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1// SPDX-License-Identifier: GPL-2.02 3/*4 * Copyright 2019 Cadence5 *6 * Authors:7 * Jan Kotas <jank@cadence.com>8 */9 10#include <linux/module.h>11#include <linux/platform_device.h>12#include <linux/of.h>13#include <linux/io.h>14#include <linux/rtc.h>15#include <linux/clk.h>16#include <linux/bcd.h>17#include <linux/bitfield.h>18#include <linux/interrupt.h>19#include <linux/pm_wakeirq.h>20 21/* Registers */22#define CDNS_RTC_CTLR 0x0023#define CDNS_RTC_HMR 0x0424#define CDNS_RTC_TIMR 0x0825#define CDNS_RTC_CALR 0x0C26#define CDNS_RTC_TIMAR 0x1027#define CDNS_RTC_CALAR 0x1428#define CDNS_RTC_AENR 0x1829#define CDNS_RTC_EFLR 0x1C30#define CDNS_RTC_IENR 0x2031#define CDNS_RTC_IDISR 0x2432#define CDNS_RTC_IMSKR 0x2833#define CDNS_RTC_STSR 0x2C34#define CDNS_RTC_KRTCR 0x3035 36/* Control */37#define CDNS_RTC_CTLR_TIME BIT(0)38#define CDNS_RTC_CTLR_CAL BIT(1)39#define CDNS_RTC_CTLR_TIME_CAL (CDNS_RTC_CTLR_TIME | CDNS_RTC_CTLR_CAL)40 41/* Status */42#define CDNS_RTC_STSR_VT BIT(0)43#define CDNS_RTC_STSR_VC BIT(1)44#define CDNS_RTC_STSR_VTA BIT(2)45#define CDNS_RTC_STSR_VCA BIT(3)46#define CDNS_RTC_STSR_VT_VC (CDNS_RTC_STSR_VT | CDNS_RTC_STSR_VC)47#define CDNS_RTC_STSR_VTA_VCA (CDNS_RTC_STSR_VTA | CDNS_RTC_STSR_VCA)48 49/* Keep RTC */50#define CDNS_RTC_KRTCR_KRTC BIT(0)51 52/* Alarm, Event, Interrupt */53#define CDNS_RTC_AEI_HOS BIT(0)54#define CDNS_RTC_AEI_SEC BIT(1)55#define CDNS_RTC_AEI_MIN BIT(2)56#define CDNS_RTC_AEI_HOUR BIT(3)57#define CDNS_RTC_AEI_DATE BIT(4)58#define CDNS_RTC_AEI_MNTH BIT(5)59#define CDNS_RTC_AEI_ALRM BIT(6)60 61/* Time */62#define CDNS_RTC_TIME_H GENMASK(7, 0)63#define CDNS_RTC_TIME_S GENMASK(14, 8)64#define CDNS_RTC_TIME_M GENMASK(22, 16)65#define CDNS_RTC_TIME_HR GENMASK(29, 24)66#define CDNS_RTC_TIME_PM BIT(30)67#define CDNS_RTC_TIME_CH BIT(31)68 69/* Calendar */70#define CDNS_RTC_CAL_DAY GENMASK(2, 0)71#define CDNS_RTC_CAL_M GENMASK(7, 3)72#define CDNS_RTC_CAL_D GENMASK(13, 8)73#define CDNS_RTC_CAL_Y GENMASK(23, 16)74#define CDNS_RTC_CAL_C GENMASK(29, 24)75#define CDNS_RTC_CAL_CH BIT(31)76 77#define CDNS_RTC_MAX_REGS_TRIES 378 79struct cdns_rtc {80 struct rtc_device *rtc_dev;81 struct clk *pclk;82 struct clk *ref_clk;83 void __iomem *regs;84 int irq;85};86 87static void cdns_rtc_set_enabled(struct cdns_rtc *crtc, bool enabled)88{89 u32 reg = enabled ? 0x0 : CDNS_RTC_CTLR_TIME_CAL;90 91 writel(reg, crtc->regs + CDNS_RTC_CTLR);92}93 94static bool cdns_rtc_get_enabled(struct cdns_rtc *crtc)95{96 return !(readl(crtc->regs + CDNS_RTC_CTLR) & CDNS_RTC_CTLR_TIME_CAL);97}98 99static irqreturn_t cdns_rtc_irq_handler(int irq, void *id)100{101 struct device *dev = id;102 struct cdns_rtc *crtc = dev_get_drvdata(dev);103 104 /* Reading the register clears it */105 if (!