diff options
Diffstat (limited to 'drivers/rtc/rtc-m48t86.c')
| -rw-r--r-- | drivers/rtc/rtc-m48t86.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-m48t86.c b/drivers/rtc/rtc-m48t86.c new file mode 100644 index 000000000..a17b7a3ce --- /dev/null +++ b/drivers/rtc/rtc-m48t86.c @@ -0,0 +1,182 @@ +/* + * 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/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) + +#define DRV_VERSION "0.1" + + +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_VERSION(DRV_VERSION); +MODULE_ALIAS("platform:rtc-m48t86"); |