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