(readl(crtc->regs + CDNS_RTC_EFLR) & CDNS_RTC_AEI_ALRM))106 return IRQ_NONE;107 108 rtc_update_irq(crtc->rtc_dev, 1, RTC_IRQF | RTC_AF);109 return IRQ_HANDLED;110}111 112static u32 cdns_rtc_time2reg(struct rtc_time *tm)113{114 return FIELD_PREP(CDNS_RTC_TIME_S, bin2bcd(tm->tm_sec))115 | FIELD_PREP(CDNS_RTC_TIME_M, bin2bcd(tm->tm_min))116 | FIELD_PREP(CDNS_RTC_TIME_HR, bin2bcd(tm->tm_hour));117}118 119static void cdns_rtc_reg2time(u32 reg, struct rtc_time *tm)120{121 tm->tm_sec = bcd2bin(FIELD_GET(CDNS_RTC_TIME_S, reg));122 tm->tm_min = bcd2bin(FIELD_GET(CDNS_RTC_TIME_M, reg));123 tm->tm_hour = bcd2bin(FIELD_GET(CDNS_RTC_TIME_HR, reg));124}125 126static int cdns_rtc_read_time(struct device *dev, struct rtc_time *tm)127{128 struct cdns_rtc *crtc = dev_get_drvdata(dev);129 u32 reg;130 131 /* If the RTC is disabled, assume the values are invalid */132 if (!cdns_rtc_get_enabled(crtc))133 return -EINVAL;134 135 cdns_rtc_set_enabled(crtc, false);136 137 reg = readl(crtc->regs + CDNS_RTC_TIMR);138 cdns_rtc_reg2time(reg, tm);139 140 reg = readl(crtc->regs + CDNS_RTC_CALR);141 tm->tm_mday = bcd2bin(FIELD_GET(CDNS_RTC_CAL_D, reg));142 tm->tm_mon = bcd2bin(FIELD_GET(CDNS_RTC_CAL_M, reg)) - 1;143 tm->tm_year = bcd2bin(FIELD_GET(CDNS_RTC_CAL_Y, reg))144 + bcd2bin(FIELD_GET(CDNS_RTC_CAL_C, reg)) * 100 - 1900;145 tm->tm_wday = bcd2bin(FIELD_GET(CDNS_RTC_CAL_DAY, reg)) - 1;146 147 cdns_rtc_set_enabled(crtc, true);148 return 0;149}150 151static int cdns_rtc_set_time(struct device *dev, struct rtc_time *tm)152{153 struct cdns_rtc *crtc = dev_get_drvdata(dev);154 u32 timr, calr, stsr;155 int ret = -EIO;156 int year = tm->tm_year + 1900;157 int tries;158 159 cdns_rtc_set_enabled(crtc, false);160 161 timr = cdns_rtc_time2reg(tm);162 163 calr = FIELD_PREP(CDNS_RTC_CAL_D, bin2bcd(tm->tm_mday))164 | FIELD_PREP(CDNS_RTC_CAL_M, bin2bcd(tm->tm_mon + 1))165 | FIELD_PREP(CDNS_RTC_CAL_Y, bin2bcd(year % 100))166 | FIELD_PREP(CDNS_RTC_CAL_C, bin2bcd(year / 100))167 | FIELD_PREP(CDNS_RTC_CAL_DAY, tm->tm_wday + 1);168 169 /* Update registers, check valid flags */170 for (tries = 0; tries < CDNS_RTC_MAX_REGS_TRIES; tries++) {171 writel(timr, crtc->regs + CDNS_RTC_TIMR);172 writel(calr, crtc->regs + CDNS_RTC_CALR);173 stsr = readl(crtc->regs + CDNS_RTC_STSR);174 175 if ((stsr & CDNS_RTC_STSR_VT_VC) == CDNS_RTC_STSR_VT_VC) {176 ret = 0;177 break;178 }179 }180 181 cdns_rtc_set_enabled(crtc, true);182 return ret;183}184 185static int cdns_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)186{187 struct cdns_rtc *crtc = dev_get_drvdata(dev);188 189 if (enabled) {190 writel((CDNS_RTC_AEI_SEC | CDNS_RTC_AEI_MIN | CDNS_RTC_AEI_HOUR191 | CDNS_RTC_AEI_DATE | CDNS_RTC_AEI_MNTH),192 crtc->regs + CDNS_RTC_AENR);193 writel(CDNS_RTC_AEI_ALRM, crtc->regs + CDNS_RTC_IENR);194 } else {195 writel(0, crtc->regs + CDNS_RTC_AENR);196 writel(CDNS_RTC_AEI_ALRM, crtc->regs + CDNS_RTC_IDISR);197 }198 199 return 0;200}201 202static int cdns_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)203{204 struct cdns_rtc *crtc = dev_get_drvdata(dev);205 u32 reg;206 207 reg = readl(crtc->regs + CDNS_RTC_TIMAR);208 cdns_rtc_reg2time(reg, &alarm->time);209 210 reg = readl(crtc->regs + CDNS_RTC_CALAR);211 alarm->time.tm_mday = bcd2bin(FIELD_GET(CDNS_RTC_CAL_D, reg));212 alarm->time.tm_mon = bcd2bin(FIELD_GET(CDNS_RTC_CAL_M, reg)) - 1;213 214 return 0;215}216 217static int cdns_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)218{219 struct cdns_rtc *crtc = dev_get_drvdata(dev);220 int ret = -EIO;221 int tries;222 u32 timar, calar, stsr;223 224 cdns_rtc_alarm_irq_enable(dev, 0);225 226 timar = cdns_rtc_time2reg(&alarm->time);227 calar = FIELD_PREP(CDNS_RTC_CAL_D, bin2bcd(alarm->time.tm_mday))228 | FIELD_PREP(CDNS_RTC_CAL_M, bin2bcd(alarm->time.tm_mon + 1));229 230 /* Update registers, check valid alarm flags */231 for (tries = 0; tries < CDNS_RTC_MAX_REGS_TRIES; tries++) {232 writel(timar, crtc->regs + CDNS_RTC_TIMAR);233 writel(calar, crtc->regs + CDNS_RTC_CALAR);234 stsr = readl(crtc->regs + CDNS_RTC_STSR);235 236 if ((stsr & CDNS_RTC_STSR_VTA_VCA) == CDNS_RTC_STSR_VTA_VCA) {237 ret = 0;238 break;239 }240 }241 242 if (!ret)243 cdns_rtc_alarm_irq_enable(dev, alarm->enabled);244 return ret;245}246 247static const struct rtc_class_ops cdns_rtc_ops = {248 .read_time = cdns_rtc_read_time,249 .set_time = cdns_rtc_set_time,250 .read_alarm = cdns_rtc_read_alarm,251 .set_alarm = cdns_rtc_set_alarm,252 .alarm_irq_enable = cdns_rtc_alarm_irq_enable,253};254 255static int cdns_rtc_probe(struct platform_device *pdev)256{257 struct cdns_rtc *crtc;258 int ret;259 unsigned long ref_clk_freq;260 261 crtc = devm_kzalloc(&pdev->dev, sizeof(*crtc), GFP_KERNEL);262 if (!crtc)263 return -ENOMEM;264 265 crtc->regs = devm_platform_ioremap_resource(pdev, 0);266 if (IS_ERR(crtc->regs))267 return PTR_ERR(crtc->regs);268 269 crtc->irq = platform_get_irq(pdev, 0);270 if (crtc->irq < 0)271 return -EINVAL;272 273 crtc->pclk = devm_clk_get(&pdev->dev, "pclk");274 if (IS_ERR(crtc->pclk)) {275 ret = PTR_ERR(crtc->pclk);276 dev_err(&pdev->dev,277 "Failed to retrieve the peripheral clock, %d\n", ret);278 return ret;279 }280 281 crtc->ref_clk = devm_clk_get(&pdev->dev, "ref_clk");282 if (IS_ERR(crtc->ref_clk)) {283 ret = PTR_ERR(crtc->ref_clk);284 dev_err(&pdev->dev,285 "Failed to retrieve the reference clock, %d\n", ret);286 return ret;287 }288 289 crtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);290 if (IS_ERR(crtc->rtc_dev))291 return PTR_ERR(crtc->rtc_dev);292 293 platform_set_drvdata(pdev, crtc);294 295 ret = clk_prepare_enable(crtc->pclk);296 if (ret) {297 dev_err(&pdev->dev,298 "Failed to enable the peripheral clock, %d\n", ret);299 return ret;300 }301 302 ret = clk_prepare_enable(crtc->ref_clk);303 if (ret) {304 dev_err(&pdev->dev,305 "Failed to enable the reference clock, %d\n", ret);306 goto err_disable_pclk;307 }308 309 ref_clk_freq = clk_get_rate(crtc->ref_clk);310 if ((ref_clk_freq != 1) && (ref_clk_freq != 100)) {311 dev_err(&pdev->dev,312 "Invalid reference clock frequency %lu Hz.