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-rw-r--r--drivers/rtc/rtc-ds1685.c1452
1 files changed, 1452 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ds1685.c b/drivers/rtc/rtc-ds1685.c
new file mode 100644
index 000000000..98932ab0f
--- /dev/null
+++ b/drivers/rtc/rtc-ds1685.c
@@ -0,0 +1,1452 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * An rtc driver for the Dallas/Maxim DS1685/DS1687 and related real-time
+ * chips.
+ *
+ * Copyright (C) 2011-2014 Joshua Kinard <kumba@gentoo.org>.
+ * Copyright (C) 2009 Matthias Fuchs <matthias.fuchs@esd-electronics.com>.
+ *
+ * References:
+ * DS1685/DS1687 3V/5V Real-Time Clocks, 19-5215, Rev 4/10.
+ * DS17x85/DS17x87 3V/5V Real-Time Clocks, 19-5222, Rev 4/10.
+ * DS1689/DS1693 3V/5V Serialized Real-Time Clocks, Rev 112105.
+ * Application Note 90, Using the Multiplex Bus RTC Extended Features.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/bcd.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/workqueue.h>
+
+#include <linux/rtc/ds1685.h>
+
+#ifdef CONFIG_PROC_FS
+#include <linux/proc_fs.h>
+#endif
+
+
+/* ----------------------------------------------------------------------- */
+/*
+ * Standard read/write
+ * all registers are mapped in CPU address space
+ */
+
+/**
+ * ds1685_read - read a value from an rtc register.
+ * @rtc: pointer to the ds1685 rtc structure.
+ * @reg: the register address to read.
+ */
+static u8
+ds1685_read(struct ds1685_priv *rtc, int reg)
+{
+ return readb((u8 __iomem *)rtc->regs +
+ (reg * rtc->regstep));
+}
+
+/**
+ * ds1685_write - write a value to an rtc register.
+ * @rtc: pointer to the ds1685 rtc structure.
+ * @reg: the register address to write.
+ * @value: value to write to the register.
+ */
+static void
+ds1685_write(struct ds1685_priv *rtc, int reg, u8 value)
+{
+ writeb(value, ((u8 __iomem *)rtc->regs +
+ (reg * rtc->regstep)));
+}
+/* ----------------------------------------------------------------------- */
+
+/*
+ * Indirect read/write functions
+ * access happens via address and data register mapped in CPU address space
+ */
+
+/**
+ * ds1685_indirect_read - read a value from an rtc register.
+ * @rtc: pointer to the ds1685 rtc structure.
+ * @reg: the register address to read.
+ */
+static u8
+ds1685_indirect_read(struct ds1685_priv *rtc, int reg)
+{
+ writeb(reg, rtc->regs);
+ return readb(rtc->data);
+}
+
+/**
+ * ds1685_indirect_write - write a value to an rtc register.
+ * @rtc: pointer to the ds1685 rtc structure.
+ * @reg: the register address to write.
+ * @value: value to write to the register.
+ */
+static void
+ds1685_indirect_write(struct ds1685_priv *rtc, int reg, u8 value)
+{
+ writeb(reg, rtc->regs);
+ writeb(value, rtc->data);
+}
+
+/* ----------------------------------------------------------------------- */
+/* Inlined functions */
+
+/**
+ * ds1685_rtc_bcd2bin - bcd2bin wrapper in case platform doesn't support BCD.
+ * @rtc: pointer to the ds1685 rtc structure.
+ * @val: u8 time value to consider converting.
+ * @bcd_mask: u8 mask value if BCD mode is used.
+ * @bin_mask: u8 mask value if BIN mode is used.
+ *
+ * Returns the value, converted to BIN if originally in BCD and bcd_mode TRUE.
+ */
+static inline u8
+ds1685_rtc_bcd2bin(struct ds1685_priv *rtc, u8 val, u8 bcd_mask, u8 bin_mask)
+{
+ if (rtc->bcd_mode)
+ return (bcd2bin(val) & bcd_mask);
+
+ return (val & bin_mask);
+}
+
+/**
+ * ds1685_rtc_bin2bcd - bin2bcd wrapper in case platform doesn't support BCD.
+ * @rtc: pointer to the ds1685 rtc structure.
+ * @val: u8 time value to consider converting.
+ * @bin_mask: u8 mask value if BIN mode is used.
+ * @bcd_mask: u8 mask value if BCD mode is used.
+ *
+ * Returns the value, converted to BCD if originally in BIN and bcd_mode TRUE.
+ */
+static inline u8
+ds1685_rtc_bin2bcd(struct ds1685_priv *rtc, u8 val, u8 bin_mask, u8 bcd_mask)
+{
+ if (rtc->bcd_mode)
+ return (bin2bcd(val) & bcd_mask);
+
+ return (val & bin_mask);
+}
+
+/**
+ * s1685_rtc_check_mday - check validity of the day of month.
+ * @rtc: pointer to the ds1685 rtc structure.
+ * @mday: day of month.
+ *
+ * Returns -EDOM if the day of month is not within 1..31 range.
+ */
+static inline int
+ds1685_rtc_check_mday(struct ds1685_priv *rtc, u8 mday)
+{
+ if (rtc->bcd_mode) {
+ if (mday < 0x01 || mday > 0x31 || (mday & 0x0f) > 0x09)
+ return -EDOM;
+ } else {
+ if (mday < 1 || mday > 31)
+ return -EDOM;
+ }
+ return 0;
+}
+
+/**
+ * ds1685_rtc_switch_to_bank0 - switch the rtc to bank 0.
+ * @rtc: pointer to the ds1685 rtc structure.
+ */
+static inline void
+ds1685_rtc_switch_to_bank0(struct ds1685_priv *rtc)
+{
+ rtc->write(rtc, RTC_CTRL_A,
+ (rtc->read(rtc, RTC_CTRL_A) & ~(RTC_CTRL_A_DV0)));
+}
+
+/**
+ * ds1685_rtc_switch_to_bank1 - switch the rtc to bank 1.
+ * @rtc: pointer to the ds1685 rtc structure.
+ */
+static inline void
+ds1685_rtc_switch_to_bank1(struct ds1685_priv *rtc)
+{
+ rtc->write(rtc, RTC_CTRL_A,
+ (rtc->read(rtc, RTC_CTRL_A) | RTC_CTRL_A_DV0));
+}
+
+/**
+ * ds1685_rtc_begin_data_access - prepare the rtc for data access.
+ * @rtc: pointer to the ds1685 rtc structure.
+ *
+ * This takes several steps to prepare the rtc for access to get/set time
+ * and alarm values from the rtc registers:
+ * - Sets the SET bit in Control Register B.
+ * - Reads Ext Control Register 4A and checks the INCR bit.
+ * - If INCR is active, a short delay is added before Ext Control Register 4A
+ * is read again in a loop until INCR is inactive.
+ * - Switches the rtc to bank 1. This allows access to all relevant
+ * data for normal rtc operation, as bank 0 contains only the nvram.
+ */
+static inline void
+ds1685_rtc_begin_data_access(struct ds1685_priv *rtc)
+{
+ /* Set the SET bit in Ctrl B */
+ rtc->write(rtc, RTC_CTRL_B,
+ (rtc->read(rtc, RTC_CTRL_B) | RTC_CTRL_B_SET));
+
+ /* Switch to Bank 1 */
+ ds1685_rtc_switch_to_bank1(rtc);
+
+ /* Read Ext Ctrl 4A and check the INCR bit to avoid a lockout. */
+ while (rtc->read(rtc, RTC_EXT_CTRL_4A) & RTC_CTRL_4A_INCR)
+ cpu_relax();
+}
+
+/**
+ * ds1685_rtc_end_data_access - end data access on the rtc.
