1 /* 2 * A RTC driver for the Simtek STK17TA8 3 * 4 * By Thomas Hommel <thomas.hommel@gefanuc.com> 5 * 6 * Based on the DS1553 driver from 7 * Atsushi Nemoto <anemo@mba.ocn.ne.jp> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 */ 13 14 #include <linux/bcd.h> 15 #include <linux/init.h> 16 #include <linux/kernel.h> 17 #include <linux/delay.h> 18 #include <linux/jiffies.h> 19 #include <linux/interrupt.h> 20 #include <linux/rtc.h> 21 #include <linux/platform_device.h> 22 #include <linux/io.h> 23 24 #define DRV_VERSION "0.1" 25 26 #define RTC_REG_SIZE 0x20000 27 #define RTC_OFFSET 0x1fff0 28 29 #define RTC_FLAGS (RTC_OFFSET + 0) 30 #define RTC_CENTURY (RTC_OFFSET + 1) 31 #define RTC_SECONDS_ALARM (RTC_OFFSET + 2) 32 #define RTC_MINUTES_ALARM (RTC_OFFSET + 3) 33 #define RTC_HOURS_ALARM (RTC_OFFSET + 4) 34 #define RTC_DATE_ALARM (RTC_OFFSET + 5) 35 #define RTC_INTERRUPTS (RTC_OFFSET + 6) 36 #define RTC_WATCHDOG (RTC_OFFSET + 7) 37 #define RTC_CALIBRATION (RTC_OFFSET + 8) 38 #define RTC_SECONDS (RTC_OFFSET + 9) 39 #define RTC_MINUTES (RTC_OFFSET + 10) 40 #define RTC_HOURS (RTC_OFFSET + 11) 41 #define RTC_DAY (RTC_OFFSET + 12) 42 #define RTC_DATE (RTC_OFFSET + 13) 43 #define RTC_MONTH (RTC_OFFSET + 14) 44 #define RTC_YEAR (RTC_OFFSET + 15) 45 46 #define RTC_SECONDS_MASK 0x7f 47 #define RTC_DAY_MASK 0x07 48 #define RTC_CAL_MASK 0x3f 49 50 /* Bits in the Calibration register */ 51 #define RTC_STOP 0x80 52 53 /* Bits in the Flags register */ 54 #define RTC_FLAGS_AF 0x40 55 #define RTC_FLAGS_PF 0x20 56 #define RTC_WRITE 0x02 57 #define RTC_READ 0x01 58 59 /* Bits in the Interrupts register */ 60 #define RTC_INTS_AIE 0x40 61 62 struct rtc_plat_data { 63 struct rtc_device *rtc; 64 void __iomem *ioaddr; 65 unsigned long baseaddr; 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 }; 74 75 static int stk17ta8_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 flags; 81 82 flags = readb(pdata->ioaddr + RTC_FLAGS); 83 writeb(flags | RTC_WRITE, pdata->ioaddr + RTC_FLAGS); 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 writeb(BIN2BCD((tm->tm_year + 1900) / 100), ioaddr + RTC_CENTURY); 93 94 writeb(flags & ~RTC_WRITE, pdata->ioaddr + RTC_FLAGS); 95 return 0; 96 } 97 98 static int stk17ta8_rtc_read_time(struct device *dev, struct rtc_time *tm) 99 { 100 struct platform_device *pdev = to_platform_device(dev); 101 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 102 void __iomem *ioaddr = pdata->ioaddr; 103 unsigned int year, month, day, hour, minute, second, week; 104 unsigned int century; 105 u8 flags; 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; 111 112 flags = readb(pdata->ioaddr + RTC_FLAGS); 113 writeb(flags | RTC_READ, ioaddr + RTC_FLAGS); 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); 122 writeb(flags & ~RTC_READ, ioaddr + RTC_FLAGS); 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 stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata) 140 { 141 void __iomem *ioaddr = pdata->ioaddr; 142 unsigned long irqflags; 143 u8 flags; 144 145 spin_lock_irqsave(&pdata->rtc->irq_lock, irqflags); 146 147 flags = readb(ioaddr + RTC_FLAGS); 148 writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS); 149 150 writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? 151 0x80 : BIN2BCD(pdata->alrm_mday), 152 ioaddr + RTC_DATE_ALARM); 153 writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? 154 0x80 : BIN2BCD(pdata->alrm_hour), 155 ioaddr + RTC_HOURS_ALARM); 156 writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? 157 0x80 : BIN2BCD(pdata->alrm_min), 158 ioaddr + RTC_MINUTES_ALARM); 159 writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? 