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 52 struct 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 resource_size_t baseaddr; 59 unsigned long last_jiffies; 60 }; 61 62 static 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 87 static 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 } 124 125 static const struct rtc_class_ops ds1742_rtc_ops = { 126 .read_time = ds1742_rtc_read_time, 127 .set_time = ds1742_rtc_set_time, 128 }; 129 130 static 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 platform_device *pdev = 135 to_platform_device(container_of(kobj, struct device, kobj)); 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 } 144 145 static 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 platform_device *pdev = 150 to_platform_device(container_of(kobj, struct device, kobj)); 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 } 159 160 static struct bin_attribute ds1742_nvram_attr = { 161 .attr = { 162 .name = "nvram", 163 .mode = S_IRUGO | S_IWUSR, 164 }, 165 .read = ds1742_nvram_read, 166 .write = ds1742_nvram_write, 167 /* REVISIT: size in sysfs won't match actual size... if it's 168 * not a constant, each RTC should have its own attribute. 169 */ 170 }; 171 172 static int __devinit ds1742_rtc_probe(struct platform_device *pdev) 173 { 174 struct rtc_device *rtc; 175 struct resource *res; 176 unsigned int cen, sec; 177 struct rtc_plat_data *pdata = NULL; 178 void __iomem *ioaddr = NULL; 179 int ret = 0; 180 181 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 182 if (!res) 183 return -ENODEV; 184 pdata = kzalloc(sizeof(*pdata), GFP_KERNEL); 185 if (!pdata) 186 return -ENOMEM; 187 pdata->size = res->end - res->start + 1; 188 if (!request_mem_region(res->start, pdata->size, pdev->name)) { 189 ret = -EBUSY; 190 goto out; 191 } 192 pdata->baseaddr = res->start; 193 ioaddr = ioremap(pdata->baseaddr, pdata->size); 194 if (!ioaddr) { 195 ret = -ENOMEM; 196 goto out; 197 } 198 pdata->ioaddr_nvram = ioaddr; 199 pdata->size_nvram = pdata->size - RTC_SIZE; 200 pdata->ioaddr_rtc = ioaddr + pdata->size_nvram; 201 202 /* turn RTC on if it was not on */ 203 ioaddr = pdata->ioaddr_rtc; 204 sec = readb(ioaddr + RTC_SECONDS); 205 if (sec & RTC_STOP) { 206 sec &= RTC_SECONDS_MASK; 207 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 208 writeb(RTC_WRITE, ioaddr + RTC_CONTROL); 209 writeb(sec, ioaddr + RTC_SECONDS); 210 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 211 } 212 if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG)) 213 dev_warn(&pdev->dev, "voltage-low detected.\n"); 214 215 rtc = rtc_device_register(pdev->name, &pdev->dev, 216 &ds1742_rtc_ops, THIS_MODULE); 217 if (IS_ERR(rtc)) { 218 ret = PTR_ERR(rtc); 219 goto out; 220 } 221 pdata->rtc = rtc; 222 pdata->last_jiffies = jiffies; 223 platform_set_drvdata(pdev, pdata); 224 ds1742_nvram_attr.size = max(ds1742_nvram_attr.size, 225 pdata->size_nvram); 226 ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1742_nvram_attr); 227 if (ret) 228 goto out; 229 return 0; 230 out: 231 if (pdata->rtc) 232 rtc_device_unregister(pdata->rtc); 233 if (pdata->ioaddr_nvram) 234 iounmap(pdata->ioaddr_nvram); 235 if (pdata->baseaddr) 236 release_mem_region(pdata->baseaddr, pdata->size); 237 kfree(pdata); 238 return ret; 239 } 240 241 static int __devexit ds1742_rtc_remove(struct platform_device *pdev) 242 { 243 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 244 245 sysfs_remove_bin_file(&pdev->dev.kobj, &ds1742_nvram_attr); 246 rtc_device_unregister(pdata->rtc); 247 iounmap(pdata->ioaddr_nvram); 248 release_mem_region(pdata->baseaddr, pdata->size); 249 kfree(pdata); 250 return 0; 251 } 252 253 static struct platform_driver ds1742_rtc_driver = { 254 .probe = ds1742_rtc_probe, 255 .remove = __devexit_p(ds1742_rtc_remove), 256 .driver = { 257 .name = "rtc-ds1742", 258 .owner = THIS_MODULE, 259 }, 260 }; 261 262 static __init int ds1742_init(void) 263 { 264 return platform_driver_register(&ds1742_rtc_driver); 265 } 266 267 static __exit void ds1742_exit(void) 268 { 269 platform_driver_unregister(&ds1742_rtc_driver); 270 } 271 272 module_init(ds1742_init); 273 module_exit(ds1742_exit); 274 275 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 276 MODULE_DESCRIPTION("Dallas DS1742 RTC driver"); 277 MODULE_LICENSE("GPL"); 278 MODULE_VERSION(DRV_VERSION); 279