1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * I2C client/driver for the ST M41T80 family of i2c rtc chips. 4 * 5 * Author: Alexander Bigga <ab@mycable.de> 6 * 7 * Based on m41t00.c by Mark A. Greer <mgreer@mvista.com> 8 * 9 * 2006 (c) mycable GmbH 10 */ 11 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13 14 #include <linux/bcd.h> 15 #include <linux/clk-provider.h> 16 #include <linux/i2c.h> 17 #include <linux/init.h> 18 #include <linux/kernel.h> 19 #include <linux/module.h> 20 #include <linux/of_device.h> 21 #include <linux/rtc.h> 22 #include <linux/slab.h> 23 #include <linux/mutex.h> 24 #include <linux/string.h> 25 #ifdef CONFIG_RTC_DRV_M41T80_WDT 26 #include <linux/fs.h> 27 #include <linux/ioctl.h> 28 #include <linux/miscdevice.h> 29 #include <linux/reboot.h> 30 #include <linux/watchdog.h> 31 #endif 32 33 #define M41T80_REG_SSEC 0x00 34 #define M41T80_REG_SEC 0x01 35 #define M41T80_REG_MIN 0x02 36 #define M41T80_REG_HOUR 0x03 37 #define M41T80_REG_WDAY 0x04 38 #define M41T80_REG_DAY 0x05 39 #define M41T80_REG_MON 0x06 40 #define M41T80_REG_YEAR 0x07 41 #define M41T80_REG_ALARM_MON 0x0a 42 #define M41T80_REG_ALARM_DAY 0x0b 43 #define M41T80_REG_ALARM_HOUR 0x0c 44 #define M41T80_REG_ALARM_MIN 0x0d 45 #define M41T80_REG_ALARM_SEC 0x0e 46 #define M41T80_REG_FLAGS 0x0f 47 #define M41T80_REG_SQW 0x13 48 49 #define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1) 50 #define M41T80_ALARM_REG_SIZE \ 51 (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON) 52 53 #define M41T80_SQW_MAX_FREQ 32768 54 55 #define M41T80_SEC_ST BIT(7) /* ST: Stop Bit */ 56 #define M41T80_ALMON_AFE BIT(7) /* AFE: AF Enable Bit */ 57 #define M41T80_ALMON_SQWE BIT(6) /* SQWE: SQW Enable Bit */ 58 #define M41T80_ALHOUR_HT BIT(6) /* HT: Halt Update Bit */ 59 #define M41T80_FLAGS_OF BIT(2) /* OF: Oscillator Failure Bit */ 60 #define M41T80_FLAGS_AF BIT(6) /* AF: Alarm Flag Bit */ 61 #define M41T80_FLAGS_BATT_LOW BIT(4) /* BL: Battery Low Bit */ 62 #define M41T80_WATCHDOG_RB2 BIT(7) /* RB: Watchdog resolution */ 63 #define M41T80_WATCHDOG_RB1 BIT(1) /* RB: Watchdog resolution */ 64 #define M41T80_WATCHDOG_RB0 BIT(0) /* RB: Watchdog resolution */ 65 66 #define M41T80_FEATURE_HT BIT(0) /* Halt feature */ 67 #define M41T80_FEATURE_BL BIT(1) /* Battery low indicator */ 68 #define M41T80_FEATURE_SQ BIT(2) /* Squarewave feature */ 69 #define M41T80_FEATURE_WD BIT(3) /* Extra watchdog resolution */ 70 #define M41T80_FEATURE_SQ_ALT BIT(4) /* RSx bits are in reg 4 */ 71 72 static const struct i2c_device_id m41t80_id[] = { 73 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT }, 74 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD }, 75 { "m41t80", M41T80_FEATURE_SQ }, 76 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ}, 77 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 78 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 79 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 80 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 81 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 82 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 83 { "rv4162", M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT }, 84 { } 85 }; 86 MODULE_DEVICE_TABLE(i2c, m41t80_id); 87 88 static const struct of_device_id m41t80_of_match[] = { 89 { 90 .compatible = "st,m41t62", 91 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT) 92 }, 93 { 94 .compatible = "st,m41t65", 95 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_WD) 96 }, 97 { 98 .compatible = "st,m41t80", 99 .data = (void *)(M41T80_FEATURE_SQ) 100 }, 101 { 102 .compatible = "st,m41t81", 103 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_SQ) 104 }, 105 { 106 .compatible = "st,m41t81s", 107 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) 108 }, 109 { 110 .compatible = "st,m41t82", 111 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) 112 }, 113 { 114 .compatible = "st,m41t83", 115 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) 116 }, 117 { 118 .compatible = "st,m41t84", 119 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) 120 }, 121 { 122 .compatible = "st,m41t85", 123 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) 124 }, 125 { 126 .compatible = "st,m41t87", 127 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) 128 }, 129 { 130 .compatible = "microcrystal,rv4162", 131 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT) 132 }, 133 /* DT compatibility only, do not use compatibles below: */ 134 { 135 .compatible = "st,rv4162", 136 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT) 137 }, 138 { 139 .compatible = "rv4162", 140 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT) 141 }, 142 { } 143 }; 144 MODULE_DEVICE_TABLE(of, m41t80_of_match); 145 146 struct m41t80_data { 147 unsigned long features; 148 struct i2c_client *client; 149 struct rtc_device *rtc; 150 #ifdef CONFIG_COMMON_CLK 151 struct clk_hw sqw; 152 unsigned long freq; 153 unsigned int sqwe; 154 #endif 155 }; 156 157 static irqreturn_t m41t80_handle_irq(int irq, void *dev_id) 158 { 159 struct i2c_client *client = dev_id; 160 struct m41t80_data *m41t80 = i2c_get_clientdata(client); 161 struct mutex *lock = &m41t80->rtc->ops_lock; 162 unsigned long events = 0; 163 int flags, flags_afe; 164 165 mutex_lock(lock); 166 167 flags_afe = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 168 if (flags_afe < 0) { 169 mutex_unlock(lock); 170 return IRQ_NONE; 171 } 172 173 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 174 if (flags <= 0) { 175 mutex_unlock(lock); 176 return IRQ_NONE; 177 } 178 179 if (flags & M41T80_FLAGS_AF) { 180 flags &= ~M41T80_FLAGS_AF; 181 flags_afe &= ~M41T80_ALMON_AFE; 182 events |= RTC_AF; 183 } 184 185 if (events) { 186 rtc_update_irq(m41t80->rtc, 1, events); 187 i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, flags); 188 i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 189 flags_afe); 190 } 191 192 mutex_unlock(lock); 193 194 return IRQ_HANDLED; 195 } 196 197 static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm) 198 { 199 struct i2c_client *client = to_i2c_client(dev); 200 unsigned char buf[8]; 201 int err, flags; 202 203 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 204 if (flags < 0) 205 return flags; 206 207 if (flags & M41T80_FLAGS_OF) { 208 dev_err(&client->dev, "Oscillator failure, data is invalid.\n"); 209 return -EINVAL; 210 } 211 212 err = i2c_smbus_read_i2c_block_data(client, M41T80_REG_SSEC, 213 sizeof(buf), buf); 214 if (err < 0) { 215 dev_err(&client->dev, "Unable to read date\n"); 216 return err; 217 } 218 219 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f); 220 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f); 221 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f); 222 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f); 223 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07; 224 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1; 225 226 /* assume 20YY not 19YY, and ignore the Century Bit */ 227 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100; 228 return 0; 229 } 230 231 