1 /* 2 * Real Time Clock driver for Wolfson Microelectronics WM831x 3 * 4 * Copyright (C) 2009 Wolfson Microelectronics PLC. 5 * 6 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com> 7 * 8 * This program is free software; you can redistribute it and/or modify it 9 * under the terms of the GNU General Public License as published by the 10 * Free Software Foundation; either version 2 of the License, or (at your 11 * option) any later version. 12 * 13 */ 14 15 #include <linux/module.h> 16 #include <linux/kernel.h> 17 #include <linux/time.h> 18 #include <linux/rtc.h> 19 #include <linux/slab.h> 20 #include <linux/bcd.h> 21 #include <linux/interrupt.h> 22 #include <linux/ioctl.h> 23 #include <linux/completion.h> 24 #include <linux/mfd/wm831x/core.h> 25 #include <linux/delay.h> 26 #include <linux/platform_device.h> 27 28 29 /* 30 * R16416 (0x4020) - RTC Write Counter 31 */ 32 #define WM831X_RTC_WR_CNT_MASK 0xFFFF /* RTC_WR_CNT - [15:0] */ 33 #define WM831X_RTC_WR_CNT_SHIFT 0 /* RTC_WR_CNT - [15:0] */ 34 #define WM831X_RTC_WR_CNT_WIDTH 16 /* RTC_WR_CNT - [15:0] */ 35 36 /* 37 * R16417 (0x4021) - RTC Time 1 38 */ 39 #define WM831X_RTC_TIME_MASK 0xFFFF /* RTC_TIME - [15:0] */ 40 #define WM831X_RTC_TIME_SHIFT 0 /* RTC_TIME - [15:0] */ 41 #define WM831X_RTC_TIME_WIDTH 16 /* RTC_TIME - [15:0] */ 42 43 /* 44 * R16418 (0x4022) - RTC Time 2 45 */ 46 #define WM831X_RTC_TIME_MASK 0xFFFF /* RTC_TIME - [15:0] */ 47 #define WM831X_RTC_TIME_SHIFT 0 /* RTC_TIME - [15:0] */ 48 #define WM831X_RTC_TIME_WIDTH 16 /* RTC_TIME - [15:0] */ 49 50 /* 51 * R16419 (0x4023) - RTC Alarm 1 52 */ 53 #define WM831X_RTC_ALM_MASK 0xFFFF /* RTC_ALM - [15:0] */ 54 #define WM831X_RTC_ALM_SHIFT 0 /* RTC_ALM - [15:0] */ 55 #define WM831X_RTC_ALM_WIDTH 16 /* RTC_ALM - [15:0] */ 56 57 /* 58 * R16420 (0x4024) - RTC Alarm 2 59 */ 60 #define WM831X_RTC_ALM_MASK 0xFFFF /* RTC_ALM - [15:0] */ 61 #define WM831X_RTC_ALM_SHIFT 0 /* RTC_ALM - [15:0] */ 62 #define WM831X_RTC_ALM_WIDTH 16 /* RTC_ALM - [15:0] */ 63 64 /* 65 * R16421 (0x4025) - RTC Control 66 */ 67 #define WM831X_RTC_VALID 0x8000 /* RTC_VALID */ 68 #define WM831X_RTC_VALID_MASK 0x8000 /* RTC_VALID */ 69 #define WM831X_RTC_VALID_SHIFT 15 /* RTC_VALID */ 70 #define WM831X_RTC_VALID_WIDTH 1 /* RTC_VALID */ 71 #define WM831X_RTC_SYNC_BUSY 0x4000 /* RTC_SYNC_BUSY */ 72 #define WM831X_RTC_SYNC_BUSY_MASK 0x4000 /* RTC_SYNC_BUSY */ 73 #define WM831X_RTC_SYNC_BUSY_SHIFT 14 /* RTC_SYNC_BUSY */ 74 #define WM831X_RTC_SYNC_BUSY_WIDTH 1 /* RTC_SYNC_BUSY */ 75 #define WM831X_RTC_ALM_ENA 0x0400 /* RTC_ALM_ENA */ 76 #define WM831X_RTC_ALM_ENA_MASK 0x0400 /* RTC_ALM_ENA */ 77 #define WM831X_RTC_ALM_ENA_SHIFT 10 /* RTC_ALM_ENA */ 78 #define WM831X_RTC_ALM_ENA_WIDTH 1 /* RTC_ALM_ENA */ 79 #define WM831X_RTC_PINT_FREQ_MASK 0x0070 /* RTC_PINT_FREQ - [6:4] */ 80 #define WM831X_RTC_PINT_FREQ_SHIFT 4 /* RTC_PINT_FREQ - [6:4] */ 81 #define WM831X_RTC_PINT_FREQ_WIDTH 3 /* RTC_PINT_FREQ - [6:4] */ 82 83 /* 84 * R16422 (0x4026) - RTC Trim 85 */ 86 #define WM831X_RTC_TRIM_MASK 0x03FF /* RTC_TRIM - [9:0] */ 87 #define WM831X_RTC_TRIM_SHIFT 0 /* RTC_TRIM - [9:0] */ 88 #define WM831X_RTC_TRIM_WIDTH 10 /* RTC_TRIM - [9:0] */ 89 90 #define WM831X_SET_TIME_RETRIES 5 91 #define WM831X_GET_TIME_RETRIES 5 92 93 struct wm831x_rtc { 94 struct wm831x *wm831x; 95 struct rtc_device *rtc; 96 unsigned int alarm_enabled:1; 97 }; 98 99 /* 100 * Read current time and date in RTC 101 */ 102 static int wm831x_rtc_readtime(struct device *dev, struct rtc_time *tm) 103 { 104 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev); 105 struct wm831x *wm831x = wm831x_rtc->wm831x; 106 u16 time1[2], time2[2]; 107 int ret; 108 int count = 0; 109 110 /* Has the RTC been programmed? */ 111 ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL); 112 if (ret < 0) { 113 dev_err(dev, "Failed to read RTC control: %d\n", ret); 114 return ret; 115 } 116 if (!(ret & WM831X_RTC_VALID)) { 117 dev_dbg(dev, "RTC not yet configured\n"); 118 return -EINVAL; 119 } 120 121 /* Read twice to make sure we don't read a corrupt, partially 122 * incremented, value. 123 */ 124 do { 125 ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1, 126 2, time1); 127 if (ret != 0) 128 continue; 129 130 ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1, 131 2, time2); 132 if (ret != 0) 133 continue; 134 135 if (memcmp(time1, time2, sizeof(time1)) == 0) { 136 u32 time = (time1[0] << 16) | time1[1]; 137 138 rtc_time_to_tm(time, tm); 139 return rtc_valid_tm(tm); 140 } 141 142 } while (++count < WM831X_GET_TIME_RETRIES); 143 144 dev_err(dev, "Timed out reading current time\n"); 145 146 return -EIO; 147 } 148 149 /* 150 * Set current time and date in RTC 151 */ 152 static int wm831x_rtc_set_mmss(struct device *dev, unsigned long time) 153 { 154 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev); 155 struct wm831x *wm831x = wm831x_rtc->wm831x; 156 struct rtc_time new_tm; 157 unsigned long new_time; 158 int ret; 159 int count = 0; 160 161 ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_1, 162 (time >> 16) & 0xffff); 163 if (ret < 0) { 164 dev_err(dev, "Failed to write TIME_1: %d\n", ret); 165 return ret; 166 } 167 168 ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_2, time & 0xffff); 169 if (ret < 0) { 170 dev_err(dev, "Failed to write TIME_2: %d\n", ret); 171 return ret; 172 } 173 174 /* Wait for the update to complete - should happen first time 175 * round but be conservative. 176 */ 177 do { 178 msleep(1); 179 180 ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL); 181 if (ret < 0) 182 ret = WM831X_RTC_SYNC_BUSY; 183 } while (!(ret & WM831X_RTC_SYNC_BUSY) && 184 ++count < WM831X_SET_TIME_RETRIES); 185 186 if (ret & WM831X_RTC_SYNC_BUSY) { 187 dev_err(dev, "Timed out writing RTC update\n"); 188 return -EIO; 189 } 190 191 /* Check that the update was accepted; security features may 192 * have caused the update to be ignored. 193 */ 194 ret = wm831x_rtc_readtime(dev, &new_tm); 195 if (ret < 0) 196 return ret; 197 198 ret = rtc_tm_to_time(&new_tm, &new_time); 199 if (ret < 0) { 200 dev_err(dev, "Failed to convert time: %d\n", ret); 201 return ret; 202 } 203 204 /* Allow a second of change in case of tick */ 205 if (new_time - time > 1) { 206 dev_err(dev, "RTC update not permitted by hardware\n"); 207 return -EPERM; 208 } 209 210 return 0; 211 } 212 213 /* 214 * Read alarm time and date in RTC 215 */ 216 static int wm831x_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm) 217 { 218 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev); 219 int ret; 220 u16 data[2]; 221 u32 time; 222 223 ret = wm831x_bulk_read(wm831x_rtc->wm831x, WM831X_RTC_ALARM_1, 224 2, data); 225 if (ret != 0) { 226 dev_err(dev, "Failed to read alarm time: %d\n", ret); 227 