1 /* 2 * An rtc driver for the Dallas DS1553 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 11 #include <linux/bcd.h> 12 #include <linux/init.h> 13 #include <linux/kernel.h> 14 #include <linux/gfp.h> 15 #include <linux/delay.h> 16 #include <linux/jiffies.h> 17 #include <linux/interrupt.h> 18 #include <linux/rtc.h> 19 #include <linux/platform_device.h> 20 #include <linux/io.h> 21 #include <linux/module.h> 22 23 #define DRV_VERSION "0.3" 24 25 #define RTC_REG_SIZE 0x2000 26 #define RTC_OFFSET 0x1ff0 27 28 #define RTC_FLAGS (RTC_OFFSET + 0) 29 #define RTC_SECONDS_ALARM (RTC_OFFSET + 2) 30 #define RTC_MINUTES_ALARM (RTC_OFFSET + 3) 31 #define RTC_HOURS_ALARM (RTC_OFFSET + 4) 32 #define RTC_DATE_ALARM (RTC_OFFSET + 5) 33 #define RTC_INTERRUPTS (RTC_OFFSET + 6) 34 #define RTC_WATCHDOG (RTC_OFFSET + 7) 35 #define RTC_CONTROL (RTC_OFFSET + 8) 36 #define RTC_CENTURY (RTC_OFFSET + 8) 37 #define RTC_SECONDS (RTC_OFFSET + 9) 38 #define RTC_MINUTES (RTC_OFFSET + 10) 39 #define RTC_HOURS (RTC_OFFSET + 11) 40 #define RTC_DAY (RTC_OFFSET + 12) 41 #define RTC_DATE (RTC_OFFSET + 13) 42 #define RTC_MONTH (RTC_OFFSET + 14) 43 #define RTC_YEAR (RTC_OFFSET + 15) 44 45 #define RTC_CENTURY_MASK 0x3f 46 #define RTC_SECONDS_MASK 0x7f 47 #define RTC_DAY_MASK 0x07 48 49 /* Bits in the Control/Century register */ 50 #define RTC_WRITE 0x80 51 #define RTC_READ 0x40 52 53 /* Bits in the Seconds register */ 54 #define RTC_STOP 0x80 55 56 /* Bits in the Flags register */ 57 #define RTC_FLAGS_AF 0x40 58 #define RTC_FLAGS_BLF 0x10 59 60 /* Bits in the Interrupts register */ 61 #define RTC_INTS_AE 0x80 62 63 struct rtc_plat_data { 64 struct rtc_device *rtc; 65 void __iomem *ioaddr; 66 unsigned long last_jiffies; 67 int irq; 68 unsigned int irqen; 69 int alrm_sec; 70 int alrm_min; 71 int alrm_hour; 72 int alrm_mday; 73 spinlock_t lock; 74 }; 75 76 static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm) 77 { 78 struct platform_device *pdev = to_platform_device(dev); 79 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 80 void __iomem *ioaddr = pdata->ioaddr; 81 u8 century; 82 83 century = bin2bcd((tm->tm_year + 1900) / 100); 84 85 writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL); 86 87 writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR); 88 writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH); 89 writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY); 90 writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE); 91 writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS); 92 writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES); 93 writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS); 94 95 /* RTC_CENTURY and RTC_CONTROL share same register */ 96 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY); 97 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 98 return 0; 99 } 100 101 static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm) 102 { 103 struct platform_device *pdev = to_platform_device(dev); 104 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 105 void __iomem *ioaddr = pdata->ioaddr; 106 unsigned int year, month, day, hour, minute, second, week; 107 unsigned int century; 108 109 /* give enough time to update RTC in case of continuous read */ 110 if (pdata->last_jiffies == jiffies) 111 msleep(1); 112 pdata->last_jiffies = jiffies; 113 writeb(RTC_READ, ioaddr + RTC_CONTROL); 114 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK; 115 minute = readb(ioaddr + RTC_MINUTES); 116 hour = readb(ioaddr + RTC_HOURS); 117 day = readb(ioaddr + RTC_DATE); 118 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK; 119 month = readb(ioaddr + RTC_MONTH); 120 year = readb(ioaddr + RTC_YEAR); 121 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 122 writeb(0, ioaddr + RTC_CONTROL); 123 tm->tm_sec = bcd2bin(second); 124 tm->tm_min = bcd2bin(minute); 125 tm->tm_hour = bcd2bin(hour); 126 tm->tm_mday = bcd2bin(day); 127 tm->tm_wday = bcd2bin(week); 128 tm->tm_mon = bcd2bin(month) - 1; 129 /* year is 1900 + tm->tm_year */ 130 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900; 131 132 if (rtc_valid_tm(tm) < 0) { 133 dev_err(dev, "retrieved date/time is not valid.