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 rtc_plat_data *pdata = dev_get_drvdata(dev); 78 void __iomem *ioaddr = pdata->ioaddr; 79 u8 flags; 80 81 flags = readb(pdata->ioaddr + RTC_FLAGS); 82 writeb(flags | RTC_WRITE, pdata->ioaddr + RTC_FLAGS); 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 writeb(bin2bcd((tm->tm_year + 1900) / 100), ioaddr + RTC_CENTURY); 92 93 writeb(flags & ~RTC_WRITE, pdata->ioaddr + RTC_FLAGS); 94 return 0; 95 } 96 97 static int stk17ta8_rtc_read_time(struct device *dev, struct rtc_time *tm) 98 { 99 struct rtc_plat_data *pdata = dev_get_drvdata(dev); 100 void __iomem *ioaddr = pdata->ioaddr; 101 unsigned int year, month, day, hour, minute, second, week; 102 unsigned int century; 103 u8 flags; 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; 109 110 flags = readb(pdata->ioaddr + RTC_FLAGS); 111 writeb(flags | RTC_READ, ioaddr + RTC_FLAGS); 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); 120 writeb(flags & ~RTC_READ, ioaddr + RTC_FLAGS); 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 stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata) 134 { 135 void __iomem *ioaddr = pdata->ioaddr; 136 unsigned long irqflags; 137 u8 flags; 138 139 spin_lock_irqsave(&pdata->lock, irqflags); 140 141 flags = readb(ioaddr + RTC_FLAGS); 142 writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS); 143 144 writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? 145 0x80 : bin2bcd(pdata->alrm_mday), 146 ioaddr + RTC_DATE_ALARM); 147 writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? 148 0x80 : bin2bcd(pdata->alrm_hour), 149 ioaddr + RTC_HOURS_ALARM); 150 writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? 151 0x80 : bin2bcd(pdata->alrm_min), 152 ioaddr + RTC_MINUTES_ALARM); 153 writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? 154 0x80 : bin2bcd(pdata->alrm_sec), 155 ioaddr + RTC_SECONDS_ALARM); 156 writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr + RTC_INTERRUPTS); 157 readb(ioaddr + RTC_FLAGS); /* clear interrupts */ 158 writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS); 159 spin_unlock_irqrestore(&pdata->lock, irqflags); 160 } 161 162 static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 163 { 164 struct rtc_plat_data *pdata = dev_get_drvdata(dev); 165 166 if (pdata->irq <= 0) 167 return -EINVAL; 168 pdata->alrm_mday = alrm->time.tm_mday; 169 pdata->alrm_hour = alrm->time.tm_hour; 170 pdata->alrm_min = alrm->time.tm_min; 171 pdata->alrm_sec = alrm->time.tm_sec; 172 if (alrm->enabled) 173 pdata->irqen |= RTC_AF; 174 stk17ta8_rtc_update_alarm(pdata); 175 return 0; 176 } 177 178 static int stk17ta8_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 179 { 180 struct rtc_plat_data *pdata = dev_get_drvdata(dev); 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 stk17ta8_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 stk17ta8_rtc_alarm_irq_enable(struct device *dev, 214 unsigned int enabled) 215 { 216 struct rtc_plat_data *pdata = dev_get_drvdata(dev); 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 stk17ta8_rtc_update_alarm(pdata); 225 return 0; 226 } 227 228 static const struct rtc_class_ops stk17ta8_rtc_ops = { 229 .read_time = stk17ta8_rtc_read_time, 230 .set_time = stk17ta8_rtc_set_time, 231 .read_alarm = stk17ta8_rtc_read_alarm, 232 .set_alarm = stk17ta8_rtc_set_alarm, 233 .alarm_irq_enable = stk17ta8_rtc_alarm_irq_enable, 234 }; 235 236 static int stk17ta8_nvram_read(void *priv, unsigned int pos, void *val, 237 size_t bytes) 238 { 239 struct rtc_plat_data *pdata = priv; 240 void __iomem *ioaddr = pdata->ioaddr; 241 u8 *buf = val; 242 243 for (; bytes; bytes--) 244 *buf++ = readb(ioaddr + pos++); 245 return 0; 246 } 247 248 static int stk17ta8_nvram_write(void *priv, unsigned int pos, void *val, 249 size_t bytes) 250 { 251 struct rtc_plat_data *pdata = priv; 252 void __iomem *ioaddr = pdata->ioaddr; 253 u8 *buf = val; 254 255 for (; bytes; bytes--) 256 writeb(*buf++, ioaddr + pos++); 257 return 0; 258 } 259 260 static int stk17ta8_rtc_probe(struct platform_device *pdev) 261 { 262 struct resource *res; 263 unsigned int cal; 264 unsigned int flags; 265 struct rtc_plat_data *pdata; 266 void __iomem *ioaddr; 267 int ret = 0; 268 struct nvmem_config nvmem_cfg = { 269 .name = "stk17ta8_nvram", 270 .word_size = 1, 271 .stride = 1, 272 .size = RTC_OFFSET, 273 .reg_read = stk17ta8_nvram_read, 274 .reg_write = stk17ta8_nvram_write, 275 }; 276 277 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 278 if (!pdata) 279 return -ENOMEM; 280 281 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 282 ioaddr = devm_ioremap_resource(&pdev->dev, res); 283 if (IS_ERR(ioaddr)) 284 return PTR_ERR(ioaddr); 285 pdata->ioaddr = ioaddr; 286 pdata->irq = platform_get_irq(pdev, 0); 287 288 /* turn RTC on if it was not on */ 289 cal = readb(ioaddr + RTC_CALIBRATION); 290 if (cal & RTC_STOP) { 291 cal &= RTC_CAL_MASK; 292 flags = readb(ioaddr + RTC_FLAGS); 293 writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS); 294 writeb(cal, ioaddr + RTC_CALIBRATION); 295 writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS); 296 } 297 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF) 298 dev_warn(&pdev->dev, "voltage-low detected.\n"); 299 300 spin_lock_init(&pdata->lock); 301 pdata->last_jiffies = jiffies; 302 platform_set_drvdata(pdev, pdata); 303 if (pdata->irq > 0) { 304 writeb(0, ioaddr + RTC_INTERRUPTS); 305 if (devm_request_irq(&pdev->dev, pdata->irq, 306 stk17ta8_rtc_interrupt, 307 IRQF_SHARED, 308 pdev->name, pdev) < 0) { 309 dev_warn(&pdev->dev, "interrupt not available.\n"); 310 pdata->irq = 0; 311 } 312 } 313 314 pdata->rtc = devm_rtc_allocate_device(&pdev->dev); 315 if (IS_ERR(pdata->rtc)) 316 return PTR_ERR(pdata->rtc); 317 318 pdata->rtc->ops = &stk17ta8_rtc_ops; 319 pdata->rtc->nvram_old_abi = true; 320 321 nvmem_cfg.priv = pdata; 322 ret = rtc_nvmem_register(pdata->rtc, &nvmem_cfg); 323 if (ret) 324 return ret; 325 326 return rtc_register_device(pdata->rtc); 327 } 328 329 /* work with hotplug and coldplug */ 330 MODULE_ALIAS("platform:stk17ta8"); 331 332 static struct platform_driver stk17ta8_rtc_driver = { 333 .probe = stk17ta8_rtc_probe, 334 .driver = { 335 .name = "stk17ta8", 336 }, 337 }; 338 339 module_platform_driver(stk17ta8_rtc_driver); 340 341 MODULE_AUTHOR("Thomas Hommel <thomas.hommel@ge.com>"); 342 MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver"); 343 MODULE_LICENSE("GPL"); 344