+ * @rtc: pointer to the ds1685 rtc structure.
+ *
+ * This ends what was started by ds1685_rtc_begin_data_access:
+ * - Switches the rtc back to bank 0.
+ * - Clears the SET bit in Control Register B.
+ */
+static inline void
+ds1685_rtc_end_data_access(struct ds1685_priv *rtc)
+{
+ /* Switch back to Bank 0 */
+ ds1685_rtc_switch_to_bank0(rtc);
+
+ /* Clear the SET bit in Ctrl B */
+ rtc->write(rtc, RTC_CTRL_B,
+ (rtc->read(rtc, RTC_CTRL_B) & ~(RTC_CTRL_B_SET)));
+}
+
+/**
+ * ds1685_rtc_get_ssn - retrieve the silicon serial number.
+ * @rtc: pointer to the ds1685 rtc structure.
+ * @ssn: u8 array to hold the bits of the silicon serial number.
+ *
+ * This number starts at 0x40, and is 8-bytes long, ending at 0x47. The
+ * first byte is the model number, the next six bytes are the serial number
+ * digits, and the final byte is a CRC check byte. Together, they form the
+ * silicon serial number.
+ *
+ * These values are stored in bank1, so ds1685_rtc_switch_to_bank1 must be
+ * called first before calling this function, else data will be read out of
+ * the bank0 NVRAM. Be sure to call ds1685_rtc_switch_to_bank0 when done.
+ */
+static inline void
+ds1685_rtc_get_ssn(struct ds1685_priv *rtc, u8 *ssn)
+{
+ ssn[0] = rtc->read(rtc, RTC_BANK1_SSN_MODEL);
+ ssn[1] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_1);
+ ssn[2] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_2);
+ ssn[3] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_3);
+ ssn[4] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_4);
+ ssn[5] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_5);
+ ssn[6] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_6);
+ ssn[7] = rtc->read(rtc, RTC_BANK1_SSN_CRC);
+}
+/* ----------------------------------------------------------------------- */
+
+
+/* ----------------------------------------------------------------------- */
+/* Read/Set Time & Alarm functions */
+
+/**
+ * ds1685_rtc_read_time - reads the time registers.
+ * @dev: pointer to device structure.
+ * @tm: pointer to rtc_time structure.
+ */
+static int
+ds1685_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct ds1685_priv *rtc = dev_get_drvdata(dev);
+ u8 century;
+ u8 seconds, minutes, hours, wday, mday, month, years;
+
+ /* Fetch the time info from the RTC registers. */
+ ds1685_rtc_begin_data_access(rtc);
+ seconds = rtc->read(rtc, RTC_SECS);
+ minutes = rtc->read(rtc, RTC_MINS);
+ hours = rtc->read(rtc, RTC_HRS);
+ wday = rtc->read(rtc, RTC_WDAY);
+ mday = rtc->read(rtc, RTC_MDAY);
+ month = rtc->read(rtc, RTC_MONTH);
+ years = rtc->read(rtc, RTC_YEAR);
+ century = rtc->read(rtc, RTC_CENTURY);
+ ds1685_rtc_end_data_access(rtc);
+
+ /* bcd2bin if needed, perform fixups, and store to rtc_time. */
+ years = ds1685_rtc_bcd2bin(rtc, years, RTC_YEAR_BCD_MASK,
+ RTC_YEAR_BIN_MASK);
+ century = ds1685_rtc_bcd2bin(rtc, century, RTC_CENTURY_MASK,
+ RTC_CENTURY_MASK);
+ tm->tm_sec = ds1685_rtc_bcd2bin(rtc, seconds, RTC_SECS_BCD_MASK,
+ RTC_SECS_BIN_MASK);
+ tm->tm_min = ds1685_rtc_bcd2bin(rtc, minutes, RTC_MINS_BCD_MASK,
+ RTC_MINS_BIN_MASK);
+ tm->tm_hour = ds1685_rtc_bcd2bin(rtc, hours, RTC_HRS_24_BCD_MASK,
+ RTC_HRS_24_BIN_MASK);
+ tm->tm_wday = (ds1685_rtc_bcd2bin(rtc, wday, RTC_WDAY_MASK,
+ RTC_WDAY_MASK) - 1);
+ tm->tm_mday = ds1685_rtc_bcd2bin(rtc, mday, RTC_MDAY_BCD_MASK,
+ RTC_MDAY_BIN_MASK);
+ tm->tm_mon = (ds1685_rtc_bcd2bin(rtc, month, RTC_MONTH_BCD_MASK,
+ RTC_MONTH_BIN_MASK) - 1);
+ tm->tm_year = ((years + (century * 100)) - 1900);
+ tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
+ tm->tm_isdst = 0; /* RTC has hardcoded timezone, so don't use. */
+
+ return 0;
+}
+
+/**
+ * ds1685_rtc_set_time - sets the time registers.
+ * @dev: pointer to device structure.
+ * @tm: pointer to rtc_time structure.
+ */
+static int
+ds1685_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct ds1685_priv *rtc = dev_get_drvdata(dev);
+ u8 ctrlb, seconds, minutes, hours, wday, mday, month, years, century;
+
+ /* Fetch the time info from rtc_time. */
+ seconds = ds1685_rtc_bin2bcd(rtc, tm->tm_sec, RTC_SECS_BIN_MASK,
+ RTC_SECS_BCD_MASK);
+ minutes = ds1685_rtc_bin2bcd(rtc, tm->tm_min, RTC_MINS_BIN_MASK,
+ RTC_MINS_BCD_MASK);
+ hours = ds1685_rtc_bin2bcd(rtc, tm->tm_hour, RTC_HRS_24_BIN_MASK,
+ RTC_HRS_24_BCD_MASK);
+ wday = ds1685_rtc_bin2bcd(rtc, (tm->tm_wday + 1), RTC_WDAY_MASK,
+ RTC_WDAY_MASK);
+ mday = ds1685_rtc_bin2bcd(rtc, tm->tm_mday, RTC_MDAY_BIN_MASK,
+ RTC_MDAY_BCD_MASK);
+ month = ds1685_rtc_bin2bcd(rtc, (tm->tm_mon + 1), RTC_MONTH_BIN_MASK,
+ RTC_MONTH_BCD_MASK);
+ years = ds1685_rtc_bin2bcd(rtc, (tm->tm_year % 100),
+ RTC_YEAR_BIN_MASK, RTC_YEAR_BCD_MASK);
+ century = ds1685_rtc_bin2bcd(rtc, ((tm->tm_year + 1900) / 100),
+ RTC_CENTURY_MASK, RTC_CENTURY_MASK);
+
+ /*
+ * Perform Sanity Checks:
+ * - Months: !> 12, Month Day != 0.
+ * - Month Day !> Max days in current month.
+ * - Hours !>= 24, Mins !>= 60, Secs !>= 60, & Weekday !> 7.
+ */
+ if ((tm->tm_mon > 11) || (mday == 0))
+ return -EDOM;
+
+ if (tm->tm_mday > rtc_month_days(tm->tm_mon, tm->tm_year))
+ return -EDOM;
+
+ if ((tm->tm_hour >= 24) || (tm->tm_min >= 60) ||
+ (tm->tm_sec >= 60) || (wday > 7))
+ return -EDOM;
+
+ /*
+ * Set the data mode to use and store the time values in the
+ * RTC registers.