return ret; 228 } 229 230 time = (data[0] << 16) | data[1]; 231 232 rtc_time_to_tm(time, &alrm->time); 233 234 ret = wm831x_reg_read(wm831x_rtc->wm831x, WM831X_RTC_CONTROL); 235 if (ret < 0) { 236 dev_err(dev, "Failed to read RTC control: %d\n", ret); 237 return ret; 238 } 239 240 if (ret & WM831X_RTC_ALM_ENA) 241 alrm->enabled = 1; 242 else 243 alrm->enabled = 0; 244 245 return 0; 246 } 247 248 static int wm831x_rtc_stop_alarm(struct wm831x_rtc *wm831x_rtc) 249 { 250 wm831x_rtc->alarm_enabled = 0; 251 252 return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL, 253 WM831X_RTC_ALM_ENA, 0); 254 } 255 256 static int wm831x_rtc_start_alarm(struct wm831x_rtc *wm831x_rtc) 257 { 258 wm831x_rtc->alarm_enabled = 1; 259 260 return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL, 261 WM831X_RTC_ALM_ENA, WM831X_RTC_ALM_ENA); 262 } 263 264 static int wm831x_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) 265 { 266 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev); 267 struct wm831x *wm831x = wm831x_rtc->wm831x; 268 int ret; 269 unsigned long time; 270 271 ret = rtc_tm_to_time(&alrm->time, &time); 272 if (ret < 0) { 273 dev_err(dev, "Failed to convert time: %d\n", ret); 274 return ret; 275 } 276 277 ret = wm831x_rtc_stop_alarm(wm831x_rtc); 278 if (ret < 0) { 279 dev_err(dev, "Failed to stop alarm: %d\n", ret); 280 return ret; 281 } 282 283 ret = wm831x_reg_write(wm831x, WM831X_RTC_ALARM_1, 284 (time >> 16) & 0xffff); 285 if (ret < 0) { 286 dev_err(dev, "Failed to write ALARM_1: %d\n", ret); 287 return ret; 288 } 289 290 ret = wm831x_reg_write(wm831x, WM831X_RTC_ALARM_2, time & 0xffff); 291 if (ret < 0) { 292 dev_err(dev, "Failed to write ALARM_2: %d\n", ret); 293 return ret; 294 } 295 296 if (alrm->enabled) { 297 ret = wm831x_rtc_start_alarm(wm831x_rtc); 298 if (ret < 0) { 299 dev_err(dev, "Failed to start alarm: %d\n", ret); 300 return ret; 301 } 302 } 303 304 return 0; 305 } 306 307 static int wm831x_rtc_alarm_irq_enable(struct device *dev, 308 unsigned int enabled) 309 { 310 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev); 311 312 if (enabled) 313 return wm831x_rtc_start_alarm(wm831x_rtc); 314 else 315 return wm831x_rtc_stop_alarm(wm831x_rtc); 316 } 317 318 static irqreturn_t wm831x_alm_irq(int irq, void *data) 319 { 320 struct wm831x_rtc *wm831x_rtc = data; 321 322 rtc_update_irq(wm831x_rtc->rtc, 1, RTC_IRQF | RTC_AF); 323 324 return IRQ_HANDLED; 325 } 326 327 static const struct rtc_class_ops wm831x_rtc_ops = { 328 .read_time = wm831x_rtc_readtime, 329 .set_mmss = wm831x_rtc_set_mmss, 330 .read_alarm = wm831x_rtc_readalarm, 331 .set_alarm = wm831x_rtc_setalarm, 332 .alarm_irq_enable = wm831x_rtc_alarm_irq_enable, 333 }; 334 335 #ifdef CONFIG_PM 336 /* Turn off the alarm if it should not be a wake source. */ 337 static int wm831x_rtc_suspend(struct device *dev) 338 { 339 struct platform_device *pdev = to_platform_device(dev); 340 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev); 341 int ret, enable; 342 343 if (wm831x_rtc->alarm_enabled && device_may_wakeup(&pdev->dev)) 344 enable = WM831X_RTC_ALM_ENA; 345 else 346 enable = 0; 347 348 ret = wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL, 349 WM831X_RTC_ALM_ENA, enable); 350 if (ret != 0) 351 dev_err(&pdev->dev, "Failed to update RTC alarm: %d\n", ret); 352 353 return 0; 354 } 355 356 /* Enable the alarm if it should be enabled (in case it was disabled to 357 * prevent use as a wake source). 