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/delay.h> 15 #include <linux/jiffies.h> 16 #include <linux/interrupt.h> 17 #include <linux/rtc.h> 18 #include <linux/platform_device.h> 19 #include <linux/io.h> 20 21 #define DRV_VERSION "0.1" 22 23 #define RTC_REG_SIZE 0x2000 24 #define RTC_OFFSET 0x1ff0 25 26 #define RTC_FLAGS (RTC_OFFSET + 0) 27 #define RTC_SECONDS_ALARM (RTC_OFFSET + 2) 28 #define RTC_MINUTES_ALARM (RTC_OFFSET + 3) 29 #define RTC_HOURS_ALARM (RTC_OFFSET + 4) 30 #define RTC_DATE_ALARM (RTC_OFFSET + 5) 31 #define RTC_INTERRUPTS (RTC_OFFSET + 6) 32 #define RTC_WATCHDOG (RTC_OFFSET + 7) 33 #define RTC_CONTROL (RTC_OFFSET + 8) 34 #define RTC_CENTURY (RTC_OFFSET + 8) 35 #define RTC_SECONDS (RTC_OFFSET + 9) 36 #define RTC_MINUTES (RTC_OFFSET + 10) 37 #define RTC_HOURS (RTC_OFFSET + 11) 38 #define RTC_DAY (RTC_OFFSET + 12) 39 #define RTC_DATE (RTC_OFFSET + 13) 40 #define RTC_MONTH (RTC_OFFSET + 14) 41 #define RTC_YEAR (RTC_OFFSET + 15) 42 43 #define RTC_CENTURY_MASK 0x3f 44 #define RTC_SECONDS_MASK 0x7f 45 #define RTC_DAY_MASK 0x07 46 47 /* Bits in the Control/Century register */ 48 #define RTC_WRITE 0x80 49 #define RTC_READ 0x40 50 51 /* Bits in the Seconds register */ 52 #define RTC_STOP 0x80 53 54 /* Bits in the Flags register */ 55 #define RTC_FLAGS_AF 0x40 56 #define RTC_FLAGS_BLF 0x10 57 58 /* Bits in the Interrupts register */ 59 #define RTC_INTS_AE 0x80 60 61 struct rtc_plat_data { 62 struct rtc_device *rtc; 63 void __iomem *ioaddr; 64 unsigned long baseaddr; 65 unsigned long last_jiffies; 66 int irq; 67 unsigned int irqen; 68 int alrm_sec; 69 int alrm_min; 70 int alrm_hour; 71 int alrm_mday; 72 }; 73 74 static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm) 75 { 76 struct platform_device *pdev = to_platform_device(dev); 77 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 78 void __iomem *ioaddr = pdata->ioaddr; 79 u8 century; 80 81 century = BIN2BCD((tm->tm_year + 1900) / 100); 82 83 writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL); 84 85 writeb(BIN2BCD(tm->tm_year % 100), ioaddr + RTC_YEAR); 86 writeb(BIN2BCD(tm->tm_mon + 1), ioaddr + RTC_MONTH); 87 writeb(BIN2BCD(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY); 88 writeb(BIN2BCD(tm->tm_mday), ioaddr + RTC_DATE); 89 writeb(BIN2BCD(tm->tm_hour), ioaddr + RTC_HOURS); 90 writeb(BIN2BCD(tm->tm_min), ioaddr + RTC_MINUTES); 91 writeb(BIN2BCD(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS); 92 93 /* RTC_CENTURY and RTC_CONTROL share same register */ 94 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY); 95 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 96 return 0; 97 } 98 99 static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm) 100 { 101 struct platform_device *pdev = to_platform_device(dev); 102 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 103 void __iomem *ioaddr = pdata->ioaddr; 104 unsigned int year, month, day, hour, minute, second, week; 105 unsigned int century; 106 107 /* give enough time to update RTC in case of continuous read */ 108 if (pdata->last_jiffies == jiffies) 109 msleep(1); 110 pdata->last_jiffies = jiffies; 111 writeb(RTC_READ, ioaddr + RTC_CONTROL); 112 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK; 113 minute = readb(ioaddr + RTC_MINUTES); 114 hour = readb(ioaddr + RTC_HOURS); 115 day = readb(ioaddr + RTC_DATE); 116 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK; 117 month = readb(ioaddr + RTC_MONTH); 118 year = readb(ioaddr + RTC_YEAR); 119 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 120 writeb(0, ioaddr + RTC_CONTROL); 121 tm->tm_sec = BCD2BIN(second); 122 tm->tm_min = BCD2BIN(minute); 123 tm->tm_hour = BCD2BIN(hour); 124 tm->tm_mday = BCD2BIN(day); 125 tm->tm_wday = BCD2BIN(week); 126 tm->tm_mon = BCD2BIN(month) - 1; 127 /* year is 1900 + tm->tm_year */ 128 tm->tm_year = BCD2BIN(year) + BCD2BIN(century) * 100 - 1900; 129 130 if (rtc_valid_tm(tm) < 0) { 131 dev_err(dev, "retrieved date/time is not valid.