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 const struct rtc_class_ops m48t02_rtc_ops = { 317 .read_time = m48t59_rtc_read_time, 318 .set_time = m48t59_rtc_set_time, 319 }; 320 321 static int m48t59_nvram_read(void *priv, unsigned int offset, void *val, 322 size_t size) 323 { 324 struct platform_device *pdev = priv; 325 struct device *dev = &pdev->dev; 326 struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev); 327 struct m48t59_private *m48t59 = platform_get_drvdata(pdev); 328 ssize_t cnt = 0; 329 unsigned long flags; 330 u8 *buf = val; 331 332 spin_lock_irqsave(&m48t59->lock, flags); 333 334 for (; cnt < size; cnt++) 335 *buf++ = M48T59_READ(cnt); 336 337 spin_unlock_irqrestore(&m48t59->lock, flags); 338 339 return 0; 340 } 341 342 static int m48t59_nvram_write(void *priv, unsigned int offset, void *val, 343 size_t size) 344 { 345 struct platform_device *pdev = priv; 346 struct device *dev = &pdev->dev; 347 struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev); 348 struct m48t59_private *m48t59 = platform_get_drvdata(pdev); 349 ssize_t cnt = 0; 350 unsigned long flags; 351 u8 *buf = val; 352 353 spin_lock_irqsave(&m48t59->lock, flags); 354 355 for (; cnt < size; cnt++) 356 M48T59_WRITE(*buf++, cnt); 357 358 spin_unlock_irqrestore(&m48t59->lock, flags); 359 360 return 0; 361 } 362 363 static int m48t59_rtc_probe(struct platform_device *pdev) 364 { 365 struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev); 366 struct m48t59_private *m48t59 = NULL; 367 struct resource *res; 368 int ret = -ENOMEM; 369 const struct rtc_class_ops *ops; 370 struct nvmem_config nvmem_cfg = { 371 .name = "m48t59-", 372 .word_size = 1, 373 .stride = 1, 374 .reg_read = m48t59_nvram_read, 375 .reg_write = m48t59_nvram_write, 376 .priv = pdev, 377 }; 378 379 /* This chip could be memory-mapped or I/O-mapped */ 380 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 381 if (!res) { 382 res = platform_get_resource(pdev, IORESOURCE_IO, 0); 383 if (!res) 384 return -EINVAL; 385 } 386 387 if (res->flags & IORESOURCE_IO) { 388 /* If we are I/O-mapped, the platform should provide 389 * the operations accessing chip registers. 390 */ 391 if (!pdata || !pdata->write_byte || !pdata->read_byte) 392 return -EINVAL; 393 } else if (res->flags & IORESOURCE_MEM) { 394 /* we are memory-mapped */ 395 if (!pdata) { 396 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), 397 GFP_KERNEL); 398 if (!pdata) 399 return -ENOMEM; 400 /* Ensure we only kmalloc platform data once */ 401 pdev->dev.platform_data = pdata; 402 } 403 if (!pdata->type) 404 pdata->type = M48T59RTC_TYPE_M48T59; 405 406 /* Try to use the generic memory read/write ops */ 407 if (!pdata->write_byte) 408 pdata->write_byte = m48t59_mem_writeb; 409 if (!pdata->read_byte) 410 pdata->read_byte = m48t59_mem_readb; 411 } 412 413 m48t59 = devm_kzalloc(&pdev->dev, sizeof(*m48t59), GFP_KERNEL); 414 if (!m48t59) 415 return -ENOMEM; 416 417 m48t59->ioaddr = pdata->ioaddr; 418 419 if (!m48t59->ioaddr) { 420 /* ioaddr not mapped externally */ 421 m48t59->ioaddr = devm_ioremap(&pdev->dev, res->start, 422 resource_size(res)); 423 if (!m48t59->ioaddr) 424 return ret; 425 } 426 427 /* Try to get irq number. We also can work in 428 * the mode without IRQ. 429 */ 430 m48t59->irq = platform_get_irq(pdev, 0); 431 if (m48t59->irq <= 0) 432 m48t59->irq = NO_IRQ; 433 434 if (m48t59->irq != NO_IRQ) { 435 ret = devm_request_irq(&pdev->dev, m48t59->irq, 436 m48t59_rtc_interrupt, IRQF_SHARED, 437 "rtc-m48t59", &pdev->dev); 438 if (ret) 439 return ret; 440 } 441 switch (pdata->type) { 442 case M48T59RTC_TYPE_M48T59: 443 ops = &m48t59_rtc_ops; 444 pdata->offset = 0x1ff0; 445 break; 446 case M48T59RTC_TYPE_M48T02: 447 ops = &m48t02_rtc_ops; 448 pdata->offset = 0x7f0; 449 break; 450 case M48T59RTC_TYPE_M48T08: 451 ops = &m48t02_rtc_ops; 452 pdata->offset = 0x1ff0; 453 break; 454 default: 455 dev_err(&pdev->dev, "Unknown RTC type\n"); 456 return -ENODEV; 457 } 458 459 spin_lock_init(&m48t59->lock); 460 platform_set_drvdata(pdev, m48t59); 461 462 m48t59->rtc = devm_rtc_allocate_device(&pdev->dev); 463 if (IS_ERR(m48t59->rtc)) 464 return PTR_ERR(m48t59->rtc); 465 466 m48t59->rtc->nvram_old_abi = true; 467 m48t59->rtc->ops = ops; 468 469 nvmem_cfg.size = pdata->offset; 470 ret = rtc_nvmem_register(m48t59->rtc, &nvmem_cfg); 471 if (ret) 472 return ret; 473 474 ret = rtc_register_device(m48t59->rtc); 475 if (ret) 476 return ret; 477 478 return 0; 479 } 480 481 /* work with hotplug and coldplug */ 482 MODULE_ALIAS("platform:rtc-m48t59"); 483 484 static struct platform_driver m48t59_rtc_driver = { 485 .driver = { 486 .name = "rtc-m48t59", 487 }, 488 .probe = m48t59_rtc_probe, 489 }; 490 491 module_platform_driver(m48t59_rtc_driver); 492 493 MODULE_AUTHOR("Mark Zhan <rongkai.zhan@windriver.com>"); 494 MODULE_DESCRIPTION("M48T59/M48T02/M48T08 RTC driver"); 495 MODULE_LICENSE("GPL"); 496