// SPDX-License-Identifier: GPL-2.0 /* * RTC driver for tps6594 PMIC * * Copyright (C) 2022 BayLibre Incorporated - https://www.baylibre.com/ */ #include #include #include #include #include #include #include #include #include #include #include #include #define TPS6594_GET_TIME_ON TPS6594_BIT_GET_TIME #define TPS6594_GET_TIME_OFF 0 #define TPS6594_IT_ALARM_ON TPS6594_BIT_IT_ALARM #define TPS6594_IT_ALARM_OFF 0 #define TPS6594_AUTO_COMP_ON TPS6594_BIT_IT_ALARM /* Total number of RTC registers needed to set time*/ #define NUM_TIME_REGS (TPS6594_REG_RTC_WEEKS - TPS6594_REG_RTC_SECONDS + 1) /* Total number of RTC alarm register */ #define NUM_TIME_ALARM_REGS (NUM_TIME_REGS - 1) /* Total number of RTC registers needed to set compensation registers */ #define NUM_COMP_REGS (TPS6594_REG_RTC_COMP_MSB - TPS6594_REG_RTC_COMP_LSB + 1) /* * Min and max values supported with 'offset' interface (swapped sign) * After conversion, the values does not exceed the range [-32767, 33767] which COMP_REG must * conform to */ #define MIN_OFFSET (-277774) #define MAX_OFFSET (277774) /* Number of ticks per hour */ #define TICKS_PER_HOUR (32768 * 3600) /* Multiplier for ppb conversions */ #define PPB_MULT (1000000000LL) static int tps6594_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) { struct tps6594 *tps = dev_get_drvdata(dev->parent); u8 val = 0; int ret; val = enabled ? TPS6594_IT_ALARM_ON : TPS6594_IT_ALARM_OFF; ret = regmap_update_bits(tps->regmap, TPS6594_REG_RTC_INTERRUPTS, TPS6594_BIT_IT_ALARM, val); return ret; } /* Pulse GET_TIME field of RTC_CTRL_1 to store a timestamp in shadow registers */ static int tps6594_rtc_shadow_timestamp(struct device *dev, struct tps6594 *tps) { int ret; /* * Set GET_TIME to 0. This way, next time we set GET_TIME to 1 we are sure to store an * up-to-date timestamp */ ret = regmap_clear_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1, TPS6594_BIT_GET_TIME); if (ret < 0) return ret; /* * Copy content of RTC registers to shadow registers or latches to read a coherent * timestamp */ return regmap_set_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1, TPS6594_BIT_GET_TIME); } /* * Gets current tps6594 RTC time and date parameters. * * The RTC's time/alarm representation is not what gmtime(3) requires * Linux to use: * * - Months are 1..12 vs Linux 0-11 * - Years are 0..99 vs Linux 1900..N (we assume 21st century) */ static int tps6594_rtc_read_time(struct device *dev, struct rtc_time *tm) { unsigned char rtc_data[NUM_TIME_REGS]; struct tps6594 *tps = dev_get_drvdata(dev->parent); int ret; /* Check if RTC is running. */ ret = regmap_test_bits(tps->regmap, TPS6594_REG_RTC_STATUS, TPS6594_BIT_RUN); if (ret < 0) return ret; if (ret == 0) return -EINVAL; ret = tps6594_rtc_shadow_timestamp(dev, tps); if (ret < 0) return ret; /* Read shadowed RTC registers */ ret = regmap_bulk_read(tps->regmap, TPS6594_REG_RTC_SECONDS, rtc_data, NUM_TIME_REGS); if (ret < 0) return ret; tm->tm_sec = bcd2bin(rtc_data[0]); tm->tm_min = bcd2bin(rtc_data[1]); tm->tm_hour = bcd2bin(rtc_data[2]); tm->tm_mday = bcd2bin(rtc_data[3]); tm->tm_mon = bcd2bin(rtc_data[4]) - 1; tm->tm_year = bcd2bin(rtc_data[5]) + 100; tm->tm_wday = bcd2bin(rtc_data[6]); return ret; } /* * Sets current tps6594 RTC time and date parameters. * * The RTC's time/alarm representation is not what gmtime(3) requires * Linux to use: * * - Months are 1..12 vs Linux 0-11 * - Years are 0..99 vs Linux 1900..N (we assume 21st century) */ static int tps6594_rtc_set_time(struct device *dev, struct rtc_time *tm) { unsigned char rtc_data[NUM_TIME_REGS]; struct tps6594 *tps = dev_get_drvdata(dev->parent); int ret; rtc_data[0] = bin2bcd(tm->tm_sec); rtc_data[1] = bin2bcd(tm->tm_min); rtc_data[2] = bin2bcd(tm->tm_hour); rtc_data[3] = bin2bcd(tm->tm_mday); rtc_data[4] = bin2bcd(tm->tm_mon + 1); rtc_data[5] = bin2bcd(tm->tm_year - 