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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * drivers/rtc/rtc-spear.c4 *5 * Copyright (C) 2010 ST Microelectronics6 * Rajeev Kumar<rajeev-dlh.kumar@st.com>7 */8 9#include <linux/bcd.h>10#include <linux/clk.h>11#include <linux/delay.h>12#include <linux/init.h>13#include <linux/io.h>14#include <linux/irq.h>15#include <linux/module.h>16#include <linux/of.h>17#include <linux/platform_device.h>18#include <linux/rtc.h>19#include <linux/slab.h>20#include <linux/spinlock.h>21 22/* RTC registers */23#define TIME_REG 0x0024#define DATE_REG 0x0425#define ALARM_TIME_REG 0x0826#define ALARM_DATE_REG 0x0C27#define CTRL_REG 0x1028#define STATUS_REG 0x1429 30/* TIME_REG & ALARM_TIME_REG */31#define SECONDS_UNITS (0xf<<0) /* seconds units position */32#define SECONDS_TENS (0x7<<4) /* seconds tens position */33#define MINUTES_UNITS (0xf<<8) /* minutes units position */34#define MINUTES_TENS (0x7<<12) /* minutes tens position */35#define HOURS_UNITS (0xf<<16) /* hours units position */36#define HOURS_TENS (0x3<<20) /* hours tens position */37 38/* DATE_REG & ALARM_DATE_REG */39#define DAYS_UNITS (0xf<<0) /* days units position */40#define DAYS_TENS (0x3<<4) /* days tens position */41#define MONTHS_UNITS (0xf<<8) /* months units position */42#define MONTHS_TENS (0x1<<12) /* months tens position */43#define YEARS_UNITS (0xf<<16) /* years units position */44#define YEARS_TENS (0xf<<20) /* years tens position */45#define YEARS_HUNDREDS (0xf<<24) /* years hundereds position */46#define YEARS_MILLENIUMS (0xf<<28) /* years millenium position */47 48/* MASK SHIFT TIME_REG & ALARM_TIME_REG*/49#define SECOND_SHIFT 0x00 /* seconds units */50#define MINUTE_SHIFT 0x08 /* minutes units position */51#define HOUR_SHIFT 0x10 /* hours units position */52#define MDAY_SHIFT 0x00 /* Month day shift */53#define MONTH_SHIFT 0x08 /* Month shift */54#define YEAR_SHIFT 0x10 /* Year shift */55 56#define SECOND_MASK 0x7F57#define MIN_MASK 0x7F58#define HOUR_MASK 0x3F59#define DAY_MASK 0x3F60#define MONTH_MASK 0x7F61#define YEAR_MASK 0xFFFF62 63/* date reg equal to time reg, for debug only */64#define TIME_BYP (1<<9)65#define INT_ENABLE (1<<31) /* interrupt enable */66 67/* STATUS_REG */68#define CLK_UNCONNECTED (1<<0)69#define PEND_WR_TIME (1<<2)70#define PEND_WR_DATE (1<<3)71#define LOST_WR_TIME (1<<4)72#define LOST_WR_DATE (1<<5)73#define RTC_INT_MASK (1<<31)74#define STATUS_BUSY (PEND_WR_TIME | PEND_WR_DATE)75#define STATUS_FAIL (LOST_WR_TIME | LOST_WR_DATE)76 77struct spear_rtc_config {78 struct rtc_device *rtc;79 struct clk *clk;80 spinlock_t lock;81 void __iomem *ioaddr;82 unsigned int irq_wake;83};84 85static inline void spear_rtc_clear_interrupt(struct spear_rtc_config *config)86{87 unsigned int val;88 unsigned long flags;89 90 spin_lock_irqsave(&config->lock, flags);91 val = readl(config->ioaddr + STATUS_REG);92 val |= RTC_INT_MASK;93 writel(val, config->ioaddr + STATUS_REG);94 spin_unlock_irqrestore(&config->lock, flags);95}96 97static inline void spear_rtc_enable_interrupt(struct spear_rtc_config *config)98{99 unsigned int val;100 101 val = readl(config->ioaddr + CTRL_REG);102 if (!