+ */
+ ds1685_rtc_begin_data_access(rtc);
+ ctrlb = rtc->read(rtc, RTC_CTRL_B);
+ if (rtc->bcd_mode)
+ ctrlb &= ~(RTC_CTRL_B_DM);
+ else
+ ctrlb |= RTC_CTRL_B_DM;
+ rtc->write(rtc, RTC_CTRL_B, ctrlb);
+ rtc->write(rtc, RTC_SECS, seconds);
+ rtc->write(rtc, RTC_MINS, minutes);
+ rtc->write(rtc, RTC_HRS, hours);
+ rtc->write(rtc, RTC_WDAY, wday);
+ rtc->write(rtc, RTC_MDAY, mday);
+ rtc->write(rtc, RTC_MONTH, month);
+ rtc->write(rtc, RTC_YEAR, years);
+ rtc->write(rtc, RTC_CENTURY, century);
+ ds1685_rtc_end_data_access(rtc);
+
+ return 0;
+}
+
+/**
+ * ds1685_rtc_read_alarm - reads the alarm registers.
+ * @dev: pointer to device structure.
+ * @alrm: pointer to rtc_wkalrm structure.
+ *
+ * There are three primary alarm registers: seconds, minutes, and hours.
+ * A fourth alarm register for the month date is also available in bank1 for
+ * kickstart/wakeup features. The DS1685/DS1687 manual states that a
+ * "don't care" value ranging from 0xc0 to 0xff may be written into one or
+ * more of the three alarm bytes to act as a wildcard value. The fourth
+ * byte doesn't support a "don't care" value.
+ */
+static int
+ds1685_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct ds1685_priv *rtc = dev_get_drvdata(dev);
+ u8 seconds, minutes, hours, mday, ctrlb, ctrlc;
+ int ret;
+
+ /* Fetch the alarm info from the RTC alarm registers. */
+ ds1685_rtc_begin_data_access(rtc);
+ seconds = rtc->read(rtc, RTC_SECS_ALARM);
+ minutes = rtc->read(rtc, RTC_MINS_ALARM);
+ hours = rtc->read(rtc, RTC_HRS_ALARM);
+ mday = rtc->read(rtc, RTC_MDAY_ALARM);
+ ctrlb = rtc->read(rtc, RTC_CTRL_B);
+ ctrlc = rtc->read(rtc, RTC_CTRL_C);
+ ds1685_rtc_end_data_access(rtc);
+
+ /* Check the month date for validity. */
+ ret = ds1685_rtc_check_mday(rtc, mday);
+ if (ret)
+ return ret;
+
+ /*
+ * Check the three alarm bytes.
+ *
+ * The Linux RTC system doesn't support the "don't care" capability
+ * of this RTC chip. We check for it anyways in case support is
+ * added in the future and only assign when we care.
+ */
+ if (likely(seconds < 0xc0))
+ alrm->time.tm_sec = ds1685_rtc_bcd2bin(rtc, seconds,
+ RTC_SECS_BCD_MASK,
+ RTC_SECS_BIN_MASK);
+
+ if (likely(minutes < 0xc0))
+ alrm->time.tm_min = ds1685_rtc_bcd2bin(rtc, minutes,
+ RTC_MINS_BCD_MASK,
+ RTC_MINS_BIN_MASK);
+
+ if (likely(hours < 0xc0))
+ alrm->time.tm_hour = ds1685_rtc_bcd2bin(rtc, hours,
+ RTC_HRS_24_BCD_MASK,
+ RTC_HRS_24_BIN_MASK);
+
+ /* Write the data to rtc_wkalrm. */
+ alrm->time.tm_mday = ds1685_rtc_bcd2bin(rtc, mday, RTC_MDAY_BCD_MASK,
+ RTC_MDAY_BIN_MASK);
+ alrm->enabled = !!(ctrlb & RTC_CTRL_B_AIE);
+ alrm->pending = !!(ctrlc & RTC_CTRL_C_AF);
+
+ return 0;
+}
+
+/**
+ * ds1685_rtc_set_alarm - sets the alarm in registers.
+ * @dev: pointer to device structure.
+ * @alrm: pointer to rtc_wkalrm structure.
+ */
+static int
+ds1685_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct ds1685_priv *rtc = dev_get_drvdata(dev);
+ u8 ctrlb, seconds, minutes, hours, mday;
+ int ret;
+
+ /* Fetch the alarm info and convert to BCD. */
+ seconds = ds1685_rtc_bin2bcd(rtc, alrm->time.tm_sec,
+ RTC_SECS_BIN_MASK,
+ RTC_SECS_BCD_MASK);
+ minutes = ds1685_rtc_bin2bcd(rtc, alrm->time.tm_min,
+ RTC_MINS_BIN_MASK,
+ RTC_MINS_BCD_MASK);
+ hours = ds1685_rtc_bin2bcd(rtc, alrm->time.tm_hour,
+ RTC_HRS_24_BIN_MASK,
+ RTC_HRS_24_BCD_MASK);
+ mday = ds1685_rtc_bin2bcd(rtc, alrm->time.tm_mday,
+ RTC_MDAY_BIN_MASK,
+ RTC_MDAY_BCD_MASK);
+
+ /* Check the month date for validity. */
+ ret = ds1685_rtc_check_mday(rtc, mday);
+ if (ret)
+ return ret;
+
+ /*
+ * Check the three alarm bytes.
+ *
+ * The Linux RTC system doesn't support the "don't care" capability
+ * of this RTC chip because rtc_valid_tm tries to validate every
+ * field, and we only support four fields. We put the support
+ * here anyways for the future.
+ */
+ if (unlikely(seconds >= 0xc0))
+ seconds = 0xff;
+
+ if (unlikely(minutes >= 0xc0))
+ minutes = 0xff;
+
+ if (unlikely(hours >= 0xc0))
+ hours = 0xff;
+
+ alrm->time.tm_mon = -1;
+ alrm->time.tm_year = -1;
+ alrm->time.tm_wday = -1;
+ alrm->time.tm_yday = -1;
+ alrm->time.tm_isdst = -1;
+
+ /* Disable the alarm interrupt first. */
+ ds1685_rtc_begin_data_access(rtc);
+ ctrlb = rtc->read(rtc, RTC_CTRL_B);
+ rtc->write(rtc, RTC_CTRL_B, (ctrlb & ~(RTC_CTRL_B_AIE)));
+
+ /* Read ctrlc to clear RTC_CTRL_C_AF. */
+ rtc->read(rtc, RTC_CTRL_C);
+
+ /*
+ * Set the data mode to use and store the time values in the
+ * RTC registers.
+ */
+ ctrlb = rtc->read(rtc, RTC_CTRL_B);
+ if (rtc->bcd_mode)
+ ctrlb &= ~(RTC_CTRL_B_DM);
+ else
+ ctrlb |= RTC_CTRL_B_DM;
+ rtc->write(rtc, RTC_CTRL_B, ctrlb);
+ rtc->write(rtc, RTC_SECS_ALARM, seconds);
+ rtc->write(rtc, RTC_MINS_ALARM, minutes);
+ rtc->write(rtc, RTC_HRS_ALARM, hours);
+ rtc->write(rtc, RTC_MDAY_ALARM, mday);
+
+ /* Re-enable the alarm if needed. */
+ if (alrm->enabled) {
+ ctrlb = rtc->read(rtc, RTC_CTRL_B);
+ ctrlb |= RTC_CTRL_B_AIE;
+ rtc->write(rtc, RTC_CTRL_B, ctrlb);
+ }
+
+ /* Done! */
+ ds1685_rtc_end_data_access(rtc);
+
+ return 0;
+}
+/* ----------------------------------------------------------------------- */
+
+
+/* ----------------------------------------------------------------------- */
+/* /dev/rtcX Interface functions */
+
+/**
+ * ds1685_rtc_alarm_irq_enable - replaces ioctl() RTC_AIE on/off.
