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Diffstat (limited to '')
| -rw-r--r-- | drivers/rtc/rtc-ab-b5ze-s3.c | 955 |
1 files changed, 955 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ab-b5ze-s3.c b/drivers/rtc/rtc-ab-b5ze-s3.c new file mode 100644 index 000000000..2370ac0cd --- /dev/null +++ b/drivers/rtc/rtc-ab-b5ze-s3.c @@ -0,0 +1,955 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * rtc-ab-b5ze-s3 - Driver for Abracon AB-RTCMC-32.768Khz-B5ZE-S3 + * I2C RTC / Alarm chip + * + * Copyright (C) 2014, Arnaud EBALARD <arno@natisbad.org> + * + * Detailed datasheet of the chip is available here: + * + * https://www.abracon.com/realtimeclock/AB-RTCMC-32.768kHz-B5ZE-S3-Application-Manual.pdf + * + * This work is based on ISL12057 driver (drivers/rtc/rtc-isl12057.c). + * + */ + +#include <linux/module.h> +#include <linux/rtc.h> +#include <linux/i2c.h> +#include <linux/bcd.h> +#include <linux/of.h> +#include <linux/regmap.h> +#include <linux/interrupt.h> + +#define DRV_NAME "rtc-ab-b5ze-s3" + +/* Control section */ +#define ABB5ZES3_REG_CTRL1 0x00 /* Control 1 register */ +#define ABB5ZES3_REG_CTRL1_CIE BIT(0) /* Pulse interrupt enable */ +#define ABB5ZES3_REG_CTRL1_AIE BIT(1) /* Alarm interrupt enable */ +#define ABB5ZES3_REG_CTRL1_SIE BIT(2) /* Second interrupt enable */ +#define ABB5ZES3_REG_CTRL1_PM BIT(3) /* 24h/12h mode */ +#define ABB5ZES3_REG_CTRL1_SR BIT(4) /* Software reset */ +#define ABB5ZES3_REG_CTRL1_STOP BIT(5) /* RTC circuit enable */ +#define ABB5ZES3_REG_CTRL1_CAP BIT(7) + +#define ABB5ZES3_REG_CTRL2 0x01 /* Control 2 register */ +#define ABB5ZES3_REG_CTRL2_CTBIE BIT(0) /* Countdown timer B int. enable */ +#define ABB5ZES3_REG_CTRL2_CTAIE BIT(1) /* Countdown timer A int. enable */ +#define ABB5ZES3_REG_CTRL2_WTAIE BIT(2) /* Watchdog timer A int. enable */ +#define ABB5ZES3_REG_CTRL2_AF BIT(3) /* Alarm interrupt status */ +#define ABB5ZES3_REG_CTRL2_SF BIT(4) /* Second interrupt status */ +#define ABB5ZES3_REG_CTRL2_CTBF BIT(5) /* Countdown timer B int. status */ +#define ABB5ZES3_REG_CTRL2_CTAF BIT(6) /* Countdown timer A int. status */ +#define ABB5ZES3_REG_CTRL2_WTAF BIT(7) /* Watchdog timer A int. status */ + +#define ABB5ZES3_REG_CTRL3 0x02 /* Control 3 register */ +#define ABB5ZES3_REG_CTRL3_PM2 BIT(7) /* Power Management bit 2 */ +#define ABB5ZES3_REG_CTRL3_PM1 BIT(6) /* Power Management bit 1 */ +#define ABB5ZES3_REG_CTRL3_PM0 BIT(5) /* Power Management bit 0 */ +#define ABB5ZES3_REG_CTRL3_BSF BIT(3) /* Battery switchover int. status */ +#define ABB5ZES3_REG_CTRL3_BLF BIT(2) /* Battery low int. status */ +#define ABB5ZES3_REG_CTRL3_BSIE BIT(1) /* Battery switchover int. enable */ +#define ABB5ZES3_REG_CTRL3_BLIE BIT(0) /* Battery low int. enable */ + +#define ABB5ZES3_CTRL_SEC_LEN 3 + +/* RTC section */ +#define ABB5ZES3_REG_RTC_SC 0x03 /* RTC Seconds register */ +#define ABB5ZES3_REG_RTC_SC_OSC BIT(7) /* Clock integrity status */ +#define ABB5ZES3_REG_RTC_MN 0x04 /* RTC Minutes register */ +#define ABB5ZES3_REG_RTC_HR 0x05 /* RTC Hours register */ +#define ABB5ZES3_REG_RTC_HR_PM BIT(5) /* RTC Hours PM bit */ +#define ABB5ZES3_REG_RTC_DT 0x06 /* RTC Date register */ +#define ABB5ZES3_REG_RTC_DW 0x07 /* RTC Day of the week register */ +#define ABB5ZES3_REG_RTC_MO 0x08 /* RTC Month register */ +#define ABB5ZES3_REG_RTC_YR 0x09 /* RTC Year register */ + +#define ABB5ZES3_RTC_SEC_LEN 7 + +/* Alarm section (enable bits are all active low) */ +#define ABB5ZES3_REG_ALRM_MN 0x0A /* Alarm - minute register */ +#define ABB5ZES3_REG_ALRM_MN_AE BIT(7) /* Minute enable */ +#define ABB5ZES3_REG_ALRM_HR 0x0B /* Alarm - hours register */ +#define ABB5ZES3_REG_ALRM_HR_AE BIT(7) /* Hour