(val & INT_ENABLE)) {103 spear_rtc_clear_interrupt(config);104 val |= INT_ENABLE;105 writel(val, config->ioaddr + CTRL_REG);106 }107}108 109static inline void spear_rtc_disable_interrupt(struct spear_rtc_config *config)110{111 unsigned int val;112 113 val = readl(config->ioaddr + CTRL_REG);114 if (val & INT_ENABLE) {115 val &= ~INT_ENABLE;116 writel(val, config->ioaddr + CTRL_REG);117 }118}119 120static inline int is_write_complete(struct spear_rtc_config *config)121{122 int ret = 0;123 unsigned long flags;124 125 spin_lock_irqsave(&config->lock, flags);126 if ((readl(config->ioaddr + STATUS_REG)) & STATUS_FAIL)127 ret = -EIO;128 spin_unlock_irqrestore(&config->lock, flags);129 130 return ret;131}132 133static void rtc_wait_not_busy(struct spear_rtc_config *config)134{135 int status, count = 0;136 unsigned long flags;137 138 /* Assuming BUSY may stay active for 80 msec) */139 for (count = 0; count < 80; count++) {140 spin_lock_irqsave(&config->lock, flags);141 status = readl(config->ioaddr + STATUS_REG);142 spin_unlock_irqrestore(&config->lock, flags);143 if ((status & STATUS_BUSY) == 0)144 break;145 /* check status busy, after each msec */146 msleep(1);147 }148}149 150static irqreturn_t spear_rtc_irq(int irq, void *dev_id)151{152 struct spear_rtc_config *config = dev_id;153 unsigned long events = 0;154 unsigned int irq_data;155 156 spin_lock(&config->lock);157 irq_data = readl(config->ioaddr + STATUS_REG);158 spin_unlock(&config->lock);159 160 if ((irq_data & RTC_INT_MASK)) {161 spear_rtc_clear_interrupt(config);162 events = RTC_IRQF | RTC_AF;163 rtc_update_irq(config->rtc, 1, events);164 return IRQ_HANDLED;165 } else166 return IRQ_NONE;167 168}169 170static void tm2bcd(struct rtc_time *tm)171{172 tm->tm_sec = bin2bcd(tm->tm_sec);173 tm->tm_min = bin2bcd(tm->tm_min);174 tm->tm_hour = bin2bcd(tm->tm_hour);175 tm->tm_mday = bin2bcd(tm->tm_mday);176 tm->tm_mon = bin2bcd(tm->tm_mon + 1);177 tm->tm_year = bin2bcd(tm->tm_year);178}179 180static void bcd2tm(struct rtc_time *tm)181{182 tm->tm_sec = bcd2bin(tm->tm_sec);183 tm->tm_min = bcd2bin(tm->tm_min);184 tm->tm_hour = bcd2bin(tm->tm_hour);185 tm->tm_mday = bcd2bin(tm->tm_mday);186 tm->tm_mon = bcd2bin(tm->tm_mon) - 1;187 /* epoch == 1900 */188 tm->tm_year = bcd2bin(tm->tm_year);189}190 191/*192 * spear_rtc_read_time - set the time193 * @dev: rtc device in use194 * @tm: holds date and time195 *196 * This function read time and date. On success it will return 0197 * otherwise -ve error is returned.198 */199static int spear_rtc_read_time(struct device *dev, struct rtc_time *tm)200{201 struct spear_rtc_config *config = dev_get_drvdata(dev);202 unsigned int time, date;203 204 /* we don't report wday/yday/isdst ... */205 rtc_wait_not_busy(config);206 207 do {208 time = readl(config->ioaddr + TIME_REG);209 date = readl(config->ioaddr + DATE_REG);210 } while (time == readl(config->ioaddr + TIME_REG));211 tm->tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;212 tm->tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;213 tm->tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;214 tm->tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;215 tm->tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;216 tm->tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;217 218 bcd2tm(tm);219 return 0;220}221 222/*223 * spear_rtc_set_time - set the time224 * @dev: rtc device in use225 * @tm: holds date and time226 *227 * This function set time and date. On success it will return 0228 * otherwise -ve error is returned.229 */230static int spear_rtc_set_time(struct device *dev, struct rtc_time *tm)231{232 struct spear_rtc_config *config = dev_get_drvdata(dev);233 unsigned int time, date;234 235 tm2bcd(tm);236 237 