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 rtc_plat_data *pdata = dev_get_drvdata(dev); 77 void __iomem *ioaddr = pdata->ioaddr; 78 u8 century; 79 80 century = bin2bcd((tm->tm_year + 1900) / 100); 81 82 writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL); 83 84 writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR); 85 writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH); 86 writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY); 87 writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE); 88 writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS); 89 writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES); 90 writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS); 91 92 /* RTC_CENTURY and RTC_CONTROL share same register */ 93 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY); 94 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 95 return 0; 96 } 97 98 static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm) 99 { 100 struct rtc_plat_data *pdata = dev_get_drvdata(dev); 101 void __iomem *ioaddr = pdata->ioaddr; 102 unsigned int year, month, day, hour, minute, second, week; 103 unsigned int century; 104 105 /* give enough time to update RTC in case of continuous read */ 106 if (pdata->last_jiffies == jiffies) 107 msleep(1); 108 pdata->last_jiffies = jiffies; 109 writeb(RTC_READ, ioaddr + RTC_CONTROL); 110 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK; 111 minute = readb(ioaddr + RTC_MINUTES); 112 hour = readb(ioaddr + RTC_HOURS); 113 day = readb(ioaddr + RTC_DATE); 114 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK; 115 month = readb(ioaddr + RTC_MONTH); 116 year = readb(ioaddr + RTC_YEAR); 117 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 118 writeb(0, ioaddr + RTC_CONTROL); 119 tm->tm_sec = bcd2bin(second); 120 tm->tm_min = bcd2bin(minute); 121 tm->tm_hour = bcd2bin(hour); 122 tm->tm_mday = bcd2bin(day); 123 tm->tm_wday = bcd2bin(week); 124 tm->tm_mon = bcd2bin(month) - 1; 125 /* year is 1900 + tm->tm_year */ 126 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900; 127 128 return 0; 129 } 130 131 static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata) 132 { 133 void __iomem *ioaddr = pdata->ioaddr; 134 unsigned long flags; 135 136 spin_lock_irqsave(&pdata->lock, flags); 137 writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? 138 0x80 : bin2bcd(pdata->alrm_mday), 139 ioaddr + RTC_DATE_ALARM); 140 writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? 141 0x80 : bin2bcd(pdata->alrm_hour), 142 ioaddr + RTC_HOURS_ALARM); 143 writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? 144 0x80 : bin2bcd(pdata->alrm_min), 145 ioaddr + RTC_MINUTES_ALARM); 146 writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? 147 0x80 : bin2bcd(pdata->alrm_sec), 148 ioaddr + RTC_SECONDS_ALARM); 149 writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS); 150 readb(ioaddr + RTC_FLAGS); /* clear interrupts */ 151 spin_unlock_irqrestore(&pdata->lock, flags); 152 } 153 154 static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 155 { 156 struct rtc_plat_data *pdata = dev_get_drvdata(dev); 157 158 if (pdata->irq <= 0) 159 return -EINVAL; 160 pdata->alrm_mday = alrm->time.tm_mday; 161 pdata->alrm_hour = alrm->time.tm_hour; 162 pdata->alrm_min = alrm->time.tm_min; 163 pdata->alrm_sec = alrm->time.tm_sec; 164 if (alrm->enabled) 165 pdata->irqen |= RTC_AF; 166 ds1553_rtc_update_alarm(pdata); 167 return 0; 168 } 169 170 static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 171 { 172 struct rtc_plat_data *pdata = dev_get_drvdata(dev); 173 174 if (pdata->irq <= 0) 175 return -EINVAL; 176 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; 177 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; 178 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; 179 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; 180 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; 181 return 0; 182 } 183 184 static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id) 185 { 186 struct platform_device *pdev = dev_id; 187 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 188 void __iomem *ioaddr = pdata->ioaddr; 189 unsigned long events = 0; 190 191 spin_lock(&pdata->lock); 192 /* read and clear interrupt */ 193 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) { 194 events = RTC_IRQF; 195 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80) 196 events |= RTC_UF; 197 else 198 events |= RTC_AF; 199 rtc_update_irq(pdata->rtc, 1, events); 200 } 201 spin_unlock(&pdata->lock); 202 return events ? IRQ_HANDLED : IRQ_NONE; 203 } 204 205 static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 206 { 207 struct rtc_plat_data *pdata = dev_get_drvdata(dev); 208 209 if (pdata->irq <= 0) 210 return -EINVAL; 211 if (enabled) 212 pdata->irqen |= RTC_AF; 213 else 214 pdata->irqen &= ~RTC_AF; 215 ds1553_rtc_update_alarm(pdata); 216 return 0; 217 } 218 219 static const struct rtc_class_ops ds1553_rtc_ops = { 220 .read_time = ds1553_rtc_read_time, 221 .set_time = ds1553_rtc_set_time, 222 .read_alarm = ds1553_rtc_read_alarm, 223 .set_alarm = ds1553_rtc_set_alarm, 224 .alarm_irq_enable = ds1553_rtc_alarm_irq_enable, 225 }; 226 227 static int ds1553_nvram_read(void *priv, unsigned int pos, void *val, 228 size_t bytes) 229 { 230 struct platform_device *pdev = priv; 231 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 232 void __iomem *ioaddr = pdata->ioaddr; 233 u8 *buf = val; 234 235 for (; bytes; bytes--) 236 *buf++ = readb(ioaddr + pos++); 237 return 0; 238 } 239 240 static int ds1553_nvram_write(void *priv, unsigned int pos, void *val, 241 size_t bytes) 242 { 243 struct platform_device *pdev = priv; 244 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 245 void __iomem *ioaddr = pdata->ioaddr; 246 u8 *buf = val; 247 248 for (; bytes; bytes--) 249 writeb(*buf++, ioaddr + pos++); 250 return 0; 251 } 252 253 static int ds1553_rtc_probe(struct platform_device *pdev) 254 { 255 struct resource *res; 256 unsigned int cen, sec; 257 struct rtc_plat_data *pdata; 258 void __iomem *ioaddr; 259 int ret = 0; 260 struct nvmem_config nvmem_cfg = { 261 .name = "ds1553_nvram", 262 .word_size = 1, 263 .stride = 1, 264 .size = RTC_OFFSET, 265 .reg_read = ds1553_nvram_read, 266 .reg_write = ds1553_nvram_write, 267 .priv = pdev, 268 }; 269 270 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 271 if (!pdata) 272 return -ENOMEM; 273 274 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 275 ioaddr = devm_ioremap_resource(&pdev->dev, res); 276 if (IS_ERR(ioaddr)) 277 return PTR_ERR(ioaddr); 278 pdata->ioaddr = ioaddr; 279 pdata->irq = platform_get_irq(pdev, 0); 280 281 /* turn RTC on if it was not on */ 282 sec = readb(ioaddr + RTC_SECONDS); 283 if (sec & RTC_STOP) { 284 sec &= RTC_SECONDS_MASK; 285 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; 286 writeb(RTC_WRITE, ioaddr + RTC_CONTROL); 287 writeb(sec, ioaddr + RTC_SECONDS); 288 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); 289 } 290 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF) 291 dev_warn(&pdev->dev, "voltage-low detected.\n"); 292 293 spin_lock_init(&pdata->lock); 294 pdata->last_jiffies = jiffies; 295 platform_set_drvdata(pdev, pdata); 296 297 pdata->rtc = devm_rtc_allocate_device(&pdev->dev); 298 if (IS_ERR(pdata->rtc)) 299 return PTR_ERR(pdata->rtc); 300 301 pdata->rtc->ops = &ds1553_rtc_ops; 302 pdata->rtc->nvram_old_abi = true; 303 304 ret = rtc_register_device(pdata->rtc); 305 if (ret) 306 return ret; 307 308 if (pdata->irq > 0) { 309 writeb(0, ioaddr + RTC_INTERRUPTS); 310 if (devm_request_irq(&pdev->dev, pdata->irq, 311 ds1553_rtc_interrupt, 312 0, pdev->name, pdev) < 0) { 313 dev_warn(&pdev->dev, "interrupt not available.\n"); 314 pdata->irq = 0; 315 } 316 } 317 318 if (rtc_nvmem_register(pdata->rtc, &nvmem_cfg)) 319 dev_err(&pdev->dev, "unable to register nvmem\n"); 320 321 return 0; 322 } 323 324 /* work with hotplug and coldplug */ 325 MODULE_ALIAS("platform:rtc-ds1553"); 326 327 static struct platform_driver ds1553_rtc_driver = { 328 .probe = ds1553_rtc_probe, 329 .driver = { 330 .name = "rtc-ds1553", 331 }, 332 }; 333 334 module_platform_driver(ds1553_rtc_driver); 335 336 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 337 MODULE_DESCRIPTION("Dallas DS1553 RTC driver"); 338 MODULE_LICENSE("GPL"); 339