\n"); 132 rtc_time_to_tm(0, tm); 133 } 134 return 0; 135 } 136 137 static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata) 138 { 139 void __iomem *ioaddr = pdata->ioaddr; 140 unsigned long flags; 141 142 spin_lock_irqsave(&pdata->rtc->irq_lock, flags); 143 writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? 144 0x80 : BIN2BCD(pdata->alrm_mday), 145 ioaddr + RTC_DATE_ALARM); 146 writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? 147 0x80 : BIN2BCD(pdata->alrm_hour), 148 ioaddr + RTC_HOURS_ALARM); 149 writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? 150 0x80 : BIN2BCD(pdata->alrm_min), 151 ioaddr + RTC_MINUTES_ALARM); 152 writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? 153 0x80 : BIN2BCD(pdata->alrm_sec), 154 ioaddr + RTC_SECONDS_ALARM); 155 writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS); 156 readb(ioaddr + RTC_FLAGS); /* clear interrupts */ 157 spin_unlock_irqrestore(&pdata->rtc->irq_lock, flags); 158 } 159 160 static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 161 { 162 struct platform_device *pdev = to_platform_device(dev); 163 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 164 165 if (pdata->irq < 0) 166 return -EINVAL; 167 pdata->alrm_mday = alrm->time.tm_mday; 168 pdata->alrm_hour = alrm->time.tm_hour; 169 pdata->alrm_min = alrm->time.tm_min; 170 pdata->alrm_sec = alrm->time.tm_sec; 171 if (alrm->enabled) 172 pdata->irqen |= RTC_AF; 173 ds1553_rtc_update_alarm(pdata); 174 return 0; 175 } 176 177 static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 178 { 179 struct platform_device *pdev = to_platform_device(dev); 180 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 181 182 if (pdata->irq < 0) 183 return -EINVAL; 184 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; 185 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; 186 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; 187 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; 188 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; 189 return 0; 190 } 191 192 static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id, 193 struct pt_regs *regs) 194 { 195 struct platform_device *pdev = dev_id; 196 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 197 void __iomem *ioaddr = pdata->ioaddr; 198 unsigned long events = RTC_IRQF; 199 200 /* read and clear interrupt */ 201 if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF)) 202 return IRQ_NONE; 203 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80) 204 events |= RTC_UF; 205 else 206 events |= RTC_AF; 207 rtc_update_irq(&pdata->rtc->class_dev, 1, events); 208 return IRQ_HANDLED; 209 } 210 211 static void ds1553_rtc_release(struct device *dev) 212 { 213 struct platform_device *pdev = to_platform_device(dev); 214 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 215 216 if (pdata->irq >= 0) { 217 pdata->irqen = 0; 218 ds1553_rtc_update_alarm(pdata); 219 } 220 } 221 222 static int ds1553_rtc_ioctl(struct device *dev, unsigned int cmd, 223 unsigned long arg) 224 { 225 struct platform_device *pdev = to_platform_device(dev); 226 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 227 228 if (pdata->irq < 0) 229 return -ENOIOCTLCMD; /* fall back into rtc-dev's emulation */ 230 switch (cmd) { 231 case RTC_AIE_OFF: 232 pdata->irqen &= ~RTC_AF; 233 ds1553_rtc_update_alarm(pdata); 234 break; 235 case RTC_AIE_ON: 236 pdata->irqen |= RTC_AF; 237 ds1553_rtc_update_alarm(pdata); 238 break; 239 case RTC_UIE_OFF: 240 pdata->irqen &= ~RTC_UF; 241 ds1553_rtc_update_alarm(pdata); 242 break; 243 case RTC_UIE_ON: 244 pdata->irqen |= RTC_UF; 245 ds1553_rtc_update_alarm(pdata); 246 break; 247 default: 248 return -ENOIOCTLCMD; 249 } 250 return 0; 251 } 252 253 static struct rtc_class_ops ds1553_rtc_ops = { 254 .read_time = ds1553_rtc_read_time, 255 .set_time = ds1553_rtc_set_time, 256 .read_alarm = ds1553_rtc_read_alarm, 257 .set_alarm = ds1553_rtc_set_alarm, 258 .release = ds1553_rtc_release, 259 .ioctl = ds1553_rtc_ioctl, 260 }; 261 262 static ssize_t ds1553_nvram_read(struct kobject *kobj, char *buf, 263 loff_t pos, size_t size) 264 { 265 struct platform_device *pdev = 266 to_platform_device(container_of(kobj, struct device, kobj)); 267 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 