160 0x80 : BIN2BCD(pdata->alrm_sec), 161 ioaddr + RTC_SECONDS_ALARM); 162 writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr + RTC_INTERRUPTS); 163 readb(ioaddr + RTC_FLAGS); /* clear interrupts */ 164 writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS); 165 spin_unlock_irqrestore(&pdata->rtc->irq_lock, irqflags); 166 } 167 168 static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 169 { 170 struct platform_device *pdev = to_platform_device(dev); 171 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 172 173 if (pdata->irq < 0) 174 return -EINVAL; 175 pdata->alrm_mday = alrm->time.tm_mday; 176 pdata->alrm_hour = alrm->time.tm_hour; 177 pdata->alrm_min = alrm->time.tm_min; 178 pdata->alrm_sec = alrm->time.tm_sec; 179 if (alrm->enabled) 180 pdata->irqen |= RTC_AF; 181 stk17ta8_rtc_update_alarm(pdata); 182 return 0; 183 } 184 185 static int stk17ta8_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 186 { 187 struct platform_device *pdev = to_platform_device(dev); 188 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 189 190 if (pdata->irq < 0) 191 return -EINVAL; 192 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; 193 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; 194 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; 195 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; 196 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; 197 return 0; 198 } 199 200 static irqreturn_t stk17ta8_rtc_interrupt(int irq, void *dev_id) 201 { 202 struct platform_device *pdev = dev_id; 203 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 204 void __iomem *ioaddr = pdata->ioaddr; 205 unsigned long events = RTC_IRQF; 206 207 /* read and clear interrupt */ 208 if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF)) 209 return IRQ_NONE; 210 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80) 211 events |= RTC_UF; 212 else 213 events |= RTC_AF; 214 rtc_update_irq(pdata->rtc, 1, events); 215 return IRQ_HANDLED; 216 } 217 218 static void stk17ta8_rtc_release(struct device *dev) 219 { 220 struct platform_device *pdev = to_platform_device(dev); 221 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 222 223 if (pdata->irq >= 0) { 224 pdata->irqen = 0; 225 stk17ta8_rtc_update_alarm(pdata); 226 } 227 } 228 229 static int stk17ta8_rtc_ioctl(struct device *dev, unsigned int cmd, 230 unsigned long arg) 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 -ENOIOCTLCMD; /* fall back into rtc-dev's emulation */ 237 switch (cmd) { 238 case RTC_AIE_OFF: 239 pdata->irqen &= ~RTC_AF; 240 stk17ta8_rtc_update_alarm(pdata); 241 break; 242 case RTC_AIE_ON: 243 pdata->irqen |= RTC_AF; 244 stk17ta8_rtc_update_alarm(pdata); 245 break; 246 default: 247 return -ENOIOCTLCMD; 248 } 249 return 0; 250 } 251 252 static const struct rtc_class_ops stk17ta8_rtc_ops = { 253 .read_time = stk17ta8_rtc_read_time, 254 .set_time = stk17ta8_rtc_set_time, 255 .read_alarm = stk17ta8_rtc_read_alarm, 256 .set_alarm = stk17ta8_rtc_set_alarm, 257 .release = stk17ta8_rtc_release, 258 .ioctl = stk17ta8_rtc_ioctl, 259 }; 260 261 static ssize_t stk17ta8_nvram_read(struct kobject *kobj, 262 struct bin_attribute *attr, 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 stk17ta8_nvram_write(struct kobject *kobj, 277 struct bin_attribute *attr, char *buf, 278 loff_t pos, size_t size) 279 { 280 struct platform_device *pdev = 281 to_platform_device(container_of(kobj, struct device, kobj)); 282 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 283 void __iomem *ioaddr = pdata->ioaddr; 284 ssize_t count; 285 286 for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--) 287 writeb(*buf++, ioaddr + pos++); 288 return count; 289 } 290 