1 /* 2 * Copyright (C) ST-Ericsson SA 2010 3 * 4 * License terms: GNU General Public License (GPL) version 2 5 * Author: Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com> 6 * 7 * RTC clock driver for the RTC part of the AB8500 Power management chip. 8 * Based on RTC clock driver for the AB3100 Analog Baseband Chip by 9 * Linus Walleij <linus.walleij@stericsson.com> 10 */ 11 12 #include <linux/module.h> 13 #include <linux/kernel.h> 14 #include <linux/init.h> 15 #include <linux/platform_device.h> 16 #include <linux/rtc.h> 17 #include <linux/mfd/abx500.h> 18 #include <linux/mfd/abx500/ab8500.h> 19 #include <linux/delay.h> 20 21 #define AB8500_RTC_SOFF_STAT_REG 0x00 22 #define AB8500_RTC_CC_CONF_REG 0x01 23 #define AB8500_RTC_READ_REQ_REG 0x02 24 #define AB8500_RTC_WATCH_TSECMID_REG 0x03 25 #define AB8500_RTC_WATCH_TSECHI_REG 0x04 26 #define AB8500_RTC_WATCH_TMIN_LOW_REG 0x05 27 #define AB8500_RTC_WATCH_TMIN_MID_REG 0x06 28 #define AB8500_RTC_WATCH_TMIN_HI_REG 0x07 29 #define AB8500_RTC_ALRM_MIN_LOW_REG 0x08 30 #define AB8500_RTC_ALRM_MIN_MID_REG 0x09 31 #define AB8500_RTC_ALRM_MIN_HI_REG 0x0A 32 #define AB8500_RTC_STAT_REG 0x0B 33 #define AB8500_RTC_BKUP_CHG_REG 0x0C 34 #define AB8500_RTC_FORCE_BKUP_REG 0x0D 35 #define AB8500_RTC_CALIB_REG 0x0E 36 #define AB8500_RTC_SWITCH_STAT_REG 0x0F 37 38 /* RtcReadRequest bits */ 39 #define RTC_READ_REQUEST 0x01 40 #define RTC_WRITE_REQUEST 0x02 41 42 /* RtcCtrl bits */ 43 #define RTC_ALARM_ENA 0x04 44 #define RTC_STATUS_DATA 0x01 45 46 #define COUNTS_PER_SEC (0xF000 / 60) 47 #define AB8500_RTC_EPOCH 2000 48 49 static const u8 ab8500_rtc_time_regs[] = { 50 AB8500_RTC_WATCH_TMIN_HI_REG, AB8500_RTC_WATCH_TMIN_MID_REG, 51 AB8500_RTC_WATCH_TMIN_LOW_REG, AB8500_RTC_WATCH_TSECHI_REG, 52 AB8500_RTC_WATCH_TSECMID_REG 53 }; 54 55 static const u8 ab8500_rtc_alarm_regs[] = { 56 AB8500_RTC_ALRM_MIN_HI_REG, AB8500_RTC_ALRM_MIN_MID_REG, 57 AB8500_RTC_ALRM_MIN_LOW_REG 58 }; 59 60 /* Calculate the seconds from 1970 to 01-01-2000 00:00:00 */ 61 static unsigned long get_elapsed_seconds(int year) 62 { 63 unsigned long secs; 64 struct rtc_time tm = { 65 .tm_year = year - 1900, 66 .tm_mday = 1, 67 }; 68 69 /* 70 * This function calculates secs from 1970 and not from 71 * 1900, even if we supply the offset from year 1900. 72 */ 73 rtc_tm_to_time(&tm, &secs); 74 return secs; 75 } 76 77 static int ab8500_rtc_read_time(struct device *dev, struct rtc_time *tm) 78 { 79 unsigned long timeout = jiffies + HZ; 80 int retval, i; 81 unsigned long mins, secs; 82 unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)]; 83 u8 value; 84 85 /* Request a data read */ 86 retval = abx500_set_register_interruptible(dev, 87 AB8500_RTC, AB8500_RTC_READ_REQ_REG, RTC_READ_REQUEST); 88 if (retval < 0) 89 return retval; 90 91 /* Early AB8500 chips will not clear the rtc read request bit */ 92 if (abx500_get_chip_id(dev) == 0) { 93 usleep_range(1000, 1000); 94 } else { 95 /* Wait for some cycles after enabling the rtc read in ab8500 */ 96 while (time_before(jiffies, timeout)) { 97 retval = abx500_get_register_interruptible(dev, 98 AB8500_RTC, AB8500_RTC_READ_REQ_REG, &value); 99 if (retval < 0) 100 return retval; 101 102 if (!