rtc-ds1742.c revision f9231a0ca1afd05543d9f83539d6ecd5c018e8cf
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 "0.3" 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 baseaddr; 59 unsigned long last_jiffies; 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, char *buf, 131 loff_t pos, size_t size) 132{ 133 struct platform_device *pdev = 134 to_platform_device(container_of(kobj, struct device, kobj)); 135 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 136 void __iomem *ioaddr = pdata->ioaddr_nvram; 137 ssize_t count; 138 139 for (count = 0; size > 0 && pos < pdata->size_nvram; count++, size--) 140 *buf++ = readb(ioaddr + pos++); 141 return count; 142} 143 144static ssize_t ds1742_nvram_write(struct kobject *kobj, char *buf, 145 loff_t pos, size_t size) 146{ 147 struct platform_device *pdev = 148 to_platform_device(container_of(kobj, struct device, kobj)); 149 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 150 void __iomem *ioaddr = pdata->ioaddr_nvram; 151 ssize_t count; 152 153 for (count = 0; size > 0 && pos < pdata->size_nvram; count++, size--) 154 writeb(*buf++, ioaddr + pos++); 155 return count; 156} 157 158static struct bin_attribute ds1742_nvram_attr = { 159 .attr = { 160 .name = "nvram", 161 .mode = S_IRUGO | S_IWUGO, 162 .owner = THIS_MODULE, 163 }, 164 .read = ds1742_nvram_read, 165 .write = ds1742_nvram_write, 166}; 167 168static int __init ds1742_rtc_probe(struct platform_device *pdev) 169{ 170 struct rtc_device *rtc; 171 struct resource *res; 172 unsigned int cen, sec; 173 struct rtc_plat_data *pdata = NULL; 174 void __iomem *ioaddr = NULL; 175 int ret = 0; 176 177 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 178 if (!res) 179 return -ENODEV; 180 pdata = kzalloc(sizeof(*pdata), GFP_KERNEL); 181 if (!pdata) 182 return -ENOMEM; 183 pdata->size = res->end - res->start + 1; 184 if (!request_mem_region(res->start, pdata->size, pdev->name)) { 185 ret = -EBUSY; 186 goto out; 187 } 188 pdata->baseaddr = res->start; 189 ioaddr = ioremap(pdata->baseaddr, pdata->size); 190 if (!ioaddr) { 191 ret = -ENOMEM; 192 goto out; 193 } 194 pdata->ioaddr_nvram = ioaddr; 195 pdata->size_nvram = pdata->size - RTC_SIZE; 196 pdata->ioaddr_rtc = ioaddr + pdata->size_nvram; 197 198 /* turn RTC on if it was not on */ 199 ioaddr = pdata->ioaddr_rtc; 200 sec = readb(ioaddr + RTC_SECONDS); 201 if (sec & RTC_STOP) { 202 sec &= RTC_SECONDS_MASK; 203 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 204 writeb(RTC_WRITE, ioaddr + RTC_CONTROL); 205 writeb(sec, ioaddr + RTC_SECONDS); 206 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 207 } 208 if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG)) 209 dev_warn(&pdev->dev, "voltage-low detected.\n"); 210 211 rtc = rtc_device_register(pdev->name, &pdev->dev, 212 &ds1742_rtc_ops, THIS_MODULE); 213 if (IS_ERR(rtc)) { 214 ret = PTR_ERR(rtc); 215 goto out; 216 } 217 pdata->rtc = rtc; 218 pdata->last_jiffies = jiffies; 219 platform_set_drvdata(pdev, pdata); 220 ds1742_nvram_attr.size = max(ds1742_nvram_attr.size, 221 pdata->size_nvram); 222 ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1742_nvram_attr); 223 if (ret) 224 goto out; 225 return 0; 226 out: 227 if (pdata->rtc) 228 rtc_device_unregister(pdata->rtc); 229 if (pdata->ioaddr_nvram) 230 iounmap(pdata->ioaddr_nvram); 231 if (pdata->baseaddr) 232 release_mem_region(pdata->baseaddr, pdata->size); 233 kfree(pdata); 234 return ret; 235} 236 237static int __devexit ds1742_rtc_remove(struct platform_device *pdev) 238{ 239 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 240 241 sysfs_remove_bin_file(&pdev->dev.kobj, &ds1742_nvram_attr); 242 rtc_device_unregister(pdata->rtc); 243 iounmap(pdata->ioaddr_nvram); 244 release_mem_region(pdata->baseaddr, pdata->size); 245 kfree(pdata); 246 return 0; 247} 248 249static struct platform_driver ds1742_rtc_driver = { 250 .probe = ds1742_rtc_probe, 251 .remove = __devexit_p(ds1742_rtc_remove), 252 .driver = { 253 .name = "ds1742", 254 .owner = THIS_MODULE, 255 }, 256}; 257 258static __init int ds1742_init(void) 259{ 260 return platform_driver_register(&ds1742_rtc_driver); 261} 262 263static __exit void ds1742_exit(void) 264{ 265 return platform_driver_unregister(&ds1742_rtc_driver); 266} 267 268module_init(ds1742_init); 269module_exit(ds1742_exit); 270 271MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 272MODULE_DESCRIPTION("Dallas DS1742 RTC driver"); 273MODULE_LICENSE("GPL"); 274MODULE_VERSION(DRV_VERSION); 275