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 #include <linux/module.h> 25 26 #define DRV_VERSION "0.1" 27 28 #define RTC_REG_SIZE 0x20000 29 #define RTC_OFFSET 0x1fff0 30 31 #define RTC_FLAGS (RTC_OFFSET + 0) 32 #define RTC_CENTURY (RTC_OFFSET + 1) 33 #define RTC_SECONDS_ALARM (RTC_OFFSET + 2) 34 #define RTC_MINUTES_ALARM (RTC_OFFSET + 3) 35 #define RTC_HOURS_ALARM (RTC_OFFSET + 4) 36 #define RTC_DATE_ALARM (RTC_OFFSET + 5) 37 #define RTC_INTERRUPTS (RTC_OFFSET + 6) 38 #define RTC_WATCHDOG (RTC_OFFSET + 7) 39 #define RTC_CALIBRATION (RTC_OFFSET + 8) 40 #define RTC_SECONDS (RTC_OFFSET + 9) 41 #define RTC_MINUTES (RTC_OFFSET + 10) 42 #define RTC_HOURS (RTC_OFFSET + 11) 43 #define RTC_DAY (RTC_OFFSET + 12) 44 #define RTC_DATE (RTC_OFFSET + 13) 45 #define RTC_MONTH (RTC_OFFSET + 14) 46 #define RTC_YEAR (RTC_OFFSET + 15) 47 48 #define RTC_SECONDS_MASK 0x7f 49 #define RTC_DAY_MASK 0x07 50 #define RTC_CAL_MASK 0x3f 51 52 /* Bits in the Calibration register */ 53 #define RTC_STOP 0x80 54 55 /* Bits in the Flags register */ 56 #define RTC_FLAGS_AF 0x40 57 #define RTC_FLAGS_PF 0x20 58 #define RTC_WRITE 0x02 59 #define RTC_READ 0x01 60 61 /* Bits in the Interrupts register */ 62 #define RTC_INTS_AIE 0x40 63 64 struct rtc_plat_data { 65 struct rtc_device *rtc; 66 void __iomem *ioaddr; 67 unsigned long last_jiffies; 68 int irq; 69 unsigned int irqen; 70 int alrm_sec; 71 int alrm_min; 72 int alrm_hour; 73 int alrm_mday; 74 spinlock_t lock; 75 }; 76 77 static int stk17ta8_rtc_set_time(struct device *dev, struct rtc_time *tm) 78 { 79 struct platform_device *pdev = to_platform_device(dev); 80 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 81 void __iomem *ioaddr = pdata->ioaddr; 82 u8 flags; 83 84 flags = readb(pdata->ioaddr + RTC_FLAGS); 85 writeb(flags | RTC_WRITE, pdata->ioaddr + RTC_FLAGS); 86 87 writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR); 88 writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH); 89 writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY); 90 writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE); 91 writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS); 92 writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES); 93 writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS); 94 writeb(bin2bcd((tm->tm_year + 1900) / 100), ioaddr + RTC_CENTURY); 95 96 writeb(flags & ~RTC_WRITE, pdata->ioaddr + RTC_FLAGS); 97 return 0; 98 } 99 100 static int stk17ta8_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 u8 flags; 108 109 /* give enough time to update RTC in case of continuous read */ 110 if (pdata->last_jiffies == jiffies) 111 msleep(1); 112 pdata->last_jiffies = jiffies; 113 114 flags = readb(pdata->ioaddr + RTC_FLAGS); 115 writeb(flags | RTC_READ, ioaddr + RTC_FLAGS); 116 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK; 117 minute = readb(ioaddr + RTC_MINUTES); 118 hour = readb(ioaddr + RTC_HOURS); 119 day = readb(ioaddr + RTC_DATE); 120 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK; 121 month = readb(ioaddr + RTC_MONTH); 122 year = readb(ioaddr + RTC_YEAR); 123 century = readb(ioaddr + RTC_CENTURY); 124 writeb(flags & ~RTC_READ, ioaddr + RTC_FLAGS); 125 tm->tm_sec = bcd2bin(second); 126 tm->tm_min = bcd2bin(minute); 127 tm->tm_hour = bcd2bin(hour); 128 tm->tm_mday = bcd2bin(day); 129 tm->tm_wday = bcd2bin(week); 130 tm->tm_mon = bcd2bin(month) - 1; 131 /* year is 1900 + tm->tm_year */ 132 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900; 133 134 if (rtc_valid_tm(tm) < 0) { 135 dev_err(dev, "retrieved date/time is not valid.\n"); 136 rtc_time_to_tm(0, tm); 137 } 138 return 0; 139 } 140 141 static void stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata) 142 { 143 void __iomem *ioaddr = pdata->ioaddr; 144 unsigned long irqflags; 145 u8 flags; 146 147 spin_lock_irqsave(&pdata->lock, irqflags); 148 149 flags = readb(ioaddr + RTC_FLAGS); 150 writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS); 151 152 writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? 153 0x80 : bin2bcd(pdata->alrm_mday), 154 ioaddr + RTC_DATE_ALARM); 155 writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? 156 0x80 : bin2bcd(pdata->alrm_hour), 157 ioaddr + RTC_HOURS_ALARM); 158 writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? 159 0x80 : bin2bcd(pdata->alrm_min), 160 ioaddr + RTC_MINUTES_ALARM); 161 writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? 