1 /* 2 * A RTC driver for the Simtek STK17TA8 3 * 4 * By Thomas Hommel <thomas.hommel@ge.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/gfp.h> 18 #include <linux/delay.h> 19 #include <linux/jiffies.h> 20 #include <linux/interrupt.h> 21 #include <linux/rtc.h> 22 #include <linux/platform_device.h> 23 #include <linux/io.h> 24 25 #define DRV_VERSION "0.1" 26 27 #define RTC_REG_SIZE 0x20000 28 #define RTC_OFFSET 0x1fff0 29 30 #define RTC_FLAGS (RTC_OFFSET + 0) 31 #define RTC_CENTURY (RTC_OFFSET + 1) 32 #define RTC_SECONDS_ALARM (RTC_OFFSET + 2) 33 #define RTC_MINUTES_ALARM (RTC_OFFSET + 3) 34 #define RTC_HOURS_ALARM (RTC_OFFSET + 4) 35 #define RTC_DATE_ALARM (RTC_OFFSET + 5) 36 #define RTC_INTERRUPTS (RTC_OFFSET + 6) 37 #define RTC_WATCHDOG (RTC_OFFSET + 7) 38 #define RTC_CALIBRATION (RTC_OFFSET + 8) 39 #define RTC_SECONDS (RTC_OFFSET + 9) 40 #define RTC_MINUTES (RTC_OFFSET + 10) 41 #define RTC_HOURS (RTC_OFFSET + 11) 42 #define RTC_DAY (RTC_OFFSET + 12) 43 #define RTC_DATE (RTC_OFFSET + 13) 44 #define RTC_MONTH (RTC_OFFSET + 14) 45 #define RTC_YEAR (RTC_OFFSET + 15) 46 47 #define RTC_SECONDS_MASK 0x7f 48 #define RTC_DAY_MASK 0x07 49 #define RTC_CAL_MASK 0x3f 50 51 /* Bits in the Calibration register */ 52 #define RTC_STOP 0x80 53 54 /* Bits in the Flags register */ 55 #define RTC_FLAGS_AF 0x40 56 #define RTC_FLAGS_PF 0x20 57 #define RTC_WRITE 0x02 58 #define RTC_READ 0x01 59 60 /* Bits in the Interrupts register */ 61 #define RTC_INTS_AIE 0x40 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 stk17ta8_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 flags; 82 83 flags = readb(pdata->ioaddr + RTC_FLAGS); 84 writeb(flags | RTC_WRITE, pdata->ioaddr + RTC_FLAGS); 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 writeb(bin2bcd((tm->tm_year + 1900) / 100), ioaddr + RTC_CENTURY); 94 95 writeb(flags & ~RTC_WRITE, pdata->ioaddr + RTC_FLAGS); 96 return 0; 97 } 98 99 static int stk17ta8_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 u8 flags; 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; 112 113 flags = readb(pdata->ioaddr + RTC_FLAGS); 114 writeb(flags | RTC_READ, ioaddr + RTC_FLAGS); 115 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK; 116 minute = readb(ioaddr + RTC_MINUTES); 117 hour = readb(ioaddr + RTC_HOURS); 118 day = readb(ioaddr + RTC_DATE); 119 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK; 120 month = readb(ioaddr + RTC_MONTH); 121 year = readb(ioaddr + RTC_YEAR); 122 century = readb(ioaddr + RTC_CENTURY); 123 writeb(flags & ~RTC_READ, ioaddr + RTC_FLAGS); 124 tm->tm_sec = bcd2bin(second); 125 tm->tm_min = bcd2bin(minute); 126 tm->tm_hour = bcd2bin(hour); 127 tm->tm_mday = bcd2bin(day); 128 tm->tm_wday = bcd2bin(week); 129 tm->tm_mon = bcd2bin(month) - 1; 130 /* year is 1900 + tm->tm_year */ 131 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900; 132 133 if (rtc_valid_tm(tm) < 0) { 134 dev_err(dev, "retrieved date/time is not valid.\n"); 135 rtc_time_to_tm(0, tm); 136 } 137 return 0; 138 } 139 140 static void stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata) 141 { 142 void __iomem *ioaddr = pdata->ioaddr; 143 unsigned long irqflags; 144 u8 flags; 145 146 spin_lock_irqsave(&pdata->lock, irqflags); 147 148 flags = readb(ioaddr + RTC_FLAGS); 149 writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS); 150 151 writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? 152 0x80 : bin2bcd(pdata->alrm_mday), 153 ioaddr + RTC_DATE_ALARM); 154 writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? 155 0x80 : bin2bcd(pdata->alrm_hour), 156 ioaddr + RTC_HOURS_ALARM); 157 writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? 