+ * @dev: pointer to device structure.
+ * @enabled: flag indicating whether to enable or disable.
+ */
+static int
+ds1685_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct ds1685_priv *rtc = dev_get_drvdata(dev);
+
+ /* Flip the requisite interrupt-enable bit. */
+ if (enabled)
+ rtc->write(rtc, RTC_CTRL_B, (rtc->read(rtc, RTC_CTRL_B) |
+ RTC_CTRL_B_AIE));
+ else
+ rtc->write(rtc, RTC_CTRL_B, (rtc->read(rtc, RTC_CTRL_B) &
+ ~(RTC_CTRL_B_AIE)));
+
+ /* Read Control C to clear all the flag bits. */
+ rtc->read(rtc, RTC_CTRL_C);
+
+ return 0;
+}
+/* ----------------------------------------------------------------------- */
+
+
+/* ----------------------------------------------------------------------- */
+/* IRQ handler */
+
+/**
+ * ds1685_rtc_extended_irq - take care of extended interrupts
+ * @rtc: pointer to the ds1685 rtc structure.
+ * @pdev: platform device pointer.
+ */
+static void
+ds1685_rtc_extended_irq(struct ds1685_priv *rtc, struct platform_device *pdev)
+{
+ u8 ctrl4a, ctrl4b;
+
+ ds1685_rtc_switch_to_bank1(rtc);
+ ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
+ ctrl4b = rtc->read(rtc, RTC_EXT_CTRL_4B);
+
+ /*
+ * Check for a kickstart interrupt. With Vcc applied, this
+ * typically means that the power button was pressed, so we
+ * begin the shutdown sequence.
+ */
+ if ((ctrl4b & RTC_CTRL_4B_KSE) && (ctrl4a & RTC_CTRL_4A_KF)) {
+ /* Briefly disable kickstarts to debounce button presses. */
+ rtc->write(rtc, RTC_EXT_CTRL_4B,
+ (rtc->read(rtc, RTC_EXT_CTRL_4B) &
+ ~(RTC_CTRL_4B_KSE)));
+
+ /* Clear the kickstart flag. */
+ rtc->write(rtc, RTC_EXT_CTRL_4A,
+ (ctrl4a & ~(RTC_CTRL_4A_KF)));
+
+
+ /*
+ * Sleep 500ms before re-enabling kickstarts. This allows
+ * adequate time to avoid reading signal jitter as additional
+ * button presses.
+ */
+ msleep(500);
+ rtc->write(rtc, RTC_EXT_CTRL_4B,
+ (rtc->read(rtc, RTC_EXT_CTRL_4B) |
+ RTC_CTRL_4B_KSE));
+
+ /* Call the platform pre-poweroff function. Else, shutdown. */
+ if (rtc->prepare_poweroff != NULL)
+ rtc->prepare_poweroff();
+ else
+ ds1685_rtc_poweroff(pdev);
+ }
+
+ /*
+ * Check for a wake-up interrupt. With Vcc applied, this is
+ * essentially a second alarm interrupt, except it takes into
+ * account the 'date' register in bank1 in addition to the
+ * standard three alarm registers.
+ */
+ if ((ctrl4b & RTC_CTRL_4B_WIE) && (ctrl4a & RTC_CTRL_4A_WF)) {
+ rtc->write(rtc, RTC_EXT_CTRL_4A,
+ (ctrl4a & ~(RTC_CTRL_4A_WF)));
+
+ /* Call the platform wake_alarm function if defined. */
+ if (rtc->wake_alarm != NULL)
+ rtc->wake_alarm();
+ else
+ dev_warn(&pdev->dev,
+ "Wake Alarm IRQ just occurred!\n");
+ }
+
+ /*
+ * Check for a ram-clear interrupt. This happens if RIE=1 and RF=0
+ * when RCE=1 in 4B. This clears all NVRAM bytes in bank0 by setting
+ * each byte to a logic 1. This has no effect on any extended
+ * NV-SRAM that might be present, nor on the time/calendar/alarm
+ * registers. After a ram-clear is completed, there is a minimum
+ * recovery time of ~150ms in which all reads/writes are locked out.
+ * NOTE: A ram-clear can still occur if RCE=1 and RIE=0. We cannot
+ * catch this scenario.
+ */
+ if ((ctrl4b & RTC_CTRL_4B_RIE) && (ctrl4a & RTC_CTRL_4A_RF)) {
+ rtc->write(rtc, RTC_EXT_CTRL_4A,
+ (ctrl4a & ~(RTC_CTRL_4A_RF)));
+ msleep(150);
+
+ /* Call the platform post_ram_clear function if defined. */
+ if (rtc->post_ram_clear != NULL)
+ rtc->post_ram_clear();
+ else
+ dev_warn(&pdev->dev,
+ "RAM-Clear IRQ just occurred!\n");
+ }
+ ds1685_rtc_switch_to_bank0(rtc);
+}
+
+/**
+ * ds1685_rtc_irq_handler - IRQ handler.
+ * @irq: IRQ number.
+ * @dev_id: platform device pointer.
+ */
+static irqreturn_t
+ds1685_rtc_irq_handler(int irq, void *dev_id)
+{
+ struct platform_device *pdev = dev_id;
+ struct ds1685_priv *rtc = platform_get_drvdata(pdev);
+ struct mutex *rtc_mutex;
+ u8 ctrlb, ctrlc;
+ unsigned long events = 0;
+ u8 num_irqs = 0;
+
+ /* Abort early if the device isn't ready yet (i.e., DEBUG_SHIRQ). */
+ if (unlikely(!rtc))
+ return IRQ_HANDLED;
+
+ rtc_mutex = &rtc->dev->ops_lock;
+ mutex_lock(rtc_mutex);
+
+ /* Ctrlb holds the interrupt-enable bits and ctrlc the flag bits. */
+ ctrlb = rtc->read(rtc, RTC_CTRL_B);
+ ctrlc = rtc->read(rtc, RTC_CTRL_C);
+
+ /* Is the IRQF bit set? */
+ if (likely(ctrlc & RTC_CTRL_C_IRQF)) {
+ /*
+ * We need to determine if it was one of the standard
+ * events: PF, AF, or UF. If so, we handle them and
+ * update the RTC core.
+ */
+ if (likely(ctrlc & RTC_CTRL_B_PAU_MASK)) {
+ events = RTC_IRQF;
+
+ /* Check for a periodic interrupt. */
+ if ((ctrlb & RTC_CTRL_B_PIE) &&
+ (ctrlc & RTC_CTRL_C_PF)) {
+ events |= RTC_PF;
+ num_irqs++;
+ }
+
+ /* Check for an alarm interrupt. */
+ if ((ctrlb & RTC_CTRL_B_AIE) &&
+ (ctrlc & RTC_CTRL_C_AF)) {
+ events |= RTC_AF;
+ num_irqs++;
+ }
+
+ /* Check for an update interrupt. */
+ if ((ctrlb & RTC_CTRL_B_UIE) &&
+ (ctrlc & RTC_CTRL_C_UF)) {
+ events |= RTC_UF;
+ num_irqs++;
+ }
+ } else {
+ /*
+ * One of the "extended" interrupts was received that
+ * is not recognized by the RTC core.
+ */
+ ds1685_rtc_extended_irq(rtc, pdev);
+ }
+ }
+ rtc_update_irq(rtc->dev, num_irqs, events);
+ mutex_unlock(rtc_mutex);
+
+ return events ? IRQ_HANDLED : IRQ_NONE;
+}
+/* ----------------------------------------------------------------------- */
+
+
+/* ----------------------------------------------------------------------- */
+/* ProcFS interface */
+
+#ifdef CONFIG_PROC_FS
+#define NUM_REGS 6 /* Num of control registers. */
+#define NUM_BITS 8 /* Num bits per register. */
+#define NUM_SPACES 4 /* Num spaces between each bit. */
+
+/*
+ * Periodic Interrupt Rates.