358 */ 359 static int wm831x_rtc_resume(struct device *dev) 360 { 361 struct platform_device *pdev = to_platform_device(dev); 362 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev); 363 int ret; 364 365 if (wm831x_rtc->alarm_enabled) { 366 ret = wm831x_rtc_start_alarm(wm831x_rtc); 367 if (ret != 0) 368 dev_err(&pdev->dev, 369 "Failed to restart RTC alarm: %d\n", ret); 370 } 371 372 return 0; 373 } 374 375 /* Unconditionally disable the alarm */ 376 static int wm831x_rtc_freeze(struct device *dev) 377 { 378 struct platform_device *pdev = to_platform_device(dev); 379 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev); 380 int ret; 381 382 ret = wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL, 383 WM831X_RTC_ALM_ENA, 0); 384 if (ret != 0) 385 dev_err(&pdev->dev, "Failed to stop RTC alarm: %d\n", ret); 386 387 return 0; 388 } 389 #else 390 #define wm831x_rtc_suspend NULL 391 #define wm831x_rtc_resume NULL 392 #define wm831x_rtc_freeze NULL 393 #endif 394 395 static int wm831x_rtc_probe(struct platform_device *pdev) 396 { 397 struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent); 398 struct wm831x_rtc *wm831x_rtc; 399 int alm_irq = wm831x_irq(wm831x, platform_get_irq_byname(pdev, "ALM")); 400 int ret = 0; 401 402 wm831x_rtc = devm_kzalloc(&pdev->dev, sizeof(*wm831x_rtc), GFP_KERNEL); 403 if (wm831x_rtc == NULL) 404 return -ENOMEM; 405 406 platform_set_drvdata(pdev, wm831x_rtc); 407 wm831x_rtc->wm831x = wm831x; 408 409 ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL); 410 if (ret < 0) { 411 dev_err(&pdev->dev, "Failed to read RTC control: %d\n", ret); 412 goto err; 413 } 414 if (ret & WM831X_RTC_ALM_ENA) 415 wm831x_rtc->alarm_enabled = 1; 416 417 device_init_wakeup(&pdev->dev, 1); 418 419 wm831x_rtc->rtc = rtc_device_register("wm831x", &pdev->dev, 420 &wm831x_rtc_ops, THIS_MODULE); 421 if (IS_ERR(wm831x_rtc->rtc)) { 422 ret = PTR_ERR(wm831x_rtc->rtc); 423 goto err; 424 } 425 426 ret = request_threaded_irq(alm_irq, NULL, wm831x_alm_irq, 427 IRQF_TRIGGER_RISING, "RTC alarm", 428 wm831x_rtc); 429 if (ret != 0) { 430 dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n", 431 alm_irq, ret); 432 } 433 434 return 0; 435 436 err: 437 return ret; 438 } 439 440 static int __devexit wm831x_rtc_remove(struct platform_device *pdev) 441 { 442 struct wm831x_rtc *wm831x_rtc = platform_get_drvdata(pdev); 443 int alm_irq = platform_get_irq_byname(pdev, "ALM"); 444 445 free_irq(alm_irq, wm831x_rtc); 446 rtc_device_unregister(wm831x_rtc->rtc); 447 448 return 0; 449 } 450 451 static const struct dev_pm_ops wm831x_rtc_pm_ops = { 452 .suspend = wm831x_rtc_suspend, 453 .resume = wm831x_rtc_resume, 454 455 .freeze = wm831x_rtc_freeze, 456 .thaw = wm831x_rtc_resume, 457 .restore = wm831x_rtc_resume, 458 459 .poweroff = wm831x_rtc_suspend, 460 }; 461 462 static struct platform_driver wm831x_rtc_driver = { 463 .probe = wm831x_rtc_probe, 464 .remove = __devexit_p(wm831x_rtc_remove), 465 .driver = { 466 .name = "wm831x-rtc", 467 .pm = &wm831x_rtc_pm_ops, 468 }, 469 }; 470 471 module_platform_driver(wm831x_rtc_driver); 472 473 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>"); 474 MODULE_DESCRIPTION("RTC driver for the WM831x series PMICs"); 475 MODULE_LICENSE("GPL"); 476 MODULE_ALIAS("platform:wm831x-rtc"); 477