = m48t86_rtc_set_time, .proc = m48t86_rtc_proc, }; static int m48t86_rtc_probe(struct platform_device *dev) { unsigned char reg; struct m48t86_ops *ops = dev_get_platdata(&dev->dev); struct rtc_device *rtc; rtc = devm_rtc_device_register(&dev->dev, "m48t86", &m48t86_rtc_ops, THIS_MODULE); if (IS_ERR(rtc)) return PTR_ERR(rtc); platform_set_drvdata(dev, rtc); /* read battery status */ reg = ops->readbyte(M48T86_REG_D); dev_info(&dev->dev, "battery %s\n", (reg & M48T86_REG_D_VRT) ? "ok" : "exhausted"); return 0; } static struct platform_driver m48t86_rtc_platform_driver = { .driver = { .name = "rtc-m48t86", }, .probe = m48t86_rtc_probe, }; module_platform_driver(m48t86_rtc_platform_driver); MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); MODULE_DESCRIPTION("M48T86 RTC driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:rtc-m48t86");