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