1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * ST M48T59 RTC driver 4 * 5 * Copyright (c) 2007 Wind River Systems, Inc. 6 * 7 * Author: Mark Zhan <rongkai.zhan@windriver.com> 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/module.h> 12 #include <linux/init.h> 13 #include <linux/io.h> 14 #include <linux/device.h> 15 #include <linux/platform_device.h> 16 #include <linux/rtc.h> 17 #include <linux/rtc/m48t59.h> 18 #include <linux/bcd.h> 19 #include <linux/slab.h> 20 21 #ifndef NO_IRQ 22 #define NO_IRQ (-1) 23 #endif 24 25 #define M48T59_READ(reg) (pdata->read_byte(dev, pdata->offset + reg)) 26 #define M48T59_WRITE(val, reg) \ 27 (pdata->write_byte(dev, pdata->offset + reg, val)) 28 29 #define M48T59_SET_BITS(mask, reg) \ 30 M48T59_WRITE((M48T59_READ(reg) | (mask)), (reg)) 31 #define M48T59_CLEAR_BITS(mask, reg) \ 32 M48T59_WRITE((M48T59_READ(reg) & ~(mask)), (reg)) 33 34 struct m48t59_private { 35 void __iomem *ioaddr; 36 int irq; 37 struct rtc_device *rtc; 38 spinlock_t lock; /* serialize the NVRAM and RTC access */ 39 }; 40 41 /* 42 * This is the generic access method when the chip is memory-mapped 43 */ 44 static void 45 m48t59_mem_writeb(struct device *dev, u32 ofs, u8 val) 46 { 47 struct m48t59_private *m48t59 = dev_get_drvdata(dev); 48 49 writeb(val, m48t59->ioaddr+ofs); 50 } 51 52 static u8 53 m48t59_mem_readb(struct device *dev, u32 ofs) 54 { 55 struct m48t59_private *m48t59 = dev_get_drvdata(dev); 56 57 return readb(m48t59->ioaddr+ofs); 58 } 59 60 /* 61 * NOTE: M48T59 only uses BCD mode 62 */ 63 static int m48t59_rtc_read_time(struct device *dev, struct rtc_time *tm) 64 { 65 struct m48t59_plat_data *pdata = dev_get_platdata(dev); 66 struct m48t59_private *m48t59 = dev_get_drvdata(dev); 67 unsigned long flags; 68 u8 val; 69 70 spin_lock_irqsave(&m48t59->lock, flags); 71 /* Issue the READ command */ 72 M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL); 73 74 tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR)); 75 /* tm_mon is 0-11 */ 76 tm->tm_mon = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1; 77 tm->tm_mday = bcd2bin(M48T59_READ(M48T59_MDAY)); 78 79 val = M48T59_READ(M48T59_WDAY); 80 if ((pdata->type == M48T59RTC_TYPE_M48T59) && 81 (val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB)) { 82 dev_dbg(dev, "Century bit is enabled\n"); 83 tm->tm_year += 100; /* one century */ 84 } 85 #ifdef CONFIG_SPARC 86 /* Sun SPARC machines count years since 1968 */ 87 tm->tm_year += 68; 88 #endif 89 90 tm->tm_wday = bcd2bin(val & 0x07); 91 tm->tm_hour = bcd2bin(M48T59_READ(M48T59_HOUR) & 0x3F); 92 tm->tm_min = bcd2bin(M48T59_READ(M48T59_MIN) & 0x7F); 93 tm->tm_sec = bcd2bin(M48T59_READ(M48T59_SEC) & 0x7F); 94 95 /* Clear the READ bit */ 96 M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL); 97 spin_unlock_irqrestore(&m48t59->lock, flags); 98 99 dev_dbg(dev, "RTC read time %ptR\n", tm); 100 return 0; 101 } 102 103 static int m48t59_rtc_set_time(struct device *dev, struct rtc_time *tm) 104 { 105 struct m48t59_plat_data *pdata = dev_get_platdata(dev); 106 struct m48t59_private *m48t59 = dev_get_drvdata(dev); 107 unsigned long flags; 108 u8 val = 0; 109 int year = tm->tm_year; 110 111 #ifdef CONFIG_SPARC 112 /* Sun SPARC machines count years since 1968 */ 113 year -= 68; 114 #endif 115 116 dev_dbg(dev, "RTC set time %04d-%02d-%02d %02d/%02d/%02d\n", 117 year + 1900, tm->tm_mon, tm->tm_mday, 118 tm->tm_hour, tm->tm_min, tm->tm_sec); 119 120 if (year < 0) 121 return -EINVAL; 122 123 spin_lock_irqsave(&m48t59->lock, flags); 124 /* Issue the WRITE