+ */
+static const char *ds1685_rtc_pirq_rate[16] = {
+ "none", "3.90625ms", "7.8125ms", "0.122070ms", "0.244141ms",
+ "0.488281ms", "0.9765625ms", "1.953125ms", "3.90625ms", "7.8125ms",
+ "15.625ms", "31.25ms", "62.5ms", "125ms", "250ms", "500ms"
+};
+
+/*
+ * Square-Wave Output Frequencies.
+ */
+static const char *ds1685_rtc_sqw_freq[16] = {
+ "none", "256Hz", "128Hz", "8192Hz", "4096Hz", "2048Hz", "1024Hz",
+ "512Hz", "256Hz", "128Hz", "64Hz", "32Hz", "16Hz", "8Hz", "4Hz", "2Hz"
+};
+
+/**
+ * ds1685_rtc_proc - procfs access function.
+ * @dev: pointer to device structure.
+ * @seq: pointer to seq_file structure.
+ */
+static int
+ds1685_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+ struct ds1685_priv *rtc = dev_get_drvdata(dev);
+ u8 ctrla, ctrlb, ctrld, ctrl4a, ctrl4b, ssn[8];
+ char *model;
+
+ /* Read all the relevant data from the control registers. */
+ ds1685_rtc_switch_to_bank1(rtc);
+ ds1685_rtc_get_ssn(rtc, ssn);
+ ctrla = rtc->read(rtc, RTC_CTRL_A);
+ ctrlb = rtc->read(rtc, RTC_CTRL_B);
+ ctrld = rtc->read(rtc, RTC_CTRL_D);
+ ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
+ ctrl4b = rtc->read(rtc, RTC_EXT_CTRL_4B);
+ ds1685_rtc_switch_to_bank0(rtc);
+
+ /* Determine the RTC model. */
+ switch (ssn[0]) {
+ case RTC_MODEL_DS1685:
+ model = "DS1685/DS1687\0";
+ break;
+ case RTC_MODEL_DS1689:
+ model = "DS1689/DS1693\0";
+ break;
+ case RTC_MODEL_DS17285:
+ model = "DS17285/DS17287\0";
+ break;
+ case RTC_MODEL_DS17485:
+ model = "DS17485/DS17487\0";
+ break;
+ case RTC_MODEL_DS17885:
+ model = "DS17885/DS17887\0";
+ break;
+ default:
+ model = "Unknown\0";
+ break;
+ }
+
+ /* Print out the information. */
+ seq_printf(seq,
+ "Model\t\t: %s\n"
+ "Oscillator\t: %s\n"
+ "12/24hr\t\t: %s\n"
+ "DST\t\t: %s\n"
+ "Data mode\t: %s\n"
+ "Battery\t\t: %s\n"
+ "Aux batt\t: %s\n"
+ "Update IRQ\t: %s\n"
+ "Periodic IRQ\t: %s\n"
+ "Periodic Rate\t: %s\n"
+ "SQW Freq\t: %s\n"
+ "Serial #\t: %8phC\n",
+ model,
+ ((ctrla & RTC_CTRL_A_DV1) ? "enabled" : "disabled"),
+ ((ctrlb & RTC_CTRL_B_2412) ? "24-hour" : "12-hour"),
+ ((ctrlb & RTC_CTRL_B_DSE) ? "enabled" : "disabled"),
+ ((ctrlb & RTC_CTRL_B_DM) ? "binary" : "BCD"),
+ ((ctrld & RTC_CTRL_D_VRT) ? "ok" : "exhausted or n/a"),
+ ((ctrl4a & RTC_CTRL_4A_VRT2) ? "ok" : "exhausted or n/a"),
+ ((ctrlb & RTC_CTRL_B_UIE) ? "yes" : "no"),
+ ((ctrlb & RTC_CTRL_B_PIE) ? "yes" : "no"),
+ (!(ctrl4b & RTC_CTRL_4B_E32K) ?
+ ds1685_rtc_pirq_rate[(ctrla & RTC_CTRL_A_RS_MASK)] : "none"),
+ (!((ctrl4b & RTC_CTRL_4B_E32K)) ?
+ ds1685_rtc_sqw_freq[(ctrla & RTC_CTRL_A_RS_MASK)] : "32768Hz"),
+ ssn);
+ return 0;
+}
+#else
+#define ds1685_rtc_proc NULL
+#endif /* CONFIG_PROC_FS */
+/* ----------------------------------------------------------------------- */
+
+
+/* ----------------------------------------------------------------------- */
+/* RTC Class operations */
+
+static const struct rtc_class_ops
+ds1685_rtc_ops = {
+ .proc = ds1685_rtc_proc,
+ .read_time = ds1685_rtc_read_time,
+ .set_time = ds1685_rtc_set_time,
+ .read_alarm = ds1685_rtc_read_alarm,
+ .set_alarm = ds1685_rtc_set_alarm,
+ .alarm_irq_enable = ds1685_rtc_alarm_irq_enable,
+};
+/* ----------------------------------------------------------------------- */
+
+static int ds1685_nvram_read(void *priv, unsigned int pos, void *val,
+ size_t size)
+{
+ struct ds1685_priv *rtc = priv;
+ struct mutex *rtc_mutex = &rtc->dev->ops_lock;
+ ssize_t count;
+ u8 *buf = val;
+ int err;
+
+ err = mutex_lock_interruptible(rtc_mutex);
+ if (err)
+ return err;
+
+ ds1685_rtc_switch_to_bank0(rtc);
+
+ /* Read NVRAM in time and bank0 registers. */
+ for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ_BANK0;
+ count++, size--) {
+ if (count < NVRAM_SZ_TIME)
+ *buf++ = rtc->read(rtc, (NVRAM_TIME_BASE + pos++));
+ else
+ *buf++ = rtc->read(rtc, (NVRAM_BANK0_BASE + pos++));
+ }
+
+#ifndef CONFIG_RTC_DRV_DS1689
+ if (size > 0) {
+ ds1685_rtc_switch_to_bank1(rtc);
+
+#ifndef CONFIG_RTC_DRV_DS1685
+ /* Enable burst-mode on DS17x85/DS17x87 */
+ rtc->write(rtc, RTC_EXT_CTRL_4A,
+ (rtc->read(rtc, RTC_EXT_CTRL_4A) |
+ RTC_CTRL_4A_BME));
+
+ /* We need one write to RTC_BANK1_RAM_ADDR_LSB to start
+ * reading with burst-mode */
+ rtc->write(rtc, RTC_BANK1_RAM_ADDR_LSB,
+ (pos - NVRAM_TOTAL_SZ_BANK0));
+#endif
+
+ /* Read NVRAM in bank1 registers. */
+ for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ;
+ count++, size--) {
+#ifdef CONFIG_RTC_DRV_DS1685
+ /* DS1685/DS1687 has to write to RTC_BANK1_RAM_ADDR
+ * before each read. */
+ rtc->write(rtc, RTC_BANK1_RAM_ADDR,
+ (pos - NVRAM_TOTAL_SZ_BANK0));
+#endif
+ *buf++ = rtc->read(rtc, RTC_BANK1_RAM_DATA_PORT);
+ pos++;
+ }
+