(value & RTC_READ_REQUEST)) 103 break; 104 105 usleep_range(1000, 5000); 106 } 107 } 108 109 /* Read the Watchtime registers */ 110 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) { 111 retval = abx500_get_register_interruptible(dev, 112 AB8500_RTC, ab8500_rtc_time_regs[i], &value); 113 if (retval < 0) 114 return retval; 115 buf[i] = value; 116 } 117 118 mins = (buf[0] << 16) | (buf[1] << 8) | buf[2]; 119 120 secs = (buf[3] << 8) | buf[4]; 121 secs = secs / COUNTS_PER_SEC; 122 secs = secs + (mins * 60); 123 124 /* Add back the initially subtracted number of seconds */ 125 secs += get_elapsed_seconds(AB8500_RTC_EPOCH); 126 127 rtc_time_to_tm(secs, tm); 128 return rtc_valid_tm(tm); 129 } 130 131 static int ab8500_rtc_set_time(struct device *dev, struct rtc_time *tm) 132 { 133 int retval, i; 134 unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)]; 135 unsigned long no_secs, no_mins, secs = 0; 136 137 if (tm->tm_year < (AB8500_RTC_EPOCH - 1900)) { 138 dev_dbg(dev, "year should be equal to or greater than %d\n", 139 AB8500_RTC_EPOCH); 140 return -EINVAL; 141 } 142 143 /* Get the number of seconds since 1970 */ 144 rtc_tm_to_time(tm, &secs); 145 146 /* 147 * Convert it to the number of seconds since 01-01-2000 00:00:00, since 148 * we only have a small counter in the RTC. 149 */ 150 secs -= get_elapsed_seconds(AB8500_RTC_EPOCH); 151 152 no_mins = secs / 60; 153 154 no_secs = secs % 60; 155 /* Make the seconds count as per the RTC resolution */ 156 no_secs = no_secs * COUNTS_PER_SEC; 157 158 buf[4] = no_secs & 0xFF; 159 buf[3] = (no_secs >> 8) & 0xFF; 160 161 buf[2] = no_mins & 0xFF; 162 buf[1] = (no_mins >> 8) & 0xFF; 163 buf[0] = (no_mins >> 16) & 0xFF; 164 165 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) { 166 retval = abx500_set_register_interruptible(dev, AB8500_RTC, 167 ab8500_rtc_time_regs[i], buf[i]); 168 if (retval < 0) 169 return retval; 170 } 171 172 /* Request a data write */ 173 return abx500_set_register_interruptible(dev, AB8500_RTC, 174 AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST); 175 } 176 177 static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) 178 { 179 int retval, i; 180 u8 rtc_ctrl, value; 181 unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)]; 182 unsigned long secs, mins; 183 184 /* Check if the alarm is enabled or not */ 185 retval = abx500_get_register_interruptible(dev, AB8500_RTC, 186 AB8500_RTC_STAT_REG, &rtc_ctrl); 187 if (retval < 0) 188 return retval; 189 190 if (rtc_ctrl & RTC_ALARM_ENA) 191 alarm->enabled = 1; 192 else 193 alarm->enabled = 0; 194 195 alarm->pending = 0; 196 197 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) { 198 retval = abx500_get_register_interruptible(dev, AB8500_RTC, 199 ab8500_rtc_alarm_regs[i], &value); 200 if (retval < 0) 201 return retval; 202 buf[i] = value; 203 } 204 205 mins = (buf[0] << 16) | (buf[1] << 8) | (buf[2]); 206 secs = mins * 60; 207 208 /* Add back the initially subtracted number of seconds */ 209 secs += get_elapsed_seconds(AB8500_RTC_EPOCH); 210 211 rtc_time_to_tm(secs, &alarm->time); 212 213 return rtc_valid_tm(&alarm->time); 214 } 215 216 static int ab8500_rtc_irq_enable(struct device *dev, unsigned int enabled) 217 { 218 return abx500_mask_and_set_register_interruptible(dev, AB8500_RTC, 219 AB8500_RTC_STAT_REG, RTC_ALARM_ENA, 220 enabled ? RTC_ALARM_ENA : 0); 221 } 222 223 static int ab8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) 224 { 225 int retval, i; 226 unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)]; 227 unsigned long mins, secs = 0; 228 229 if (alarm->time.tm_year < (AB8500_RTC_EPOCH - 1900)) { 230 dev_dbg(dev, "year should be equal to or greater than %d\n", 231 AB8500_RTC_EPOCH); 232 return -EINVAL; 233 } 234 235 /* Get the number of seconds since 1970 */ 236 rtc_tm_to_time(&alarm->time, &secs); 237 238 /* 239 * Convert it to the number of seconds since 01-01-2000 00:00:00, since 240 * we only have a small counter in the RTC. 241 */ 242 secs -= get_elapsed_seconds(AB8500_RTC_EPOCH); 243 244 mins = secs / 60; 245 246 buf[2] = mins & 0xFF; 247 buf[1] = (mins >> 8) & 0xFF; 248 buf[0] = (mins >> 16) & 0xFF; 249 250 /* Set the alarm time */ 251 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) { 252 retval = abx500_set_register_interruptible(dev, AB8500_RTC, 253 ab8500_rtc_alarm_regs[i], buf[i]); 254 if (retval < 0) 255 return retval; 256 } 257 258 return ab8500_rtc_irq_enable(dev, alarm->enabled); 259 } 260 261 262 static int ab8500_rtc_set_calibration(struct device *dev, int calibration) 263 { 264 int retval; 265 u8 rtccal = 0; 266 267 /* 268 * Check that the calibration value (which is in units of 0.5 269 * parts-per-million) is in the AB8500's range for RtcCalibration 270 * register. -128 (0x80) is not permitted because the AB8500 uses 271 * a sign-bit rather than two's complement, so 0x80 is just another 272 * representation of zero. 273 */ 274 if ((calibration < -127) || (calibration > 127)) { 275 dev_err(dev, "RtcCalibration value outside permitted range\n"); 276 return -EINVAL; 277 } 278 279 /* 280 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7) 281 * so need to convert to this sort of representation before writing 282 * into RtcCalibration register... 283 */ 284 if (calibration >= 0) 285 rtccal = 0x7F & calibration; 286 else 287 rtccal = ~(calibration - 1) | 0x80; 288 289 retval = abx500_set_register_interruptible(dev, AB8500_RTC, 290 AB8500_RTC_CALIB_REG, rtccal); 291 292 return retval; 293 } 294 295 static int ab8500_rtc_get_calibration(struct device *dev, int *calibration) 296 { 297 int retval; 298 u8 rtccal = 0; 299 300 retval = abx500_get_register_interruptible(dev, AB8500_RTC, 301 AB8500_RTC_CALIB_REG, &rtccal); 302 if (retval >= 0) { 303 /* 304 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7) 305 * so need to convert value from RtcCalibration register into 306 * a two's complement signed value... 307 */ 308 if (rtccal & 0x80) 309 *calibration = 0 - (rtccal & 0x7F); 310 else 311 *calibration = 0x7F & rtccal; 312 } 313 314 return retval; 315 } 316 317 static ssize_t ab8500_sysfs_store_rtc_calibration(struct device *dev, 318 struct device_attribute *attr, 319 const char *buf, size_t count) 320 { 321 int retval; 322 int calibration = 0; 323 324 if (sscanf(buf, " %i ", &calibration) != 1) { 325 dev_err(dev, "Failed to store RTC calibration attribute\n"); 326 return -EINVAL; 327 } 328 329 retval = ab8500_rtc_set_calibration(dev, calibration); 330 331 return retval ? retval : count; 332 } 333 334 static ssize_t ab8500_sysfs_show_rtc_calibration(struct device *dev, 335 struct device_attribute *attr, char *buf) 336 { 337 int retval = 0; 338 int calibration = 0; 339 340 retval = ab8500_rtc_get_calibration(dev, &calibration); 341 if (retval < 0) { 342 dev_err(dev, "Failed to read RTC calibration