command */ 125 M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL); 126 127 M48T59_WRITE((bin2bcd(tm->tm_sec) & 0x7F), M48T59_SEC); 128 M48T59_WRITE((bin2bcd(tm->tm_min) & 0x7F), M48T59_MIN); 129 M48T59_WRITE((bin2bcd(tm->tm_hour) & 0x3F), M48T59_HOUR); 130 M48T59_WRITE((bin2bcd(tm->tm_mday) & 0x3F), M48T59_MDAY); 131 /* tm_mon is 0-11 */ 132 M48T59_WRITE((bin2bcd(tm->tm_mon + 1) & 0x1F), M48T59_MONTH); 133 M48T59_WRITE(bin2bcd(year % 100), M48T59_YEAR); 134 135 if (pdata->type == M48T59RTC_TYPE_M48T59 && (year >= 100)) 136 val = (M48T59_WDAY_CEB | M48T59_WDAY_CB); 137 val |= (bin2bcd(tm->tm_wday) & 0x07); 138 M48T59_WRITE(val, M48T59_WDAY); 139 140 /* Clear the WRITE bit */ 141 M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL); 142 spin_unlock_irqrestore(&m48t59->lock, flags); 143 return 0; 144 } 145 146 /* 147 * Read alarm time and date in RTC 148 */ 149 static int m48t59_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm) 150 { 151 struct m48t59_plat_data *pdata = dev_get_platdata(dev); 152 struct m48t59_private *m48t59 = dev_get_drvdata(dev); 153 struct rtc_time *tm = &alrm->time; 154 unsigned long flags; 155 u8 val; 156 157 /* If no irq, we don't support ALARM */ 158 if (m48t59->irq == NO_IRQ) 159 return -EIO; 160 161 spin_lock_irqsave(&m48t59->lock, flags); 162 /* Issue the READ command */ 163 M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL); 164 165 tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR)); 166 #ifdef CONFIG_SPARC 167 /* Sun SPARC machines count years since 1968 */ 168 tm->tm_year += 68; 169 #endif 170 /* tm_mon is 0-11 */ 171 tm->tm_mon = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1; 172 173 val = M48T59_READ(M48T59_WDAY); 174 if ((val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB)) 175 tm->tm_year += 100; /* one century */ 176 177 tm->tm_mday = bcd2bin(M48T59_READ(M48T59_ALARM_DATE)); 178 tm->tm_hour = bcd2bin(M48T59_READ(M48T59_ALARM_HOUR)); 179 tm->tm_min = bcd2bin(M48T59_READ(M48T59_ALARM_MIN)); 180 tm->tm_sec = bcd2bin(M48T59_READ(M48T59_ALARM_SEC)); 181 182 /* Clear the READ bit */ 183 M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL); 184 spin_unlock_irqrestore(&m48t59->lock, flags); 185 186 dev_dbg(dev, "RTC read alarm time %ptR\n", tm); 187 return rtc_valid_tm(tm); 188 } 189 190 /* 191 * Set alarm time and date in RTC 192 */ 193 static int m48t59_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) 194 { 195 struct m48t59_plat_data *pdata = dev_get_platdata(dev); 196 struct m48t59_private *m48t59 = dev_get_drvdata(dev); 197 struct rtc_time *tm = &alrm->time; 198 u8 mday, hour, min, sec; 199 unsigned long flags; 200 int year = tm->tm_year; 201 202 #ifdef CONFIG_SPARC 203 /* Sun SPARC machines count years since 1968 */ 204 year -= 68; 205 #endif 206 207 /* If no irq, we don't support ALARM */ 208 if (m48t59->irq == NO_IRQ) 209 return -EIO; 210 211 if (year < 0) 212 return -EINVAL; 213 214 /* 215 * 0xff means "always match" 216 */ 217 mday = tm->tm_mday; 218 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff; 219 if (mday == 0xff) 220 mday = M48T59_READ(M48T59_MDAY); 221 222 hour = tm->tm_hour; 223 hour = (hour < 24) ? bin2bcd(hour) : 0x00; 224 225 min = tm->tm_min; 226 min = (min < 60) ? bin2bcd(min) : 0x00; 227 228 sec = tm->tm_sec; 229 sec = (sec < 60) ? bin2bcd(sec) : 0x00; 230 231 spin_lock_irqsave(&m48t59->lock, flags); 232 /* Issue the WRITE command */ 233 M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL); 234 235 M48T59_WRITE(mday, M48T59_ALARM_DATE); 236 M48T59_WRITE(hour, M48T59_ALARM_HOUR); 