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/gfp.h> 19 #include <linux/delay.h> 20 #include <linux/jiffies.h> 21 #include <linux/rtc.h> 22 #include <linux/platform_device.h> 23 #include <linux/io.h> 24 25 #define DRV_VERSION "0.4" 26 27 #define RTC_SIZE 8 28 29 #define RTC_CONTROL 0 30 #define RTC_CENTURY 0 31 #define RTC_SECONDS 1 32 #define RTC_MINUTES 2 33 #define RTC_HOURS 3 34 #define RTC_DAY 4 35 #define RTC_DATE 5 36 #define RTC_MONTH 6 37 #define RTC_YEAR 7 38 39 #define RTC_CENTURY_MASK 0x3f 40 #define RTC_SECONDS_MASK 0x7f 41 #define RTC_DAY_MASK 0x07 42 43 /* Bits in the Control/Century register */ 44 #define RTC_WRITE 0x80 45 #define RTC_READ 0x40 46 47 /* Bits in the Seconds register */ 48 #define RTC_STOP 0x80 49 50 /* Bits in the Day register */ 51 #define RTC_BATT_FLAG 0x80 52 53 struct rtc_plat_data { 54 struct rtc_device *rtc; 55 void __iomem *ioaddr_nvram; 56 void __iomem *ioaddr_rtc; 57 size_t size_nvram; 58 size_t size; 59 unsigned long last_jiffies; 60 struct bin_attribute nvram_attr; 61 }; 62 63 static int ds1742_rtc_set_time(struct device *dev, struct rtc_time *tm) 64 { 65 struct platform_device *pdev = to_platform_device(dev); 66 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 67 void __iomem *ioaddr = pdata->ioaddr_rtc; 68 u8 century; 69 70 century = bin2bcd((tm->tm_year + 1900) / 100); 71 72 writeb(RTC_WRITE, ioaddr + RTC_CONTROL); 73 74 writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR); 75 writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH); 76 writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY); 77 writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE); 78 writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS); 79 writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES); 80 writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS); 81 82 /* RTC_CENTURY and RTC_CONTROL share same register */ 83 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY); 84 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 85 return 0; 86 } 87 88 static int ds1742_rtc_read_time(struct device *dev, struct rtc_time *tm) 89 { 90 struct platform_device *pdev = to_platform_device(dev); 91 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 92 void __iomem *ioaddr = pdata->ioaddr_rtc; 93 unsigned int year, month, day, hour, minute, second, week; 94 unsigned int century; 95 96 /* give enough time to update RTC in case of continuous read */ 97 if (pdata->last_jiffies == jiffies) 98 msleep(1); 99 pdata->last_jiffies = jiffies; 100 writeb(RTC_READ, ioaddr + RTC_CONTROL); 101 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK; 102 minute = readb(ioaddr + RTC_MINUTES); 103 hour = readb(ioaddr + RTC_HOURS); 104 day = readb(ioaddr + RTC_DATE); 105 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK; 106 month = readb(ioaddr + RTC_MONTH); 107 year = readb(ioaddr + RTC_YEAR); 108 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 109 writeb(0, ioaddr + RTC_CONTROL); 110 tm->tm_sec = bcd2bin(second); 111 tm->tm_min = bcd2bin(minute); 112 tm->tm_hour = bcd2bin(hour); 113 tm->tm_mday = bcd2bin(day); 114 tm->tm_wday = bcd2bin(week); 115 tm->tm_mon = bcd2bin(month) - 1; 116 /* year is 1900 + tm->tm_year */ 117 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900; 118 119 if (rtc_valid_tm(tm) < 0) { 120 dev_err(dev, "retrieved date/time is not valid.