1 /* 2 * RTC driver for Rockchip RK808 3 * 4 * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd 5 * 6 * Author: Chris Zhong <zyw@rock-chips.com> 7 * Author: Zhang Qing <zhangqing@rock-chips.com> 8 * 9 * This program is free software; you can redistribute it and/or modify it 10 * under the terms and conditions of the GNU General Public License, 11 * version 2, as published by the Free Software Foundation. 12 * 13 * This program is distributed in the hope it will be useful, but WITHOUT 14 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 15 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 16 * more details. 17 */ 18 19 #include <linux/module.h> 20 #include <linux/kernel.h> 21 #include <linux/rtc.h> 22 #include <linux/bcd.h> 23 #include <linux/mfd/rk808.h> 24 #include <linux/platform_device.h> 25 #include <linux/i2c.h> 26 27 /* RTC_CTRL_REG bitfields */ 28 #define BIT_RTC_CTRL_REG_STOP_RTC_M BIT(0) 29 30 /* RK808 has a shadowed register for saving a "frozen" RTC time. 31 * When user setting "GET_TIME" to 1, the time will save in this shadowed 32 * register. If set "READSEL" to 1, user read rtc time register, actually 33 * get the time of that moment. If we need the real time, clr this bit. 34 */ 35 #define BIT_RTC_CTRL_REG_RTC_GET_TIME BIT(6) 36 #define BIT_RTC_CTRL_REG_RTC_READSEL_M BIT(7) 37 #define BIT_RTC_INTERRUPTS_REG_IT_ALARM_M BIT(3) 38 #define RTC_STATUS_MASK 0xFE 39 40 #define SECONDS_REG_MSK 0x7F 41 #define MINUTES_REG_MAK 0x7F 42 #define HOURS_REG_MSK 0x3F 43 #define DAYS_REG_MSK 0x3F 44 #define MONTHS_REG_MSK 0x1F 45 #define YEARS_REG_MSK 0xFF 46 #define WEEKS_REG_MSK 0x7 47 48 /* REG_SECONDS_REG through REG_YEARS_REG is how many registers? */ 49 50 #define NUM_TIME_REGS (RK808_WEEKS_REG - RK808_SECONDS_REG + 1) 51 #define NUM_ALARM_REGS (RK808_ALARM_YEARS_REG - RK808_ALARM_SECONDS_REG + 1) 52 53 struct rk808_rtc { 54 struct rk808 *rk808; 55 struct rtc_device *rtc; 56 int irq; 57 }; 58 59 /* 60 * The Rockchip calendar used by the RK808 counts November with 31 days. We use 61 * these translation functions to convert its dates to/from the Gregorian 62 * calendar used by the rest of the world. We arbitrarily define Jan 1st, 2016 63 * as the day when both calendars were in sync, and treat all other dates 64 * relative to that. 65 * NOTE: Other system software (e.g. firmware) that reads the same hardware must 66 * implement this exact same conversion algorithm, with the same anchor date. 67 */ 68 static time64_t nov2dec_transitions(struct rtc_time *tm) 69 { 70 return (tm->tm_year + 1900) - 2016 + (tm->tm_mon + 1 > 11 ? 1 : 0); 71 } 72 73 static void rockchip_to_gregorian(struct rtc_time *tm) 74 { 75 /* If it's Nov 31st, rtc_tm_to_time64() will count that like Dec 1st */ 76 time64_t time = rtc_tm_to_time64(tm); 77 rtc_time64_to_tm(time + nov2dec_transitions(tm) * 86400, tm); 78 } 79 80 static void gregorian_to_rockchip(struct rtc_time *tm) 81 { 82 time64_t extra_days = nov2dec_transitions(tm); 83 time64_t time = rtc_tm_to_time64(tm); 84 rtc_time64_to_tm(time - extra_days * 86400, tm); 85 86 /* Compensate if we went back over Nov 31st (will work up to 2381) */ 87 if (nov2dec_transitions(tm) < extra_days) { 88 if (tm->tm_mon + 1 == 11) 89 tm->tm_mday++; /* This may result in 31! */ 90 else 91 rtc_time64_to_tm(time - (extra_days - 1) * 86400, tm); 92 } 93 } 94 95 /* Read current time and date in RTC */ 96 static int rk808_rtc_readtime(struct device *dev, struct rtc_time *tm) 97 { 98 struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev); 99 struct rk808 *rk808 = rk808_rtc->rk808; 100 u8 rtc_data[NUM_TIME_REGS]; 101 int ret; 102 