100); rtc_data[6] = bin2bcd(tm->tm_wday); /* Stop RTC while updating the RTC time registers */ ret = regmap_clear_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1, TPS6594_BIT_STOP_RTC); if (ret < 0) return ret; /* Update all the time registers in one shot */ ret = regmap_bulk_write(tps->regmap, TPS6594_REG_RTC_SECONDS, rtc_data, NUM_TIME_REGS); if (ret < 0) return ret; /* Start back RTC */ return regmap_set_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1, TPS6594_BIT_STOP_RTC); } /* * Gets current tps6594 RTC alarm time. */ static int tps6594_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) { unsigned char alarm_data[NUM_TIME_ALARM_REGS]; u32 int_val; struct tps6594 *tps = dev_get_drvdata(dev->parent); int ret; ret = regmap_bulk_read(tps->regmap, TPS6594_REG_ALARM_SECONDS, alarm_data, NUM_TIME_ALARM_REGS); if (ret < 0) return ret; alm->time.tm_sec = bcd2bin(alarm_data[0]); alm->time.tm_min = bcd2bin(alarm_data[1]); alm->time.tm_hour = bcd2bin(alarm_data[2]); alm->time.tm_mday = bcd2bin(alarm_data[3]); alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1; alm->time.tm_year = bcd2bin(alarm_data[5]) + 100; ret = regmap_read(tps->regmap, TPS6594_REG_RTC_INTERRUPTS, &int_val); if (ret < 0) return ret; alm->enabled = int_val & TPS6594_BIT_IT_ALARM ? 1 : 0; return ret; } static int tps6594_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) { unsigned char alarm_data[NUM_TIME_ALARM_REGS]; struct tps6594 *tps = dev_get_drvdata(dev->parent); int ret; /* Disable alarm irq before changing the alarm timestamp */ ret = tps6594_rtc_alarm_irq_enable(dev, 0); if (ret) return ret; alarm_data[0] = bin2bcd(alm->time.tm_sec); alarm_data[1] = bin2bcd(alm->time.tm_min); alarm_data[2] = bin2bcd(alm->time.tm_hour); alarm_data[3] = bin2bcd(alm->time.tm_mday); alarm_data[4] = bin2bcd(alm->time.tm_mon + 1); alarm_data[5] = bin2bcd(alm->time.tm_year - 100); /* Update all the alarm registers in one shot */ ret = regmap_bulk_write(tps->regmap, TPS6594_REG_ALARM_SECONDS, alarm_data, NUM_TIME_ALARM_REGS); if (ret < 0) return ret; if (alm->enabled) ret = tps6594_rtc_alarm_irq_enable(dev, 1); return ret; } static int tps6594_rtc_set_calibration(struct device *dev, int calibration) { unsigned char comp_data[NUM_COMP_REGS]; struct tps6594 *tps = dev_get_drvdata(dev->parent); s16 value; int ret; /* * TPS6594 uses two's complement 16 bit value for compensation for RTC * crystal inaccuracies. One time every hour when seconds counter * increments from 0 to 1 compensation value will be added to internal * RTC counter value. * * * Valid range for compensation value: [-32767 .. 32767] */ if (calibration < -32767 || calibration > 32767) { dev_err(dev, "RTC calibration value out of range: %d\n", calibration); return -EINVAL; } value = (s16)calibration; comp_data[0] = (u16)value & 0xFF; comp_data[1] = ((u16)value >> 8) & 0xFF; /* Update all the compensation registers in one shot */ ret = regmap_bulk_write(tps->regmap, TPS6594_REG_RTC_COMP_LSB, comp_data, NUM_COMP_REGS); if (ret < 0) return ret; /* Enable automatic compensation */ return regmap_set_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1, TPS6594_BIT_AUTO_COMP); } static int tps6594_rtc_get_calibration(struct device *dev, int *calibration) { unsigned char comp_data[NUM_COMP_REGS]; struct tps6594 *tps = dev_get_drvdata(dev->parent); unsigned int ctrl; u16 value; int ret; ret = regmap_read(tps->regmap, TPS6594_REG_RTC_CTRL_1, &ctrl); if (ret < 0) return ret; /* If automatic compensation is not enabled report back zero */ if (!