| 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 ssize_t ds1553_nvram_read(struct file *filp, struct kobject *kobj, |
| 237 | struct bin_attribute *bin_attr, |
| 238 | char *buf, loff_t pos, size_t size) |
| 239 | { |
| 240 | struct device *dev = container_of(kobj, struct device, kobj); |
| 241 | struct platform_device *pdev = to_platform_device(dev); |
| 242 | struct rtc_plat_data *pdata = platform_get_drvdata(pdev); |
| 243 | void __iomem *ioaddr = pdata->ioaddr; |
| 244 | ssize_t count; |
| 245 | |
| 246 | for (count = 0; count < size; count++) |
| 247 | *buf++ = readb(ioaddr + pos++); |
| 248 | return count; |
| 249 | } |
| 250 | |
| 251 | static ssize_t ds1553_nvram_write(struct file *filp, struct kobject *kobj, |
| 252 | struct bin_attribute *bin_attr, |
| 253 | char *buf, loff_t pos, size_t size) |
| 254 | { |
| 255 | struct device *dev = container_of(kobj, struct device, kobj); |
| 256 | struct platform_device *pdev = to_platform_device(dev); |
| 257 | struct rtc_plat_data *pdata = platform_get_drvdata(pdev); |
| 258 | void __iomem *ioaddr = pdata->ioaddr; |
| 259 | ssize_t count; |
| 260 | |
| 261 | for (count = 0; count < size; count++) |
| 262 | writeb(*buf++, ioaddr + pos++); |
| 263 | return count; |
| 264 | } |
| 265 | |
| 266 | static struct bin_attribute ds1553_nvram_attr = { |
| 267 | .attr = { |
| 268 | .name = "nvram", |
| 269 | .mode = S_IRUGO | S_IWUSR, |
| 270 | }, |
| 271 | .size = RTC_OFFSET, |
| 272 | .read = ds1553_nvram_read, |
| 273 | .write = ds1553_nvram_write, |
| 274 | }; |
| 275 | |
| 276 | static int ds1553_rtc_probe(struct platform_device *pdev) |
| 277 | { |
| 278 | struct resource *res; |
| 279 | unsigned int cen, sec; |
| 280 | struct rtc_plat_data *pdata; |
| 281 | void __iomem *ioaddr; |
| 282 | int ret = 0; |
| 283 | |
| 284 | pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); |
| 285 | if (!pdata) |
| 286 | return -ENOMEM; |
| 287 | |
| 288 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 289 | ioaddr = devm_ioremap_resource(&pdev->dev, res); |
| 290 | if (IS_ERR(ioaddr)) |
| 291 | return PTR_ERR(ioaddr); |
| 292 | pdata->ioaddr = ioaddr; |
| 293 | pdata->irq = platform_get_irq(pdev, 0); |
| 294 | |
| 295 | /* turn RTC on if it was not on */ |
| 296 | sec = readb(ioaddr + RTC_SECONDS); |
| 297 | if (sec & RTC_STOP) { |
| 298 | sec &= RTC_SECONDS_MASK; |
| 299 | cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; |
| 300 | writeb(RTC_WRITE, ioaddr + RTC_CONTROL); |
| 301 | writeb(sec, ioaddr + RTC_SECONDS); |
| 302 | writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); |
| 303 | } |
| 304 | if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF) |
| 305 | dev_warn(&pdev->dev, "voltage-low detected.\n"); |
| 306 | |
| 307 | spin_lock_init(&pdata->lock); |
| 308 | pdata->last_jiffies = jiffies; |
| 309 | platform_set_drvdata(pdev, pdata); |
| 310 | |
| 311 | pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, |
| 312 | &ds1553_rtc_ops, THIS_MODULE); |
| 313 | if (IS_ERR(pdata->rtc)) |
| 314 | return PTR_ERR(pdata->rtc); |
| 315 | |
| 316 | if (pdata->irq > 0) { |
| 317 | writeb(0, ioaddr + RTC_INTERRUPTS); |
| 318 | if (devm_request_irq(&pdev->dev, pdata->irq, |
| 319 | ds1553_rtc_interrupt, |
| 320 | 0, pdev->name, pdev) < 0) { |
| 321 | dev_warn(&pdev->dev, "interrupt not available.\n"); |
| 322 | pdata->irq = 0; |
| 323 | } |
| 324 | } |
| 325 | |
| 326 | ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr); |
| 327 | if (ret) |
| 328 | dev_err(&pdev->dev, "unable to create sysfs file: %s\n", |
| 329 | ds1553_nvram_attr.attr.name); |
| 330 | |
| 331 | return 0; |
| 332 | } |
| 333 | |
| 334 | static int ds1553_rtc_remove(struct platform_device *pdev) |
| 335 | { |
| 336 | struct rtc_plat_data *pdata = platform_get_drvdata(pdev); |
| 337 | |
| 338 | sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr); |
| 339 | if (pdata->irq > 0) |
| 340 | writeb(0, pdata->ioaddr + RTC_INTERRUPTS); |
| 341 | return 0; |
| 342 | } |
| 343 | |
| 344 | /* work with hotplug and coldplug */ |
| 345 | MODULE_ALIAS("platform:rtc-ds1553"); |
| 346 | |
| 347 | static struct platform_driver ds1553_rtc_driver = { |
| 348 | .probe = ds1553_rtc_probe, |
| 349 | .remove = ds1553_rtc_remove, |
| 350 | .driver = { |
| 351 | .name = "rtc-ds1553", |
| 352 | }, |
| 353 | }; |
| 354 | |
| 355 | module_platform_driver(ds1553_rtc_driver); |
| 356 | |
| 357 | MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); |
| 358 | MODULE_DESCRIPTION("Dallas DS1553 RTC driver"); |
| 359 | MODULE_LICENSE("GPL"); |