237 M48T59_WRITE(min, M48T59_ALARM_MIN); 238 M48T59_WRITE(sec, M48T59_ALARM_SEC); 239 240 /* Clear the WRITE bit */ 241 M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL); 242 spin_unlock_irqrestore(&m48t59->lock, flags); 243 244 dev_dbg(dev, "RTC set alarm time %04d-%02d-%02d %02d/%02d/%02d\n", 245 year + 1900, tm->tm_mon, tm->tm_mday, 246 tm->tm_hour, tm->tm_min, tm->tm_sec); 247 return 0; 248 } 249 250 /* 251 * Handle commands from user-space 252 */ 253 static int m48t59_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 254 { 255 struct m48t59_plat_data *pdata = dev_get_platdata(dev); 256 struct m48t59_private *m48t59 = dev_get_drvdata(dev); 257 unsigned long flags; 258 259 spin_lock_irqsave(&m48t59->lock, flags); 260 if (enabled) 261 M48T59_WRITE(M48T59_INTR_AFE, M48T59_INTR); 262 else 263 M48T59_WRITE(0x00, M48T59_INTR); 264 spin_unlock_irqrestore(&m48t59->lock, flags); 265 266 return 0; 267 } 268 269 static int m48t59_rtc_proc(struct device *dev, struct seq_file *seq) 270 { 271 struct m48t59_plat_data *pdata = dev_get_platdata(dev); 272 struct m48t59_private *m48t59 = dev_get_drvdata(dev); 273 unsigned long flags; 274 u8 val; 275 276 spin_lock_irqsave(&m48t59->lock, flags); 277 val = M48T59_READ(M48T59_FLAGS); 278 spin_unlock_irqrestore(&m48t59->lock, flags); 279 280 seq_printf(seq, "battery\t\t: %s\n", 281 (val & M48T59_FLAGS_BF) ? "low" : "normal"); 282 return 0; 283 } 284 285 /* 286 * IRQ handler for the RTC 287 */ 288 static irqreturn_t m48t59_rtc_interrupt(int irq, void *dev_id) 289 { 290 struct device *dev = (struct device *)dev_id; 291 struct m48t59_plat_data *pdata = dev_get_platdata(dev); 292 struct m48t59_private *m48t59 = dev_get_drvdata(dev); 293 u8 event; 294 295 spin_lock(&m48t59->lock); 296 event = M48T59_READ(M48T59_FLAGS); 297 spin_unlock(&m48t59->lock); 298 299 if (event & M48T59_FLAGS_AF) { 300 rtc_update_irq(m48t59->rtc, 1, (RTC_AF | RTC_IRQF)); 301 return IRQ_HANDLED; 302 } 303 304 return IRQ_NONE; 305 } 306 307 static const struct rtc_class_ops m48t59_rtc_ops = { 308 .read_time = m48t59_rtc_read_time, 309 .set_time = m48t59_rtc_set_time, 310 .read_alarm = m48t59_rtc_readalarm, 311 .set_alarm = m48t59_rtc_setalarm, 312 .proc = m48t59_rtc_proc, 313 .alarm_irq_enable = m48t59_rtc_alarm_irq_enable, 314 }; 315 316 static int m48t59_nvram_read(void *priv, unsigned int offset, void *val, 317 size_t size) 318 { 319 struct platform_device *pdev = priv; 320 struct device *dev = &pdev->dev; 321 struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev); 322 struct m48t59_private *m48t59 = platform_get_drvdata(pdev); 323 ssize_t cnt = 0; 324 unsigned long flags; 325 u8 *buf = val; 326 327 spin_lock_irqsave(&m48t59->lock, flags); 328 329 for (; cnt < size; cnt++) 330 *buf++ = M48T59_READ(cnt); 331 332 spin_unlock_irqrestore(&m48t59->lock, flags); 333 334 return 0; 335 } 336 337 static int m48t59_nvram_write(void *priv, unsigned int offset, void *val, 338 size_t size) 339 { 340 struct platform_device *pdev = priv; 341 struct device *dev = &pdev->dev; 342 struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev); 343 struct m48t59_private *m48t59 = platform_get_drvdata(pdev); 344 ssize_t cnt = 0; 345 unsigned long flags; 346 u8 *buf = val; 347 348 spin_lock_irqsave(&m48t59->lock, flags); 349 350 for (; cnt < size; cnt++) 351 M48T59_WRITE(*buf++, cnt); 352 353 spin_unlock_irqrestore(&m48t59->lock, flags); 354 355 return 0; 356 } 357 358 static int m48t59_rtc_probe(struct platform_device *pdev) 359 { 360 struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev); 