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 "0.3" 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 last_jiffies; 65 int irq; 66 unsigned int irqen; 67 int alrm_sec; 68 int alrm_min; 69 int alrm_hour; 70 int alrm_mday; 71 spinlock_t lock; 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->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->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 { 194 struct platform_device *pdev = dev_id; 195 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 196 void __iomem *ioaddr = pdata->ioaddr; 197 unsigned long events = 0; 198 199 spin_lock(&pdata->lock); 200 /* read and clear interrupt */ 201 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) { 202 events = RTC_IRQF; 203 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80) 204 events |= RTC_UF; 205 else 206 events |= RTC_AF; 207 if (likely(pdata->rtc)) 208 rtc_update_irq(pdata->rtc, 1, events); 209 } 210 spin_unlock(&pdata->lock); 211 return events ? IRQ_HANDLED : IRQ_NONE; 212 } 213 214 static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 215 { 216 struct platform_device *pdev = to_platform_device(dev); 217 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 218 219 if (pdata->irq <= 0) 220 return -EINVAL; 221 if (enabled) 222 pdata->irqen |= RTC_AF; 223 else 224 pdata->irqen &= ~RTC_AF; 225 ds1553_rtc_update_alarm(pdata); 226 return 0; 227 } 228 229 static int ds1553_rtc_update_irq_enable(struct device *dev, 230 unsigned int enabled) 231 { 232 struct platform_device *pdev = to_platform_device(dev); 233 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 234 235 if (pdata->irq <= 0) 236 return -EINVAL; 237 if (enabled) 238 pdata->irqen |= RTC_UF; 239 else 240 pdata->irqen &= ~RTC_UF; 241 ds1553_rtc_update_alarm(pdata); 242 return 0; 243 } 244 245 static const struct rtc_class_ops ds1553_rtc_ops = { 246 .read_time = ds1553_rtc_read_time, 247 .set_time = ds1553_rtc_set_time, 248 .read_alarm = ds1553_rtc_read_alarm, 249 .set_alarm = ds1553_rtc_set_alarm, 250 .alarm_irq_enable = ds1553_rtc_alarm_irq_enable, 251 .update_irq_enable = ds1553_rtc_update_irq_enable, 252 }; 253 254 static ssize_t ds1553_nvram_read(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 *buf++ = readb(ioaddr + pos++); 266 return count; 267 } 268 269 static ssize_t ds1553_nvram_write(struct kobject *kobj, 270 struct bin_attribute *bin_attr, 271 char *buf, loff_t pos, size_t size) 272 { 273 struct device *dev = container_of(kobj, struct device, kobj); 274 struct platform_device *pdev = to_platform_device(dev); 275 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 276 void __iomem *ioaddr = pdata->ioaddr; 277 ssize_t count; 278 279 for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--) 280 writeb(*buf++, ioaddr + pos++); 281 return count; 282 } 283 284 static struct bin_attribute ds1553_nvram_attr = { 285 .attr = { 286 .name = "nvram", 287 .mode = S_IRUGO | S_IWUSR, 288 }, 289 .size = RTC_OFFSET, 290 .read = ds1553_nvram_read, 291 .write = ds1553_nvram_write, 292 }; 293 294 static int __devinit ds1553_rtc_probe(struct platform_device *pdev) 295 { 296 struct rtc_device *rtc; 297 struct resource *res; 298 unsigned int cen, sec; 299 struct rtc_plat_data *pdata; 300 void __iomem *ioaddr; 301 int ret = 0; 302 303 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 304 if (!res) 305 return -ENODEV; 306 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 307 if (!pdata) 308 return -ENOMEM; 309 if (!devm_request_mem_region(&pdev->dev, res->start, RTC_REG_SIZE, 310 pdev->name)) 311 return -EBUSY; 312 313 ioaddr = devm_ioremap(&pdev->dev, res->start, RTC_REG_SIZE); 314 if (!ioaddr) 315 return -ENOMEM; 316 pdata->ioaddr = ioaddr; 317 pdata->irq = platform_get_irq(pdev, 0); 318 319 /* turn RTC on if it was not on */ 320 sec = readb(ioaddr + RTC_SECONDS); 321 if (sec & RTC_STOP) { 322 sec &= RTC_SECONDS_MASK; 323 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 324 writeb(RTC_WRITE, ioaddr + RTC_CONTROL); 325 writeb(sec, ioaddr + RTC_SECONDS); 326 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 327 } 328 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF) 329 dev_warn(&pdev->dev, "voltage-low detected.\n"); 330 331 spin_lock_init(&pdata->lock); 332 pdata->last_jiffies = jiffies; 333 platform_set_drvdata(pdev, pdata); 334 if (pdata->irq > 0) { 335 writeb(0, ioaddr + RTC_INTERRUPTS); 336 if (devm_request_irq(&pdev->dev, pdata->irq, 337 ds1553_rtc_interrupt, 338 IRQF_DISABLED, pdev->name, pdev) < 0) { 339 dev_warn(&pdev->dev, "interrupt not available.\n"); 340 pdata->irq = 0; 341 } 342 } 343 344 rtc = rtc_device_register(pdev->name, &pdev->dev, 345 &ds1553_rtc_ops, THIS_MODULE); 346 if (IS_ERR(rtc)) 347 return PTR_ERR(rtc); 348 pdata->rtc = rtc; 349 350 ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr); 351 if (ret) 352 rtc_device_unregister(rtc); 353 return ret; 354 } 355 356 static int __devexit ds1553_rtc_remove(struct platform_device *pdev) 357 { 358 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 359 360 sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr); 361 rtc_device_unregister(pdata->rtc); 362 if (pdata->irq > 0) 363 writeb(0, pdata->ioaddr + RTC_INTERRUPTS); 364 return 0; 365 } 366 367 /* work with hotplug and coldplug */ 368 MODULE_ALIAS("platform:rtc-ds1553"); 369 370 static struct platform_driver ds1553_rtc_driver = { 371 .probe = ds1553_rtc_probe, 372 .remove = __devexit_p(ds1553_rtc_remove), 373 .driver = { 374 .name = "rtc-ds1553", 375 .owner = THIS_MODULE, 376 }, 377 }; 378 379 static __init int ds1553_init(void) 380 { 381 return platform_driver_register(&ds1553_rtc_driver); 382 } 383 384 static __exit void ds1553_exit(void) 385 { 386 platform_driver_unregister(&ds1553_rtc_driver); 387 } 388 389 module_init(ds1553_init); 390 module_exit(ds1553_exit); 391 392 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 393 MODULE_DESCRIPTION("Dallas DS1553 RTC driver"); 394 MODULE_LICENSE("GPL"); 395 MODULE_VERSION(DRV_VERSION); 396