+#ifndef CONFIG_RTC_DRV_DS1685
+ /* Disable burst-mode on DS17x85/DS17x87 */
+ rtc->write(rtc, RTC_EXT_CTRL_4A,
+ (rtc->read(rtc, RTC_EXT_CTRL_4A) &
+ ~(RTC_CTRL_4A_BME)));
+#endif
+ ds1685_rtc_switch_to_bank0(rtc);
+ }
+#endif /* !CONFIG_RTC_DRV_DS1689 */
+ mutex_unlock(rtc_mutex);
+
+ return 0;
+}
+
+static int ds1685_nvram_write(void *priv, unsigned int pos, void *val,
+ size_t size)
+{
+ struct ds1685_priv *rtc = priv;
+ struct mutex *rtc_mutex = &rtc->dev->ops_lock;
+ ssize_t count;
+ u8 *buf = val;
+ int err;
+
+ err = mutex_lock_interruptible(rtc_mutex);
+ if (err)
+ return err;
+
+ ds1685_rtc_switch_to_bank0(rtc);
+
+ /* Write NVRAM in time and bank0 registers. */
+ for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ_BANK0;
+ count++, size--)
+ if (count < NVRAM_SZ_TIME)
+ rtc->write(rtc, (NVRAM_TIME_BASE + pos++),
+ *buf++);
+ else
+ rtc->write(rtc, (NVRAM_BANK0_BASE), *buf++);
+
+#ifndef CONFIG_RTC_DRV_DS1689
+ if (size > 0) {
+ ds1685_rtc_switch_to_bank1(rtc);
+
+#ifndef CONFIG_RTC_DRV_DS1685
+ /* Enable burst-mode on DS17x85/DS17x87 */
+ rtc->write(rtc, RTC_EXT_CTRL_4A,
+ (rtc->read(rtc, RTC_EXT_CTRL_4A) |
+ RTC_CTRL_4A_BME));
+
+ /* We need one write to RTC_BANK1_RAM_ADDR_LSB to start
+ * writing with burst-mode */
+ rtc->write(rtc, RTC_BANK1_RAM_ADDR_LSB,
+ (pos - NVRAM_TOTAL_SZ_BANK0));
+#endif
+
+ /* Write NVRAM in bank1 registers. */
+ for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ;
+ count++, size--) {
+#ifdef CONFIG_RTC_DRV_DS1685
+ /* DS1685/DS1687 has to write to RTC_BANK1_RAM_ADDR
+ * before each read. */
+ rtc->write(rtc, RTC_BANK1_RAM_ADDR,
+ (pos - NVRAM_TOTAL_SZ_BANK0));
+#endif
+ rtc->write(rtc, RTC_BANK1_RAM_DATA_PORT, *buf++);
+ pos++;
+ }
+
+#ifndef CONFIG_RTC_DRV_DS1685
+ /* Disable burst-mode on DS17x85/DS17x87 */
+ rtc->write(rtc, RTC_EXT_CTRL_4A,
+ (rtc->read(rtc, RTC_EXT_CTRL_4A) &
+ ~(RTC_CTRL_4A_BME)));
+#endif
+ ds1685_rtc_switch_to_bank0(rtc);
+ }
+#endif /* !CONFIG_RTC_DRV_DS1689 */
+ mutex_unlock(rtc_mutex);
+
+ return 0;
+}
+
+/* ----------------------------------------------------------------------- */
+/* SysFS interface */
+
+/**
+ * ds1685_rtc_sysfs_battery_show - sysfs file for main battery status.
+ * @dev: pointer to device structure.
+ * @attr: pointer to device_attribute structure.
+ * @buf: pointer to char array to hold the output.
+ */
+static ssize_t
+ds1685_rtc_sysfs_battery_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct ds1685_priv *rtc = dev_get_drvdata(dev->parent);
+ u8 ctrld;
+
+ ctrld = rtc->read(rtc, RTC_CTRL_D);
+
+ return sprintf(buf, "%s\n",
+ (ctrld & RTC_CTRL_D_VRT) ? "ok" : "not ok or N/A");
+}
+static DEVICE_ATTR(battery, S_IRUGO, ds1685_rtc_sysfs_battery_show, NULL);
+
+/**
+ * ds1685_rtc_sysfs_auxbatt_show - sysfs file for aux battery status.
+ * @dev: pointer to device structure.
+ * @attr: pointer to device_attribute structure.
+ * @buf: pointer to char array to hold the output.
+ */
+static ssize_t
+ds1685_rtc_sysfs_auxbatt_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct ds1685_priv *rtc = dev_get_drvdata(dev->parent);
+ u8 ctrl4a;
+
+ ds1685_rtc_switch_to_bank1(rtc);
+ ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
+ ds1685_rtc_switch_to_bank0(rtc);
+
+ return sprintf(buf, "%s\n",
+ (ctrl4a & RTC_CTRL_4A_VRT2) ? "ok" : "not ok or N/A");
+}
+static DEVICE_ATTR(auxbatt, S_IRUGO, ds1685_rtc_sysfs_auxbatt_show, NULL);
+
+/**
+ * ds1685_rtc_sysfs_serial_show - sysfs file for silicon serial number.
+ * @dev: pointer to device structure.
+ * @attr: pointer to device_attribute structure.
+ * @buf: pointer to char array to hold the output.
+ */
+static ssize_t
+ds1685_rtc_sysfs_serial_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct ds1685_priv *rtc = dev_get_drvdata(dev->parent);
+ u8 ssn[8];
+
+ ds1685_rtc_switch_to_bank1(rtc);
+ ds1685_rtc_get_ssn(rtc, ssn);
+ ds1685_rtc_switch_to_bank0(rtc);
+
+ return sprintf(buf, "%8phC\n", ssn);
+}
+static DEVICE_ATTR(serial, S_IRUGO, ds1685_rtc_sysfs_serial_show, NULL);
+
+/*
+ * struct ds1685_rtc_sysfs_misc_attrs - list for misc RTC features.
+ */
+static struct attribute*
+ds1685_rtc_sysfs_misc_attrs[] = {
+ &dev_attr_battery.attr,
+ &dev_attr_auxbatt.attr,
+ &dev_attr_serial.attr,
+ NULL,
+};
+
+/*
+ * struct ds1685_rtc_sysfs_misc_grp - attr group for misc RTC features.
+ */
+static const struct attribute_group
+ds1685_rtc_sysfs_misc_grp = {
+ .name = "misc",
+ .attrs = ds1685_rtc_sysfs_misc_attrs,
+};
+
+/* ----------------------------------------------------------------------- */
+/* Driver Probe/Removal */
+
+/**
+ * ds1685_rtc_probe - initializes rtc driver.
+ * @pdev: pointer to platform_device structure.