attribute\n"); 343 sprintf(buf, "0\n"); 344 return retval; 345 } 346 347 return sprintf(buf, "%d\n", calibration); 348 } 349 350 static DEVICE_ATTR(rtc_calibration, S_IRUGO | S_IWUSR, 351 ab8500_sysfs_show_rtc_calibration, 352 ab8500_sysfs_store_rtc_calibration); 353 354 static int ab8500_sysfs_rtc_register(struct device *dev) 355 { 356 return device_create_file(dev, &dev_attr_rtc_calibration); 357 } 358 359 static void ab8500_sysfs_rtc_unregister(struct device *dev) 360 { 361 device_remove_file(dev, &dev_attr_rtc_calibration); 362 } 363 364 static irqreturn_t rtc_alarm_handler(int irq, void *data) 365 { 366 struct rtc_device *rtc = data; 367 unsigned long events = RTC_IRQF | RTC_AF; 368 369 dev_dbg(&rtc->dev, "%s\n", __func__); 370 rtc_update_irq(rtc, 1, events); 371 372 return IRQ_HANDLED; 373 } 374 375 static const struct rtc_class_ops ab8500_rtc_ops = { 376 .read_time = ab8500_rtc_read_time, 377 .set_time = ab8500_rtc_set_time, 378 .read_alarm = ab8500_rtc_read_alarm, 379 .set_alarm = ab8500_rtc_set_alarm, 380 .alarm_irq_enable = ab8500_rtc_irq_enable, 381 }; 382 383 static int __devinit ab8500_rtc_probe(struct platform_device *pdev) 384 { 385 int err; 386 struct rtc_device *rtc; 387 u8 rtc_ctrl; 388 int irq; 389 390 irq = platform_get_irq_byname(pdev, "ALARM"); 391 if (irq < 0) 392 return irq; 393 394 /* For RTC supply test */ 395 err = abx500_mask_and_set_register_interruptible(&pdev->dev, AB8500_RTC, 396 AB8500_RTC_STAT_REG, RTC_STATUS_DATA, RTC_STATUS_DATA); 397 if (err < 0) 398 return err; 399 400 /* Wait for reset by the PorRtc */ 401 usleep_range(1000, 5000); 402 403 err = abx500_get_register_interruptible(&pdev->dev, AB8500_RTC, 404 AB8500_RTC_STAT_REG, &rtc_ctrl); 405 if (err < 0) 406 return err; 407 408 /* Check if the RTC Supply fails */ 409 if (!(rtc_ctrl & RTC_STATUS_DATA)) { 410 dev_err(&pdev->dev, "RTC supply failure\n"); 411 return -ENODEV; 412 } 413 414 device_init_wakeup(&pdev->dev, true); 415 416 rtc = rtc_device_register("ab8500-rtc", &pdev->dev, &ab8500_rtc_ops, 417 THIS_MODULE); 418 if (IS_ERR(rtc)) { 419 dev_err(&pdev->dev, "Registration failed\n"); 420 err = PTR_ERR(rtc); 421 return err; 422 } 423 424 err = request_threaded_irq(irq, NULL, rtc_alarm_handler, 425 IRQF_NO_SUSPEND, "ab8500-rtc", rtc); 426 if (err < 0) { 427 rtc_device_unregister(rtc); 428 return err; 429 } 430 431 platform_set_drvdata(pdev, rtc); 432 433 434 err = ab8500_sysfs_rtc_register(&pdev->dev); 435 if (err) { 436 dev_err(&pdev->dev, "sysfs RTC failed to register\n"); 437 return err; 438 } 439 440 return 0; 441 } 442 443 static int __devexit ab8500_rtc_remove(struct platform_device *pdev) 444 { 445 struct rtc_device *rtc = platform_get_drvdata(pdev); 446 int irq = platform_get_irq_byname(pdev, "ALARM"); 447 448 ab8500_sysfs_rtc_unregister(&pdev->dev); 449 450 free_irq(irq, rtc); 451 rtc_device_unregister(rtc); 452 platform_set_drvdata(pdev, NULL); 453 454 return 0; 455 } 456 457 static struct platform_driver ab8500_rtc_driver = { 458 .driver = { 459 .name = "ab8500-rtc", 460 .owner = THIS_MODULE, 461 }, 462 .probe = ab8500_rtc_probe, 463 .remove = __devexit_p(ab8500_rtc_remove), 464 }; 465 466 module_platform_driver(ab8500_rtc_driver); 467 468 MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>"); 469 MODULE_DESCRIPTION("AB8500 RTC Driver"); 470 MODULE_LICENSE("GPL v2"); 471