\n"); 121 rtc_time_to_tm(0, tm); 122 } 123 return 0; 124 } 125 126 static const struct rtc_class_ops ds1742_rtc_ops = { 127 .read_time = ds1742_rtc_read_time, 128 .set_time = ds1742_rtc_set_time, 129 }; 130 131 static ssize_t ds1742_nvram_read(struct file *filp, struct kobject *kobj, 132 struct bin_attribute *bin_attr, 133 char *buf, loff_t pos, size_t size) 134 { 135 struct device *dev = container_of(kobj, struct device, kobj); 136 struct platform_device *pdev = to_platform_device(dev); 137 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 138 void __iomem *ioaddr = pdata->ioaddr_nvram; 139 ssize_t count; 140 141 for (count = 0; size > 0 && pos < pdata->size_nvram; count++, size--) 142 *buf++ = readb(ioaddr + pos++); 143 return count; 144 } 145 146 static ssize_t ds1742_nvram_write(struct file *filp, struct kobject *kobj, 147 struct bin_attribute *bin_attr, 148 char *buf, loff_t pos, size_t size) 149 { 150 struct device *dev = container_of(kobj, struct device, kobj); 151 struct platform_device *pdev = to_platform_device(dev); 152 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 153 void __iomem *ioaddr = pdata->ioaddr_nvram; 154 ssize_t count; 155 156 for (count = 0; size > 0 && pos < pdata->size_nvram; count++, size--) 157 writeb(*buf++, ioaddr + pos++); 158 return count; 159 } 160 161 static int __devinit ds1742_rtc_probe(struct platform_device *pdev) 162 { 163 struct rtc_device *rtc; 164 struct resource *res; 165 unsigned int cen, sec; 166 struct rtc_plat_data *pdata; 167 void __iomem *ioaddr; 168 int ret = 0; 169 170 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 171 if (!res) 172 return -ENODEV; 173 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 174 if (!pdata) 175 return -ENOMEM; 176 pdata->size = res->end - res->start + 1; 177 if (!devm_request_mem_region(&pdev->dev, res->start, pdata->size, 178 pdev->name)) 179 return -EBUSY; 180 ioaddr = devm_ioremap(&pdev->dev, res->start, pdata->size); 181 if (!ioaddr) 182 return -ENOMEM; 183 184 pdata->ioaddr_nvram = ioaddr; 185 pdata->size_nvram = pdata->size - RTC_SIZE; 186 pdata->ioaddr_rtc = ioaddr + pdata->size_nvram; 187 188 sysfs_bin_attr_init(&pdata->nvram_attr); 189 pdata->nvram_attr.attr.name = "nvram"; 190 pdata->nvram_attr.attr.mode = S_IRUGO | S_IWUSR; 191 pdata->nvram_attr.read = ds1742_nvram_read; 192 pdata->nvram_attr.write = ds1742_nvram_write; 193 pdata->nvram_attr.size = pdata->size_nvram; 194 195 /* turn RTC on if it was not on */ 196 ioaddr = pdata->ioaddr_rtc; 197 sec = readb(ioaddr + RTC_SECONDS); 198 if (sec & RTC_STOP) { 199 sec &= RTC_SECONDS_MASK; 200 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 201 writeb(RTC_WRITE, ioaddr + RTC_CONTROL); 202 writeb(sec, ioaddr + RTC_SECONDS); 203 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 204 } 205 if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG)) 206 dev_warn(&pdev->dev, "voltage-low detected.\n"); 207 208 pdata->last_jiffies = jiffies; 209 platform_set_drvdata(pdev, pdata); 210 rtc = rtc_device_register(pdev->name, &pdev->dev, 211 &ds1742_rtc_ops, THIS_MODULE); 212 if (IS_ERR(rtc)) 213 return PTR_ERR(rtc); 214 pdata->rtc = rtc; 215 216 ret = sysfs_create_bin_file(&pdev->dev.kobj, &pdata->nvram_attr); 217 if (ret) { 218 dev_err(&pdev->dev, "creating nvram file in sysfs failed\n"); 219 rtc_device_unregister(rtc); 220 } 221 return ret; 222 } 223 224 static int __devexit ds1742_rtc_remove(struct platform_device *pdev) 225 { 226 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 227 228 sysfs_remove_bin_file(&pdev->dev.kobj, &pdata->nvram_attr); 229 rtc_device_unregister(pdata->rtc); 230 return 0; 231 } 232 233 static struct platform_driver ds1742_rtc_driver = { 234 .probe = ds1742_rtc_probe, 235 .remove = __devexit_p(ds1742_rtc_remove), 236 .driver = { 237 .name = "rtc-ds1742", 238 .owner = THIS_MODULE, 239 }, 240 }; 241 242 static __init int ds1742_init(void) 243 { 244 return platform_driver_register(&ds1742_rtc_driver); 245 } 246 247 static __exit void ds1742_exit(void) 248 { 249 platform_driver_unregister(&ds1742_rtc_driver); 250 } 251 252 module_init(ds1742_init); 253 module_exit(ds1742_exit); 254 255 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 256 MODULE_DESCRIPTION("Dallas DS1742 RTC driver"); 257 MODULE_LICENSE("GPL"); 258 MODULE_VERSION(DRV_VERSION); 259 MODULE_ALIAS("platform:rtc-ds1742"); 260