\n"); 134 rtc_time_to_tm(0, tm); 135 } 136 return 0; 137 } 138 139 static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata) 140 { 141 void __iomem *ioaddr = pdata->ioaddr; 142 unsigned long flags; 143 144 spin_lock_irqsave(&pdata->lock, flags); 145 writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? 146 0x80 : bin2bcd(pdata->alrm_mday), 147 ioaddr + RTC_DATE_ALARM); 148 writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? 149 0x80 : bin2bcd(pdata->alrm_hour), 150 ioaddr + RTC_HOURS_ALARM); 151 writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? 152 0x80 : bin2bcd(pdata->alrm_min), 153 ioaddr + RTC_MINUTES_ALARM); 154 writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? 155 0x80 : bin2bcd(pdata->alrm_sec), 156 ioaddr + RTC_SECONDS_ALARM); 157 writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS); 158 readb(ioaddr + RTC_FLAGS); /* clear interrupts */ 159 spin_unlock_irqrestore(&pdata->lock, flags); 160 } 161 162 static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 163 { 164 struct platform_device *pdev = to_platform_device(dev); 165 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 166 167 if (pdata->irq <= 0) 168 return -EINVAL; 169 pdata->alrm_mday = alrm->time.tm_mday; 170 pdata->alrm_hour = alrm->time.tm_hour; 171 pdata->alrm_min = alrm->time.tm_min; 172 pdata->alrm_sec = alrm->time.tm_sec; 173 if (alrm->enabled) 174 pdata->irqen |= RTC_AF; 175 ds1553_rtc_update_alarm(pdata); 176 return 0; 177 } 178 179 static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 180 { 181 struct platform_device *pdev = to_platform_device(dev); 182 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 183 184 if (pdata->irq <= 0) 185 return -EINVAL; 186 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; 187 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; 188 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; 189 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; 190 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; 191 return 0; 192 } 193 194 static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id) 195 { 196 struct platform_device *pdev = dev_id; 197 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 198 void __iomem *ioaddr = pdata->ioaddr; 199 unsigned long events = 0; 200 201 spin_lock(&pdata->lock); 202 /* read and clear interrupt */ 203 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) { 204 events = RTC_IRQF; 205 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80) 206 events |= RTC_UF; 207 else 208 events |= RTC_AF; 209 if (likely(pdata->rtc)) 210 rtc_update_irq(pdata->rtc, 1, events); 211 } 212 spin_unlock(&pdata->lock); 213 return events ? IRQ_HANDLED : IRQ_NONE; 214 } 215 216 static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 217 { 218 struct platform_device *pdev = to_platform_device(dev); 219 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 220 221 if (pdata->irq <= 0) 222 return -EINVAL; 223 if (enabled) 224 pdata->irqen |= RTC_AF; 225 else 226 pdata->irqen &= ~RTC_AF; 227 ds1553_rtc_update_alarm(pdata); 228 return 0; 229 } 230 231 static const struct rtc_class_ops ds1553_rtc_ops = { 232 .read_time = ds1553_rtc_read_time, 233 .set_time = ds1553_rtc_set_time, 234 .read_alarm = ds1553_rtc_read_alarm, 235 .set_alarm = ds1553_rtc_set_alarm, 236 .alarm_irq_enable = ds1553_rtc_alarm_irq_enable, 237 }; 238 239 static ssize_t ds1553_nvram_read(struct file *filp, struct kobject *kobj, 240 