enable */ +#define ABB5ZES3_REG_ALRM_DT 0x0C /* Alarm - date register */ +#define ABB5ZES3_REG_ALRM_DT_AE BIT(7) /* Date (day of the month) enable */ +#define ABB5ZES3_REG_ALRM_DW 0x0D /* Alarm - day of the week reg. */ +#define ABB5ZES3_REG_ALRM_DW_AE BIT(7) /* Day of the week enable */ + +#define ABB5ZES3_ALRM_SEC_LEN 4 + +/* Frequency offset section */ +#define ABB5ZES3_REG_FREQ_OF 0x0E /* Frequency offset register */ +#define ABB5ZES3_REG_FREQ_OF_MODE 0x0E /* Offset mode: 2 hours / minute */ + +/* CLOCKOUT section */ +#define ABB5ZES3_REG_TIM_CLK 0x0F /* Timer & Clockout register */ +#define ABB5ZES3_REG_TIM_CLK_TAM BIT(7) /* Permanent/pulsed timer A/int. 2 */ +#define ABB5ZES3_REG_TIM_CLK_TBM BIT(6) /* Permanent/pulsed timer B */ +#define ABB5ZES3_REG_TIM_CLK_COF2 BIT(5) /* Clkout Freq bit 2 */ +#define ABB5ZES3_REG_TIM_CLK_COF1 BIT(4) /* Clkout Freq bit 1 */ +#define ABB5ZES3_REG_TIM_CLK_COF0 BIT(3) /* Clkout Freq bit 0 */ +#define ABB5ZES3_REG_TIM_CLK_TAC1 BIT(2) /* Timer A: - 01 : countdown */ +#define ABB5ZES3_REG_TIM_CLK_TAC0 BIT(1) /* - 10 : timer */ +#define ABB5ZES3_REG_TIM_CLK_TBC BIT(0) /* Timer B enable */ + +/* Timer A Section */ +#define ABB5ZES3_REG_TIMA_CLK 0x10 /* Timer A clock register */ +#define ABB5ZES3_REG_TIMA_CLK_TAQ2 BIT(2) /* Freq bit 2 */ +#define ABB5ZES3_REG_TIMA_CLK_TAQ1 BIT(1) /* Freq bit 1 */ +#define ABB5ZES3_REG_TIMA_CLK_TAQ0 BIT(0) /* Freq bit 0 */ +#define ABB5ZES3_REG_TIMA 0x11 /* Timer A register */ + +#define ABB5ZES3_TIMA_SEC_LEN 2 + +/* Timer B Section */ +#define ABB5ZES3_REG_TIMB_CLK 0x12 /* Timer B clock register */ +#define ABB5ZES3_REG_TIMB_CLK_TBW2 BIT(6) +#define ABB5ZES3_REG_TIMB_CLK_TBW1 BIT(5) +#define ABB5ZES3_REG_TIMB_CLK_TBW0 BIT(4) +#define ABB5ZES3_REG_TIMB_CLK_TAQ2 BIT(2) +#define ABB5ZES3_REG_TIMB_CLK_TAQ1 BIT(1) +#define ABB5ZES3_REG_TIMB_CLK_TAQ0 BIT(0) +#define ABB5ZES3_REG_TIMB 0x13 /* Timer B register */ +#define ABB5ZES3_TIMB_SEC_LEN 2 + +#define ABB5ZES3_MEM_MAP_LEN 0x14 + +struct abb5zes3_rtc_data { + struct rtc_device *rtc; + struct regmap *regmap; + + int irq; + + bool battery_low; + bool timer_alarm; /* current alarm is via timer A */ +}; + +/* + * Try and match register bits w/ fixed null values to see whether we + * are dealing with an ABB5ZES3. + */ +static int abb5zes3_i2c_validate_chip(struct regmap *regmap) +{ + u8 regs[ABB5ZES3_MEM_MAP_LEN]; + static const u8 mask[ABB5ZES3_MEM_MAP_LEN] = { 0x00, 0x00, 0x10, 0x00, + 0x80, 0xc0, 0xc0, 0xf8, + 0xe0, 0x00, 0x00, 0x40, + 0x40, 0x78, 0x00, 0x00, + 0xf8, 0x00, 0x88, 0x00 }; + int ret, i; + + ret = regmap_bulk_read(regmap, 0, regs, ABB5ZES3_MEM_MAP_LEN); + if (ret) + return ret; + + for (i = 0; i < ABB5ZES3_MEM_MAP_LEN; ++i) { + if (regs[i] & mask[i]) /* check if bits are cleared */ + return -ENODEV; + } + + return 0; +} + +/* Clear alarm status bit. */ +static int _abb5zes3_rtc_clear_alarm(struct device *dev) +{ + struct abb5zes3_rtc_data *data = dev_get_drvdata(dev); + int ret; + + ret = regmap_update_bits(data->regmap, ABB5ZES3_REG_CTRL2, + ABB5ZES3_REG_CTRL2_AF, 0); + if (ret) + dev_err(dev, "%s: clearing alarm failed (%d)\n", __func__, ret); + + return ret; +} + +/* Enable or disable alarm (i.e. alarm interrupt generation) */ +static int _abb5zes3_rtc_update_alarm(struct device *dev, bool enable) +{ + struct abb5zes3_rtc_data *data = dev_get_drvdata(dev); + int ret; + + ret = regmap_update_bits(data->regmap, ABB5ZES3_REG_CTRL1, + ABB5ZES3_REG_CTRL1_AIE, + enable ? ABB5ZES3_REG_CTRL1_AIE : 0); + if (ret) + dev_err(dev, "%s: writing alarm INT failed (%d)\n", + __func__, ret); + + return ret; +} + +/* Enable or disable timer (watchdog timer A interrupt generation) */ +static int _abb5zes3_rtc_update_timer(struct device *dev, bool enable) +{ + struct abb5zes3_rtc_data *data = dev_get_drvdata(dev); + int ret; + + ret = regmap_update_bits(data->regmap, ABB5ZES3_REG_CTRL2, + ABB5ZES3_REG_CTRL2_WTAIE, + enable ? ABB5ZES3_REG_CTRL2_WTAIE : 0); + if (ret) + dev_err(dev, "%s: writing timer INT failed (%d)\n", + __func__, ret); + + return ret; +} + +/* + * Note: we only read, so regmap inner lock protection is sufficient, i.e. + * we do not need driver's main lock protection. + */ +static int _abb5zes3_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct abb5zes3_rtc_data *data = dev_get_drvdata(dev); + u8 regs[ABB5ZES3_REG_RTC_SC + ABB5ZES3_RTC_SEC_LEN]; + int ret = 0; + + /* + * As we need to read CTRL1 register anyway to access 24/12h + * mode bit, we do a single bulk read of both control and RTC + * sections (they are consecutive). This also ease indexing + * of register values after bulk read. + */ + ret = regmap_bulk_read(data->regmap, ABB5ZES3_REG_CTRL1, regs, + sizeof(regs)); + if (ret) { + dev_err(dev, "%s: reading RTC time failed (%d)\n", + __func__, ret); + return ret; + } + + /* If clock integrity is not guaranteed, do not return a time value */ + if (regs[ABB5ZES3_REG_RTC_SC] & ABB5ZES3_REG_RTC_SC_OSC) + return -ENODATA; + + tm->tm_sec = bcd2bin(regs[ABB5ZES3_REG_RTC_SC] & 0x7F); + tm->tm_min = bcd2bin(regs[ABB5ZES3_REG_RTC_MN]); + + if (regs[ABB5ZES3_REG_CTRL1] & ABB5ZES3_REG_CTRL1_PM) { /* 12hr mode */ + tm->tm_hour = bcd2bin(regs[ABB5ZES3_REG_RTC_HR] & 0x1f); + if (regs[ABB5ZES3_REG_RTC_HR] & ABB5ZES3_REG_RTC_HR_PM) /* PM */ + tm->tm_hour += 12; + } else { /* 24hr mode */ + tm->tm_hour = bcd2bin(regs[ABB5ZES3_REG_RTC_HR]); + } + + tm->tm_mday = bcd2bin(regs[ABB5ZES3_REG_RTC_DT]); + tm->tm_wday = bcd2bin(regs[ABB5ZES3_REG_RTC_DW]); + tm->tm_mon = bcd2bin(regs[ABB5ZES3_REG_RTC_MO]) - 1; /* starts at 1 */ + tm->tm_year = bcd2bin(regs[ABB5ZES3_REG_RTC_YR]) + 100; + + return ret; +} + +static int abb5zes3_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct abb5zes3_rtc_data *data = dev_get_drvdata(dev); + u8 regs[ABB5ZES3_REG_RTC_SC + ABB5ZES3_RTC_SEC_LEN]; + int ret; + + regs[ABB5ZES3_REG_RTC_SC] = bin2bcd(tm->tm_sec); /* MSB=0 clears OSC */ + regs[ABB5ZES3_REG_RTC_MN] = bin2bcd(tm->tm_min); + regs[ABB5ZES3_REG_RTC_HR] = bin2bcd(tm->tm_hour); /* 24-hour format */ + regs[ABB5ZES3_REG_RTC_DT] = bin2bcd(tm->tm_mday); + regs[ABB5ZES3_REG_RTC_DW] = bin2bcd(tm->tm_wday); + regs[ABB5ZES3_REG_RTC_MO] = bin2bcd(tm->tm_mon + 1); + regs[ABB5ZES3_REG_RTC_YR] = bin2bcd(tm->tm_year - 100); + + ret = regmap_bulk_write(data->regmap, ABB5ZES3_REG_RTC_SC, + regs + ABB5ZES3_REG_RTC_SC, + ABB5ZES3_RTC_SEC_LEN); + + return ret; +} + +/* + * Set provided TAQ and Timer A registers (TIMA_CLK and TIMA) based on + * given number of seconds. + */ +static inline void sec_to_timer_a(u8 secs, u8 *taq, u8 *timer_a) +{ + *taq = ABB5ZES3_REG_TIMA_CLK_TAQ1; /* 1Hz */ + *timer_a = secs; +} + +/* + * Return current number of seconds in Timer A. As we only use + * timer A with a 1Hz freq, this is what we expect to have. + */ +static inline int sec_from_timer_a(u8 *secs, u8 taq, u8 timer_a) +{ + if (taq != ABB5ZES3_REG_TIMA_CLK_TAQ1) /* 1Hz */ + return -EINVAL; + + *secs = timer_a; + + return 0; +} + +/* + * Read alarm currently configured via a watchdog timer using timer A. This + * is done by reading current RTC time and adding remaining timer time. + */ +static int _abb5zes3_rtc_read_timer(struct device *dev, + struct rtc_wkalrm *alarm) +{ + struct abb5zes3_rtc_data *data = dev_get_drvdata(dev); + struct rtc_time rtc_tm, *alarm_tm = &alarm->time; + u8 regs[ABB5ZES3_TIMA_SEC_LEN + 1]; + unsigned long