158 0x80 : bin2bcd(pdata->alrm_min), 159 ioaddr + RTC_MINUTES_ALARM); 160 writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? 161 0x80 : bin2bcd(pdata->alrm_sec), 162 ioaddr + RTC_SECONDS_ALARM); 163 writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr + RTC_INTERRUPTS); 164 readb(ioaddr + RTC_FLAGS); /* clear interrupts */ 165 writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS); 166 spin_unlock_irqrestore(&pdata->lock, irqflags); 167 } 168 169 static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 170 { 171 struct platform_device *pdev = to_platform_device(dev); 172 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 173 174 if (pdata->irq <= 0) 175 return -EINVAL; 176 pdata->alrm_mday = alrm->time.tm_mday; 177 pdata->alrm_hour = alrm->time.tm_hour; 178 pdata->alrm_min = alrm->time.tm_min; 179 pdata->alrm_sec = alrm->time.tm_sec; 180 if (alrm->enabled) 181 pdata->irqen |= RTC_AF; 182 stk17ta8_rtc_update_alarm(pdata); 183 return 0; 184 } 185 186 static int stk17ta8_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 187 { 188 struct platform_device *pdev = to_platform_device(dev); 189 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 190 191 if (pdata->irq <= 0) 192 return -EINVAL; 193 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; 194 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; 195 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; 196 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; 197 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; 198 return 0; 199 } 200 201 static irqreturn_t stk17ta8_rtc_interrupt(int irq, void *dev_id) 202 { 203 struct platform_device *pdev = dev_id; 204 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 205 void __iomem *ioaddr = pdata->ioaddr; 206 unsigned long events = 0; 207 208 spin_lock(&pdata->lock); 209 /* read and clear interrupt */ 210 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) { 211 events = RTC_IRQF; 212 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80) 213 events |= RTC_UF; 214 else 215 events |= RTC_AF; 216 if (likely(pdata->rtc)) 217 rtc_update_irq(pdata->rtc, 1, events); 218 } 219 spin_unlock(&pdata->lock); 220 return events ? IRQ_HANDLED : IRQ_NONE; 221 } 222 223 static int stk17ta8_rtc_alarm_irq_enable(struct device *dev, 224 unsigned int enabled) 225 { 226 struct platform_device *pdev = to_platform_device(dev); 227 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 228 229 if (pdata->irq <= 0) 230 return -EINVAL; 231 if (enabled) 232 pdata->irqen |= RTC_AF; 233 else 234 pdata->irqen &= ~RTC_AF; 235 stk17ta8_rtc_update_alarm(pdata); 236 return 0; 237 } 238 239 static const struct rtc_class_ops stk17ta8_rtc_ops = { 240 .read_time = stk17ta8_rtc_read_time, 241 .set_time = stk17ta8_rtc_set_time, 242 .read_alarm = stk17ta8_rtc_read_alarm, 243 .set_alarm = stk17ta8_rtc_set_alarm, 244 .alarm_irq_enable = stk17ta8_rtc_alarm_irq_enable, 245 }; 246 247 static ssize_t stk17ta8_nvram_read(struct file *filp, struct kobject *kobj, 248 struct bin_attribute *attr, char *buf, 249 loff_t pos, size_t size) 250 { 251 struct device *dev = container_of(kobj, struct device, kobj); 252 struct platform_device *pdev = to_platform_device(dev); 253 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 254 void __iomem *ioaddr = pdata->ioaddr; 255 ssize_t count; 256 257 for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--) 258 *buf++ = readb(ioaddr + pos++); 259 return count; 260 } 261 262 static ssize_t stk17ta8_nvram_write(struct file *filp, struct kobject *kobj, 263 struct bin_attribute *attr, char *buf, 264 loff_t pos, size_t size) 265 { 266 struct