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 #include <linux/module.h> 22 23 #define DRV_VERSION "0.3" 24 25 #define RTC_REG_SIZE 0x2000 26 #define RTC_OFFSET 0x1ff0 27 28 #define RTC_FLAGS (RTC_OFFSET + 0) 29 #define RTC_SECONDS_ALARM (RTC_OFFSET + 2) 30 #define RTC_MINUTES_ALARM (RTC_OFFSET + 3) 31 #define RTC_HOURS_ALARM (RTC_OFFSET + 4) 32 #define RTC_DATE_ALARM (RTC_OFFSET + 5) 33 #define RTC_INTERRUPTS (RTC_OFFSET + 6) 34 #define RTC_WATCHDOG (RTC_OFFSET + 7) 35 #define RTC_CONTROL (RTC_OFFSET + 8) 36 #define RTC_CENTURY (RTC_OFFSET + 8) 37 #define RTC_SECONDS (RTC_OFFSET + 9) 38 #define RTC_MINUTES (RTC_OFFSET + 10) 39 #define RTC_HOURS (RTC_OFFSET + 11) 40 #define RTC_DAY (RTC_OFFSET + 12) 41 #define RTC_DATE (RTC_OFFSET + 13) 42 #define RTC_MONTH (RTC_OFFSET + 14) 43 #define RTC_YEAR (RTC_OFFSET + 15) 44 45 #define RTC_CENTURY_MASK 0x3f 46 #define RTC_SECONDS_MASK 0x7f 47 #define RTC_DAY_MASK 0x07 48 49 /* Bits in the Control/Century register */ 50 #define RTC_WRITE 0x80 51 #define RTC_READ 0x40 52 53 /* Bits in the Seconds register */ 54 #define RTC_STOP 0x80 55 56 /* Bits in the Flags register */ 57 #define RTC_FLAGS_AF 0x40 58 #define RTC_FLAGS_BLF 0x10 59 60 /* Bits in the Interrupts register */ 61 #define RTC_INTS_AE 0x80 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 ds1553_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 century; 82 83 century = bin2bcd((tm->tm_year + 1900) / 100); 84 85 writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL); 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 95 /* RTC_CENTURY and RTC_CONTROL share same register */ 96 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY); 97 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 98 return 0; 99 } 100 101 static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm) 102 { 103 struct platform_device *pdev = to_platform_device(dev); 104 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 105 void __iomem *ioaddr = pdata->ioaddr; 106 unsigned int year, month, day, hour, minute, second, week; 107 unsigned int century; 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 writeb(RTC_READ, ioaddr + RTC_CONTROL); 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) & RTC_CENTURY_MASK; 122 writeb(0, ioaddr + RTC_CONTROL); 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 ds1553_rtc_update_alarm(struct rtc_plat_data *pdata) 140 { 141 void __iomem *ioaddr = pdata->ioaddr; 142 unsigned long flags; 143 144 spin_lock_irqsave(&pdata->lock, flags); 145 writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? 146 0x80 : bin2bcd(pdata->alrm_mday), 147 ioaddr + RTC_DATE_ALARM); 148 writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? 149 0x80 : bin2bcd(pdata->alrm_hour), 150 ioaddr + RTC_HOURS_ALARM); 151 writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? 152 0x80 : bin2bcd(pdata->alrm_min), 153 ioaddr + RTC_MINUTES_ALARM); 154 writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? 155 0x80 : bin2bcd(pdata->alrm_sec), 156 ioaddr + RTC_SECONDS_ALARM); 157 writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS); 158 readb(ioaddr + RTC_FLAGS); /* clear interrupts */ 159 spin_unlock_irqrestore(&pdata->lock, flags); 160 } 161 162 static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 163 { 164 struct platform_device *pdev = to_platform_device(dev); 165 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 166 167 if (pdata->irq <= 0) 168 return -EINVAL; 169 pdata->alrm_mday = alrm->time.tm_mday; 170 pdata->alrm_hour = alrm->time.tm_hour; 171 pdata->alrm_min = alrm->time.tm_min; 172 pdata->alrm_sec = alrm->time.tm_sec; 173 if (alrm->enabled) 174 pdata->irqen |= RTC_AF; 175 ds1553_rtc_update_alarm(pdata); 176 return 0; 177 } 178 179 static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 180 { 181 struct platform_device *pdev = to_platform_device(dev); 182 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 183 184 if (pdata->irq <= 0) 185 return -EINVAL; 186 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; 187 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; 188 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; 189 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; 190 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; 191 return 0; 192 } 193 194 static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id) 195 { 196 struct platform_device *pdev = dev_id; 197 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 