--- /dev/null
+/*
+ * 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:
+ *
+ * http://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).
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/mutex.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;
+ struct mutex lock;
+
+ 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. Note: this function is called early
+ * during init and hence does need mutex protection.
+ */
+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;
+
+ /*
+ * 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);
+ goto err;
+ }
+
+ /* If clock integrity is not guaranteed, do not return a time value */
+ if (regs[ABB5ZES3_REG_RTC_SC] & ABB5ZES3_REG_RTC_SC_OSC) {
+ ret = -ENODATA;
+ goto err;
+ }
+
+ 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;
+
+ ret = rtc_valid_tm(tm);
+
+err:
+ 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;
+
+ /*
+ * Year register is 8-bit wide and bcd-coded, i.e records values
+ * between 0 and 99. tm_year is an offset from 1900 and we are
+ * interested in the 2000-2099 range, so any value less than 100
+ * is invalid.
+ */
+ if (tm->tm_year < 100)
+ return -EINVAL;
+
+ 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);
+
+ mutex_lock(&data->lock);
+ ret = regmap_bulk_write(data->regmap, ABB5ZES3_REG_RTC_SC,
+ regs + ABB5ZES3_REG_RTC_SC,
+ ABB5ZES3_RTC_SEC_LEN);
+ mutex_unlock(&data->lock);
+
+
+ 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);
+ goto err;
+ }
+
+ /* get current time ... */
+ ret = _abb5zes3_rtc_read_time(dev, &rtc_tm);
+ if (ret)
+ goto err;
+
+ /* ... convert to seconds ... */
+ ret = rtc_tm_to_time(&rtc_tm, &rtc_secs);
+ if (ret)
+ goto err;
+
+ /* ... add remaining timer A time ... */
+ ret = sec_from_timer_a(&timer_secs, regs[1], regs[2]);
+ if (ret)
+ goto err;
+
+ /* ... and convert back. */
+ rtc_time_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);
+ goto err;
+ }
+
+ alarm->enabled = !!(reg & ABB5ZES3_REG_CTRL2_WTAIE);
+
+err:
+ return ret;
+}
+
+/* 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);
+ goto err;
+ }
+
+ 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)
+ goto err;
+
+ alarm_tm->tm_year = rtc_tm.tm_year;
+ alarm_tm->tm_mon = rtc_tm.tm_mon;
+
+ ret = rtc_tm_to_time(&rtc_tm, &rtc_secs);
+ if (ret)
+ goto err;
+
+ ret = rtc_tm_to_time(alarm_tm, &alarm_secs);
+ if (ret)
+ goto err;
+
+ 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);
+ goto err;
+ }
+
+ alarm->enabled = !!(reg & ABB5ZES3_REG_CTRL1_AIE);
+
+err:
+ return ret;
+}
+
+/*
+ * 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;
+
+ mutex_lock(&data->lock);
+ if (data->timer_alarm)
+ ret = _abb5zes3_rtc_read_timer(dev, alarm);
+ else
+ ret = _abb5zes3_rtc_read_alarm(dev, alarm);
+ mutex_unlock(&data->lock);
+
+ 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;
+ unsigned long rtc_secs, alarm_secs;
+ u8 regs[ABB5ZES3_ALRM_SEC_LEN];
+ struct rtc_time rtc_tm;
+ int ret, enable = 1;
+
+ ret = _abb5zes3_rtc_read_time(dev, &rtc_tm);
+ if (ret)
+ goto err;
+
+ ret = rtc_tm_to_time(&rtc_tm, &rtc_secs);
+ if (ret)
+ goto err;
+
+ ret = rtc_tm_to_time(alarm_tm, &alarm_secs);
+ if (ret)
+ goto err;
+
+ /* If alarm time is before current time, disable the alarm */
+ if (!alarm->enabled || alarm_secs <= rtc_secs) {
+ enable = 0;
+ } else {
+ /*
+ * 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.