device *dev = container_of(kobj, struct device, kobj); 267 struct platform_device *pdev = to_platform_device(dev); 268 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 269 void __iomem *ioaddr = pdata->ioaddr; 270 ssize_t count; 271 272 for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--) 273 writeb(*buf++, ioaddr + pos++); 274 return count; 275 } 276 277 static struct bin_attribute stk17ta8_nvram_attr = { 278 .attr = { 279 .name = "nvram", 280 .mode = S_IRUGO | S_IWUSR, 281 }, 282 .size = RTC_OFFSET, 283 .read = stk17ta8_nvram_read, 284 .write = stk17ta8_nvram_write, 285 }; 286 287 static int __devinit stk17ta8_rtc_probe(struct platform_device *pdev) 288 { 289 struct resource *res; 290 unsigned int cal; 291 unsigned int flags; 292 struct rtc_plat_data *pdata; 293 void __iomem *ioaddr; 294 int ret = 0; 295 296 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 297 if (!res) 298 return -ENODEV; 299 300 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 301 if (!pdata) 302 return -ENOMEM; 303 if (!devm_request_mem_region(&pdev->dev, res->start, RTC_REG_SIZE, 304 pdev->name)) 305 return -EBUSY; 306 ioaddr = devm_ioremap(&pdev->dev, res->start, RTC_REG_SIZE); 307 if (!ioaddr) 308 return -ENOMEM; 309 pdata->ioaddr = ioaddr; 310 pdata->irq = platform_get_irq(pdev, 0); 311 312 /* turn RTC on if it was not on */ 313 cal = readb(ioaddr + RTC_CALIBRATION); 314 if (cal & RTC_STOP) { 315 cal &= RTC_CAL_MASK; 316 flags = readb(ioaddr + RTC_FLAGS); 317 writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS); 318 writeb(cal, ioaddr + RTC_CALIBRATION); 319 writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS); 320 } 321 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF) 322 dev_warn(&pdev->dev, "voltage-low detected.\n"); 323 324 spin_lock_init(&pdata->lock); 325 pdata->last_jiffies = jiffies; 326 platform_set_drvdata(pdev, pdata); 327 if (pdata->irq > 0) { 328 writeb(0, ioaddr + RTC_INTERRUPTS); 329 if (devm_request_irq(&pdev->dev, pdata->irq, 330 stk17ta8_rtc_interrupt, 331 IRQF_DISABLED | IRQF_SHARED, 332 pdev->name, pdev) < 0) { 333 dev_warn(&pdev->dev, "interrupt not available.\n"); 334 pdata->irq = 0; 335 } 336 } 337 338 pdata->rtc = rtc_device_register(pdev->name, &pdev->dev, 339 &stk17ta8_rtc_ops, THIS_MODULE); 340 if (IS_ERR(pdata->rtc)) 341 return PTR_ERR(pdata->rtc); 342 343 ret = sysfs_create_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr); 344 if (ret) 345 rtc_device_unregister(pdata->rtc); 346 return ret; 347 } 348 349 static int __devexit stk17ta8_rtc_remove(struct platform_device *pdev) 350 { 351 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 352 353 sysfs_remove_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr); 354 rtc_device_unregister(pdata->rtc); 355 if (pdata->irq > 0) 356 writeb(0, pdata->ioaddr + RTC_INTERRUPTS); 357 return 0; 358 } 359 360 /* work with hotplug and coldplug */ 361 MODULE_ALIAS("platform:stk17ta8"); 362 363 static struct platform_driver stk17ta8_rtc_driver = { 364 .probe = stk17ta8_rtc_probe, 365 .remove = __devexit_p(stk17ta8_rtc_remove), 366 .driver = { 367 .name = "stk17ta8", 368 .owner = THIS_MODULE, 369 }, 370 }; 371 372 static __init int stk17ta8_init(void) 373 { 374 return platform_driver_register(&stk17ta8_rtc_driver); 375 } 376 377 static __exit void stk17ta8_exit(void) 378 { 379 platform_driver_unregister(&stk17ta8_rtc_driver); 380 } 381 382 module_init(stk17ta8_init); 383 module_exit(stk17ta8_exit); 384 385 MODULE_AUTHOR("Thomas Hommel <thomas.hommel@ge.com>"); 386 MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver"); 387 MODULE_LICENSE("GPL"); 388 MODULE_VERSION(DRV_VERSION); 389