268 void __iomem *ioaddr = pdata->ioaddr; 269 ssize_t count; 270 271 for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--) 272 *buf++ = readb(ioaddr + pos++); 273 return count; 274 } 275 276 static ssize_t ds1553_nvram_write(struct kobject *kobj, char *buf, 277 loff_t pos, size_t size) 278 { 279 struct platform_device *pdev = 280 to_platform_device(container_of(kobj, struct device, kobj)); 281 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 282 void __iomem *ioaddr = pdata->ioaddr; 283 ssize_t count; 284 285 for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--) 286 writeb(*buf++, ioaddr + pos++); 287 return count; 288 } 289 290 static struct bin_attribute ds1553_nvram_attr = { 291 .attr = { 292 .name = "nvram", 293 .mode = S_IRUGO | S_IWUGO, 294 .owner = THIS_MODULE, 295 }, 296 .size = RTC_OFFSET, 297 .read = ds1553_nvram_read, 298 .write = ds1553_nvram_write, 299 }; 300 301 static int __init ds1553_rtc_probe(struct platform_device *pdev) 302 { 303 struct rtc_device *rtc; 304 struct resource *res; 305 unsigned int cen, sec; 306 struct rtc_plat_data *pdata = NULL; 307 void __iomem *ioaddr = NULL; 308 int ret = 0; 309 310 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 311 if (!res) 312 return -ENODEV; 313 pdata = kzalloc(sizeof(*pdata), GFP_KERNEL); 314 if (!pdata) 315 return -ENOMEM; 316 pdata->irq = -1; 317 if (!request_mem_region(res->start, RTC_REG_SIZE, pdev->name)) { 318 ret = -EBUSY; 319 goto out; 320 } 321 pdata->baseaddr = res->start; 322 ioaddr = ioremap(pdata->baseaddr, RTC_REG_SIZE); 323 if (!ioaddr) { 324 ret = -ENOMEM; 325 goto out; 326 } 327 pdata->ioaddr = ioaddr; 328 pdata->irq = platform_get_irq(pdev, 0); 329 330 /* turn RTC on if it was not on */ 331 sec = readb(ioaddr + RTC_SECONDS); 332 if (sec & RTC_STOP) { 333 sec &= RTC_SECONDS_MASK; 334 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 335 writeb(RTC_WRITE, ioaddr + RTC_CONTROL); 336 writeb(sec, ioaddr + RTC_SECONDS); 337 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 338 } 339 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF) 340 dev_warn(&pdev->dev, "voltage-low detected.\n"); 341 342 if (pdata->irq >= 0) { 343 writeb(0, ioaddr + RTC_INTERRUPTS); 344 if (request_irq(pdata->irq, ds1553_rtc_interrupt, IRQF_SHARED, 345 pdev->name, pdev) < 0) { 346 dev_warn(&pdev->dev, "interrupt not available.\n"); 347 pdata->irq = -1; 348 } 349 } 350 351 rtc = rtc_device_register(pdev->name, &pdev->dev, 352 &ds1553_rtc_ops, THIS_MODULE); 353 if (IS_ERR(rtc)) { 354 ret = PTR_ERR(rtc); 355 goto out; 356 } 357 pdata->rtc = rtc; 358 pdata->last_jiffies = jiffies; 359 platform_set_drvdata(pdev, pdata); 360 sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr); 361 return 0; 362 out: 363 if (pdata->irq >= 0) 364 free_irq(pdata->irq, pdev); 365 if (ioaddr) 366 iounmap(ioaddr); 367 if (pdata->baseaddr) 368 release_mem_region(pdata->baseaddr, RTC_REG_SIZE); 369 kfree(pdata); 370 return ret; 371 } 372 373 static int __devexit ds1553_rtc_remove(struct platform_device *pdev) 374 { 375 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 376 377 sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr); 378 rtc_device_unregister(pdata->rtc); 379 if (pdata->irq >= 0) { 380 writeb(0, pdata->ioaddr + RTC_INTERRUPTS); 381 free_irq(pdata->irq, pdev); 382 } 383 iounmap(pdata->ioaddr); 384 release_mem_region(pdata->baseaddr, RTC_REG_SIZE); 385 kfree(pdata); 386 return 0; 387 } 388 389 static struct platform_driver ds1553_rtc_driver = { 390 .probe = ds1553_rtc_probe, 391 .remove = __devexit_p(ds1553_rtc_remove), 392 .driver = { 393 .name = "ds1553", 394 .owner = THIS_MODULE, 395 }, 396 }; 397 398 static __init int ds1553_init(void) 399 { 400 return platform_driver_register(&ds1553_rtc_driver); 401 } 402 403 static __exit void ds1553_exit(void) 404 { 405 return platform_driver_unregister(&ds1553_rtc_driver); 406 } 407 408 module_init(ds1553_init); 409 module_exit(ds1553_exit); 410 411 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 412 MODULE_DESCRIPTION("Dallas DS1553 RTC driver"); 413 MODULE_LICENSE("GPL"); 414 MODULE_VERSION(DRV_VERSION); 415