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 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 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 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->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->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 = 0; 206 207 spin_lock(&pdata->lock); 208 /* read and clear interrupt */ 209 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) { 210 events = RTC_IRQF; 211 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80) 212 events |= RTC_UF; 213 else 214 events |= RTC_AF; 215 rtc_update_irq(pdata->rtc, 1, events); 216 } 217 spin_unlock(&pdata->lock); 218 return events ? IRQ_HANDLED : IRQ_NONE; 219 } 220 221 static int stk17ta8_rtc_alarm_irq_enable(struct device *dev, 222 unsigned int enabled) 223 { 224 struct platform_device *pdev = to_platform_device(dev); 225 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 226 227 if (pdata->irq <= 0) 228 return -EINVAL; 229 if (enabled) 230 pdata->irqen |= RTC_AF; 231 else 232 pdata->irqen &= ~RTC_AF; 233 stk17ta8_rtc_update_alarm(pdata); 234 return 0; 235 } 236 237 static const struct rtc_class_ops stk17ta8_rtc_ops = { 238 .read_time = stk17ta8_rtc_read_time, 239 .set_time = stk17ta8_rtc_set_time, 240 .read_alarm = stk17ta8_rtc_read_alarm, 241 .set_alarm = stk17ta8_rtc_set_alarm, 242 .alarm_irq_enable = stk17ta8_rtc_alarm_irq_enable, 243 }; 244 245 static ssize_t stk17ta8_nvram_read(struct file *filp, struct kobject *kobj, 246 struct bin_attribute *attr, char *buf, 247 loff_t pos, size_t size) 248 { 249 struct device *dev = container_of(kobj, struct device, kobj); 250 struct platform_device *pdev = to_platform_device(dev); 251 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 252 void __iomem *ioaddr = pdata->ioaddr; 253 ssize_t count; 254 255 for (count = 0; count < size; count++) 256 *buf++ = readb(ioaddr + pos++); 257 return count; 258 } 259 260 static ssize_t stk17ta8_nvram_write(struct file *filp, struct kobject *kobj, 261 struct bin_attribute *attr, char *buf, 262 loff_t pos, size_t size) 263 { 264 struct device *dev = container_of(kobj, struct device, kobj); 265 struct platform_device *pdev = to_platform_device(dev); 266 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 267 void __iomem *ioaddr = pdata->ioaddr; 268 ssize_t count; 269 270 for (count = 0; count < size; count++) 271 writeb(*buf++, ioaddr + pos++); 272 return count; 273 } 274 275 static struct bin_attribute stk17ta8_nvram_attr = { 276 .attr = { 277 .name = "nvram", 278 .mode = S_IRUGO | S_IWUSR, 279 }, 280 .size = RTC_OFFSET, 281 .read = stk17ta8_nvram_read, 282 .write = stk17ta8_nvram_write, 283 }; 284 285 static int stk17ta8_rtc_probe(struct platform_device *pdev) 286 { 287 struct resource *res; 288 unsigned int cal; 289 unsigned int flags; 290 struct rtc_plat_data *pdata; 291 void __iomem *ioaddr; 292 int ret = 0; 293 294 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 295 if (!pdata) 296 return -ENOMEM; 297 298 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 299 ioaddr = devm_ioremap_resource(&pdev->dev, res); 300 if (IS_ERR(ioaddr)) 301 return PTR_ERR(ioaddr); 302 pdata->ioaddr = ioaddr; 303 pdata->irq = platform_get_irq(pdev, 0); 304 305 /* turn RTC on if it was not on */ 306 cal = readb(ioaddr + RTC_CALIBRATION); 307 if (cal & RTC_STOP) { 308 cal &= RTC_CAL_MASK; 309 flags = readb(ioaddr + RTC_FLAGS); 310 writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS); 311 writeb(cal, ioaddr + RTC_CALIBRATION); 312 writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS); 313 } 314 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF) 315 dev_warn(&pdev->dev, "voltage-low detected.\n"); 316 317 spin_lock_init(&pdata->lock); 318 pdata->last_jiffies = jiffies; 319 platform_set_drvdata(pdev, pdata); 320 if (pdata->irq > 0) { 321 writeb(0, ioaddr + RTC_INTERRUPTS); 322 if (devm_request_irq(&pdev->dev, pdata->irq, 323 stk17ta8_rtc_interrupt, 324 IRQF_SHARED, 325 pdev->name, pdev) < 0) { 326 dev_warn(&pdev->dev, "interrupt not available.\n"); 327 pdata->irq = 0; 328 } 329 } 330 331 pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, 332 &stk17ta8_rtc_ops, THIS_MODULE); 333 if (IS_ERR(pdata->rtc)) 334 return PTR_ERR(pdata->rtc); 335 336 ret = sysfs_create_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr); 337 338 return ret; 339 } 340 341 static int stk17ta8_rtc_remove(struct platform_device *pdev) 342 { 343 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 344 345 sysfs_remove_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr); 346 if (pdata->irq > 0) 347 writeb(0, pdata->ioaddr + RTC_INTERRUPTS); 348 return 0; 349 } 350 351 /* work with hotplug and coldplug */ 352 MODULE_ALIAS("platform:stk17ta8"); 353 354 static struct platform_driver stk17ta8_rtc_driver = { 355 .probe = stk17ta8_rtc_probe, 356 .remove = stk17ta8_rtc_remove, 357 .driver = { 358 .name = "stk17ta8", 359 }, 360 }; 361 362 module_platform_driver(stk17ta8_rtc_driver); 363 364 MODULE_AUTHOR("Thomas Hommel <thomas.hommel@ge.com>"); 365 MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver"); 366 MODULE_LICENSE("GPL"); 367