+ */
+static int
+ds1685_rtc_probe(struct platform_device *pdev)
+{
+ struct rtc_device *rtc_dev;
+ struct ds1685_priv *rtc;
+ struct ds1685_rtc_platform_data *pdata;
+ u8 ctrla, ctrlb, hours;
+ unsigned char am_pm;
+ int ret = 0;
+ struct nvmem_config nvmem_cfg = {
+ .name = "ds1685_nvram",
+ .size = NVRAM_TOTAL_SZ,
+ .reg_read = ds1685_nvram_read,
+ .reg_write = ds1685_nvram_write,
+ };
+
+ /* Get the platform data. */
+ pdata = (struct ds1685_rtc_platform_data *) pdev->dev.platform_data;
+ if (!pdata)
+ return -ENODEV;
+
+ /* Allocate memory for the rtc device. */
+ rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
+ if (!rtc)
+ return -ENOMEM;
+
+ /* Setup resources and access functions */
+ switch (pdata->access_type) {
+ case ds1685_reg_direct:
+ rtc->regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(rtc->regs))
+ return PTR_ERR(rtc->regs);
+ rtc->read = ds1685_read;
+ rtc->write = ds1685_write;
+ break;
+ case ds1685_reg_indirect:
+ rtc->regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(rtc->regs))
+ return PTR_ERR(rtc->regs);
+ rtc->data = devm_platform_ioremap_resource(pdev, 1);
+ if (IS_ERR(rtc->data))
+ return PTR_ERR(rtc->data);
+ rtc->read = ds1685_indirect_read;
+ rtc->write = ds1685_indirect_write;
+ break;
+ }
+
+ if (!rtc->read || !rtc->write)
+ return -ENXIO;
+
+ /* Get the register step size. */
+ if (pdata->regstep > 0)
+ rtc->regstep = pdata->regstep;
+ else
+ rtc->regstep = 1;
+
+ /* Platform pre-shutdown function, if defined. */
+ if (pdata->plat_prepare_poweroff)
+ rtc->prepare_poweroff = pdata->plat_prepare_poweroff;
+
+ /* Platform wake_alarm function, if defined. */
+ if (pdata->plat_wake_alarm)
+ rtc->wake_alarm = pdata->plat_wake_alarm;
+
+ /* Platform post_ram_clear function, if defined. */
+ if (pdata->plat_post_ram_clear)
+ rtc->post_ram_clear = pdata->plat_post_ram_clear;
+
+ /* set the driver data. */
+ platform_set_drvdata(pdev, rtc);
+
+ /* Turn the oscillator on if is not already on (DV1 = 1). */
+ ctrla = rtc->read(rtc, RTC_CTRL_A);
+ if (!(ctrla & RTC_CTRL_A_DV1))
+ ctrla |= RTC_CTRL_A_DV1;
+
+ /* Enable the countdown chain (DV2 = 0) */
+ ctrla &= ~(RTC_CTRL_A_DV2);
+
+ /* Clear RS3-RS0 in Control A. */
+ ctrla &= ~(RTC_CTRL_A_RS_MASK);
+
+ /*
+ * All done with Control A. Switch to Bank 1 for the remainder of
+ * the RTC setup so we have access to the extended functions.
+ */
+ ctrla |= RTC_CTRL_A_DV0;
+ rtc->write(rtc, RTC_CTRL_A, ctrla);
+
+ /* Default to 32768kHz output. */
+ rtc->write(rtc, RTC_EXT_CTRL_4B,
+ (rtc->read(rtc, RTC_EXT_CTRL_4B) | RTC_CTRL_4B_E32K));
+
+ /* Set the SET bit in Control B so we can do some housekeeping. */
+ rtc->write(rtc, RTC_CTRL_B,
+ (rtc->read(rtc, RTC_CTRL_B) | RTC_CTRL_B_SET));
+
+ /* Read Ext Ctrl 4A and check the INCR bit to avoid a lockout. */
+ while (rtc->read(rtc, RTC_EXT_CTRL_4A) & RTC_CTRL_4A_INCR)
+ cpu_relax();
+
+ /*
+ * If the platform supports BCD mode, then set DM=0 in Control B.
+ * Otherwise, set DM=1 for BIN mode.
+ */
+ ctrlb = rtc->read(rtc, RTC_CTRL_B);
+ if (pdata->bcd_mode)
+ ctrlb &= ~(RTC_CTRL_B_DM);
+ else
+ ctrlb |= RTC_CTRL_B_DM;
+ rtc->bcd_mode = pdata->bcd_mode;
+
+ /*
+ * Disable Daylight Savings Time (DSE = 0).
+ * The RTC has hardcoded timezone information that is rendered
+ * obselete. We'll let the OS deal with DST settings instead.
+ */
+ if (ctrlb & RTC_CTRL_B_DSE)
+ ctrlb &= ~(RTC_CTRL_B_DSE);
+
+ /* Force 24-hour mode (2412 = 1). */
+ if (!(ctrlb & RTC_CTRL_B_2412)) {
+ /* Reinitialize the time hours. */
+ hours = rtc->read(rtc, RTC_HRS);
+ am_pm = hours & RTC_HRS_AMPM_MASK;
+ hours = ds1685_rtc_bcd2bin(rtc, hours, RTC_HRS_12_BCD_MASK,
+ RTC_HRS_12_BIN_MASK);
+ hours = ((hours == 12) ? 0 : ((am_pm) ? hours + 12 : hours));
+
+ /* Enable 24-hour mode. */
+ ctrlb |= RTC_CTRL_B_2412;
+
+ /* Write back to Control B, including DM & DSE bits. */
+ rtc->write(rtc, RTC_CTRL_B, ctrlb);
+
+ /* Write the time hours back. */
+ rtc->write(rtc, RTC_HRS,
+ ds1685_rtc_bin2bcd(rtc, hours,
+ RTC_HRS_24_BIN_MASK,
+ RTC_HRS_24_BCD_MASK));
+
+ /* Reinitialize the alarm hours. */
+ hours = rtc->read(rtc, RTC_HRS_ALARM);
+ am_pm = hours & RTC_HRS_AMPM_MASK;
+ hours = ds1685_rtc_bcd2bin(rtc, hours, RTC_HRS_12_BCD_MASK,
+ RTC_HRS_12_BIN_MASK);
+ hours = ((hours == 12) ? 0 : ((am_pm) ? hours + 12 : hours));
+
+ /* Write the alarm hours back. */
+ rtc->write(rtc, RTC_HRS_ALARM,
+ ds1685_rtc_bin2bcd(rtc, hours,
+ RTC_HRS_24_BIN_MASK,
+ RTC_HRS_24_BCD_MASK));
+ } else {
+ /* 24-hour mode is already set, so write Control B back. */
+ rtc->write(rtc, RTC_CTRL_B, ctrlb);
+ }
+
+ /* Unset the SET bit in Control B so the RTC can update. */
+ rtc->write(rtc, RTC_CTRL_B,
+ (rtc->read(rtc, RTC_CTRL_B) & ~(RTC_CTRL_B_SET)));
+
+ /* Check the main battery. */
+ if (!(rtc->read(rtc, RTC_CTRL_D) & RTC_CTRL_D_VRT))
+ dev_warn(&pdev->dev,
+ "Main battery is exhausted! RTC may be invalid!\n");
+
+ /* Check the auxillary battery. It is optional. */
+ if (!(rtc->read(rtc, RTC_EXT_CTRL_4A) & RTC_CTRL_4A_VRT2))
+ dev_warn(&pdev->dev,
+ "Aux battery is exhausted or not available.\n");
+
+ /* Read Ctrl B and clear PIE/AIE/UIE. */
+ rtc->write(rtc, RTC_CTRL_B,
+ (rtc->read(rtc, RTC_CTRL_B) & ~(RTC_CTRL_B_PAU_MASK)));
+
+ /* Reading Ctrl C auto-clears PF/AF/UF. */
+ rtc->read(rtc, RTC_CTRL_C);
+
+ /* Read Ctrl 4B and clear RIE/WIE/KSE. */
+ rtc->write(rtc, RTC_EXT_CTRL_4B,
+ (rtc->read(rtc, RTC_EXT_CTRL_4B) & ~(RTC_CTRL_4B_RWK_MASK)));
+
+ /* Clear RF/WF/KF in Ctrl 4A. */
+ rtc->write(rtc, RTC_EXT_CTRL_4A,
+ (rtc->read(rtc, RTC_EXT_CTRL_4A) & ~(RTC_CTRL_4A_RWK_MASK)));
+
+ /*
+ * Re-enable KSE to handle power button events. We do not enable
+ * WIE or RIE by default.