rtc_wait_not_busy(config);238 time = (tm->tm_sec << SECOND_SHIFT) | (tm->tm_min << MINUTE_SHIFT) |239 (tm->tm_hour << HOUR_SHIFT);240 date = (tm->tm_mday << MDAY_SHIFT) | (tm->tm_mon << MONTH_SHIFT) |241 (tm->tm_year << YEAR_SHIFT);242 writel(time, config->ioaddr + TIME_REG);243 writel(date, config->ioaddr + DATE_REG);244 245 return is_write_complete(config);246}247 248/*249 * spear_rtc_read_alarm - read the alarm time250 * @dev: rtc device in use251 * @alm: holds alarm date and time252 *253 * This function read alarm time and date. On success it will return 0254 * otherwise -ve error is returned.255 */256static int spear_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)257{258 struct spear_rtc_config *config = dev_get_drvdata(dev);259 unsigned int time, date;260 261 rtc_wait_not_busy(config);262 263 time = readl(config->ioaddr + ALARM_TIME_REG);264 date = readl(config->ioaddr + ALARM_DATE_REG);265 alm->time.tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;266 alm->time.tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;267 alm->time.tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;268 alm->time.tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;269 alm->time.tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;270 alm->time.tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;271 272 bcd2tm(&alm->time);273 alm->enabled = readl(config->ioaddr + CTRL_REG) & INT_ENABLE;274 275 return 0;276}277 278/*279 * spear_rtc_set_alarm - set the alarm time280 * @dev: rtc device in use281 * @alm: holds alarm date and time282 *283 * This function set alarm time and date. On success it will return 0284 * otherwise -ve error is returned.285 */286static int spear_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)287{288 struct spear_rtc_config *config = dev_get_drvdata(dev);289 unsigned int time, date;290 int err;291 292 tm2bcd(&alm->time);293 294 rtc_wait_not_busy(config);295 296 time = (alm->time.tm_sec << SECOND_SHIFT) | (alm->time.tm_min <<297 MINUTE_SHIFT) | (alm->time.tm_hour << HOUR_SHIFT);298 date = (alm->time.tm_mday << MDAY_SHIFT) | (alm->time.tm_mon <<299 MONTH_SHIFT) | (alm->time.tm_year << YEAR_SHIFT);300 301 writel(time, config->ioaddr + ALARM_TIME_REG);302 writel(date, config->ioaddr + ALARM_DATE_REG);303 err = is_write_complete(config);304 if (err < 0)305 return err;306 307 if (alm->enabled)308 spear_rtc_enable_interrupt(config);309 else310 spear_rtc_disable_interrupt(config);311 312 return 0;313}314 315static int spear_alarm_irq_enable(struct device *dev, unsigned int enabled)316{317 struct spear_rtc_config *config = dev_get_drvdata(dev);318 int ret = 0;319 320 spear_rtc_clear_interrupt(config);321 322 switch (enabled) {323 case 0:324 /* alarm off */325 spear_rtc_disable_interrupt(config);326 break;327 case 1:328 /* alarm on */329 spear_rtc_enable_interrupt(config);330 break;331 default:332 ret = -EINVAL;333 break;334 }335 336 return ret;337}338 339static const struct rtc_class_ops spear_rtc_ops = {340 .read_time = spear_rtc_read_time,341 .set_time = spear_rtc_set_time,342 .read_alarm = spear_rtc_read_alarm,343 .set_alarm = spear_rtc_set_alarm,344 .alarm_irq_enable = spear_alarm_irq_enable,345};346 347static int spear_rtc_probe(struct platform_device *pdev)348{349 struct spear_rtc_config *config;350 int status = 0;351 int irq;352 353 config = devm_kzalloc(&pdev->dev, sizeof(*config), GFP_KERNEL);354 if (!config)355 return -ENOMEM;356 357 config->rtc = devm_rtc_allocate_device(&pdev->dev);358 if (IS_ERR(config->rtc))359 return PTR_ERR(config->rtc);360 361 /* alarm irqs */362 irq = platform_get_irq(pdev, 0);363 if (irq < 0)364 return irq;365 366 status = devm_request_irq(&pdev->dev, irq, spear_rtc_irq, 0, pdev->name,367 config);368 if (status) {369 dev_err(&pdev->dev, "Alarm interrupt IRQ%d already claimed\n",370 irq);371 return status;372 }373 374 config->ioaddr = devm_platform_ioremap_resource(pdev, 0);375 if (IS_ERR(config->ioaddr))376 return PTR_ERR(config->ioaddr);377 378 config->clk = devm_clk_get(&pdev->dev, NULL);379 if (IS_ERR(config->clk))380 return PTR_ERR(config->clk);381 382 status = clk_prepare_enable(config->clk);383 if (status < 0)384 return status;385 386 spin_lock_init(&config->lock);387 platform_set_drvdata(pdev, config);388 389 config->rtc->ops = &spear_rtc_ops;390 config->rtc->range_min = RTC_TIMESTAMP_BEGIN_0000;391 config->rtc->range_max = RTC_TIMESTAMP_END_9999;392 393 status = devm_rtc_register_device(config->rtc);394 if (status)395 goto err_disable_clock;396 397 if (!device_can_wakeup(&pdev->dev))398 device_init_wakeup(&pdev->dev, 1);399 400 return 0;401 402err_disable_clock:403 clk_disable_unprepare(config->clk);404 405 return status;406}407 408static void spear_rtc_remove(struct platform_device *pdev)409{410 struct spear_rtc_config *config = platform_get_drvdata(pdev);411 412 spear_rtc_disable_interrupt(config);413 clk_disable_unprepare(config->clk);414 device_init_wakeup(&pdev->dev, 0);415}416 417#ifdef CONFIG_PM_SLEEP418static int spear_rtc_suspend(struct device *dev)419{420 struct platform_device *pdev = to_platform_device(dev);421 struct spear_rtc_config *config = platform_get_drvdata(pdev);422 int irq;423 424 irq = platform_get_irq(pdev, 0);425 if (device_may_wakeup(&pdev->dev)) {426 if (!enable_irq_wake(irq))427 config->irq_wake = 1;428 } else {429 spear_rtc_disable_interrupt(config);430 clk_disable(config->clk);431 }432 433 return 0;434}435 436static int spear_rtc_resume(struct device *dev)437{438 struct platform_device *pdev = to_platform_device(dev);439 struct spear_rtc_config *config = platform_get_drvdata(pdev);440 int irq;441 442 irq = platform_get_irq(pdev, 0);443 444 if (device_may_wakeup(&pdev->dev)) {445 if (config->irq_wake) {446 disable_irq_wake(irq);447 config->irq_wake = 0;448 }449 } else {450 clk_enable(config->clk);451 spear_rtc_enable_interrupt(config);452 }453 454 return 0;455}456#endif457 458static SIMPLE_DEV_PM_OPS(spear_rtc_pm_ops, spear_rtc_suspend, spear_rtc_resume);459 460static void spear_rtc_shutdown(struct platform_device *pdev)461{462 struct spear_rtc_config *config = platform_get_drvdata(pdev);463 464 spear_rtc_disable_interrupt(config);465 clk_disable(config->clk);466}467 468#ifdef CONFIG_OF469static const struct of_device_id spear_rtc_id_table[] = {470 { .compatible = "st,spear600-rtc" },471 {}472};473MODULE_DEVICE_TABLE(of, spear_rtc_id_table);474#endif475 476static struct platform_driver spear_rtc_driver = {477 .probe = spear_rtc_probe,478 .remove_new = spear_rtc_remove,479 .shutdown = spear_rtc_shutdown,480 .driver = {481 .name = "rtc-spear",482 .pm = &spear_rtc_pm_ops,483 .of_match_table = of_match_ptr(spear_rtc_id_table),484 },485};486 487module_platform_driver(spear_rtc_driver);488 489MODULE_ALIAS("platform:rtc-spear");490MODULE_AUTHOR("Rajeev Kumar <rajeev-dlh.kumar@st.com>");491MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");492MODULE_LICENSE("GPL");493