361 struct m48t59_private *m48t59 = NULL; 362 struct resource *res; 363 int ret = -ENOMEM; 364 struct nvmem_config nvmem_cfg = { 365 .name = "m48t59-", 366 .word_size = 1, 367 .stride = 1, 368 .reg_read = m48t59_nvram_read, 369 .reg_write = m48t59_nvram_write, 370 .priv = pdev, 371 }; 372 373 /* This chip could be memory-mapped or I/O-mapped */ 374 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 375 if (!res) { 376 res = platform_get_resource(pdev, IORESOURCE_IO, 0); 377 if (!res) 378 return -EINVAL; 379 } 380 381 if (res->flags & IORESOURCE_IO) { 382 /* If we are I/O-mapped, the platform should provide 383 * the operations accessing chip registers. 384 */ 385 if (!pdata || !pdata->write_byte || !pdata->read_byte) 386 return -EINVAL; 387 } else if (res->flags & IORESOURCE_MEM) { 388 /* we are memory-mapped */ 389 if (!pdata) { 390 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), 391 GFP_KERNEL); 392 if (!pdata) 393 return -ENOMEM; 394 /* Ensure we only kmalloc platform data once */ 395 pdev->dev.platform_data = pdata; 396 } 397 if (!pdata->type) 398 pdata->type = M48T59RTC_TYPE_M48T59; 399 400 /* Try to use the generic memory read/write ops */ 401 if (!pdata->write_byte) 402 pdata->write_byte = m48t59_mem_writeb; 403 if (!pdata->read_byte) 404 pdata->read_byte = m48t59_mem_readb; 405 } 406 407 m48t59 = devm_kzalloc(&pdev->dev, sizeof(*m48t59), GFP_KERNEL); 408 if (!m48t59) 409 return -ENOMEM; 410 411 m48t59->ioaddr = pdata->ioaddr; 412 413 if (!m48t59->ioaddr) { 414 /* ioaddr not mapped externally */ 415 m48t59->ioaddr = devm_ioremap(&pdev->dev, res->start, 416 resource_size(res)); 417 if (!m48t59->ioaddr) 418 return ret; 419 } 420 421 /* Try to get irq number. We also can work in 422 * the mode without IRQ. 423 */ 424 m48t59->irq = platform_get_irq_optional(pdev, 0); 425 if (m48t59->irq <= 0) 426 m48t59->irq = NO_IRQ; 427 428 if (m48t59->irq != NO_IRQ) { 429 ret = devm_request_irq(&pdev->dev, m48t59->irq, 430 m48t59_rtc_interrupt, IRQF_SHARED, 431 "rtc-m48t59", &pdev->dev); 432 if (ret) 433 return ret; 434 } 435 436 m48t59->rtc = devm_rtc_allocate_device(&pdev->dev); 437 if (IS_ERR(m48t59->rtc)) 438 return PTR_ERR(m48t59->rtc); 439 440 switch (pdata->type) { 441 case M48T59RTC_TYPE_M48T59: 442 pdata->offset = 0x1ff0; 443 break; 444 case M48T59RTC_TYPE_M48T02: 445 clear_bit(RTC_FEATURE_ALARM, m48t59->rtc->features); 446 pdata->offset = 0x7f0; 447 break; 448 case M48T59RTC_TYPE_M48T08: 449 clear_bit(RTC_FEATURE_ALARM, m48t59->rtc->features); 450 pdata->offset = 0x1ff0; 451 break; 452 default: 453 dev_err(&pdev->dev, "Unknown RTC type\n"); 454 return -ENODEV; 455 } 456 457 spin_lock_init(&m48t59->lock); 458 platform_set_drvdata(pdev, m48t59); 459 460 m48t59->rtc->ops = &m48t59_rtc_ops; 461 m48t59->rtc->range_min = RTC_TIMESTAMP_BEGIN_1900; 462 m48t59->rtc->range_max = RTC_TIMESTAMP_END_2099; 463 464 nvmem_cfg.size = pdata->offset; 465 ret = devm_rtc_nvmem_register(m48t59->rtc, &nvmem_cfg); 466 if (ret) 467 return ret; 468 469 ret = devm_rtc_register_device(m48t59->rtc); 470 if (ret) 471 return ret; 472 473 return 0; 474 } 475 476 /* work with hotplug and coldplug */ 477 MODULE_ALIAS("platform:rtc-m48t59"); 478 479 static struct platform_driver m48t59_rtc_driver = { 480 .driver = { 481 .name = "rtc-m48t59", 482 }, 483 .probe = m48t59_rtc_probe, 484 }; 485 486 module_platform_driver(m48t59_rtc_driver); 487 488 MODULE_AUTHOR("Mark Zhan <rongkai.zhan@windriver.com>"); 489 MODULE_DESCRIPTION("M48T59/M48T02/M48T08 RTC driver"); 490 MODULE_LICENSE("GPL"); 491