103 /* Force an update of the shadowed registers right now */ 104 ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG, 105 BIT_RTC_CTRL_REG_RTC_GET_TIME, 106 BIT_RTC_CTRL_REG_RTC_GET_TIME); 107 if (ret) { 108 dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret); 109 return ret; 110 } 111 112 /* 113 * After we set the GET_TIME bit, the rtc time can't be read 114 * immediately. So we should wait up to 31.25 us, about one cycle of 115 * 32khz. If we clear the GET_TIME bit here, the time of i2c transfer 116 * certainly more than 31.25us: 16 * 2.5us at 400kHz bus frequency. 117 */ 118 ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG, 119 BIT_RTC_CTRL_REG_RTC_GET_TIME, 120 0); 121 if (ret) { 122 dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret); 123 return ret; 124 } 125 126 ret = regmap_bulk_read(rk808->regmap, RK808_SECONDS_REG, 127 rtc_data, NUM_TIME_REGS); 128 if (ret) { 129 dev_err(dev, "Failed to bulk read rtc_data: %d\n", ret); 130 return ret; 131 } 132 133 tm->tm_sec = bcd2bin(rtc_data[0] & SECONDS_REG_MSK); 134 tm->tm_min = bcd2bin(rtc_data[1] & MINUTES_REG_MAK); 135 tm->tm_hour = bcd2bin(rtc_data[2] & HOURS_REG_MSK); 136 tm->tm_mday = bcd2bin(rtc_data[3] & DAYS_REG_MSK); 137 tm->tm_mon = (bcd2bin(rtc_data[4] & MONTHS_REG_MSK)) - 1; 138 tm->tm_year = (bcd2bin(rtc_data[5] & YEARS_REG_MSK)) + 100; 139 tm->tm_wday = bcd2bin(rtc_data[6] & WEEKS_REG_MSK); 140 rockchip_to_gregorian(tm); 141 dev_dbg(dev, "RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n", 142 1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday, 143 tm->tm_wday, tm->tm_hour, tm->tm_min, tm->tm_sec); 144 145 return ret; 146 } 147 148 /* Set current time and date in RTC */ 149 static int rk808_rtc_set_time(struct device *dev, struct rtc_time *tm) 150 { 151 struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev); 152 struct rk808 *rk808 = rk808_rtc->rk808; 153 u8 rtc_data[NUM_TIME_REGS]; 154 int ret; 155 156 dev_dbg(dev, "set RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n", 157 1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday, 158 tm->tm_wday, tm->tm_hour, tm->tm_min, tm->tm_sec); 159 gregorian_to_rockchip(tm); 160 rtc_data[0] = bin2bcd(tm->tm_sec); 161 rtc_data[1] = bin2bcd(tm->tm_min); 162 rtc_data[2] = bin2bcd(tm->tm_hour); 163 rtc_data[3] = bin2bcd(tm->tm_mday); 164 rtc_data[4] = bin2bcd(tm->tm_mon + 1); 165 rtc_data[5] = bin2bcd(tm->tm_year - 100); 166 rtc_data[6] = bin2bcd(tm->tm_wday); 167 168 /* Stop RTC while updating the RTC registers */ 169 ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG, 170 BIT_RTC_CTRL_REG_STOP_RTC_M, 171 BIT_RTC_CTRL_REG_STOP_RTC_M); 172 if (ret) { 173 dev_err(dev, "Failed to update RTC control: %d\n", ret); 174 return ret; 175 } 176 177 ret = regmap_bulk_write(rk808->regmap, RK808_SECONDS_REG, 178 rtc_data, NUM_TIME_REGS); 179 if (ret) { 180 dev_err(dev, "Failed to bull write rtc_data: %d\n", ret); 181 return ret; 182 } 183 /* Start RTC again */ 184 ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG, 185 BIT_RTC_CTRL_REG_STOP_RTC_M, 0); 186 if (ret) { 187 dev_err(dev, "Failed to update RTC control: %d\n", ret); 188 return ret; 189 } 190 return 0; 191 } 192 193 /* Read alarm time and date in RTC */ 194 static int rk808_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm) 195 { 196 struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev); 197 struct rk808 *rk808 = rk808_rtc->rk808; 198 u8 alrm_data[NUM_ALARM_REGS]; 199 uint32_t int_reg; 200 int ret; 201 202 ret = regmap_bulk_read(rk808->regmap, RK808_ALARM_SECONDS_REG, 203 alrm_data, NUM_ALARM_REGS); 204 205 alrm->time.tm_sec = bcd2bin(alrm_data[0] & SECONDS_REG_MSK); 206 alrm->time.tm_min = bcd2bin(alrm_data[1] & MINUTES_REG_MAK); 207 alrm->time.tm_hour = bcd2bin(alrm_data[2] & HOURS_REG_MSK); 208 alrm->time.tm_mday = bcd2bin(alrm_data[3] & DAYS_REG_MSK); 209 alrm->time.tm_mon = (bcd2bin(alrm_data[4] & MONTHS_REG_MSK)) - 1; 210 alrm->time.tm_year = (bcd2bin(alrm_data[5] & YEARS_REG_MSK)) + 100; 211 rockchip_to_gregorian(&alrm->time); 212 213 ret = regmap_read(rk808->regmap, RK808_RTC_INT_REG, &int_reg); 214 if (ret) { 215 dev_err(dev, "Failed to read RTC INT REG: %d\n", ret); 216 return ret; 217 } 218 219 dev_dbg(dev, "alrm read RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n", 220 1900 + alrm->time.tm_year, alrm->time.tm_mon + 1, 221 alrm->time.tm_mday, alrm->time.tm_wday, alrm->time.tm_hour, 222 alrm->time.tm_min, alrm->time.tm_sec); 223 224 alrm->enabled = (int_reg & BIT_RTC_INTERRUPTS_REG_IT_ALARM_M) ? 1 : 0; 225 226 return 0; 227 } 228 229 static int rk808_rtc_stop_alarm(struct rk808_rtc *rk808_rtc) 230 { 231 struct rk808 *rk808 = rk808_rtc->rk808; 232 int ret; 233 234 ret = regmap_update_bits(rk808->regmap, RK808_RTC_INT_REG, 235 BIT_RTC_INTERRUPTS_REG_IT_ALARM_M, 0); 236 237 return ret; 238 } 239 240 static int rk808_rtc_start_alarm(struct rk808_rtc *rk808_rtc) 241 { 242 struct rk808 *rk808 = rk808_rtc->rk808; 243 int ret; 244 245 ret = regmap_update_bits(rk808->regmap, RK808_RTC_INT_REG, 246 BIT_RTC_INTERRUPTS_REG_IT_ALARM_M, 247 BIT_RTC_INTERRUPTS_REG_IT_ALARM_M); 248 249 return ret; 250 } 251 252 static int rk808_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) 253 { 254 struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev); 255 struct rk808 *rk808 = rk808_rtc->rk808; 256 u8 alrm_data[NUM_ALARM_REGS]; 257 int ret; 258 259 ret = rk808_rtc_stop_alarm(rk808_rtc); 260 if (ret) { 261 dev_err(dev, "Failed to stop alarm: %d\n", ret); 262 return ret; 263 } 264 dev_dbg(dev, "alrm set RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n", 265 1900 + alrm->time.tm_year, alrm->time.tm_mon + 1, 266 alrm->time.tm_mday, alrm->time.tm_wday, alrm->time.tm_hour, 267 alrm->time.tm_min, alrm->time.tm_sec); 268 269 gregorian_to_rockchip(&alrm->time); 270 alrm_data[0] = bin2bcd(alrm->time.tm_sec); 271 alrm_data[1] = bin2bcd(alrm->time.tm_min); 272 alrm_data[2] = bin2bcd(alrm->time.tm_hour); 273 alrm_data[3] = bin2bcd(alrm->time.tm_mday); 274 alrm_data[4] = bin2bcd(alrm->time.tm_mon + 1); 275 alrm_data[5] = bin2bcd(alrm->time.tm_year - 100); 276 277 ret = regmap_bulk_write(rk808->regmap, RK808_ALARM_SECONDS_REG, 278 alrm_data, NUM_ALARM_REGS); 279 if (ret) { 280 dev_err(dev, "Failed to bulk write: %d\n", ret); 281 return ret; 282 } 283 if (alrm->enabled) { 284 ret = rk808_rtc_start_alarm(rk808_rtc); 285 if (ret) { 286 dev_err(dev, "Failed to start alarm: %d\n", ret); 287 return ret; 288 } 289 } 290 return 0; 291 } 292 293 static int rk808_rtc_alarm_irq_enable(struct device *dev, 294 unsigned int enabled) 295 { 296 struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev); 297 298 if (enabled) 299 return rk808_rtc_start_alarm(rk808_rtc); 300 301 return rk808_rtc_stop_alarm(rk808_rtc); 302 } 303 304 /* 305 * We will just handle setting the frequency and make use the framework for 306 * reading the periodic interupts. 