static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm) 232 { 233 struct i2c_client *client = to_i2c_client(dev); 234 struct m41t80_data *clientdata = i2c_get_clientdata(client); 235 unsigned char buf[8]; 236 int err, flags; 237 238 buf[M41T80_REG_SSEC] = 0; 239 buf[M41T80_REG_SEC] = bin2bcd(tm->tm_sec); 240 buf[M41T80_REG_MIN] = bin2bcd(tm->tm_min); 241 buf[M41T80_REG_HOUR] = bin2bcd(tm->tm_hour); 242 buf[M41T80_REG_DAY] = bin2bcd(tm->tm_mday); 243 buf[M41T80_REG_MON] = bin2bcd(tm->tm_mon + 1); 244 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year - 100); 245 buf[M41T80_REG_WDAY] = tm->tm_wday; 246 247 /* If the square wave output is controlled in the weekday register */ 248 if (clientdata->features & M41T80_FEATURE_SQ_ALT) { 249 int val; 250 251 val = i2c_smbus_read_byte_data(client, M41T80_REG_WDAY); 252 if (val < 0) 253 return val; 254 255 buf[M41T80_REG_WDAY] |= (val & 0xf0); 256 } 257 258 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_SSEC, 259 sizeof(buf), buf); 260 if (err < 0) { 261 dev_err(&client->dev, "Unable to write to date registers\n"); 262 return err; 263 } 264 265 /* Clear the OF bit of Flags Register */ 266 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 267 if (flags < 0) 268 return flags; 269 270 err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, 271 flags & ~M41T80_FLAGS_OF); 272 if (err < 0) { 273 dev_err(&client->dev, "Unable to write flags register\n"); 274 return err; 275 } 276 277 return err; 278 } 279 280 static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq) 281 { 282 struct i2c_client *client = to_i2c_client(dev); 283 struct m41t80_data *clientdata = i2c_get_clientdata(client); 284 int reg; 285 286 if (clientdata->features & M41T80_FEATURE_BL) { 287 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 288 if (reg < 0) 289 return reg; 290 seq_printf(seq, "battery\t\t: %s\n", 291 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok"); 292 } 293 return 0; 294 } 295 296 static int m41t80_alarm_irq_enable(struct device *dev, unsigned int enabled) 297 { 298 struct i2c_client *client = to_i2c_client(dev); 299 int flags, retval; 300 301 flags = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 302 if (flags < 0) 303 return flags; 304 305 if (enabled) 306 flags |= M41T80_ALMON_AFE; 307 else 308 flags &= ~M41T80_ALMON_AFE; 309 310 retval = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, flags); 311 if (retval < 0) { 312 dev_err(dev, "Unable to enable alarm IRQ %d\n", retval); 313 return retval; 314 } 315 return 0; 316 } 317 318 static int m41t80_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 319 { 320 struct i2c_client *client = to_i2c_client(dev); 321 u8 alarmvals[5]; 322 int ret, err; 323 324 alarmvals[0] = bin2bcd(alrm->time.tm_mon + 1); 325 alarmvals[1] = bin2bcd(alrm->time.tm_mday); 326 alarmvals[2] = bin2bcd(alrm->time.tm_hour); 327 alarmvals[3] = bin2bcd(alrm->time.tm_min); 328 alarmvals[4] = bin2bcd(alrm->time.tm_sec); 329 330 /* Clear AF and AFE flags */ 331 ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 332 if (ret < 0) 333 return ret; 334 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 335 ret & ~(M41T80_ALMON_AFE)); 336 if (err < 0) { 337 dev_err(dev, "Unable to clear AFE bit\n"); 338 return err; 339 } 340 341 /* Keep SQWE bit value */ 342 alarmvals[0] |= (ret & M41T80_ALMON_SQWE); 343 344 ret = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 345 if (ret < 0) 346 return ret; 347 348 err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, 349 ret & ~(M41T80_FLAGS_AF)); 350 