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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) ST-Ericsson SA 20104 *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 by9 * 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#include <linux/of.h>21#include <linux/pm_wakeirq.h>22 23#define AB8500_RTC_SOFF_STAT_REG 0x0024#define AB8500_RTC_CC_CONF_REG 0x0125#define AB8500_RTC_READ_REQ_REG 0x0226#define AB8500_RTC_WATCH_TSECMID_REG 0x0327#define AB8500_RTC_WATCH_TSECHI_REG 0x0428#define AB8500_RTC_WATCH_TMIN_LOW_REG 0x0529#define AB8500_RTC_WATCH_TMIN_MID_REG 0x0630#define AB8500_RTC_WATCH_TMIN_HI_REG 0x0731#define AB8500_RTC_ALRM_MIN_LOW_REG 0x0832#define AB8500_RTC_ALRM_MIN_MID_REG 0x0933#define AB8500_RTC_ALRM_MIN_HI_REG 0x0A34#define AB8500_RTC_STAT_REG 0x0B35#define AB8500_RTC_BKUP_CHG_REG 0x0C36#define AB8500_RTC_FORCE_BKUP_REG 0x0D37#define AB8500_RTC_CALIB_REG 0x0E38#define AB8500_RTC_SWITCH_STAT_REG 0x0F39 40/* RtcReadRequest bits */41#define RTC_READ_REQUEST 0x0142#define RTC_WRITE_REQUEST 0x0243 44/* RtcCtrl bits */45#define RTC_ALARM_ENA 0x0446#define RTC_STATUS_DATA 0x0147 48#define COUNTS_PER_SEC (0xF000 / 60)49 50static const u8 ab8500_rtc_time_regs[] = {51 AB8500_RTC_WATCH_TMIN_HI_REG, AB8500_RTC_WATCH_TMIN_MID_REG,52 AB8500_RTC_WATCH_TMIN_LOW_REG, AB8500_RTC_WATCH_TSECHI_REG,53 AB8500_RTC_WATCH_TSECMID_REG54};55 56static const u8 ab8500_rtc_alarm_regs[] = {57 AB8500_RTC_ALRM_MIN_HI_REG, AB8500_RTC_ALRM_MIN_MID_REG,58 AB8500_RTC_ALRM_MIN_LOW_REG59};60 61static int ab8500_rtc_read_time(struct device *dev, struct rtc_time *tm)62{63 unsigned long timeout = jiffies + HZ;64 int retval, i;65 unsigned long mins, secs;66 unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];67 u8 value;68 69 /* Request a data read */70 retval = abx500_set_register_interruptible(dev,71 AB8500_RTC, AB8500_RTC_READ_REQ_REG, RTC_READ_REQUEST);72 if (retval < 0)73 return retval;74 75 /* Wait for some cycles after enabling the rtc read in ab8500 */76 while (time_before(jiffies, timeout)) {77 retval = abx500_get_register_interruptible(dev,78 AB8500_RTC, AB8500_RTC_READ_REQ_REG, &value);79 if (retval < 0)80 return retval;81 82 if (!(value & RTC_READ_REQUEST))83 break;84 85 usleep_range(1000, 5000);86 }87 88 /* Read the Watchtime registers */89 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {90 retval = abx500_get_register_interruptible(dev,91 AB8500_RTC, ab8500_rtc_time_regs[i], &value);92 if (retval < 0)93 return retval;94 buf[i] = value;95 }96 97 mins = (buf[0] << 16) | (buf[1] << 8) | buf[2];98 99 secs = (buf[3] << 8) | buf[4];100 secs = secs / COUNTS_PER_SEC;101 secs = secs + (mins * 60);102 103 rtc_time64_to_tm(secs, tm);104 return 0;105}106 107static int ab8500_rtc_set_time(struct device *dev, struct rtc_time *tm)108{109 int retval, i;110 unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];111 unsigned long no_secs, no_mins, secs = 0;112 113 secs = rtc_tm_to_time64(tm);114 115 no_mins = secs / 60;116 117 no_secs = secs % 60;118 /* Make the seconds count as per the RTC resolution */119 no_secs = no_secs * COUNTS_PER_SEC;120 121 buf[4] = no_secs & 0xFF;122 buf[3] = (no_secs >> 8) & 0xFF;123 124 buf[2] = no_mins & 0xFF;125 buf[1] = (no_mins >> 8) & 0xFF;126 buf[0] = (no_mins >> 16) & 0xFF;127 128 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {129 retval = abx500_set_register_interruptible(dev, AB8500_RTC,130 ab8500_rtc_time_regs[i], buf[i]);131 if (retval < 0)132 return retval;133 }134 135 /* Request a data write */136 return abx500_set_register_interruptible(dev, AB8500_RTC,137 AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST);138}139 140static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)141{142 