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 RTC_REG_SIZE 0x2000 24 #define RTC_OFFSET 0x1ff0 25 26 #define RTC_FLAGS (RTC_OFFSET + 0) 27 #define RTC_SECONDS_ALARM (RTC_OFFSET + 2) 28 #define RTC_MINUTES_ALARM (RTC_OFFSET + 3) 29 #define RTC_HOURS_ALARM (RTC_OFFSET + 4) 30 #define RTC_DATE_ALARM (RTC_OFFSET + 5) 31 #define RTC_INTERRUPTS (RTC_OFFSET + 6) 32 #define RTC_WATCHDOG (RTC_OFFSET + 7) 33 #define RTC_CONTROL (RTC_OFFSET + 8) 34 #define RTC_CENTURY (RTC_OFFSET + 8) 35 #define RTC_SECONDS (RTC_OFFSET + 9) 36 #define RTC_MINUTES (RTC_OFFSET + 10) 37 #define RTC_HOURS (RTC_OFFSET + 11) 38 #define RTC_DAY (RTC_OFFSET + 12) 39 #define RTC_DATE (RTC_OFFSET + 13) 40 #define RTC_MONTH (RTC_OFFSET + 14) 41 #define RTC_YEAR (RTC_OFFSET + 15) 42 43 #define RTC_CENTURY_MASK 0x3f 44 #define RTC_SECONDS_MASK 0x7f 45 #define RTC_DAY_MASK 0x07 46 47 /* Bits in the Control/Century register */ 48 #define RTC_WRITE 0x80 49 #define RTC_READ 0x40 50 51 /* Bits in the Seconds register */ 52 #define RTC_STOP 0x80 53 54 /* Bits in the Flags register */ 55 #define RTC_FLAGS_AF 0x40 56 #define RTC_FLAGS_BLF 0x10 57 58 /* Bits in the Interrupts register */ 59 #define RTC_INTS_AE 0x80 60 61 struct rtc_plat_data { 62 struct rtc_device *rtc; 63 void __iomem *ioaddr; 64 unsigned long last_jiffies; 65 int irq; 66 unsigned int irqen; 67 int alrm_sec; 68 int alrm_min; 69 int alrm_hour; 70 int alrm_mday; 71 spinlock_t lock; 72 }; 73 74 static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm) 75 { 76 struct platform_device *pdev = to_platform_device(dev); 77 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 78 void __iomem *ioaddr = pdata->ioaddr; 79 u8 century; 80 81 century = bin2bcd((tm->tm_year + 1900) / 100); 82 83 writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL); 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 93 /* RTC_CENTURY and RTC_CONTROL share same register */ 94 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY); 95 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 96 return 0; 97 } 98 99 static int ds1553_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; 106 107 /* 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 writeb(RTC_READ, ioaddr + RTC_CONTROL); 112 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK; 113 minute = readb(ioaddr + RTC_MINUTES); 114 hour = readb(ioaddr + RTC_HOURS); 115 day = readb(ioaddr + RTC_DATE); 116 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK; 117 month = readb(ioaddr + RTC_MONTH); 118 year = readb(ioaddr + RTC_YEAR); 119 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 120 writeb(0, ioaddr + RTC_CONTROL); 121 tm->tm_sec = bcd2bin(second); 122 tm->tm_min = bcd2bin(minute); 123 tm->tm_hour = bcd2bin(hour); 124 tm->tm_mday = bcd2bin(day); 125 tm->tm_wday = bcd2bin(week); 126 tm->tm_mon = bcd2bin(month) - 1; 127 /* year is 1900 + tm->tm_year */ 128 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900; 129 130 if (rtc_valid_tm(tm) < 0) { 131 dev_err(dev, "retrieved date/time is not valid.\n"); 132 rtc_time_to_tm(0, tm); 133 } 134 return 0; 135 } 136 137 static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata) 138 { 139 void __iomem *ioaddr = pdata->ioaddr; 140 unsigned long flags; 141 142 spin_lock_irqsave(&pdata->lock, flags); 143 writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? 144 0x80 : bin2bcd(pdata->alrm_mday), 145 ioaddr + RTC_DATE_ALARM); 146 writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? 147 0x80 : bin2bcd(pdata->alrm_hour), 148 ioaddr + RTC_HOURS_ALARM); 149 writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? 150 0x80 : bin2bcd(pdata->alrm_min), 151 ioaddr + RTC_MINUTES_ALARM); 152 writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? 153 0x80 : bin2bcd(pdata->alrm_sec), 154 ioaddr + RTC_SECONDS_ALARM); 155 writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS); 156 readb(ioaddr + RTC_FLAGS); /* clear interrupts */ 157 spin_unlock_irqrestore(&pdata->lock, flags); 158 } 159 160 static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 161 { 162 struct platform_device *pdev = to_platform_device(dev); 163 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 164 165 if (pdata->irq <= 0) 166 return -EINVAL; 167 pdata->alrm_mday = alrm->time.tm_mday; 168 pdata->alrm_hour = alrm->time.tm_hour; 169 pdata->alrm_min = alrm->time.tm_min; 170 pdata->alrm_sec = alrm->time.tm_sec; 171 if (alrm->enabled) 172 pdata->irqen |= RTC_AF; 173 ds1553_rtc_update_alarm(pdata); 174 return 0; 175 } 176 177 static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 178 { 179 struct platform_device *pdev = to_platform_device(dev); 180 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 181 182 if (pdata->irq <= 0) 183 return -EINVAL; 184 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; 185 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; 186 