rtc-ds1742.c revision 50e49bee3fc5c0cd0aff80ebd8061f356b7b9bd8
1/* 2 * An rtc driver for the Dallas DS1742 3 * 4 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * Copyright (C) 2006 Torsten Ertbjerg Rasmussen <tr@newtec.dk> 11 * - nvram size determined from resource 12 * - this ds1742 driver now supports ds1743. 13 */ 14 15#include <linux/bcd.h> 16#include <linux/init.h> 17#include <linux/kernel.h> 18#include <linux/delay.h> 19#include <linux/jiffies.h> 20#include <linux/rtc.h> 21#include <linux/platform_device.h> 22#include <linux/io.h> 23 24#define DRV_VERSION "0.4" 25 26#define RTC_SIZE 8 27 28#define RTC_CONTROL 0 29#define RTC_CENTURY 0 30#define RTC_SECONDS 1 31#define RTC_MINUTES 2 32#define RTC_HOURS 3 33#define RTC_DAY 4 34#define RTC_DATE 5 35#define RTC_MONTH 6 36#define RTC_YEAR 7 37 38#define RTC_CENTURY_MASK 0x3f 39#define RTC_SECONDS_MASK 0x7f 40#define RTC_DAY_MASK 0x07 41 42/* Bits in the Control/Century register */ 43#define RTC_WRITE 0x80 44#define RTC_READ 0x40 45 46/* Bits in the Seconds register */ 47#define RTC_STOP 0x80 48 49/* Bits in the Day register */ 50#define RTC_BATT_FLAG 0x80 51 52struct rtc_plat_data { 53 struct rtc_device *rtc; 54 void __iomem *ioaddr_nvram; 55 void __iomem *ioaddr_rtc; 56 size_t size_nvram; 57 size_t size; 58 unsigned long last_jiffies; 59 struct bin_attribute nvram_attr; 60}; 61 62static int ds1742_rtc_set_time(struct device *dev, struct rtc_time *tm) 63{ 64 struct platform_device *pdev = to_platform_device(dev); 65 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 66 void __iomem *ioaddr = pdata->ioaddr_rtc; 67 u8 century; 68 69 century = bin2bcd((tm->tm_year + 1900) / 100); 70 71 writeb(RTC_WRITE, ioaddr + RTC_CONTROL); 72 73 writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR); 74 writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH); 75 writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY); 76 writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE); 77 writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS); 78 writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES); 79 writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS); 80 81 /* RTC_CENTURY and RTC_CONTROL share same register */ 82 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY); 83 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 84 return 0; 85} 86 87static int ds1742_rtc_read_time(struct device *dev, struct rtc_time *tm) 88{ 89 struct platform_device *pdev = to_platform_device(dev); 90 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 91 void __iomem *ioaddr = pdata->ioaddr_rtc; 92 unsigned int year, month, day, hour, minute, second, week; 93 unsigned int century; 94 95 /* give enough time to update RTC in case of continuous read */ 96 if (pdata->last_jiffies == jiffies) 97 msleep(1); 98 pdata->last_jiffies = jiffies; 99 writeb(RTC_READ, ioaddr + RTC_CONTROL); 100 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK; 101 minute = readb(ioaddr + RTC_MINUTES); 102 hour = readb(ioaddr + RTC_HOURS); 103 day = readb(ioaddr + RTC_DATE); 104 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK; 105 month = readb(ioaddr + RTC_MONTH); 106 year = readb(ioaddr + RTC_YEAR); 107 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 108 writeb(0, ioaddr + RTC_CONTROL); 109 tm->tm_sec = bcd2bin(second); 110 tm->tm_min = bcd2bin(minute); 111 tm->tm_hour = bcd2bin(hour); 112 tm->tm_mday = bcd2bin(day); 113 tm->tm_wday = bcd2bin(week); 114 tm->tm_mon = bcd2bin(month) - 1; 115 /* year is 1900 + tm->tm_year */ 116 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900; 117 118 if (rtc_valid_tm(tm) < 0) { 119 dev_err(dev, "retrieved date/time is not valid.