+ */
+ 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;
+ }
+
+ ret = rtc_tm_to_time(&rtc_tm, &rtc_secs);
+ if (ret)
+ goto err;
+
+ if (alarm_secs > rtc_secs) {
+ dev_err(dev, "%s: alarm maximum is one month in the "
+ "future (%d)\n", __func__, ret);
+ ret = -EINVAL;
+ goto err;
+ }
+ }
+
+ /*
+ * 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);
+ goto err;
+ }
+
+ /* Record currently configured alarm is not a timer */
+ data->timer_alarm = 0;
+
+ /* Enable or disable alarm interrupt generation */
+ ret = _abb5zes3_rtc_update_alarm(dev, enable);
+
+err:
+ return ret;
+}
+
+/*
+ * 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__);
+ goto err;
+ }
+
+ /* 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 */
+ ret = _abb5zes3_rtc_update_timer(dev, alarm->enabled);
+
+err:
+ return ret;
+}
+
+/*
+ * 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;
+
+ mutex_lock(&data->lock);
+ ret = _abb5zes3_rtc_read_time(dev, &rtc_tm);
+ if (ret)
+ goto err;
+
+ ret = rtc_tm_to_time(&rtc_tm, &rtc_secs);
+ if (ret)
+ goto err;
+
+ ret = rtc_tm_to_time(alarm_tm, &alarm_secs);
+ if (ret)
+ goto err;
+
+ /* 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);
+ goto err;
+ }
+ ret = _abb5zes3_rtc_update_timer(dev, false);
+ if (ret < 0) {
+ dev_err(dev, "%s: unable to disable timer (%d)\n", __func__,
+ ret);
+ goto err;
+ }
+
+ 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);
+
+ err:
+ mutex_unlock(&data->lock);
+
+ 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. Note: this function
+ * is called early during init and hence does need mutex protection.
+ */
+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) {
+ mutex_lock(&rtc_data->lock);
+ if (rtc_data->timer_alarm)
+ ret = _abb5zes3_rtc_update_timer(dev, enable);
+ else
+ ret = _abb5zes3_rtc_update_alarm(dev, enable);
+ mutex_unlock(&rtc_data->lock);
+ }
+
+ 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)) {
+ ret = -ENODEV;
+ goto err;
+ }
+
+ 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);
+ goto err;
+ }
+
+ ret = abb5zes3_i2c_validate_chip(regmap);
+ if (ret)
+ goto err;
+
+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+ if (!data) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ mutex_init(&data->lock);
+ data->regmap = regmap;
+ dev_set_drvdata(dev, data);
+
+ ret = abb5zes3_rtc_check_setup(dev);
+ if (ret)
+ goto err;
+
+ 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 = devm_rtc_device_register(dev, DRV_NAME, &rtc_ops,
+ THIS_MODULE);
+ ret = PTR_ERR_OR_ZERO(data->rtc);
+ if (ret) {
+ dev_err(dev, "%s: unable to register RTC device (%d)\n",
+ __func__, ret);
+ goto err;
+ }
+
+ /* 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;
+ }
+ }
+
+err:
+ if (ret && data && data->irq)
+ device_init_wakeup(dev, false);
+ return ret;
+}
+
+static int abb5zes3_remove(struct i2c_client *client)
+{
+ struct abb5zes3_rtc_data *rtc_data = dev_get_drvdata(&client->dev);
+
+ if (rtc_data->irq > 0)
+ device_init_wakeup(&client->dev, false);
+
+ return 0;
+}
+
+#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" },
+ { },
+};
+#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,
+ .owner = THIS_MODULE,
+ .pm = &abb5zes3_rtc_pm_ops,
+ .of_match_table = of_match_ptr(abb5zes3_dt_match),
+ },
+ .probe = abb5zes3_probe,
+ .remove = abb5zes3_remove,
+ .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");
Code Review / kvmfornfv.git / blobdiff