if (err < 0) { 351 dev_err(dev, "Unable to clear AF bit\n"); 352 return err; 353 } 354 355 /* Write the alarm */ 356 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_ALARM_MON, 357 5, alarmvals); 358 if (err) 359 return err; 360 361 /* Enable the alarm interrupt */ 362 if (alrm->enabled) { 363 alarmvals[0] |= M41T80_ALMON_AFE; 364 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 365 alarmvals[0]); 366 if (err) 367 return err; 368 } 369 370 return 0; 371 } 372 373 static int m41t80_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 374 { 375 struct i2c_client *client = to_i2c_client(dev); 376 u8 alarmvals[5]; 377 int flags, ret; 378 379 ret = i2c_smbus_read_i2c_block_data(client, M41T80_REG_ALARM_MON, 380 5, alarmvals); 381 if (ret != 5) 382 return ret < 0 ? ret : -EIO; 383 384 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 385 if (flags < 0) 386 return flags; 387 388 alrm->time.tm_sec = bcd2bin(alarmvals[4] & 0x7f); 389 alrm->time.tm_min = bcd2bin(alarmvals[3] & 0x7f); 390 alrm->time.tm_hour = bcd2bin(alarmvals[2] & 0x3f); 391 alrm->time.tm_mday = bcd2bin(alarmvals[1] & 0x3f); 392 alrm->time.tm_mon = bcd2bin(alarmvals[0] & 0x3f) - 1; 393 394 alrm->enabled = !!(alarmvals[0] & M41T80_ALMON_AFE); 395 alrm->pending = (flags & M41T80_FLAGS_AF) && alrm->enabled; 396 397 return 0; 398 } 399 400 static struct rtc_class_ops m41t80_rtc_ops = { 401 .read_time = m41t80_rtc_read_time, 402 .set_time = m41t80_rtc_set_time, 403 .proc = m41t80_rtc_proc, 404 }; 405 406 #ifdef CONFIG_PM_SLEEP 407 static int m41t80_suspend(struct device *dev) 408 { 409 struct i2c_client *client = to_i2c_client(dev); 410 411 if (client->irq >= 0 && device_may_wakeup(dev)) 412 enable_irq_wake(client->irq); 413 414 return 0; 415 } 416 417 static int m41t80_resume(struct device *dev) 418 { 419 struct i2c_client *client = to_i2c_client(dev); 420 421 if (client->irq >= 0 && device_may_wakeup(dev)) 422 disable_irq_wake(client->irq); 423 424 return 0; 425 } 426 #endif 427 428 static SIMPLE_DEV_PM_OPS(m41t80_pm, m41t80_suspend, m41t80_resume); 429 430 #ifdef CONFIG_COMMON_CLK 431 #define sqw_to_m41t80_data(_hw) container_of(_hw, struct m41t80_data, sqw) 432 433 static unsigned long m41t80_decode_freq(int setting) 434 { 435 return (setting == 0) ? 0 : (setting == 1) ? M41T80_SQW_MAX_FREQ : 436 M41T80_SQW_MAX_FREQ >> setting; 437 } 438 439 static unsigned long m41t80_get_freq(struct m41t80_data *m41t80) 440 { 441 struct i2c_client *client = m41t80->client; 442 int reg_sqw = (m41t80->features & M41T80_FEATURE_SQ_ALT) ? 443 M41T80_REG_WDAY : M41T80_REG_SQW; 444 int ret = i2c_smbus_read_byte_data(client, reg_sqw); 445 446 if (ret < 0) 447 return 0; 448 return m41t80_decode_freq(ret >> 4); 449 } 450 451 static unsigned long m41t80_sqw_recalc_rate(struct clk_hw *hw, 452 unsigned long parent_rate) 453 { 454 return sqw_to_m41t80_data(hw)->freq; 455 } 456 457 static long m41t80_sqw_round_rate(struct clk_hw *hw, unsigned long rate, 458 unsigned long *prate) 459 { 460 if (rate >= M41T80_SQW_MAX_FREQ) 461 return M41T80_SQW_MAX_FREQ; 462 if (rate >= M41T80_SQW_MAX_FREQ / 4) 463 return M41T80_SQW_MAX_FREQ / 4; 464 if (!rate) 465 return 0; 466 return 1 << ilog2(rate); 467 } 468 469 static int m41t80_sqw_set_rate(struct clk_hw *hw, unsigned long rate, 470 unsigned long parent_rate) 471 { 472 struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw); 473 struct i2c_client *client = m41t80->client; 474 int reg_sqw = (m41t80->features & M41T80_FEATURE_SQ_ALT) ? 