162 0x80 : bin2bcd(pdata->alrm_sec), 163 ioaddr + RTC_SECONDS_ALARM); 164 writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr + RTC_INTERRUPTS); 165 readb(ioaddr + RTC_FLAGS); /* clear interrupts */ 166 writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS); 167 spin_unlock_irqrestore(&pdata->lock, irqflags); 168 } 169 170 static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 171 { 172 struct platform_device *pdev = to_platform_device(dev); 173 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 174 175 if (pdata->irq <= 0) 176 return -EINVAL; 177 pdata->alrm_mday = alrm->time.tm_mday; 178 pdata->alrm_hour = alrm->time.tm_hour; 179 pdata->alrm_min = alrm->time.tm_min; 180 pdata->alrm_sec = alrm->time.tm_sec; 181 if (alrm->enabled) 182 pdata->irqen |= RTC_AF; 183 stk17ta8_rtc_update_alarm(pdata); 184 return 0; 185 } 186 187 static int stk17ta8_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 188 { 189 struct platform_device *pdev = to_platform_device(dev); 190 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 191 192 if (pdata->irq <= 0) 193 return -EINVAL; 194 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; 195 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; 196 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; 197 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; 198 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; 199 return 0; 200 } 201 202 static irqreturn_t stk17ta8_rtc_interrupt(int irq, void *dev_id) 203 { 204 struct platform_device *pdev = dev_id; 205 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 206 void __iomem *ioaddr = pdata->ioaddr; 207 unsigned long events = 0; 208 209 spin_lock(&pdata->lock); 210 /* read and clear interrupt */ 211 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) { 212 events = RTC_IRQF; 213 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80) 214 events |= RTC_UF; 215 else 216 events |= RTC_AF; 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 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 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 297 if (!pdata) 298 return -ENOMEM; 299 300 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 301 ioaddr = devm_ioremap_resource(&pdev->dev, res); 302 if (IS_ERR(ioaddr)) 303 return PTR_ERR(ioaddr); 304 pdata->ioaddr = ioaddr; 305 pdata->irq = platform_get_irq(pdev, 0); 306 307 /* turn RTC on if it was not on */ 308 cal = readb(ioaddr + RTC_CALIBRATION); 309 if (cal & RTC_STOP) { 310 cal &= RTC_CAL_MASK; 311 flags = readb(ioaddr + RTC_FLAGS); 312 writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS); 313 writeb(cal, ioaddr + RTC_CALIBRATION); 314 writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS); 315 } 316 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF) 317 dev_warn(&pdev->dev, "voltage-low detected.\n"); 318 319 spin_lock_init(&pdata->lock); 320 pdata->last_jiffies = jiffies; 321 platform_set_drvdata(pdev, pdata); 322 if (pdata->irq > 0) { 323 writeb(0, ioaddr + RTC_INTERRUPTS); 324 if (devm_request_irq(&pdev->dev, pdata->irq, 325 stk17ta8_rtc_interrupt, 326 IRQF_SHARED, 327 pdev->name, pdev) < 0) { 328 dev_warn(&pdev->dev, "interrupt not available.\n"); 329 pdata->irq = 0; 330 } 331 } 332 333 pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, 334 &stk17ta8_rtc_ops, THIS_MODULE); 335 if (IS_ERR(pdata->rtc)) 336 return PTR_ERR(pdata->rtc); 337 338 ret = sysfs_create_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr); 339 340 return ret; 341 } 342 343 static int stk17ta8_rtc_remove(struct platform_device *pdev) 344 { 345 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 346 347 sysfs_remove_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr); 348 if (pdata->irq > 0) 349 writeb(0, pdata->ioaddr + RTC_INTERRUPTS); 350 return 0; 351 } 352 353 /* work with hotplug and coldplug */ 354 MODULE_ALIAS("platform:stk17ta8"); 355 356 static struct platform_driver stk17ta8_rtc_driver = { 357 .probe = stk17ta8_rtc_probe, 358 .remove = stk17ta8_rtc_remove, 359 .driver = { 360 .name = "stk17ta8", 361 }, 362 }; 363 364 module_platform_driver(stk17ta8_rtc_driver); 365 366 MODULE_AUTHOR("Thomas Hommel <thomas.hommel@ge.com>"); 367 MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver"); 368 MODULE_LICENSE("GPL"); 369 MODULE_VERSION(DRV_VERSION); 370