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 return 0; 131 } 132 133 static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata) 134 { 135 void __iomem *ioaddr = pdata->ioaddr; 136 unsigned long flags; 137 138 spin_lock_irqsave(&pdata->lock, flags); 139 writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? 140 0x80 : bin2bcd(pdata->alrm_mday), 141 ioaddr + RTC_DATE_ALARM); 142 writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? 143 0x80 : bin2bcd(pdata->alrm_hour), 144 ioaddr + RTC_HOURS_ALARM); 145 writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? 146 0x80 : bin2bcd(pdata->alrm_min), 147 ioaddr + RTC_MINUTES_ALARM); 148 writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? 149 0x80 : bin2bcd(pdata->alrm_sec), 150 ioaddr + RTC_SECONDS_ALARM); 151 writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS); 152 readb(ioaddr + RTC_FLAGS); /* clear interrupts */ 153 spin_unlock_irqrestore(&pdata->lock, flags); 154 } 155 156 static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 157 { 158 struct platform_device *pdev = to_platform_device(dev); 159 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 160 161 if (pdata->irq <= 0) 162 return -EINVAL; 163 pdata->alrm_mday = alrm->time.tm_mday; 164 pdata->alrm_hour = alrm->time.tm_hour; 165 pdata->alrm_min = alrm->time.tm_min; 166 pdata->alrm_sec = alrm->time.tm_sec; 167 if (alrm->enabled) 168 pdata->irqen |= RTC_AF; 169 ds1553_rtc_update_alarm(pdata); 170 return 0; 171 } 172 173 static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 174 { 175 struct platform_device *pdev = to_platform_device(dev); 176 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 177 178 if (pdata->irq <= 0) 179 return -EINVAL; 180 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; 181 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; 182 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; 183 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; 184 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; 185 return 0; 186 } 187 188 static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id) 189 { 190 struct platform_device *pdev = dev_id; 191 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 192 void __iomem *ioaddr = pdata->ioaddr; 193 unsigned long events = 0; 194 195 spin_lock(&pdata->lock); 196 /* read and clear interrupt */ 197 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) { 198 events = RTC_IRQF; 199 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80) 200 events |= RTC_UF; 201 else 202 events |= RTC_AF; 203 rtc_update_irq(pdata->rtc, 1, events); 204 } 205 spin_unlock(&pdata->lock); 206 return events ? IRQ_HANDLED : IRQ_NONE; 207 } 208 209 static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 210 { 211 struct platform_device *pdev = to_platform_device(dev); 212 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 213 214 if (pdata->irq <= 0) 215 return -EINVAL; 216 if (enabled) 217 pdata->irqen |= RTC_AF; 218 else 219 pdata->irqen &= ~RTC_AF; 220 ds1553_rtc_update_alarm(pdata); 221 return 0; 222 } 223 224 static const struct rtc_class_ops ds1553_rtc_ops = { 225 .read_time = ds1553_rtc_read_time, 226 .set_time = ds1553_rtc_set_time, 227 .read_alarm = ds1553_rtc_read_alarm, 228 .set_alarm = ds1553_rtc_set_alarm, 229 .alarm_irq_enable = ds1553_rtc_alarm_irq_enable, 230 }; 231 232 static int ds1553_nvram_read(void *priv, unsigned int pos, void *val, 233 size_t bytes) 234 { 235 struct platform_device *pdev = priv; 236 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 237 void __iomem *ioaddr = pdata->ioaddr; 238 u8 *buf = val; 239 240 for (; bytes; bytes--) 241 *buf++ = readb(ioaddr + pos++); 242 return 0; 243 } 244 245 static int ds1553_nvram_write(void *priv, unsigned int pos, void *val, 246 size_t bytes) 247 { 248 struct platform_device *pdev = priv; 249 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 250 void __iomem *ioaddr = pdata->ioaddr; 251 u8 *buf = val; 252 253 for (; bytes; bytes--) 254 writeb(*buf++, ioaddr + pos++); 255 return 0; 256 } 257 258 static int ds1553_rtc_probe(struct platform_device *pdev) 259 { 260 struct resource *res; 261 unsigned int cen, sec; 262 struct rtc_plat_data *pdata; 263 void __iomem *ioaddr; 264 int ret = 0; 265 struct nvmem_config nvmem_cfg = { 266 .name = "ds1553_nvram", 267 .word_size = 1, 268 .stride = 1, 269 .size = RTC_OFFSET, 270 .reg_read = ds1553_nvram_read, 271 .reg_write = ds1553_nvram_write, 272 .priv = pdev, 273 }; 274 275 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 276 if (!pdata) 277 return -ENOMEM; 278 279 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 280 ioaddr = devm_ioremap_resource(&pdev->dev, res); 281 if (IS_ERR(ioaddr)) 282 return PTR_ERR(ioaddr); 283 pdata->ioaddr = ioaddr; 284 pdata->irq = platform_get_irq(pdev, 0); 285 286 /* turn RTC on if it was not on */ 287 sec = readb(ioaddr + RTC_SECONDS); 288 if (sec & RTC_STOP) { 289 sec &= RTC_SECONDS_MASK; 290 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 291 writeb(RTC_WRITE, ioaddr + RTC_CONTROL); 292 writeb(sec, ioaddr + RTC_SECONDS); 293 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 294 } 295 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF) 296 dev_warn(&pdev->dev, "voltage-low detected.\n"); 297 298 spin_lock_init(&pdata->lock); 299 pdata->last_jiffies = jiffies; 300 platform_set_drvdata(pdev, pdata); 301 302 pdata->rtc = devm_rtc_allocate_device(&pdev->dev); 303 if (IS_ERR(pdata->rtc)) 304 return PTR_ERR(pdata->rtc); 305 306 pdata->rtc->ops = &ds1553_rtc_ops; 307 pdata->rtc->nvram_old_abi = true; 308 309 ret = rtc_register_device(pdata->rtc); 310 if (ret) 311 return ret; 312 313 if (pdata->irq > 0) { 314 writeb(0, ioaddr + RTC_INTERRUPTS); 315 if (devm_request_irq(&pdev->dev, pdata->irq, 316 ds1553_rtc_interrupt, 317 0, pdev->name, pdev) < 0) { 318 dev_warn(&pdev->dev, "interrupt not available.\n"); 319 pdata->irq = 0; 320 } 321 } 322 323 if (rtc_nvmem_register(pdata->rtc, &nvmem_cfg)) 324 dev_err(&pdev->dev, "unable to register nvmem\n"); 325 326 return 0; 327 } 328 329 /* work with hotplug and coldplug */ 330 MODULE_ALIAS("platform:rtc-ds1553"); 331 332 static struct platform_driver ds1553_rtc_driver = { 333 .probe = ds1553_rtc_probe, 334 .driver = { 335 .name = "rtc-ds1553", 336 }, 337 }; 338 339 module_platform_driver(ds1553_rtc_driver); 340 341 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 342 MODULE_DESCRIPTION("Dallas DS1553 RTC driver"); 343 MODULE_LICENSE("GPL"); 344