475 M41T80_REG_WDAY : M41T80_REG_SQW; 476 int reg, ret, val = 0; 477 478 if (rate >= M41T80_SQW_MAX_FREQ) 479 val = 1; 480 else if (rate >= M41T80_SQW_MAX_FREQ / 4) 481 val = 2; 482 else if (rate) 483 val = 15 - ilog2(rate); 484 485 reg = i2c_smbus_read_byte_data(client, reg_sqw); 486 if (reg < 0) 487 return reg; 488 489 reg = (reg & 0x0f) | (val << 4); 490 491 ret = i2c_smbus_write_byte_data(client, reg_sqw, reg); 492 if (!ret) 493 m41t80->freq = m41t80_decode_freq(val); 494 return ret; 495 } 496 497 static int m41t80_sqw_control(struct clk_hw *hw, bool enable) 498 { 499 struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw); 500 struct i2c_client *client = m41t80->client; 501 int ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 502 503 if (ret < 0) 504 return ret; 505 506 if (enable) 507 ret |= M41T80_ALMON_SQWE; 508 else 509 ret &= ~M41T80_ALMON_SQWE; 510 511 ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, ret); 512 if (!ret) 513 m41t80->sqwe = enable; 514 return ret; 515 } 516 517 static int m41t80_sqw_prepare(struct clk_hw *hw) 518 { 519 return m41t80_sqw_control(hw, 1); 520 } 521 522 static void m41t80_sqw_unprepare(struct clk_hw *hw) 523 { 524 m41t80_sqw_control(hw, 0); 525 } 526 527 static int m41t80_sqw_is_prepared(struct clk_hw *hw) 528 { 529 return sqw_to_m41t80_data(hw)->sqwe; 530 } 531 532 static const struct clk_ops m41t80_sqw_ops = { 533 .prepare = m41t80_sqw_prepare, 534 .unprepare = m41t80_sqw_unprepare, 535 .is_prepared = m41t80_sqw_is_prepared, 536 .recalc_rate = m41t80_sqw_recalc_rate, 537 .round_rate = m41t80_sqw_round_rate, 538 .set_rate = m41t80_sqw_set_rate, 539 }; 540 541 static struct clk *m41t80_sqw_register_clk(struct m41t80_data *m41t80) 542 { 543 struct i2c_client *client = m41t80->client; 544 struct device_node *node = client->dev.of_node; 545 struct clk *clk; 546 struct clk_init_data init; 547 int ret; 548 549 /* First disable the clock */ 550 ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 551 if (ret < 0) 552 return ERR_PTR(ret); 553 ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 554 ret & ~(M41T80_ALMON_SQWE)); 555 if (ret < 0) 556 return ERR_PTR(ret); 557 558 init.name = "m41t80-sqw"; 559 init.ops = &m41t80_sqw_ops; 560 init.flags = 0; 561 init.parent_names = NULL; 562 init.num_parents = 0; 563 m41t80->sqw.init = &init; 564 m41t80->freq = m41t80_get_freq(m41t80); 565 566 /* optional override of the clockname */ 567 of_property_read_string(node, "clock-output-names", &init.name); 568 569 /* register the clock */ 570 clk = clk_register(&client->dev, &m41t80->sqw); 571 if (!IS_ERR(clk)) 572 of_clk_add_provider(node, of_clk_src_simple_get, clk); 573 574 return clk; 575 } 576 #endif 577 578 #ifdef CONFIG_RTC_DRV_M41T80_WDT 579 /* 580 ***************************************************************************** 581 * 582 * Watchdog Driver 583 * 584 ***************************************************************************** 585 */ 586 static DEFINE_MUTEX(m41t80_rtc_mutex); 587 static struct i2c_client *save_client; 588 589 /* Default margin */ 590 #define WD_TIMO 60 /* 1..31 seconds */ 591 592 static int wdt_margin = WD_TIMO; 593 module_param(wdt_margin, int, 0); 594 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)"); 595 596 static unsigned long wdt_is_open; 597 static int boot_flag; 598 599 /** 600 * wdt_ping: 601 * 602 * Reload counter one with the watchdog timeout. We don't bother reloading 603 * the cascade counter. 