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; 187 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; 188 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; 189 return 0; 190 } 191 192 static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id) 193 { 194 struct platform_device *pdev = dev_id; 195 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 196 void __iomem *ioaddr = pdata->ioaddr; 197 unsigned long events = 0; 198 199 spin_lock(&pdata->lock); 200 /* read and clear interrupt */ 201 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) { 202 events = RTC_IRQF; 203 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80) 204 events |= RTC_UF; 205 else 206 events |= RTC_AF; 207 rtc_update_irq(pdata->rtc, 1, events); 208 } 209 spin_unlock(&pdata->lock); 210 return events ? IRQ_HANDLED : IRQ_NONE; 211 } 212 213 static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 214 { 215 struct platform_device *pdev = to_platform_device(dev); 216 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 217 218 if (pdata->irq <= 0) 219 return -EINVAL; 220 if (enabled) 221 pdata->irqen |= RTC_AF; 222 else 223 pdata->irqen &= ~RTC_AF; 224 ds1553_rtc_update_alarm(pdata); 225 return 0; 226 } 227 228 static const struct rtc_class_ops ds1553_rtc_ops = { 229 .read_time = ds1553_rtc_read_time, 230 .set_time = ds1553_rtc_set_time, 231 .read_alarm = ds1553_rtc_read_alarm, 232 .set_alarm = ds1553_rtc_set_alarm, 233 .alarm_irq_enable = ds1553_rtc_alarm_irq_enable, 234 }; 235 236 static int ds1553_nvram_read(void *priv, unsigned int pos, void *val, 237 size_t bytes) 238 { 239 struct platform_device *pdev = priv; 240 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 241 void __iomem *ioaddr = pdata->ioaddr; 242 u8 *buf = val; 243 244 for (; bytes; bytes--) 245 *buf++ = readb(ioaddr + pos++); 246 return 0; 247 } 248 249 static int ds1553_nvram_write(void *priv, unsigned int pos, void *val, 250 size_t bytes) 251 { 252 struct platform_device *pdev = priv; 253 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 254 void __iomem *ioaddr = pdata->ioaddr; 255 u8 *buf = val; 256 257 for (; bytes; bytes--) 258 writeb(*buf++, ioaddr + pos++); 259 return 0; 260 } 261 262 static int ds1553_rtc_probe(struct platform_device *pdev) 263 { 264 struct resource *res; 265 unsigned int cen, sec; 266 struct rtc_plat_data *pdata; 267 void __iomem *ioaddr; 268 int ret = 0; 269 struct nvmem_config nvmem_cfg = { 270 .name = "ds1553_nvram", 271 .word_size = 1, 272 .stride = 1, 273 .size = RTC_OFFSET, 274 .reg_read = ds1553_nvram_read, 275 .reg_write = ds1553_nvram_write, 276 .priv = pdev, 277 }; 278 279 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 280 if (!pdata) 281 return -ENOMEM; 282 283 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 284 ioaddr = devm_ioremap_resource(&pdev->dev, res); 285 if (IS_ERR(ioaddr)) 286 return PTR_ERR(ioaddr); 287 pdata->ioaddr = ioaddr; 288 pdata->irq = platform_get_irq(pdev, 0); 289 290 /* turn RTC on if it was not on */ 291 sec = readb(ioaddr + RTC_SECONDS); 292 if (sec & RTC_STOP) { 293 sec &= RTC_SECONDS_MASK; 294 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 295 writeb(RTC_WRITE, ioaddr + RTC_CONTROL); 296 writeb(sec, ioaddr + RTC_SECONDS); 297 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 298 } 299 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF) 300 dev_warn(&pdev->dev, "voltage-low detected.\n"); 301 302 spin_lock_init(&pdata->lock); 303 pdata->last_jiffies = jiffies; 304 platform_set_drvdata(pdev, pdata); 305 306 pdata->rtc = devm_rtc_allocate_device(&pdev->dev); 307 if (IS_ERR(pdata->rtc)) 308 return PTR_ERR(pdata->rtc); 309 310 pdata->rtc->ops = &ds1553_rtc_ops; 311 pdata->rtc->nvram_old_abi = true; 312 313 ret = rtc_register_device(pdata->rtc); 314 if (ret) 315 return ret; 316 317 if (pdata->irq > 0) { 318 writeb(0, ioaddr + RTC_INTERRUPTS); 319 if (devm_request_irq(&pdev->dev, pdata->irq, 320 ds1553_rtc_interrupt, 321 0, pdev->name, pdev) < 0) { 322 dev_warn(&pdev->dev, "interrupt not available.\n"); 323 pdata->irq = 0; 324 } 325 } 326 327 if (rtc_nvmem_register(pdata->rtc, &nvmem_cfg)) 328 dev_err(&pdev->dev, "unable to register nvmem\n"); 329 330 return 0; 331 } 332 333 static int ds1553_rtc_remove(struct platform_device *pdev) 334 { 335 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 336 337 if (pdata->irq > 0) 338 writeb(0, pdata->ioaddr + RTC_INTERRUPTS); 339 return 0; 340 } 341 342 /* work with hotplug and coldplug */ 343 MODULE_ALIAS("platform:rtc-ds1553"); 344 345 static struct platform_driver ds1553_rtc_driver = { 346 .probe = ds1553_rtc_probe, 347 .remove = ds1553_rtc_remove, 348 .driver = { 349 .name = "rtc-ds1553", 350 }, 351 }; 352 353 module_platform_driver(ds1553_rtc_driver); 354 355 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 356 MODULE_DESCRIPTION("Dallas DS1553 RTC driver"); 357 MODULE_LICENSE("GPL"); 358