291 static struct bin_attribute stk17ta8_nvram_attr = { 292 .attr = { 293 .name = "nvram", 294 .mode = S_IRUGO | S_IWUSR, 295 .owner = THIS_MODULE, 296 }, 297 .size = RTC_OFFSET, 298 .read = stk17ta8_nvram_read, 299 .write = stk17ta8_nvram_write, 300 }; 301 302 static int __init stk17ta8_rtc_probe(struct platform_device *pdev) 303 { 304 struct rtc_device *rtc; 305 struct resource *res; 306 unsigned int cal; 307 unsigned int flags; 308 struct rtc_plat_data *pdata; 309 void __iomem *ioaddr = NULL; 310 int ret = 0; 311 312 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 313 if (!res) 314 return -ENODEV; 315 316 pdata = kzalloc(sizeof(*pdata), GFP_KERNEL); 317 if (!pdata) 318 return -ENOMEM; 319 pdata->irq = -1; 320 if (!request_mem_region(res->start, RTC_REG_SIZE, pdev->name)) { 321 ret = -EBUSY; 322 goto out; 323 } 324 pdata->baseaddr = res->start; 325 ioaddr = ioremap(pdata->baseaddr, RTC_REG_SIZE); 326 if (!ioaddr) { 327 ret = -ENOMEM; 328 goto out; 329 } 330 pdata->ioaddr = ioaddr; 331 pdata->irq = platform_get_irq(pdev, 0); 332 333 /* turn RTC on if it was not on */ 334 cal = readb(ioaddr + RTC_CALIBRATION); 335 if (cal & RTC_STOP) { 336 cal &= RTC_CAL_MASK; 337 flags = readb(ioaddr + RTC_FLAGS); 338 writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS); 339 writeb(cal, ioaddr + RTC_CALIBRATION); 340 writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS); 341 } 342 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF) 343 dev_warn(&pdev->dev, "voltage-low detected.\n"); 344 345 if (pdata->irq >= 0) { 346 writeb(0, ioaddr + RTC_INTERRUPTS); 347 if (request_irq(pdata->irq, stk17ta8_rtc_interrupt, 348 IRQF_DISABLED | IRQF_SHARED, 349 pdev->name, pdev) < 0) { 350 dev_warn(&pdev->dev, "interrupt not available.\n"); 351 pdata->irq = -1; 352 } 353 } 354 355 rtc = rtc_device_register(pdev->name, &pdev->dev, 356 &stk17ta8_rtc_ops, THIS_MODULE); 357 if (IS_ERR(rtc)) { 358 ret = PTR_ERR(rtc); 359 goto out; 360 } 361 pdata->rtc = rtc; 362 pdata->last_jiffies = jiffies; 363 platform_set_drvdata(pdev, pdata); 364 ret = sysfs_create_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr); 365 if (ret) 366 goto out; 367 return 0; 368 out: 369 if (pdata->rtc) 370 rtc_device_unregister(pdata->rtc); 371 if (pdata->irq >= 0) 372 free_irq(pdata->irq, pdev); 373 if (ioaddr) 374 iounmap(ioaddr); 375 if (pdata->baseaddr) 376 release_mem_region(pdata->baseaddr, RTC_REG_SIZE); 377 kfree(pdata); 378 return ret; 379 } 380 381 static int __devexit stk17ta8_rtc_remove(struct platform_device *pdev) 382 { 383 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 384 385 sysfs_remove_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr); 386 rtc_device_unregister(pdata->rtc); 387 if (pdata->irq >= 0) { 388 writeb(0, pdata->ioaddr + RTC_INTERRUPTS); 389 free_irq(pdata->irq, pdev); 390 } 391 iounmap(pdata->ioaddr); 392 release_mem_region(pdata->baseaddr, RTC_REG_SIZE); 393 kfree(pdata); 394 return 0; 395 } 396 397 static struct platform_driver stk17ta8_rtc_driver = { 398 .probe = stk17ta8_rtc_probe, 399 .remove = __devexit_p(stk17ta8_rtc_remove), 400 .driver = { 401 .name = "stk17ta8", 402 .owner = THIS_MODULE, 403 }, 404 }; 405 406 static __init int stk17ta8_init(void) 407 { 408 return platform_driver_register(&stk17ta8_rtc_driver); 409 } 410 411 static __exit void stk17ta8_exit(void) 412 { 413 return platform_driver_unregister(&stk17ta8_rtc_driver); 414 } 415 416 module_init(stk17ta8_init); 417 module_exit(stk17ta8_exit); 418 419 MODULE_AUTHOR("Thomas Hommel <thomas.hommel@gefanuc.com>"); 420 MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver"); 421 MODULE_LICENSE("GPL"); 422 MODULE_VERSION(DRV_VERSION); 423