604 */ 605 static void wdt_ping(void) 606 { 607 unsigned char i2c_data[2]; 608 struct i2c_msg msgs1[1] = { 609 { 610 .addr = save_client->addr, 611 .flags = 0, 612 .len = 2, 613 .buf = i2c_data, 614 }, 615 }; 616 struct m41t80_data *clientdata = i2c_get_clientdata(save_client); 617 618 i2c_data[0] = 0x09; /* watchdog register */ 619 620 if (wdt_margin > 31) 621 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */ 622 else 623 /* 624 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02) 625 */ 626 i2c_data[1] = wdt_margin << 2 | 0x82; 627 628 /* 629 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as 630 * that would be an invalid resolution. 631 */ 632 if (clientdata->features & M41T80_FEATURE_WD) 633 i2c_data[1] &= ~M41T80_WATCHDOG_RB2; 634 635 i2c_transfer(save_client->adapter, msgs1, 1); 636 } 637 638 /** 639 * wdt_disable: 640 * 641 * disables watchdog. 642 */ 643 static void wdt_disable(void) 644 { 645 unsigned char i2c_data[2], i2c_buf[0x10]; 646 struct i2c_msg msgs0[2] = { 647 { 648 .addr = save_client->addr, 649 .flags = 0, 650 .len = 1, 651 .buf = i2c_data, 652 }, 653 { 654 .addr = save_client->addr, 655 .flags = I2C_M_RD, 656 .len = 1, 657 .buf = i2c_buf, 658 }, 659 }; 660 struct i2c_msg msgs1[1] = { 661 { 662 .addr = save_client->addr, 663 .flags = 0, 664 .len = 2, 665 .buf = i2c_data, 666 }, 667 }; 668 669 i2c_data[0] = 0x09; 670 i2c_transfer(save_client->adapter, msgs0, 2); 671 672 i2c_data[0] = 0x09; 673 i2c_data[1] = 0x00; 674 i2c_transfer(save_client->adapter, msgs1, 1); 675 } 676 677 /** 678 * wdt_write: 679 * @file: file handle to the watchdog 680 * @buf: buffer to write (unused as data does not matter here 681 * @count: count of bytes 682 * @ppos: pointer to the position to write. No seeks allowed 683 * 684 * A write to a watchdog device is defined as a keepalive signal. Any 685 * write of data will do, as we we don't define content meaning. 686 */ 687 static ssize_t wdt_write(struct file *file, const char __user *buf, 688 size_t count, loff_t *ppos) 689 { 690 if (count) { 691 wdt_ping(); 692 return 1; 693 } 694 return 0; 695 } 696 697 static ssize_t wdt_read(struct file *file, char __user *buf, 698 size_t count, loff_t *ppos) 699 { 700 return 0; 701 } 702 703 /** 704 * wdt_ioctl: 705 * @file: file handle to the device 706 * @cmd: watchdog command 707 * @arg: argument pointer 708 * 709 * The watchdog API defines a common set of functions for all watchdogs 710 * according to their available features. We only actually usefully support 711 * querying capabilities and current status. 712 */ 713 static int wdt_ioctl(struct file *file, unsigned int cmd, 714 unsigned long arg) 715 { 716 int new_margin, rv; 717 static struct watchdog_info ident = { 718 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING | 719 WDIOF_SETTIMEOUT, 720 .firmware_version = 1, 721 .identity = "M41T80 WTD" 722 }; 723 724 switch (cmd) { 725 case WDIOC_GETSUPPORT: 726 return copy_to_user((struct watchdog_info __user *)arg, &ident, 727 sizeof(ident)) ? -EFAULT : 0; 728 729 case WDIOC_GETSTATUS: 730 case WDIOC_GETBOOTSTATUS: 731 return put_user(boot_flag, (int __user *)arg); 732 case WDIOC_KEEPALIVE: 733 wdt_ping(); 734 return 0; 735 case WDIOC_SETTIMEOUT: 736 if (get_user(new_margin, (int __user *)arg)) 737 return -EFAULT; 738 /* Arbitrary, can't find the card's limits */ 739 if (new_margin < 1 || new_margin > 124) 740 return -EINVAL; 741 wdt_margin = new_margin; 742 wdt_ping(); 743 fallthrough; 744 case WDIOC_GETTIMEOUT: 745 return put_user(wdt_margin, (int __user *)arg); 746 747 case WDIOC_SETOPTIONS: 748 if (copy_from_user(&rv, (int __user *)arg, sizeof(int))) 749 return -EFAULT; 750 751 if (rv & WDIOS_DISABLECARD) { 752 pr_info("disable