rtc_secs; + unsigned int reg; + u8 timer_secs; + int ret; + + /* + * Instead of doing two separate calls, because they are consecutive, + * we grab both clockout register and Timer A section. The latter is + * used to decide if timer A is enabled (as a watchdog timer). + */ + ret = regmap_bulk_read(data->regmap, ABB5ZES3_REG_TIM_CLK, regs, + ABB5ZES3_TIMA_SEC_LEN + 1); + if (ret) { + dev_err(dev, "%s: reading Timer A section failed (%d)\n", + __func__, ret); + return ret; + } + + /* get current time ... */ + ret = _abb5zes3_rtc_read_time(dev, &rtc_tm); + if (ret) + return ret; + + /* ... convert to seconds ... */ + rtc_secs = rtc_tm_to_time64(&rtc_tm); + + /* ... add remaining timer A time ... */ + ret = sec_from_timer_a(&timer_secs, regs[1], regs[2]); + if (ret) + return ret; + + /* ... and convert back. */ + rtc_time64_to_tm(rtc_secs + timer_secs, alarm_tm); + + ret = regmap_read(data->regmap, ABB5ZES3_REG_CTRL2, ®); + if (ret) { + dev_err(dev, "%s: reading ctrl reg failed (%d)\n", + __func__, ret); + return ret; + } + + alarm->enabled = !!(reg & ABB5ZES3_REG_CTRL2_WTAIE); + + return 0; +} + +/* Read alarm currently configured via a RTC alarm registers. */ +static int _abb5zes3_rtc_read_alarm(struct device *dev, + struct rtc_wkalrm *alarm) +{ + struct abb5zes3_rtc_data *data = dev_get_drvdata(dev); + struct rtc_time rtc_tm, *alarm_tm = &alarm->time; + unsigned long rtc_secs, alarm_secs; + u8 regs[ABB5ZES3_ALRM_SEC_LEN]; + unsigned int reg; + int ret; + + ret = regmap_bulk_read(data->regmap, ABB5ZES3_REG_ALRM_MN, regs, + ABB5ZES3_ALRM_SEC_LEN); + if (ret) { + dev_err(dev, "%s: reading alarm section failed (%d)\n", + __func__, ret); + return ret; + } + + alarm_tm->tm_sec = 0; + alarm_tm->tm_min = bcd2bin(regs[0] & 0x7f); + alarm_tm->tm_hour = bcd2bin(regs[1] & 0x3f); + alarm_tm->tm_mday = bcd2bin(regs[2] & 0x3f); + alarm_tm->tm_wday = -1; + + /* + * The alarm section does not store year/month. We use the ones in rtc + * section as a basis and increment month and then year if needed to get + * alarm after current time. + */ + ret = _abb5zes3_rtc_read_time(dev, &rtc_tm); + if (ret) + return ret; + + alarm_tm->tm_year = rtc_tm.tm_year; + alarm_tm->tm_mon = rtc_tm.tm_mon; + + rtc_secs = rtc_tm_to_time64(&rtc_tm); + alarm_secs = rtc_tm_to_time64(alarm_tm); + + if (alarm_secs < rtc_secs) { + if (alarm_tm->tm_mon == 11) { + alarm_tm->tm_mon = 0; + alarm_tm->tm_year += 1; + } else { + alarm_tm->tm_mon += 1; + } + } + + ret = regmap_read(data->regmap, ABB5ZES3_REG_CTRL1, ®); + if (ret) { + dev_err(dev, "%s: reading ctrl reg failed (%d)\n", + __func__, ret); + return ret; + } + + alarm->enabled = !!(reg & ABB5ZES3_REG_CTRL1_AIE); + + return 0; +} + +/* + * As the Alarm mechanism supported by the chip is only accurate to the + * minute, we use the watchdog timer mechanism provided by timer A + * (up to 256 seconds w/ a second accuracy) for low alarm values (below + * 4 minutes). Otherwise, we use the common alarm mechanism provided + * by the chip. In order for that to work, we keep track of currently + * configured timer type via 'timer_alarm' flag in our private data + * structure. + */ +static int abb5zes3_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct abb5zes3_rtc_data *data = dev_get_drvdata(dev); + int ret; + + if (data->timer_alarm) + ret = _abb5zes3_rtc_read_timer(dev, alarm); + else + ret = _abb5zes3_rtc_read_alarm(dev, alarm); + + return ret; +} + +/* + * Set alarm using chip alarm mechanism. It is only accurate to the + * minute (not the second). The function expects alarm interrupt to + * be disabled. + */ +static int _abb5zes3_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct abb5zes3_rtc_data *data = dev_get_drvdata(dev); + struct rtc_time *alarm_tm = &alarm->time; + u8 regs[ABB5ZES3_ALRM_SEC_LEN]; + struct rtc_time rtc_tm; + int ret, enable = 1; + + if (!alarm->enabled) { + enable = 0; + } else { + unsigned long rtc_secs, alarm_secs; + + /* + * Chip only support alarms up to one month in the future. Let's + * return an error if we get something after that limit. + * Comparison is done by incrementing rtc_tm month field by one + * and checking alarm value is still below. + */ + ret = _abb5zes3_rtc_read_time(dev, &rtc_tm); + if (ret) + return ret; + + if (rtc_tm.tm_mon == 11) { /* handle year wrapping */ + rtc_tm.tm_mon = 0; + rtc_tm.tm_year += 1; + } else { + rtc_tm.tm_mon += 1; + } + + rtc_secs = rtc_tm_to_time64(&rtc_tm); + alarm_secs = rtc_tm_to_time64(alarm_tm); + + if (alarm_secs > rtc_secs) { + dev_err(dev, "%s: alarm maximum is one month in the future (%d)\n", + __func__, ret); + return -EINVAL; + } + } + + /* + * Program all alarm registers but DW one. For each register, setting + * MSB to 0 enables associated alarm. + */ + regs[0] = bin2bcd(alarm_tm->tm_min) & 0x7f; + regs[1] = bin2bcd(alarm_tm->tm_hour) & 0x3f; + regs[2] = bin2bcd(alarm_tm->tm_mday) & 0x3f; + regs[3] = ABB5ZES3_REG_ALRM_DW_AE; /* do not match day of the week */ + + ret = regmap_bulk_write(data->regmap, ABB5ZES3_REG_ALRM_MN, regs, + ABB5ZES3_ALRM_SEC_LEN); + if (ret < 0) { + dev_err(dev, "%s: writing ALARM section failed (%d)\n", + __func__, ret); + return ret; + } + + /* Record currently configured alarm is not a timer */ + data->timer_alarm = 0; + + /* Enable or disable alarm interrupt generation */ + return _abb5zes3_rtc_update_alarm(dev, enable); +} + +/* + * Set alarm using timer watchdog (via timer A) mechanism. The function expects + * timer A interrupt to be disabled. + */ +static int _abb5zes3_rtc_set_timer(struct device *dev, struct rtc_wkalrm *alarm, + u8 secs) +{ + struct abb5zes3_rtc_data *data = dev_get_drvdata(dev); + u8 regs[ABB5ZES3_TIMA_SEC_LEN]; + u8 mask = ABB5ZES3_REG_TIM_CLK_TAC0 | ABB5ZES3_REG_TIM_CLK_TAC1; + int ret = 0; + + /* Program given number of seconds to Timer A registers */ + sec_to_timer_a(secs, ®s[0], ®s[1]); + ret = regmap_bulk_write(data->regmap, ABB5ZES3_REG_TIMA_CLK, regs, + ABB5ZES3_TIMA_SEC_LEN); + if (ret < 0) { + dev_err(dev, "%s: writing timer section failed\n", __func__); + return ret; + } + + /* Configure Timer A as a watchdog timer */ + ret = regmap_update_bits(data->regmap, ABB5ZES3_REG_TIM_CLK, + mask, ABB5ZES3_REG_TIM_CLK_TAC1); + if (ret) + dev_err(dev, "%s: failed to update timer\n", __func__); + + /* Record currently configured alarm is a timer */ + data->timer_alarm = 1; + + /* Enable or disable timer interrupt generation */ + return _abb5zes3_rtc_update_timer(dev, alarm->enabled); +} + +/* + * The chip has an alarm which is only accurate to the minute. In order to + * handle alarms below that limit, we use the watchdog timer function of + * timer A. More precisely, the timer method is used for alarms below 240 + * seconds. + */ +static int abb5zes3_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct abb5zes3_rtc_data *data = dev_get_drvdata(dev); + struct rtc_time *alarm_tm = &alarm->time; + unsigned long rtc_secs, alarm_secs; + struct rtc_time rtc_tm; + int ret; + + ret = _abb5zes3_rtc_read_time(dev, &rtc_tm); + if (ret) + return ret; + + rtc_secs = rtc_tm_to_time64(&rtc_tm); + alarm_secs = rtc_tm_to_time64(alarm_tm); + + /* Let's first disable both the alarm and the timer interrupts */ + ret = _abb5zes3_rtc_update_alarm(dev, false); + if (ret < 0) { + dev_err(dev, "%s: unable to disable alarm (%d)\n", __func__, + ret); + return ret; + } + ret = _abb5zes3_rtc_update_timer(dev, false); + if (ret < 0) { + dev_err(dev, "%s: unable to disable timer (%d)\n", __func__, + ret); + return ret; + } + + data->timer_alarm = 0; + + /* + * Let's now configure the alarm; if we are expected to ring in + * more than 240s, then we setup an alarm. Otherwise, a timer. + */ + if ((alarm_secs > rtc_secs) && ((alarm_secs - rtc_secs) <= 240)) + ret = _abb5zes3_rtc_set_timer(dev, alarm, + alarm_secs - rtc_secs); + else + ret = _abb5zes3_rtc_set_alarm(dev, alarm); + + if (ret) + dev_err(dev, "%s: unable to configure alarm (%d)\n", __func__, + ret); + + return ret; +} + +/* Enable or disable battery low irq generation */ +static inline int _abb5zes3_rtc_battery_low_irq_enable(struct regmap *regmap, + bool enable) +{ + return regmap_update_bits(regmap, ABB5ZES3_REG_CTRL3, + ABB5ZES3_REG_CTRL3_BLIE, + enable ? ABB5ZES3_REG_CTRL3_BLIE : 0); +} + +/* + * Check current RTC status and enable/disable what needs to be. Return 0 if + * everything went ok and a negative value upon error. + */ +static int abb5zes3_rtc_check_setup(struct device *dev) +{ + struct abb5zes3_rtc_data *data = dev_get_drvdata(dev); + struct regmap *regmap = data->regmap; + unsigned int reg; + int ret; + u8 mask; + + /* + * By default, the devices generates a 32.768KHz signal on IRQ#1 pin. It + * is disabled here to prevent polluting the interrupt line and + * uselessly triggering the IRQ handler we install for alarm and battery + * low events. Note: this is done before clearing int. status below + * in this function. + * We also disable all timers and set timer interrupt to permanent (not + * pulsed). + */ + mask = (ABB5ZES3_REG_TIM_CLK_TBC | ABB5ZES3_REG_TIM_CLK_TAC0 | + ABB5ZES3_REG_TIM_CLK_TAC1 | ABB5ZES3_REG_TIM_CLK_COF0 | + ABB5ZES3_REG_TIM_CLK_COF1 | ABB5ZES3_REG_TIM_CLK_COF2 | + ABB5ZES3_REG_TIM_CLK_TBM | ABB5ZES3_REG_TIM_CLK_TAM); + ret = regmap_update_bits(regmap, ABB5ZES3_REG_TIM_CLK, mask, + ABB5ZES3_REG_TIM_CLK_COF0 | + ABB5ZES3_REG_TIM_CLK_COF1 | + ABB5ZES3_REG_TIM_CLK_COF2); + if (ret < 0) { + dev_err(dev, "%s: unable to initialize clkout register (%d)\n", + __func__, ret); + return ret; + } + + /* + * Each component of the alarm (MN, HR, DT, DW) can be enabled/disabled + * individually by clearing/setting MSB of each associated register. So, + * we set all alarm enable bits to disable current alarm setting. + */ + mask = (ABB5ZES3_REG_ALRM_MN_AE | ABB5ZES3_REG_ALRM_HR_AE | + ABB5ZES3_REG_ALRM_DT_AE | ABB5ZES3_REG_ALRM_DW_AE); + ret = regmap_update_bits(regmap, ABB5ZES3_REG_CTRL2, mask, mask); + if (ret < 0) { + dev_err(dev, "%s: unable to disable alarm setting (%d)\n", + __func__, ret); + return ret; + } + + /* Set Control 1 register (RTC enabled, 24hr mode, all int. disabled) */ + mask = (ABB5ZES3_REG_CTRL1_CIE | ABB5ZES3_REG_CTRL1_AIE | + ABB5ZES3_REG_CTRL1_SIE | ABB5ZES3_REG_CTRL1_PM | + ABB5ZES3_REG_CTRL1_CAP | ABB5ZES3_REG_CTRL1_STOP); + ret = regmap_update_bits(regmap, ABB5ZES3_REG_CTRL1, mask, 0); + if (ret < 0) { + dev_err(dev, "%s: unable to initialize CTRL1 register (%d)\n", + __func__, ret); + return ret; + } + + /* + * Set Control 2 register (timer int. disabled, alarm status cleared). + * WTAF is read-only and cleared automatically by reading the register. + */ + mask = (ABB5ZES3_REG_CTRL2_CTBIE | ABB5ZES3_REG_CTRL2_CTAIE | + ABB5ZES3_REG_CTRL2_WTAIE | ABB5ZES3_REG_CTRL2_AF | + ABB5ZES3_REG_CTRL2_SF | ABB5ZES3_REG_CTRL2_CTBF | + ABB5ZES3_REG_CTRL2_CTAF); + ret = regmap_update_bits(regmap, ABB5ZES3_REG_CTRL2, mask, 0); + if (ret < 0) { + dev_err(dev, "%s: unable to initialize CTRL2 register (%d)\n", + __func__, ret); + return ret; + } + + /* + * Enable battery low detection function and battery