1/* 2 * ST M48T86 / Dallas DS12887 RTC driver 3 * Copyright (c) 2006 Tower Technologies 4 * 5 * Author: Alessandro Zummo <a.zummo@towertech.it> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * This drivers only supports the clock running in BCD and 24H mode. 12 * If it will be ever adapted to binary and 12H mode, care must be taken 13 * to not introduce bugs. 14 */ 15 16#include <linux/module.h> 17#include <linux/rtc.h> 18#include <linux/platform_device.h> 19#include <linux/m48t86.h> 20#include <linux/bcd.h> 21 22#define M48T86_REG_SEC 0x00 23#define M48T86_REG_SECALRM 0x01 24#define M48T86_REG_MIN 0x02 25#define M48T86_REG_MINALRM 0x03 26#define M48T86_REG_HOUR 0x04 27#define M48T86_REG_HOURALRM 0x05 28#define M48T86_REG_DOW 0x06 /* 1 = sunday */ 29#define M48T86_REG_DOM 0x07 30#define M48T86_REG_MONTH 0x08 /* 1 - 12 */ 31#define M48T86_REG_YEAR 0x09 /* 0 - 99 */ 32#define M48T86_REG_A 0x0A 33#define M48T86_REG_B 0x0B 34#define M48T86_REG_C 0x0C 35#define M48T86_REG_D 0x0D 36 37#define M48T86_REG_B_H24 (1 << 1) 38#define M48T86_REG_B_DM (1 << 2) 39#define M48T86_REG_B_SET (1 << 7) 40#define M48T86_REG_D_VRT (1 << 7) 41 42#define DRV_VERSION "0.1" 43 44 45static int m48t86_rtc_read_time(struct device *dev, struct rtc_time *tm) 46{ 47 unsigned char reg; 48 struct platform_device *pdev = to_platform_device(dev); 49 struct m48t86_ops *ops = pdev->dev.platform_data; 50 51 reg = ops->readbyte(M48T86_REG_B); 52 53 if (reg & M48T86_REG_B_DM) { 54 /* data (binary) mode */ 55 tm->tm_sec = ops->readbyte(M48T86_REG_SEC); 56 tm->tm_min = ops->readbyte(M48T86_REG_MIN); 57 tm->tm_hour = ops->readbyte(M48T86_REG_HOUR) & 0x3F; 58 tm->tm_mday = ops->readbyte(M48T86_REG_DOM); 59 /* tm_mon is 0-11 */ 60 tm->tm_mon = ops->readbyte(M48T86_REG_MONTH) - 1; 61 tm->tm_year = ops->readbyte(M48T86_REG_YEAR) + 100; 62 tm->tm_wday = ops->readbyte(M48T86_REG_DOW); 63 } else { 64 /* bcd mode */ 65 tm->tm_sec = bcd2bin(ops->readbyte(M48T86_REG_SEC)); 66 tm->tm_min = bcd2bin(ops->readbyte(M48T86_REG_MIN)); 67 tm->tm_hour = bcd2bin(ops->readbyte(M48T86_REG_HOUR) & 0x3F); 68 tm->tm_mday = bcd2bin(ops->readbyte(M48T86_REG_DOM)); 69 /* tm_mon is 0-11 */ 70 tm->tm_mon = bcd2bin(ops->readbyte(M48T86_REG_MONTH)) - 1; 71 tm->tm_year = bcd2bin(ops->readbyte(M48T86_REG_YEAR)) + 100; 72 tm->tm_wday = bcd2bin(ops->readbyte(M48T86_REG_DOW)); 73 } 74 75 /* correct the hour if the clock is in 12h mode */ 76 if (!(reg & M48T86_REG_B_H24)) 77 if (ops->readbyte(M48T86_REG_HOUR) & 0x80) 78 tm->tm_hour += 12; 79 80 return rtc_valid_tm(tm); 81} 82 83static int m48t86_rtc_set_time(struct device *dev, struct rtc_time *tm) 84{ 85 unsigned char reg; 86 struct platform_device *pdev = to_platform_device(dev); 87 struct m48t86_ops *ops = pdev->dev.platform_data; 88 89 reg = ops->readbyte(M48T86_REG_B); 90 91 /* update flag and 24h mode */ 92 reg |= M48T86_REG_B_SET | M48T86_REG_B_H24; 93 ops->writebyte(reg, M48T86_REG_B); 94 95 if (reg & M48T86_REG_B_DM) { 96 /* data (binary) mode */ 97 ops->writebyte(tm->tm_sec, M48T86_REG_SEC); 98 ops->writebyte(tm->tm_min, M48T86_REG_MIN); 