+ */
+ rtc->write(rtc, RTC_EXT_CTRL_4B,
+ (rtc->read(rtc, RTC_EXT_CTRL_4B) | RTC_CTRL_4B_KSE));
+
+ rtc_dev = devm_rtc_allocate_device(&pdev->dev);
+ if (IS_ERR(rtc_dev))
+ return PTR_ERR(rtc_dev);
+
+ rtc_dev->ops = &ds1685_rtc_ops;
+
+ /* Century bit is useless because leap year fails in 1900 and 2100 */
+ rtc_dev->range_min = RTC_TIMESTAMP_BEGIN_2000;
+ rtc_dev->range_max = RTC_TIMESTAMP_END_2099;
+
+ /* Maximum periodic rate is 8192Hz (0.122070ms). */
+ rtc_dev->max_user_freq = RTC_MAX_USER_FREQ;
+
+ /* See if the platform doesn't support UIE. */
+ if (pdata->uie_unsupported)
+ rtc_dev->uie_unsupported = 1;
+
+ rtc->dev = rtc_dev;
+
+ /*
+ * Fetch the IRQ and setup the interrupt handler.
+ *
+ * Not all platforms have the IRQF pin tied to something. If not, the
+ * RTC will still set the *IE / *F flags and raise IRQF in ctrlc, but
+ * there won't be an automatic way of notifying the kernel about it,
+ * unless ctrlc is explicitly polled.
+ */
+ if (!pdata->no_irq) {
+ ret = platform_get_irq(pdev, 0);
+ if (ret <= 0)
+ return ret;
+
+ rtc->irq_num = ret;
+
+ /* Request an IRQ. */
+ ret = devm_request_threaded_irq(&pdev->dev, rtc->irq_num,
+ NULL, ds1685_rtc_irq_handler,
+ IRQF_SHARED | IRQF_ONESHOT,
+ pdev->name, pdev);
+
+ /* Check to see if something came back. */
+ if (unlikely(ret)) {
+ dev_warn(&pdev->dev,
+ "RTC interrupt not available\n");
+ rtc->irq_num = 0;
+ }
+ }
+ rtc->no_irq = pdata->no_irq;
+
+ /* Setup complete. */
+ ds1685_rtc_switch_to_bank0(rtc);
+
+ ret = rtc_add_group(rtc_dev, &ds1685_rtc_sysfs_misc_grp);
+ if (ret)
+ return ret;
+
+ rtc_dev->nvram_old_abi = true;
+ nvmem_cfg.priv = rtc;
+ ret = rtc_nvmem_register(rtc_dev, &nvmem_cfg);
+ if (ret)
+ return ret;
+
+ return rtc_register_device(rtc_dev);
+}
+
+/**
+ * ds1685_rtc_remove - removes rtc driver.
+ * @pdev: pointer to platform_device structure.
+ */
+static int
+ds1685_rtc_remove(struct platform_device *pdev)
+{
+ struct ds1685_priv *rtc = platform_get_drvdata(pdev);
+
+ /* Read Ctrl B and clear PIE/AIE/UIE. */
+ rtc->write(rtc, RTC_CTRL_B,
+ (rtc->read(rtc, RTC_CTRL_B) &
+ ~(RTC_CTRL_B_PAU_MASK)));
+
+ /* Reading Ctrl C auto-clears PF/AF/UF. */
+ rtc->read(rtc, RTC_CTRL_C);
+
+ /* Read Ctrl 4B and clear RIE/WIE/KSE. */
+ rtc->write(rtc, RTC_EXT_CTRL_4B,
+ (rtc->read(rtc, RTC_EXT_CTRL_4B) &
+ ~(RTC_CTRL_4B_RWK_MASK)));
+
+ /* Manually clear RF/WF/KF in Ctrl 4A. */
+ rtc->write(rtc, RTC_EXT_CTRL_4A,
+ (rtc->read(rtc, RTC_EXT_CTRL_4A) &
+ ~(RTC_CTRL_4A_RWK_MASK)));
+
+ return 0;
+}
+
+/*
+ * ds1685_rtc_driver - rtc driver properties.
+ */
+static struct platform_driver ds1685_rtc_driver = {
+ .driver = {
+ .name = "rtc-ds1685",
+ },
+ .probe = ds1685_rtc_probe,
+ .remove = ds1685_rtc_remove,
+};
+module_platform_driver(ds1685_rtc_driver);
+/* ----------------------------------------------------------------------- */
+
+
+/* ----------------------------------------------------------------------- */
+/* Poweroff function */
+
+/**
+ * ds1685_rtc_poweroff - uses the RTC chip to power the system off.
+ * @pdev: pointer to platform_device structure.
+ */
+void __noreturn
+ds1685_rtc_poweroff(struct platform_device *pdev)
+{
+ u8 ctrla, ctrl4a, ctrl4b;
+ struct ds1685_priv *rtc;
+
+ /* Check for valid RTC data, else, spin forever. */
+ if (unlikely(!pdev)) {
+ pr_emerg("platform device data not available, spinning forever ...\n");
+ while(1);
+ unreachable();
+ } else {
+ /* Get the rtc data. */
+ rtc = platform_get_drvdata(pdev);
+
+ /*
+ * Disable our IRQ. We're powering down, so we're not
+ * going to worry about cleaning up. Most of that should
+ * have been taken care of by the shutdown scripts and this
+ * is the final function call.
+ */
+ if (!rtc->no_irq)
+ disable_irq_nosync(rtc->irq_num);
+
+ /* Oscillator must be on and the countdown chain enabled. */
+ ctrla = rtc->read(rtc, RTC_CTRL_A);
+ ctrla |= RTC_CTRL_A_DV1;
+ ctrla &= ~(RTC_CTRL_A_DV2);
+ rtc->write(rtc, RTC_CTRL_A, ctrla);
+
+ /*
+ * Read Control 4A and check the status of the auxillary
+ * battery. This must be present and working (VRT2 = 1)
+ * for wakeup and kickstart functionality to be useful.
+ */
+ ds1685_rtc_switch_to_bank1(rtc);
+ ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
+ if (ctrl4a & RTC_CTRL_4A_VRT2) {
+ /* Clear all of the interrupt flags on Control 4A. */
+ ctrl4a &= ~(RTC_CTRL_4A_RWK_MASK);
+ rtc->write(rtc, RTC_EXT_CTRL_4A, ctrl4a);
+
+ /*
+ * The auxillary battery is present and working.
+ * Enable extended functions (ABE=1), enable
+ * wake-up (WIE=1), and enable kickstart (KSE=1)
+ * in Control 4B.
+ */
+ ctrl4b = rtc->read(rtc, RTC_EXT_CTRL_4B);
+ ctrl4b |= (RTC_CTRL_4B_ABE | RTC_CTRL_4B_WIE |
+ RTC_CTRL_4B_KSE);
+ rtc->write(rtc, RTC_EXT_CTRL_4B, ctrl4b);
+ }
+
+ /* Set PAB to 1 in Control 4A to power the system down. */
+ dev_warn(&pdev->dev, "Powerdown.\n");
+ msleep(20);
+ rtc->write(rtc, RTC_EXT_CTRL_4A,
+ (ctrl4a | RTC_CTRL_4A_PAB));
+
+ /* Spin ... we do not switch back to bank0. */
+ while(1);
+ unreachable();
+ }
+}
+EXPORT_SYMBOL_GPL(ds1685_rtc_poweroff);
+/* ----------------------------------------------------------------------- */
+
+
+MODULE_AUTHOR("Joshua Kinard <kumba@gentoo.org>");
+MODULE_AUTHOR("Matthias Fuchs <matthias.fuchs@esd-electronics.com>");
+MODULE_DESCRIPTION("Dallas/Maxim DS1685/DS1687-series RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:rtc-ds1685");