watchdog\n"); 753 wdt_disable(); 754 } 755 756 if (rv & WDIOS_ENABLECARD) { 757 pr_info("enable watchdog\n"); 758 wdt_ping(); 759 } 760 761 return -EINVAL; 762 } 763 return -ENOTTY; 764 } 765 766 static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd, 767 unsigned long arg) 768 { 769 int ret; 770 771 mutex_lock(&m41t80_rtc_mutex); 772 ret = wdt_ioctl(file, cmd, arg); 773 mutex_unlock(&m41t80_rtc_mutex); 774 775 return ret; 776 } 777 778 /** 779 * wdt_open: 780 * @inode: inode of device 781 * @file: file handle to device 782 * 783 */ 784 static int wdt_open(struct inode *inode, struct file *file) 785 { 786 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) { 787 mutex_lock(&m41t80_rtc_mutex); 788 if (test_and_set_bit(0, &wdt_is_open)) { 789 mutex_unlock(&m41t80_rtc_mutex); 790 return -EBUSY; 791 } 792 /* 793 * Activate 794 */ 795 wdt_is_open = 1; 796 mutex_unlock(&m41t80_rtc_mutex); 797 return stream_open(inode, file); 798 } 799 return -ENODEV; 800 } 801 802 /** 803 * wdt_close: 804 * @inode: inode to board 805 * @file: file handle to board 806 * 807 */ 808 static int wdt_release(struct inode *inode, struct file *file) 809 { 810 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) 811 clear_bit(0, &wdt_is_open); 812 return 0; 813 } 814 815 /** 816 * notify_sys: 817 * @this: our notifier block 818 * @code: the event being reported 819 * @unused: unused 820 * 821 * Our notifier is called on system shutdowns. We want to turn the card 822 * off at reboot otherwise the machine will reboot again during memory 823 * test or worse yet during the following fsck. This would suck, in fact 824 * trust me - if it happens it does suck. 825 */ 826 static int wdt_notify_sys(struct notifier_block *this, unsigned long code, 827 void *unused) 828 { 829 if (code == SYS_DOWN || code == SYS_HALT) 830 /* Disable Watchdog */ 831 wdt_disable(); 832 return NOTIFY_DONE; 833 } 834 835 static const struct file_operations wdt_fops = { 836 .owner = THIS_MODULE, 837 .read = wdt_read, 838 .unlocked_ioctl = wdt_unlocked_ioctl, 839 .compat_ioctl = compat_ptr_ioctl, 840 .write = wdt_write, 841 .open = wdt_open, 842 .release = wdt_release, 843 .llseek = no_llseek, 844 }; 845 846 static struct miscdevice wdt_dev = { 847 .minor = WATCHDOG_MINOR, 848 .name = "watchdog", 849 .fops = &wdt_fops, 850 }; 851 852 /* 853 * The WDT card needs to learn about soft shutdowns in order to 854 * turn the timebomb registers off. 855 */ 856 static struct notifier_block wdt_notifier = { 857 .notifier_call = wdt_notify_sys, 858 }; 859 #endif /* CONFIG_RTC_DRV_M41T80_WDT */ 860 861 /* 862 ***************************************************************************** 863 * 864 * Driver Interface 865 * 866 ***************************************************************************** 867 */ 868 869 static int m41t80_probe(struct i2c_client *client, 870 const struct i2c_device_id *id) 871 { 872 struct i2c_adapter *adapter = client->adapter; 873 int rc = 0; 874 struct rtc_time tm; 875 struct m41t80_data *m41t80_data = NULL; 876 bool wakeup_source = false; 877 878 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK | 879 I2C_FUNC_SMBUS_BYTE_DATA)) { 880 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n"); 881 return -ENODEV; 882 } 883 884 m41t80_data = devm_kzalloc(&client->dev, sizeof(*m41t80_data), 885 GFP_KERNEL); 886 if (!m41t80_data) 887 return -ENOMEM; 888 889 m41t80_data->client = client; 890 if (client->dev.of_node) 891 m41t80_data->features = (unsigned long) 892 of_device_get_match_data(&client->dev); 893 else 894 