switchover function + * (standard mode). Disable associated interrupts. Clear battery + * switchover flag but not battery low flag. The latter is checked + * later below. + */ + mask = (ABB5ZES3_REG_CTRL3_PM0 | ABB5ZES3_REG_CTRL3_PM1 | + ABB5ZES3_REG_CTRL3_PM2 | ABB5ZES3_REG_CTRL3_BLIE | + ABB5ZES3_REG_CTRL3_BSIE | ABB5ZES3_REG_CTRL3_BSF); + ret = regmap_update_bits(regmap, ABB5ZES3_REG_CTRL3, mask, 0); + if (ret < 0) { + dev_err(dev, "%s: unable to initialize CTRL3 register (%d)\n", + __func__, ret); + return ret; + } + + /* Check oscillator integrity flag */ + ret = regmap_read(regmap, ABB5ZES3_REG_RTC_SC, ®); + if (ret < 0) { + dev_err(dev, "%s: unable to read osc. integrity flag (%d)\n", + __func__, ret); + return ret; + } + + if (reg & ABB5ZES3_REG_RTC_SC_OSC) { + dev_err(dev, "clock integrity not guaranteed. Osc. has stopped or has been interrupted.\n"); + dev_err(dev, "change battery (if not already done) and then set time to reset osc. failure flag.\n"); + } + + /* + * Check battery low flag at startup: this allows reporting battery + * is low at startup when IRQ line is not connected. Note: we record + * current status to avoid reenabling this interrupt later in probe + * function if battery is low. + */ + ret = regmap_read(regmap, ABB5ZES3_REG_CTRL3, ®); + if (ret < 0) { + dev_err(dev, "%s: unable to read battery low flag (%d)\n", + __func__, ret); + return ret; + } + + data->battery_low = reg & ABB5ZES3_REG_CTRL3_BLF; + if (data->battery_low) { + dev_err(dev, "RTC battery is low; please, consider changing it!\n"); + + ret = _abb5zes3_rtc_battery_low_irq_enable(regmap, false); + if (ret) + dev_err(dev, "%s: disabling battery low interrupt generation failed (%d)\n", + __func__, ret); + } + + return ret; +} + +static int abb5zes3_rtc_alarm_irq_enable(struct device *dev, + unsigned int enable) +{ + struct abb5zes3_rtc_data *rtc_data = dev_get_drvdata(dev); + int ret = 0; + + if (rtc_data->irq) { + if (rtc_data->timer_alarm) + ret = _abb5zes3_rtc_update_timer(dev, enable); + else + ret = _abb5zes3_rtc_update_alarm(dev, enable); + } + + return ret; +} + +static irqreturn_t _abb5zes3_rtc_interrupt(int irq, void *data) +{ + struct i2c_client *client = data; + struct device *dev = &client->dev; + struct abb5zes3_rtc_data *rtc_data = dev_get_drvdata(dev); + struct rtc_device *rtc = rtc_data->rtc; + u8 regs[ABB5ZES3_CTRL_SEC_LEN]; + int ret, handled = IRQ_NONE; + + ret = regmap_bulk_read(rtc_data->regmap, 0, regs, + ABB5ZES3_CTRL_SEC_LEN); + if (ret) { + dev_err(dev, "%s: unable to read control section (%d)!\n", + __func__, ret); + return handled; + } + + /* + * Check battery low detection flag and disable battery low interrupt + * generation if flag is set (interrupt can only be cleared when + * battery is replaced). + */ + if (regs[ABB5ZES3_REG_CTRL3] & ABB5ZES3_REG_CTRL3_BLF) { + dev_err(dev, "RTC battery is low; please change it!\n"); + + _abb5zes3_rtc_battery_low_irq_enable(rtc_data->regmap, false); + + handled = IRQ_HANDLED; + } + + /* Check alarm flag */ + if (regs[ABB5ZES3_REG_CTRL2] & ABB5ZES3_REG_CTRL2_AF) { + dev_dbg(dev, "RTC alarm!\n"); + + rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF); + + /* Acknowledge and disable the alarm */ + _abb5zes3_rtc_clear_alarm(dev); + _abb5zes3_rtc_update_alarm(dev, 0); + + handled = IRQ_HANDLED; + } + + /* Check watchdog Timer A flag */ + if (regs[ABB5ZES3_REG_CTRL2] & ABB5ZES3_REG_CTRL2_WTAF) { + dev_dbg(dev, "RTC timer!