\n"); 120 rtc_time_to_tm(0, tm); 121 } 122 return 0; 123} 124 125static const struct rtc_class_ops ds1742_rtc_ops = { 126 .read_time = ds1742_rtc_read_time, 127 .set_time = ds1742_rtc_set_time, 128}; 129 130static ssize_t ds1742_nvram_read(struct kobject *kobj, 131 struct bin_attribute *bin_attr, 132 char *buf, loff_t pos, size_t size) 133{ 134 struct device *dev = container_of(kobj, struct device, kobj); 135 struct platform_device *pdev = to_platform_device(dev); 136 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 137 void __iomem *ioaddr = pdata->ioaddr_nvram; 138 ssize_t count; 139 140 for (count = 0; size > 0 && pos < pdata->size_nvram; count++, size--) 141 *buf++ = readb(ioaddr + pos++); 142 return count; 143} 144 145static ssize_t ds1742_nvram_write(struct kobject *kobj, 146 struct bin_attribute *bin_attr, 147 char *buf, loff_t pos, size_t size) 148{ 149 struct device *dev = container_of(kobj, struct device, kobj); 150 struct platform_device *pdev = to_platform_device(dev); 151 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 152 void __iomem *ioaddr = pdata->ioaddr_nvram; 153 ssize_t count; 154 155 for (count = 0; size > 0 && pos < pdata->size_nvram; count++, size--) 156 writeb(*buf++, ioaddr + pos++); 157 return count; 158} 159 160static int __devinit ds1742_rtc_probe(struct platform_device *pdev) 161{ 162 struct rtc_device *rtc; 163 struct resource *res; 164 unsigned int cen, sec; 165 struct rtc_plat_data *pdata; 166 void __iomem *ioaddr; 167 int ret = 0; 168 169 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 170 if (!res) 171 return -ENODEV; 172 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 173 if (!pdata) 174 return -ENOMEM; 175 pdata->size = res->end - res->start + 1; 176 if (!devm_request_mem_region(&pdev->dev, res->start, pdata->size, 177 pdev->name)) 178 return -EBUSY; 179 ioaddr = devm_ioremap(&pdev->dev, res->start, pdata->size); 180 if (!ioaddr) 181 return -ENOMEM; 182 183 pdata->ioaddr_nvram = ioaddr; 184 pdata->size_nvram = pdata->size - RTC_SIZE; 185 pdata->ioaddr_rtc = ioaddr + pdata->size_nvram; 186 187 pdata->nvram_attr.attr.name = "nvram"; 188 pdata->nvram_attr.attr.mode = S_IRUGO | S_IWUSR; 189 pdata->nvram_attr.read = ds1742_nvram_read; 190 pdata->nvram_attr.write = ds1742_nvram_write; 191 pdata->nvram_attr.size = pdata->size_nvram; 192 193 /* turn RTC on if it was not on */ 194 ioaddr = pdata->ioaddr_rtc; 195 sec = readb(ioaddr + RTC_SECONDS); 196 if (sec & RTC_STOP) { 197 sec &= RTC_SECONDS_MASK; 198 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 199 writeb(RTC_WRITE, ioaddr + RTC_CONTROL); 200 writeb(sec, ioaddr + RTC_SECONDS); 201 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 202 } 203 if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG)) 204 dev_warn(&pdev->dev, "voltage-low detected.\n"); 205 206 pdata->last_jiffies = jiffies; 207 platform_set_drvdata(pdev, pdata); 208 rtc = rtc_device_register(pdev->name, &pdev->dev, 209 &ds1742_rtc_ops, THIS_MODULE); 210 if (IS_ERR(rtc)) 211 return PTR_ERR(rtc); 212 pdata->rtc = rtc; 213 214 ret = sysfs_create_bin_file(&pdev->dev.kobj, &pdata->nvram_attr); 215 if (ret) { 216 dev_err(&pdev->dev, "creating nvram file in sysfs failed\n"); 217 rtc_device_unregister(rtc); 218 } 219 return ret; 220} 221 222static int __devexit ds1742_rtc_remove(struct platform_device *pdev) 223{ 224 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 225 226 sysfs_remove_bin_file(&pdev->dev.kobj, &pdata->nvram_attr); 227 rtc_device_unregister(pdata->rtc); 228 return 0; 229} 230 231static struct platform_driver ds1742_rtc_driver = { 232 .probe = ds1742_rtc_probe, 233 .remove = __devexit_p(ds1742_rtc_remove), 234 .driver = { 235 .name = "rtc-ds1742", 236 .owner = THIS_MODULE, 237 }, 238}; 239 240static __init int ds1742_init(void) 241{ 242 return platform_driver_register(&ds1742_rtc_driver); 243} 244 245static __exit void ds1742_exit(void) 246{ 247 platform_driver_unregister(&ds1742_rtc_driver); 248} 249 250module_init(ds1742_init); 251module_exit(ds1742_exit); 252 253MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 254MODULE_DESCRIPTION("Dallas DS1742 RTC driver"); 255MODULE_LICENSE("GPL"); 256MODULE_VERSION(DRV_VERSION); 257MODULE_ALIAS("platform:rtc-ds1742"); 258