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 22 #define DRV_VERSION "0.3" 23 24 #define RTC_REG_SIZE 0x2000 25 #define RTC_OFFSET 0x1ff0 26 27 #define RTC_FLAGS (RTC_OFFSET + 0) 28 #define RTC_SECONDS_ALARM (RTC_OFFSET + 2) 29 #define RTC_MINUTES_ALARM (RTC_OFFSET + 3) 30 #define RTC_HOURS_ALARM (RTC_OFFSET + 4) 31 #define RTC_DATE_ALARM (RTC_OFFSET + 5) 32 #define RTC_INTERRUPTS (RTC_OFFSET + 6) 33 #define RTC_WATCHDOG (RTC_OFFSET + 7) 34 #define RTC_CONTROL (RTC_OFFSET + 8) 35 #define RTC_CENTURY (RTC_OFFSET + 8) 36 #define RTC_SECONDS (RTC_OFFSET + 9) 37 #define RTC_MINUTES (RTC_OFFSET + 10) 38 #define RTC_HOURS (RTC_OFFSET + 11) 39 #define RTC_DAY (RTC_OFFSET + 12) 40 #define RTC_DATE (RTC_OFFSET + 13) 41 #define RTC_MONTH (RTC_OFFSET + 14) 42 #define RTC_YEAR (RTC_OFFSET + 15) 43 44 #define RTC_CENTURY_MASK 0x3f 45 #define RTC_SECONDS_MASK 0x7f 46 #define RTC_DAY_MASK 0x07 47 48 /* Bits in the Control/Century register */ 49 #define RTC_WRITE 0x80 50 #define RTC_READ 0x40 51 52 /* Bits in the Seconds register */ 53 #define RTC_STOP 0x80 54 55 /* Bits in the Flags register */ 56 #define RTC_FLAGS_AF 0x40 57 #define RTC_FLAGS_BLF 0x10 58 59 /* Bits in the Interrupts register */ 60 #define RTC_INTS_AE 0x80 61 62 struct rtc_plat_data { 63 struct rtc_device *rtc; 64 void __iomem *ioaddr; 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 spinlock_t lock; 73 }; 74 75 static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm) 76 { 77 struct platform_device *pdev = to_platform_device(dev); 78 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 79 void __iomem *ioaddr = pdata->ioaddr; 80 u8 century; 81 82 century = bin2bcd((tm->tm_year + 1900) / 100); 83 84 writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL); 85 86 writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR); 87 writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH); 88 writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY); 89 writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE); 90 writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS); 91 writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES); 92 writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS); 93 94 /* RTC_CENTURY and RTC_CONTROL share same register */ 95 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY); 96 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 97 return 0; 98 } 99 100 static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm) 101 { 102 struct platform_device *pdev = to_platform_device(dev); 103 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 104 void __iomem *ioaddr = pdata->ioaddr; 105 unsigned int year, month, day, hour, minute, second, week; 106 unsigned int century; 107 108 /* give enough time to update RTC in case of continuous read */ 109 if (pdata->last_jiffies == jiffies) 110 msleep(1); 111 pdata->last_jiffies = jiffies; 112 writeb(RTC_READ, ioaddr + RTC_CONTROL); 113 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK; 114 minute = readb(ioaddr + RTC_MINUTES); 115 hour = readb(ioaddr + RTC_HOURS); 116 day = readb(ioaddr + RTC_DATE); 117 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK; 118 month = readb(ioaddr + RTC_MONTH); 119 year = readb(ioaddr + RTC_YEAR); 120 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 121 writeb(0, ioaddr + RTC_CONTROL); 122 tm->tm_sec = bcd2bin(second); 123 tm->tm_min = bcd2bin(minute); 124 tm->tm_hour = bcd2bin(hour); 125 tm->tm_mday = bcd2bin(day); 126 tm->tm_wday = bcd2bin(week); 127 tm->tm_mon = bcd2bin(month) - 1; 128 /* year is 1900 + tm->tm_year */ 129 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900; 130 131 if (rtc_valid_tm(tm) < 0) { 132 dev_err(dev, "retrieved date/time is not valid.\n"); 133 rtc_time_to_tm(0, tm); 134 } 135 return 0; 136 } 137 138 static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata) 139 { 140 void __iomem *ioaddr = pdata->ioaddr; 141 unsigned long flags; 142 143 spin_lock_irqsave(&pdata->lock, flags); 144 writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? 