198 void __iomem *ioaddr = pdata->ioaddr; 199 unsigned long events = 0; 200 201 spin_lock(&pdata->lock); 202 /* read and clear interrupt */ 203 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) { 204 events = RTC_IRQF; 205 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80) 206 events |= RTC_UF; 207 else 208 events |= RTC_AF; 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 const struct rtc_class_ops ds1553_rtc_ops = { 231 .read_time = ds1553_rtc_read_time, 232 .set_time = ds1553_rtc_set_time, 233 .read_alarm = ds1553_rtc_read_alarm, 234 .set_alarm = ds1553_rtc_set_alarm, 235 .alarm_irq_enable = ds1553_rtc_alarm_irq_enable, 236 }; 237 238 static ssize_t ds1553_nvram_read(struct file *filp, struct kobject *kobj, 239 struct bin_attribute *bin_attr, 240 char *buf, loff_t pos, size_t size) 241 { 242 struct device *dev = container_of(kobj, struct device, kobj); 243 struct platform_device *pdev = to_platform_device(dev); 244 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 245 void __iomem *ioaddr = pdata->ioaddr; 246 ssize_t count; 247 248 for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--) 249 *buf++ = readb(ioaddr + pos++); 250 return count; 251 } 252 253 static ssize_t ds1553_nvram_write(struct file *filp, struct kobject *kobj, 254 struct bin_attribute *bin_attr, 255 char *buf, loff_t pos, size_t size) 256 { 257 struct device *dev = container_of(kobj, struct device, kobj); 258 struct platform_device *pdev = to_platform_device(dev); 259 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 260 void __iomem *ioaddr = pdata->ioaddr; 261 ssize_t count; 262 263 for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--) 264 writeb(*buf++, ioaddr + pos++); 265 return count; 266 } 267 268 static struct bin_attribute ds1553_nvram_attr = { 269 .attr = { 270 .name = "nvram", 271 .mode = S_IRUGO | S_IWUSR, 272 }, 273 .size = RTC_OFFSET, 274 .read = ds1553_nvram_read, 275 .write = ds1553_nvram_write, 276 }; 277 278 static int ds1553_rtc_probe(struct platform_device *pdev) 279 { 280 struct resource *res; 281 unsigned int cen, sec; 282 struct rtc_plat_data *pdata; 283 void __iomem *ioaddr; 284 int ret = 0; 285 286 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 287 if (!pdata) 288 return -ENOMEM; 289 290 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 291 ioaddr = devm_ioremap_resource(&pdev->dev, res); 292 if (IS_ERR(ioaddr)) 293 return PTR_ERR(ioaddr); 294 pdata->ioaddr = ioaddr; 295 pdata->irq = platform_get_irq(pdev, 0); 296 297 /* turn RTC on if it was not on */ 298 sec = readb(ioaddr + RTC_SECONDS); 299 if (sec & RTC_STOP) { 300 sec &= RTC_SECONDS_MASK; 301 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 302 writeb(RTC_WRITE, ioaddr + RTC_CONTROL); 303 writeb(sec, ioaddr + RTC_SECONDS); 304 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 305 } 306 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF) 307 dev_warn(&pdev->dev, "voltage-low detected.\n"); 308 309 spin_lock_init(&pdata->lock); 310 pdata->last_jiffies = jiffies; 311 platform_set_drvdata(pdev, pdata); 312 313 pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, 314 &ds1553_rtc_ops, THIS_MODULE); 315 if (IS_ERR(pdata->rtc)) 316 return PTR_ERR(pdata->rtc); 317 318 if (pdata->irq > 0) { 319 writeb(0, ioaddr + RTC_INTERRUPTS); 320 if (devm_request_irq(&pdev->dev, pdata->irq, 321 ds1553_rtc_interrupt, 322 0, pdev->name, pdev) < 0) { 323 dev_warn(&pdev->dev, "interrupt not available.\n"); 324 pdata->irq = 0; 325 } 326 } 327 328 ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr); 329 if (ret) 330 dev_err(&pdev->dev, "unable to create sysfs file: %s\n", 331 ds1553_nvram_attr.attr.name); 332 333 return 0; 334 } 335 336 static int ds1553_rtc_remove(struct platform_device *pdev) 337 { 338 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 339 340 sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr); 341 if (pdata->irq > 0) 342 writeb(0, pdata->ioaddr + RTC_INTERRUPTS); 343 return 0; 344 } 345 346 /* work with hotplug and coldplug */ 347 MODULE_ALIAS("platform:rtc-ds1553"); 348 349 static struct platform_driver ds1553_rtc_driver = { 350 .probe = ds1553_rtc_probe, 351 .remove = ds1553_rtc_remove, 352 .driver = { 353 .name = "rtc-ds1553", 354 }, 355 }; 356 357 module_platform_driver(ds1553_rtc_driver); 358 359 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 360 MODULE_DESCRIPTION("Dallas DS1553 RTC driver"); 361 MODULE_LICENSE("GPL"); 362 MODULE_VERSION(DRV_VERSION); 363