\n"); + + rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF); + + /* + * Acknowledge and disable the alarm. Note: WTAF + * flag had been cleared when reading CTRL2 + */ + _abb5zes3_rtc_update_timer(dev, 0); + + rtc_data->timer_alarm = 0; + + handled = IRQ_HANDLED; + } + + return handled; +} + +static const struct rtc_class_ops rtc_ops = { + .read_time = _abb5zes3_rtc_read_time, + .set_time = abb5zes3_rtc_set_time, + .read_alarm = abb5zes3_rtc_read_alarm, + .set_alarm = abb5zes3_rtc_set_alarm, + .alarm_irq_enable = abb5zes3_rtc_alarm_irq_enable, +}; + +static const struct regmap_config abb5zes3_rtc_regmap_config = { + .reg_bits = 8, + .val_bits = 8, +}; + +static int abb5zes3_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct abb5zes3_rtc_data *data = NULL; + struct device *dev = &client->dev; + struct regmap *regmap; + int ret; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C | + I2C_FUNC_SMBUS_BYTE_DATA | + I2C_FUNC_SMBUS_I2C_BLOCK)) + return -ENODEV; + + regmap = devm_regmap_init_i2c(client, &abb5zes3_rtc_regmap_config); + if (IS_ERR(regmap)) { + ret = PTR_ERR(regmap); + dev_err(dev, "%s: regmap allocation failed: %d\n", + __func__, ret); + return ret; + } + + ret = abb5zes3_i2c_validate_chip(regmap); + if (ret) + return ret; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->regmap = regmap; + dev_set_drvdata(dev, data); + + ret = abb5zes3_rtc_check_setup(dev); + if (ret) + return ret; + + data->rtc = devm_rtc_allocate_device(dev); + ret = PTR_ERR_OR_ZERO(data->rtc); + if (ret) { + dev_err(dev, "%s: unable to allocate RTC device (%d)\n", + __func__, ret); + return ret; + } + + if (client->irq > 0) { + ret = devm_request_threaded_irq(dev, client->irq, NULL, + _abb5zes3_rtc_interrupt, + IRQF_SHARED | IRQF_ONESHOT, + DRV_NAME, client); + if (!ret) { + device_init_wakeup(dev, true); + data->irq = client->irq; + dev_dbg(dev, "%s: irq %d used by RTC\n", __func__, + client->irq); + } else { + dev_err(dev, "%s: irq %d unavailable (%d)\n", + __func__, client->irq, ret); + goto err; + } + } + + data->rtc->ops = &rtc_ops; + data->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; + data->rtc->range_max = RTC_TIMESTAMP_END_2099; + + /* Enable battery low detection interrupt if battery not already low */ + if (!data->battery_low && data->irq) { + ret = _abb5zes3_rtc_battery_low_irq_enable(regmap, true); + if (ret) { + dev_err(dev, "%s: enabling battery low interrupt generation failed (%d)\n", + __func__, ret); + goto err; + } + } + + ret = rtc_register_device(data->rtc); + +err: + if (ret && data->irq) + device_init_wakeup(dev, false); + return ret; +} + +#ifdef CONFIG_PM_SLEEP +static int abb5zes3_rtc_suspend(struct device *dev) +{ + struct abb5zes3_rtc_data *rtc_data = dev_get_drvdata(dev); + + if (device_may_wakeup(dev)) + return enable_irq_wake(rtc_data->irq); + + return 0; +} + +static int abb5zes3_rtc_resume(struct device *dev) +{ + struct abb5zes3_rtc_data *rtc_data = dev_get_drvdata(dev); + + if (device_may_wakeup(dev)) + return disable_irq_wake(rtc_data->irq); + + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(abb5zes3_rtc_pm_ops, abb5zes3_rtc_suspend, + abb5zes3_rtc_resume); + +#ifdef CONFIG_OF +static const struct of_device_id abb5zes3_dt_match[] = { + { .compatible = "abracon,abb5zes3" }, + { }, +}; +MODULE_DEVICE_TABLE(of, abb5zes3_dt_match); +#endif + +static const struct i2c_device_id abb5zes3_id[] = { + { "abb5zes3", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, abb5zes3_id); + +static struct i2c_driver abb5zes3_driver = { + .driver = { + .name = DRV_NAME, + .pm = &abb5zes3_rtc_pm_ops, + .of_match_table = of_match_ptr(abb5zes3_dt_match), + }, + .probe = abb5zes3_probe, + .id_table = abb5zes3_id, +}; +module_i2c_driver(abb5zes3_driver); + +MODULE_AUTHOR("Arnaud EBALARD <arno@natisbad.org>"); +MODULE_DESCRIPTION("Abracon AB-RTCMC-32.768kHz-B5ZE-S3 RTC/Alarm driver"); +MODULE_LICENSE("GPL"); |