145 0x80 : bin2bcd(pdata->alrm_mday), 146 ioaddr + RTC_DATE_ALARM); 147 writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? 148 0x80 : bin2bcd(pdata->alrm_hour), 149 ioaddr + RTC_HOURS_ALARM); 150 writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? 151 0x80 : bin2bcd(pdata->alrm_min), 152 ioaddr + RTC_MINUTES_ALARM); 153 writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? 154 0x80 : bin2bcd(pdata->alrm_sec), 155 ioaddr + RTC_SECONDS_ALARM); 156 writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS); 157 readb(ioaddr + RTC_FLAGS); /* clear interrupts */ 158 spin_unlock_irqrestore(&pdata->lock, flags); 159 } 160 161 static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 162 { 163 struct platform_device *pdev = to_platform_device(dev); 164 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 165 166 if (pdata->irq <= 0) 167 return -EINVAL; 168 pdata->alrm_mday = alrm->time.tm_mday; 169 pdata->alrm_hour = alrm->time.tm_hour; 170 pdata->alrm_min = alrm->time.tm_min; 171 pdata->alrm_sec = alrm->time.tm_sec; 172 if (alrm->enabled) 173 pdata->irqen |= RTC_AF; 174 ds1553_rtc_update_alarm(pdata); 175 return 0; 176 } 177 178 static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 179 { 180 struct platform_device *pdev = to_platform_device(dev); 181 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 182 183 if (pdata->irq <= 0) 184 return -EINVAL; 185 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; 186 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; 187 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; 188 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; 189 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; 190 return 0; 191 } 192 193 static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id) 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 = 0; 199 200 spin_lock(&pdata->lock); 201 /* read and clear interrupt */ 202 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) { 203 events = RTC_IRQF; 204 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80) 205 events |= RTC_UF; 206 else 207 events |= RTC_AF; 208 if (likely(pdata->rtc)) 209 rtc_update_irq(pdata->rtc, 1, events); 210 } 211 spin_unlock(&pdata->lock); 212 return events ? IRQ_HANDLED : IRQ_NONE; 213 } 214 215 static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 216 { 217 struct platform_device *pdev = to_platform_device(dev); 218 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 219 220 if (pdata->irq <= 0) 221 return -EINVAL; 222 if (enabled) 223 pdata->irqen |= RTC_AF; 224 else 225 pdata->irqen &= ~RTC_AF; 226 ds1553_rtc_update_alarm(pdata); 227 return 0; 228 } 229 230 static int ds1553_rtc_update_irq_enable(struct device *dev, 231 unsigned int enabled) 232 { 233 struct platform_device *pdev = to_platform_device(dev); 234 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 235 236 if (pdata->irq <= 0) 237 return -EINVAL; 238 if (enabled) 239 pdata->irqen |= RTC_UF; 240 else 241 pdata->irqen &= ~RTC_UF; 242 ds1553_rtc_update_alarm(pdata); 243 return 0; 244 } 245 246 static const struct rtc_class_ops ds1553_rtc_ops = { 247 .read_time = ds1553_rtc_read_time, 248 .set_time = ds1553_rtc_set_time, 249 .read_alarm = ds1553_rtc_read_alarm, 250 .set_alarm = ds1553_rtc_set_alarm, 251 .alarm_irq_enable = ds1553_rtc_alarm_irq_enable, 252 .update_irq_enable = ds1553_rtc_update_irq_enable, 253 }; 254 255 static ssize_t ds1553_nvram_read(struct file *filp, struct kobject *kobj, 256 struct bin_attribute *bin_attr, 257 char *buf, loff_t pos, size_t size) 258 { 259 struct device *dev = container_of(kobj, struct device, kobj); 260 struct platform_device *pdev = to_platform_device(dev); 261 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 262 void __iomem *ioaddr = pdata->ioaddr; 263 ssize_t count; 264 265 for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--) 266 *buf++ = readb(ioaddr + pos++); 267 return count; 268 } 269 270 static ssize_t ds1553_nvram_write(struct file *filp, struct kobject *kobj, 271 struct bin_attribute *bin_attr, 272 char *buf, loff_t pos, size_t size) 273 { 274 struct device *dev = container_of(kobj, struct device, kobj); 275 struct platform_device *pdev = to_platform_device(dev); 276 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 277 void __iomem *ioaddr = pdata->ioaddr; 278 ssize_t count; 279 280 for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--) 281 writeb(*buf++, ioaddr + pos++); 282 return count; 283 } 284 285 static struct bin_attribute ds1553_nvram_attr = { 286 .attr = { 287 .name = "nvram", 288 .mode = S_IRUGO | S_IWUSR, 289 }, 290 .size = RTC_OFFSET, 291 .read = ds1553_nvram_read, 292 .write = ds1553_nvram_write, 293 }; 294 295 static int __devinit ds1553_rtc_probe(struct platform_device *pdev) 296 { 297 struct rtc_device *rtc; 298 struct resource *res; 299 unsigned int cen, sec; 300 struct rtc_plat_data *pdata; 301 void __iomem *ioaddr; 302 int ret = 0; 303 304 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 305 if (!res) 306 return -ENODEV; 307 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 308 if (!pdata) 309 return -ENOMEM; 310 if (!devm_request_mem_region(&pdev->dev, res->start, RTC_REG_SIZE, 311 pdev->name)) 312 return -EBUSY; 313 314 ioaddr = devm_ioremap(&pdev->dev, res->start, RTC_REG_SIZE); 315 if (!ioaddr) 316 return -ENOMEM; 317 pdata->ioaddr = ioaddr; 318 pdata->irq = platform_get_irq(pdev, 0); 319 320 /* turn RTC on if it was not on */ 321 sec = readb(ioaddr + RTC_SECONDS); 322 if (sec & RTC_STOP) { 323 sec &= RTC_SECONDS_MASK; 324 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 325 writeb(RTC_WRITE, ioaddr + RTC_CONTROL); 326 writeb(sec, ioaddr + RTC_SECONDS); 327 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 328 } 329 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF) 330 dev_warn(&pdev->dev, "voltage-low detected.\n"); 331 332 spin_lock_init(&pdata->lock); 333 pdata->last_jiffies = jiffies; 334 platform_set_drvdata(pdev, pdata); 335 if (pdata->irq > 0) { 336 writeb(0, ioaddr + RTC_INTERRUPTS); 337 if (devm_request_irq(&pdev->dev, pdata->irq, 338 ds1553_rtc_interrupt, 339 IRQF_DISABLED, pdev->name, pdev) < 0) { 340 dev_warn(&pdev->dev, "interrupt not available.\n"); 341 pdata->irq = 0; 342 } 343 } 344 345 rtc = rtc_device_register(pdev->name, &pdev->dev, 346 &ds1553_rtc_ops, THIS_MODULE); 347 if (IS_ERR(rtc)) 348 return PTR_ERR(rtc); 349 pdata->rtc = rtc; 350 351 ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr); 352 if (ret) 353 rtc_device_unregister(rtc); 354 return ret; 355 } 356 357 static int __devexit ds1553_rtc_remove(struct platform_device *pdev) 358 { 359 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 360 361 sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr); 362 rtc_device_unregister(pdata->rtc); 363 if (pdata->irq > 0) 364 writeb(0, pdata->ioaddr + RTC_INTERRUPTS); 365 return 0; 366 } 367 368 /* work with hotplug and coldplug */ 369 MODULE_ALIAS("platform:rtc-ds1553"); 370 371 static struct platform_driver ds1553_rtc_driver = { 372 .probe = ds1553_rtc_probe, 373 .remove = __devexit_p(ds1553_rtc_remove), 374 .driver = { 375 .name = "rtc-ds1553", 376 .owner = THIS_MODULE, 377 }, 378 }; 379 380 static __init int ds1553_init(void) 381 { 382 return platform_driver_register(&ds1553_rtc_driver); 383 } 384 385 static __exit void ds1553_exit(void) 386 { 387 platform_driver_unregister(&ds1553_rtc_driver); 388 } 389 390 module_init(ds1553_init); 391 module_exit(ds1553_exit); 392 393 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 394 MODULE_DESCRIPTION("Dallas DS1553 RTC driver"); 395 MODULE_LICENSE("GPL"); 396 MODULE_VERSION(DRV_VERSION); 397