99 ops->writebyte(tm->tm_hour, M48T86_REG_HOUR); 100 ops->writebyte(tm->tm_mday, M48T86_REG_DOM); 101 ops->writebyte(tm->tm_mon + 1, M48T86_REG_MONTH); 102 ops->writebyte(tm->tm_year % 100, M48T86_REG_YEAR); 103 ops->writebyte(tm->tm_wday, M48T86_REG_DOW); 104 } else { 105 /* bcd mode */ 106 ops->writebyte(bin2bcd(tm->tm_sec), M48T86_REG_SEC); 107 ops->writebyte(bin2bcd(tm->tm_min), M48T86_REG_MIN); 108 ops->writebyte(bin2bcd(tm->tm_hour), M48T86_REG_HOUR); 109 ops->writebyte(bin2bcd(tm->tm_mday), M48T86_REG_DOM); 110 ops->writebyte(bin2bcd(tm->tm_mon + 1), M48T86_REG_MONTH); 111 ops->writebyte(bin2bcd(tm->tm_year % 100), M48T86_REG_YEAR); 112 ops->writebyte(bin2bcd(tm->tm_wday), M48T86_REG_DOW); 113 } 114 115 /* update ended */ 116 reg &= ~M48T86_REG_B_SET; 117 ops->writebyte(reg, M48T86_REG_B); 118 119 return 0; 120} 121 122static int m48t86_rtc_proc(struct device *dev, struct seq_file *seq) 123{ 124 unsigned char reg; 125 struct platform_device *pdev = to_platform_device(dev); 126 struct m48t86_ops *ops = pdev->dev.platform_data; 127 128 reg = ops->readbyte(M48T86_REG_B); 129 130 seq_printf(seq, "mode\t\t: %s\n", 131 (reg & M48T86_REG_B_DM) ? "binary" : "bcd"); 132 133 reg = ops->readbyte(M48T86_REG_D); 134 135 seq_printf(seq, "battery\t\t: %s\n", 136 (reg & M48T86_REG_D_VRT) ? "ok" : "exhausted"); 137 138 return 0; 139} 140 141static const struct rtc_class_ops m48t86_rtc_ops = { 142 .read_time = m48t86_rtc_read_time, 143 .set_time = m48t86_rtc_set_time, 144 .proc = m48t86_rtc_proc, 145}; 146 147static int __devinit m48t86_rtc_probe(struct platform_device *dev) 148{ 149 unsigned char reg; 150 struct m48t86_ops *ops = dev->dev.platform_data; 151 struct rtc_device *rtc = rtc_device_register("m48t86", 152 &dev->dev, &m48t86_rtc_ops, THIS_MODULE); 153 154 if (IS_ERR(rtc)) 155 return PTR_ERR(rtc); 156 157 platform_set_drvdata(dev, rtc); 158 159 /* read battery status */ 160 reg = ops->readbyte(M48T86_REG_D); 161 dev_info(&dev->dev, "battery %s\n", 162 (reg & M48T86_REG_D_VRT) ? "ok" : "exhausted"); 163 164 return 0; 165} 166 167static int __devexit m48t86_rtc_remove(struct platform_device *dev) 168{ 169 struct rtc_device *rtc = platform_get_drvdata(dev); 170 171 if (rtc) 172 rtc_device_unregister(rtc); 173 174 platform_set_drvdata(dev, NULL); 175 176 return 0; 177} 178 179static struct platform_driver m48t86_rtc_platform_driver = { 180 .driver = { 181 .name = "rtc-m48t86", 182 .owner = THIS_MODULE, 183 }, 184 .probe = m48t86_rtc_probe, 185 .remove = __devexit_p(m48t86_rtc_remove), 186}; 187 188static int __init m48t86_rtc_init(void) 189{ 190 return platform_driver_register(&m48t86_rtc_platform_driver); 191} 192 193static void __exit m48t86_rtc_exit(void) 194{ 195 platform_driver_unregister(&m48t86_rtc_platform_driver); 196} 197 198MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); 199MODULE_DESCRIPTION("M48T86 RTC driver"); 200MODULE_LICENSE("GPL"); 201MODULE_VERSION(DRV_VERSION); 202MODULE_ALIAS("platform:rtc-m48t86"); 203 204module_init(m48t86_rtc_init); 205module_exit(m48t86_rtc_exit); 206