int retval, i;143 u8 rtc_ctrl, value;144 unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];145 unsigned long secs, mins;146 147 /* Check if the alarm is enabled or not */148 retval = abx500_get_register_interruptible(dev, AB8500_RTC,149 AB8500_RTC_STAT_REG, &rtc_ctrl);150 if (retval < 0)151 return retval;152 153 if (rtc_ctrl & RTC_ALARM_ENA)154 alarm->enabled = 1;155 else156 alarm->enabled = 0;157 158 alarm->pending = 0;159 160 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {161 retval = abx500_get_register_interruptible(dev, AB8500_RTC,162 ab8500_rtc_alarm_regs[i], &value);163 if (retval < 0)164 return retval;165 buf[i] = value;166 }167 168 mins = (buf[0] << 16) | (buf[1] << 8) | (buf[2]);169 secs = mins * 60;170 171 rtc_time64_to_tm(secs, &alarm->time);172 173 return 0;174}175 176static int ab8500_rtc_irq_enable(struct device *dev, unsigned int enabled)177{178 return abx500_mask_and_set_register_interruptible(dev, AB8500_RTC,179 AB8500_RTC_STAT_REG, RTC_ALARM_ENA,180 enabled ? RTC_ALARM_ENA : 0);181}182 183static int ab8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)184{185 int retval, i;186 unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];187 unsigned long mins;188 189 mins = (unsigned long)rtc_tm_to_time64(&alarm->time) / 60;190 191 buf[2] = mins & 0xFF;192 buf[1] = (mins >> 8) & 0xFF;193 buf[0] = (mins >> 16) & 0xFF;194 195 /* Set the alarm time */196 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {197 retval = abx500_set_register_interruptible(dev, AB8500_RTC,198 ab8500_rtc_alarm_regs[i], buf[i]);199 if (retval < 0)200 return retval;201 }202 203 return ab8500_rtc_irq_enable(dev, alarm->enabled);204}205 206static int ab8500_rtc_set_calibration(struct device *dev, int calibration)207{208 int retval;209 u8 rtccal = 0;210 211 /*212 * Check that the calibration value (which is in units of 0.5213 * parts-per-million) is in the AB8500's range for RtcCalibration214 * register. -128 (0x80) is not permitted because the AB8500 uses215 * a sign-bit rather than two's complement, so 0x80 is just another216 * representation of zero.217 */218 if ((calibration < -127) || (calibration > 127)) {219 dev_err(dev, "RtcCalibration value outside permitted range\n");220 return -EINVAL;221 }222 223 /*224 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7)225 * so need to convert to this sort of representation before writing226 * into RtcCalibration register...227 */228 if (calibration >= 0)229 rtccal = 0x7F & calibration;230 else231 rtccal = ~(calibration - 1) | 0x80;232 233 retval = abx500_set_register_interruptible(dev, AB8500_RTC,234 AB8500_RTC_CALIB_REG, rtccal);235 236 return retval;237}238 239static int ab8500_rtc_get_calibration(struct device *dev, int *calibration)240{241 int retval;242 u8 rtccal = 0;243 244 retval = abx500_get_register_interruptible(dev, AB8500_RTC,245 AB8500_RTC_CALIB_REG, &rtccal);246 if (retval >= 0) {247 /*248 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7)249 * so need to convert value from RtcCalibration register into250 * a two's complement signed value...251 */252 if (rtccal & 0x80)253 *calibration = 0 - (rtccal & 0x7F);254 else255 *calibration = 0x7F & rtccal;256 }257 258 return retval;259}260 261static ssize_t ab8500_sysfs_store_rtc_calibration(struct device *dev,262 struct device_attribute *attr,263 const char *buf, size_t count)264{265 int retval;266 int calibration = 0;267 268 if (sscanf(buf, " %i ", &calibration) != 1) {269 dev_err(dev, "Failed to store RTC calibration attribute\n");270 return -EINVAL;271 }272 273 retval = ab8500_rtc_set_calibration(dev, calibration);274 275 return retval ? retval : count;276}277 278static ssize_t ab8500_sysfs_show_rtc_calibration(struct