struct bin_attribute *bin_attr, 241 char *buf, loff_t pos, size_t size) 242 { 243 struct device *dev = container_of(kobj, struct device, kobj); 244 struct platform_device *pdev = to_platform_device(dev); 245 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 246 void __iomem *ioaddr = pdata->ioaddr; 247 ssize_t count; 248 249 for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--) 250 *buf++ = readb(ioaddr + pos++); 251 return count; 252 } 253 254 static ssize_t ds1553_nvram_write(struct file *filp, struct kobject *kobj, 255 struct bin_attribute *bin_attr, 256 char *buf, loff_t pos, size_t size) 257 { 258 struct device *dev = container_of(kobj, struct device, kobj); 259 struct platform_device *pdev = to_platform_device(dev); 260 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 261 void __iomem *ioaddr = pdata->ioaddr; 262 ssize_t count; 263 264 for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--) 265 writeb(*buf++, ioaddr + pos++); 266 return count; 267 } 268 269 static struct bin_attribute ds1553_nvram_attr = { 270 .attr = { 271 .name = "nvram", 272 .mode = S_IRUGO | S_IWUSR, 273 }, 274 .size = RTC_OFFSET, 275 .read = ds1553_nvram_read, 276 .write = ds1553_nvram_write, 277 }; 278 279 static int ds1553_rtc_probe(struct platform_device *pdev) 280 { 281 struct rtc_device *rtc; 282 struct resource *res; 283 unsigned int cen, sec; 284 struct rtc_plat_data *pdata; 285 void __iomem *ioaddr; 286 int ret = 0; 287 288 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 289 if (!res) 290 return -ENODEV; 291 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 292 if (!pdata) 293 return -ENOMEM; 294 if (!devm_request_mem_region(&pdev->dev, res->start, RTC_REG_SIZE, 295 pdev->name)) 296 return -EBUSY; 297 298 ioaddr = devm_ioremap(&pdev->dev, res->start, RTC_REG_SIZE); 299 if (!ioaddr) 300 return -ENOMEM; 301 pdata->ioaddr = ioaddr; 302 pdata->irq = platform_get_irq(pdev, 0); 303 304 /* turn RTC on if it was not on */ 305 sec = readb(ioaddr + RTC_SECONDS); 306 if (sec & RTC_STOP) { 307 sec &= RTC_SECONDS_MASK; 308 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 309 writeb(RTC_WRITE, ioaddr + RTC_CONTROL); 310 writeb(sec, ioaddr + RTC_SECONDS); 311 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 312 } 313 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF) 314 dev_warn(&pdev->dev, "voltage-low detected.\n"); 315 316 spin_lock_init(&pdata->lock); 317 pdata->last_jiffies = jiffies; 318 platform_set_drvdata(pdev, pdata); 319 if (pdata->irq > 0) { 320 writeb(0, ioaddr + RTC_INTERRUPTS); 321 if (devm_request_irq(&pdev->dev, pdata->irq, 322 ds1553_rtc_interrupt, 323 0, pdev->name, pdev) < 0) { 324 dev_warn(&pdev->dev, "interrupt not available.\n"); 325 pdata->irq = 0; 326 } 327 } 328 329 rtc = devm_rtc_device_register(&pdev->dev, pdev->name, 330 &ds1553_rtc_ops, THIS_MODULE); 331 if (IS_ERR(rtc)) 332 return PTR_ERR(rtc); 333 pdata->rtc = rtc; 334 335 ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr); 336 337 return ret; 338 } 339 340 static int ds1553_rtc_remove(struct platform_device *pdev) 341 { 342 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 343 344 sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr); 345 if (pdata->irq > 0) 346 writeb(0, pdata->ioaddr + RTC_INTERRUPTS); 347 return 0; 348 } 349 350 /* work with hotplug and coldplug */ 351 MODULE_ALIAS("platform:rtc-ds1553"); 352 353 static struct platform_driver ds1553_rtc_driver = { 354 .probe = ds1553_rtc_probe, 355 .remove = ds1553_rtc_remove, 356 .driver = { 357 .name = "rtc-ds1553", 358 .owner = THIS_MODULE, 359 }, 360 }; 361 362 module_platform_driver(ds1553_rtc_driver); 363 364 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 365 MODULE_DESCRIPTION("Dallas DS1553 RTC driver"); 366 MODULE_LICENSE("GPL"); 367 MODULE_VERSION(DRV_VERSION); 368