m41t80_data->features = id->driver_data; 895 i2c_set_clientdata(client, m41t80_data); 896 897 m41t80_data->rtc = devm_rtc_allocate_device(&client->dev); 898 if (IS_ERR(m41t80_data->rtc)) 899 return PTR_ERR(m41t80_data->rtc); 900 901 #ifdef CONFIG_OF 902 wakeup_source = of_property_read_bool(client->dev.of_node, 903 "wakeup-source"); 904 #endif 905 if (client->irq > 0) { 906 rc = devm_request_threaded_irq(&client->dev, client->irq, 907 NULL, m41t80_handle_irq, 908 IRQF_TRIGGER_LOW | IRQF_ONESHOT, 909 "m41t80", client); 910 if (rc) { 911 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n"); 912 client->irq = 0; 913 wakeup_source = false; 914 } 915 } 916 if (client->irq > 0 || wakeup_source) { 917 m41t80_rtc_ops.read_alarm = m41t80_read_alarm; 918 m41t80_rtc_ops.set_alarm = m41t80_set_alarm; 919 m41t80_rtc_ops.alarm_irq_enable = m41t80_alarm_irq_enable; 920 /* Enable the wakealarm */ 921 device_init_wakeup(&client->dev, true); 922 } 923 924 m41t80_data->rtc->ops = &m41t80_rtc_ops; 925 m41t80_data->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; 926 m41t80_data->rtc->range_max = RTC_TIMESTAMP_END_2099; 927 928 if (client->irq <= 0) { 929 /* We cannot support UIE mode if we do not have an IRQ line */ 930 m41t80_data->rtc->uie_unsupported = 1; 931 } 932 933 /* Make sure HT (Halt Update) bit is cleared */ 934 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR); 935 936 if (rc >= 0 && rc & M41T80_ALHOUR_HT) { 937 if (m41t80_data->features & M41T80_FEATURE_HT) { 938 m41t80_rtc_read_time(&client->dev, &tm); 939 dev_info(&client->dev, "HT bit was set!\n"); 940 dev_info(&client->dev, "Power Down at %ptR\n", &tm); 941 } 942 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR, 943 rc & ~M41T80_ALHOUR_HT); 944 } 945 946 if (rc < 0) { 947 dev_err(&client->dev, "Can't clear HT bit\n"); 948 return rc; 949 } 950 951 /* Make sure ST (stop) bit is cleared */ 952 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC); 953 954 if (rc >= 0 && rc & M41T80_SEC_ST) 955 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC, 956 rc & ~M41T80_SEC_ST); 957 if (rc < 0) { 958 dev_err(&client->dev, "Can't clear ST bit\n"); 959 return rc; 960 } 961 962 #ifdef CONFIG_RTC_DRV_M41T80_WDT 963 if (m41t80_data->features & M41T80_FEATURE_HT) { 964 save_client = client; 965 rc = misc_register(&wdt_dev); 966 if (rc) 967 return rc; 968 rc = register_reboot_notifier(&wdt_notifier); 969 if (rc) { 970 misc_deregister(&wdt_dev); 971 return rc; 972 } 973 } 974 #endif 975 #ifdef CONFIG_COMMON_CLK 976 if (m41t80_data->features & M41T80_FEATURE_SQ) 977 m41t80_sqw_register_clk(m41t80_data); 978 #endif 979 980 rc = devm_rtc_register_device(m41t80_data->rtc); 981 if (rc) 982 return rc; 983 984 return 0; 985 } 986 987 static int m41t80_remove(struct i2c_client *client) 988 { 989 #ifdef CONFIG_RTC_DRV_M41T80_WDT 990 struct m41t80_data *clientdata = i2c_get_clientdata(client); 991 992 if (clientdata->features & M41T80_FEATURE_HT) { 993 misc_deregister(&wdt_dev); 994 unregister_reboot_notifier(&wdt_notifier); 995 } 996 #endif 997 998 return 0; 999 } 1000 1001 static struct i2c_driver m41t80_driver = { 1002 .driver = { 1003 .name = "rtc-m41t80", 1004 .of_match_table = of_match_ptr(m41t80_of_match), 1005 .pm = &m41t80_pm, 1006 }, 1007 .probe = m41t80_probe, 1008 .remove = m41t80_remove, 1009 .id_table = m41t80_id, 1010 }; 1011 1012 module_i2c_driver(m41t80_driver); 1013 1014 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>"); 1015 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver"); 1016 MODULE_LICENSE("GPL"); 1017