307 * 308 * @freq: Current periodic IRQ freq: 309 * bit 0: every second 310 * bit 1: every minute 311 * bit 2: every hour 312 * bit 3: every day 313 */ 314 static irqreturn_t rk808_alarm_irq(int irq, void *data) 315 { 316 struct rk808_rtc *rk808_rtc = data; 317 struct rk808 *rk808 = rk808_rtc->rk808; 318 struct i2c_client *client = rk808->i2c; 319 int ret; 320 321 ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG, 322 RTC_STATUS_MASK); 323 if (ret) { 324 dev_err(&client->dev, 325 "%s:Failed to update RTC status: %d\n", __func__, ret); 326 return ret; 327 } 328 329 rtc_update_irq(rk808_rtc->rtc, 1, RTC_IRQF | RTC_AF); 330 dev_dbg(&client->dev, 331 "%s:irq=%d\n", __func__, irq); 332 return IRQ_HANDLED; 333 } 334 335 static const struct rtc_class_ops rk808_rtc_ops = { 336 .read_time = rk808_rtc_readtime, 337 .set_time = rk808_rtc_set_time, 338 .read_alarm = rk808_rtc_readalarm, 339 .set_alarm = rk808_rtc_setalarm, 340 .alarm_irq_enable = rk808_rtc_alarm_irq_enable, 341 }; 342 343 #ifdef CONFIG_PM_SLEEP 344 /* Turn off the alarm if it should not be a wake source. */ 345 static int rk808_rtc_suspend(struct device *dev) 346 { 347 struct platform_device *pdev = to_platform_device(dev); 348 struct rk808_rtc *rk808_rtc = dev_get_drvdata(&pdev->dev); 349 350 if (device_may_wakeup(dev)) 351 enable_irq_wake(rk808_rtc->irq); 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 rk808_rtc_resume(struct device *dev) 360 { 361 struct platform_device *pdev = to_platform_device(dev); 362 struct rk808_rtc *rk808_rtc = dev_get_drvdata(&pdev->dev); 363 364 if (device_may_wakeup(dev)) 365 disable_irq_wake(rk808_rtc->irq); 366 367 return 0; 368 } 369 #endif 370 371 static SIMPLE_DEV_PM_OPS(rk808_rtc_pm_ops, 372 rk808_rtc_suspend, rk808_rtc_resume); 373 374 static int rk808_rtc_probe(struct platform_device *pdev) 375 { 376 struct rk808 *rk808 = dev_get_drvdata(pdev->dev.parent); 377 struct rk808_rtc *rk808_rtc; 378 int ret; 379 380 rk808_rtc = devm_kzalloc(&pdev->dev, sizeof(*rk808_rtc), GFP_KERNEL); 381 if (rk808_rtc == NULL) 382 return -ENOMEM; 383 384 platform_set_drvdata(pdev, rk808_rtc); 385 rk808_rtc->rk808 = rk808; 386 387 /* start rtc running by default, and use shadowed timer. */ 388 ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG, 389 BIT_RTC_CTRL_REG_STOP_RTC_M | 390 BIT_RTC_CTRL_REG_RTC_READSEL_M, 391 BIT_RTC_CTRL_REG_RTC_READSEL_M); 392 if (ret) { 393 dev_err(&pdev->dev, 394 "Failed to update RTC control: %d\n", ret); 395 return ret; 396 } 397 398 ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG, 399 RTC_STATUS_MASK); 400 if (ret) { 401 dev_err(&pdev->dev, 402 "Failed to write RTC status: %d\n", ret); 403 return ret; 404 } 405 406 device_init_wakeup(&pdev->dev, 1); 407 408 rk808_rtc->rtc = devm_rtc_allocate_device(&pdev->dev); 409 if (IS_ERR(rk808_rtc->rtc)) 410 return PTR_ERR(rk808_rtc->rtc); 411 412 rk808_rtc->rtc->ops = &rk808_rtc_ops; 413 414 rk808_rtc->irq = platform_get_irq(pdev, 0); 415 if (rk808_rtc->irq < 0) { 416 if (rk808_rtc->irq != -EPROBE_DEFER) 417 dev_err(&pdev->dev, "Wake up is not possible as irq = %d\n", 418 rk808_rtc->irq); 419 return rk808_rtc->irq; 420 } 421 422 /* request alarm irq of rk808 */ 423 ret = devm_request_threaded_irq(&pdev->dev, rk808_rtc->irq, NULL, 424 rk808_alarm_irq, 0, 425 "RTC alarm", rk808_rtc); 426 if (ret) { 427 dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n", 428 rk808_rtc->irq, ret); 429 return ret; 430 } 431 432 return rtc_register_device(rk808_rtc->rtc); 433 } 434 435 static struct platform_driver rk808_rtc_driver = { 436 .probe = rk808_rtc_probe, 437 .driver = { 438 .name = "rk808-rtc", 439 .pm = &rk808_rtc_pm_ops, 440 }, 441 }; 442 443 module_platform_driver(rk808_rtc_driver); 444 445 MODULE_DESCRIPTION("RTC driver for the rk808 series PMICs"); 446 MODULE_AUTHOR("Chris Zhong <zyw@rock-chips.com>"); 447 MODULE_AUTHOR("Zhang Qing <zhangqing@rock-chips.com>"); 448 MODULE_LICENSE("GPL"); 449 MODULE_ALIAS("platform:rk808-rtc"); 450