\n",313 ref_clk_freq);314 ret = -EINVAL;315 goto err_disable_ref_clk;316 }317 318 ret = devm_request_irq(&pdev->dev, crtc->irq,319 cdns_rtc_irq_handler, 0,320 dev_name(&pdev->dev), &pdev->dev);321 if (ret) {322 dev_err(&pdev->dev,323 "Failed to request interrupt for the device, %d\n",324 ret);325 goto err_disable_ref_clk;326 }327 328 /* The RTC supports 01.01.1900 - 31.12.2999 */329 crtc->rtc_dev->range_min = mktime64(1900, 1, 1, 0, 0, 0);330 crtc->rtc_dev->range_max = mktime64(2999, 12, 31, 23, 59, 59);331 332 crtc->rtc_dev->ops = &cdns_rtc_ops;333 device_init_wakeup(&pdev->dev, true);334 335 /* Always use 24-hour mode and keep the RTC values */336 writel(0, crtc->regs + CDNS_RTC_HMR);337 writel(CDNS_RTC_KRTCR_KRTC, crtc->regs + CDNS_RTC_KRTCR);338 339 ret = devm_rtc_register_device(crtc->rtc_dev);340 if (ret)341 goto err_disable_wakeup;342 343 return 0;344 345err_disable_wakeup:346 device_init_wakeup(&pdev->dev, false);347 348err_disable_ref_clk:349 clk_disable_unprepare(crtc->ref_clk);350 351err_disable_pclk:352 clk_disable_unprepare(crtc->pclk);353 354 return ret;355}356 357static void cdns_rtc_remove(struct platform_device *pdev)358{359 struct cdns_rtc *crtc = platform_get_drvdata(pdev);360 361 cdns_rtc_alarm_irq_enable(&pdev->dev, 0);362 device_init_wakeup(&pdev->dev, 0);363 364 clk_disable_unprepare(crtc->pclk);365 clk_disable_unprepare(crtc->ref_clk);366}367 368#ifdef CONFIG_PM_SLEEP369static int cdns_rtc_suspend(struct device *dev)370{371 struct cdns_rtc *crtc = dev_get_drvdata(dev);372 373 if (device_may_wakeup(dev))374 enable_irq_wake(crtc->irq);375 376 return 0;377}378 379static int cdns_rtc_resume(struct device *dev)380{381 struct cdns_rtc *crtc = dev_get_drvdata(dev);382 383 if (device_may_wakeup(dev))384 disable_irq_wake(crtc->irq);385 386 return 0;387}388#endif389 390static SIMPLE_DEV_PM_OPS(cdns_rtc_pm_ops, cdns_rtc_suspend, cdns_rtc_resume);391 392static const struct of_device_id cdns_rtc_of_match[] = {393 { .compatible = "cdns,rtc-r109v3" },394 { },395};396MODULE_DEVICE_TABLE(of, cdns_rtc_of_match);397 398static struct platform_driver cdns_rtc_driver = {399 .driver = {400 .name = "cdns-rtc",401 .of_match_table = cdns_rtc_of_match,402 .pm = &cdns_rtc_pm_ops,403 },404 .probe = cdns_rtc_probe,405 .remove_new = cdns_rtc_remove,406};407module_platform_driver(cdns_rtc_driver);408 409MODULE_AUTHOR("Jan Kotas <jank@cadence.com>");410MODULE_DESCRIPTION("Cadence RTC driver");411MODULE_LICENSE("GPL v2");412MODULE_ALIAS("platform:cdns-rtc");413