(ctrl & TPS6594_BIT_AUTO_COMP)) { *calibration = 0; return 0; } ret = regmap_bulk_read(tps->regmap, TPS6594_REG_RTC_COMP_LSB, comp_data, NUM_COMP_REGS); if (ret < 0) return ret; value = (u16)comp_data[0] | ((u16)comp_data[1] << 8); *calibration = (s16)value; return ret; } static int tps6594_rtc_read_offset(struct device *dev, long *offset) { int calibration; s64 tmp; int ret; ret = tps6594_rtc_get_calibration(dev, &calibration); if (ret < 0) return ret; /* Convert from RTC calibration register format to ppb format */ tmp = calibration * (s64)PPB_MULT; if (tmp < 0) tmp -= TICKS_PER_HOUR / 2LL; else tmp += TICKS_PER_HOUR / 2LL; tmp = div_s64(tmp, TICKS_PER_HOUR); /* * Offset value operates in negative way, so swap sign. * See 8.3.10.5, (32768 - COMP_REG) */ *offset = (long)-tmp; return ret; } static int tps6594_rtc_set_offset(struct device *dev, long offset) { int calibration; s64 tmp; /* Make sure offset value is within supported range */ if (offset < MIN_OFFSET || offset > MAX_OFFSET) return -ERANGE; /* Convert from ppb format to RTC calibration register format */ tmp = offset * (s64)TICKS_PER_HOUR; if (tmp < 0) tmp -= PPB_MULT / 2LL; else tmp += PPB_MULT / 2LL; tmp = div_s64(tmp, PPB_MULT); /* Offset value operates in negative way, so swap sign */ calibration = (int)-tmp; return tps6594_rtc_set_calibration(dev, calibration); } static irqreturn_t tps6594_rtc_interrupt(int irq, void *rtc) { struct device *dev = rtc; unsigned long events = 0; struct tps6594 *tps = dev_get_drvdata(dev->parent); struct rtc_device *rtc_dev = dev_get_drvdata(dev); int ret; u32 rtc_reg; ret = regmap_read(tps->regmap, TPS6594_REG_RTC_STATUS, &rtc_reg); if (ret) return IRQ_NONE; if (rtc_reg & TPS6594_BIT_ALARM) events = RTC_IRQF | RTC_AF; /* Notify RTC core on event */ rtc_update_irq(rtc_dev, 1, events); return IRQ_HANDLED; } static const struct rtc_class_ops tps6594_rtc_ops = { .read_time = tps6594_rtc_read_time, .set_time = tps6594_rtc_set_time, .read_alarm = tps6594_rtc_read_alarm, .set_alarm = tps6594_rtc_set_alarm, .alarm_irq_enable = tps6594_rtc_alarm_irq_enable, .read_offset = tps6594_rtc_read_offset, .set_offset = tps6594_rtc_set_offset, }; static int tps6594_rtc_probe(struct platform_device *pdev) { struct tps6594 *tps; struct rtc_device *rtc; int irq; int ret; tps = dev_get_drvdata(pdev->dev.parent); rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); if (!rtc) return -ENOMEM; rtc = devm_rtc_allocate_device(&pdev->dev); if (IS_ERR(rtc)) return PTR_ERR(rtc); /* Enable crystal oscillator */ ret = regmap_set_bits(tps->regmap, TPS6594_REG_RTC_CTRL_2, TPS6594_BIT_XTAL_EN); if (ret < 0) return ret; ret = regmap_test_bits(tps->regmap, TPS6594_REG_RTC_STATUS, TPS6594_BIT_RUN); if (ret < 0) return ret; /* RTC not running */ if (ret == 0) { /* Start rtc */ ret = regmap_set_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1, TPS6594_BIT_STOP_RTC); if (ret < 0) return ret; mdelay(100); /* * RTC should be running now. Check if this is the case. * If not it might be a missing oscillator. */ ret = regmap_test_bits(tps->regmap, TPS6594_REG_RTC_STATUS, TPS6594_BIT_RUN); if (ret < 0) return ret; if (ret == 0) return -ENODEV; /* Stop RTC until first call to `tps6594_rtc_set_time */ ret = regmap_clear_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1, TPS6594_BIT_STOP_RTC); if (ret < 0) return ret; } platform_set_drvdata(pdev, rtc); irq = platform_get_irq_byname(pdev, TPS6594_IRQ_NAME_ALARM); if (irq < 0) { dev_err(&pdev->dev, "Failed to get irq\n"); return irq; } ret = devm_request_threaded_irq(&pdev->dev, irq, NULL, tps6594_rtc_interrupt, IRQF_ONESHOT, TPS6594_IRQ_NAME_ALARM, &pdev->dev); if (ret < 0) { dev_err(&pdev->dev, "Failed to request_threaded_irq\n"); return ret; } rtc->ops = &tps6594_rtc_ops; rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; rtc->range_max = RTC_TIMESTAMP_END_2099; return devm_rtc_register_device(rtc); } static struct platform_driver tps6594_rtc_driver = { .probe = tps6594_rtc_probe, .driver = { .name = "tps6594-rtc", }, }; module_platform_driver(tps6594_rtc_driver); MODULE_ALIAS("platform:tps6594-rtc"); MODULE_AUTHOR("Esteban Blanc "); MODULE_DESCRIPTION("TPS6594 RTC driver"); MODULE_LICENSE("GPL");