device *dev,279 struct device_attribute *attr, char *buf)280{281 int retval = 0;282 int calibration = 0;283 284 retval = ab8500_rtc_get_calibration(dev, &calibration);285 if (retval < 0) {286 dev_err(dev, "Failed to read RTC calibration attribute\n");287 sprintf(buf, "0\n");288 return retval;289 }290 291 return sprintf(buf, "%d\n", calibration);292}293 294static DEVICE_ATTR(rtc_calibration, S_IRUGO | S_IWUSR,295 ab8500_sysfs_show_rtc_calibration,296 ab8500_sysfs_store_rtc_calibration);297 298static struct attribute *ab8500_rtc_attrs[] = {299 &dev_attr_rtc_calibration.attr,300 NULL301};302 303static const struct attribute_group ab8500_rtc_sysfs_files = {304 .attrs = ab8500_rtc_attrs,305};306 307static irqreturn_t rtc_alarm_handler(int irq, void *data)308{309 struct rtc_device *rtc = data;310 unsigned long events = RTC_IRQF | RTC_AF;311 312 dev_dbg(&rtc->dev, "%s\n", __func__);313 rtc_update_irq(rtc, 1, events);314 315 return IRQ_HANDLED;316}317 318static const struct rtc_class_ops ab8500_rtc_ops = {319 .read_time = ab8500_rtc_read_time,320 .set_time = ab8500_rtc_set_time,321 .read_alarm = ab8500_rtc_read_alarm,322 .set_alarm = ab8500_rtc_set_alarm,323 .alarm_irq_enable = ab8500_rtc_irq_enable,324};325 326static const struct platform_device_id ab85xx_rtc_ids[] = {327 { "ab8500-rtc", (kernel_ulong_t)&ab8500_rtc_ops, },328 { /* sentinel */ }329};330MODULE_DEVICE_TABLE(platform, ab85xx_rtc_ids);331 332static int ab8500_rtc_probe(struct platform_device *pdev)333{334 const struct platform_device_id *platid = platform_get_device_id(pdev);335 int err;336 struct rtc_device *rtc;337 u8 rtc_ctrl;338 int irq;339 340 irq = platform_get_irq_byname(pdev, "ALARM");341 if (irq < 0)342 return irq;343 344 /* For RTC supply test */345 err = abx500_mask_and_set_register_interruptible(&pdev->dev, AB8500_RTC,346 AB8500_RTC_STAT_REG, RTC_STATUS_DATA, RTC_STATUS_DATA);347 if (err < 0)348 return err;349 350 /* Wait for reset by the PorRtc */351 usleep_range(1000, 5000);352 353 err = abx500_get_register_interruptible(&pdev->dev, AB8500_RTC,354 AB8500_RTC_STAT_REG, &rtc_ctrl);355 if (err < 0)356 return err;357 358 /* Check if the RTC Supply fails */359 if (!(rtc_ctrl & RTC_STATUS_DATA)) {360 dev_err(&pdev->dev, "RTC supply failure\n");361 return -ENODEV;362 }363 364 device_init_wakeup(&pdev->dev, true);365 366 rtc = devm_rtc_allocate_device(&pdev->dev);367 if (IS_ERR(rtc))368 return PTR_ERR(rtc);369 370 rtc->ops = (struct rtc_class_ops *)platid->driver_data;371 372 err = devm_request_threaded_irq(&pdev->dev, irq, NULL,373 rtc_alarm_handler, IRQF_ONESHOT,374 "ab8500-rtc", rtc);375 if (err < 0)376 return err;377 378 dev_pm_set_wake_irq(&pdev->dev, irq);379 platform_set_drvdata(pdev, rtc);380 381 set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features);382 clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);383 384 rtc->range_max = (1ULL << 24) * 60 - 1; // 24-bit minutes + 59 secs385 rtc->start_secs = RTC_TIMESTAMP_BEGIN_2000;386 rtc->set_start_time = true;387 388 err = rtc_add_group(rtc, &ab8500_rtc_sysfs_files);389 if (err)390 return err;391 392 return devm_rtc_register_device(rtc);393}394 395static void ab8500_rtc_remove(struct platform_device *pdev)396{397 dev_pm_clear_wake_irq(&pdev->dev);398 device_init_wakeup(&pdev->dev, false);399}400 401static struct platform_driver ab8500_rtc_driver = {402 .driver = {403 .name = "ab8500-rtc",404 },405 .probe = ab8500_rtc_probe,406 .remove_new = ab8500_rtc_remove,407 .id_table = ab85xx_rtc_ids,408};409 410module_platform_driver(ab8500_rtc_driver);411 412MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>");413MODULE_DESCRIPTION("AB8500 RTC Driver");414MODULE_LICENSE("GPL v2");415